Line data Source code
1 : /* Copyright (C) 2000 The PARI group.
2 :
3 : This file is part of the PARI/GP package.
4 :
5 : PARI/GP is free software; you can redistribute it and/or modify it under the
6 : terms of the GNU General Public License as published by the Free Software
7 : Foundation; either version 2 of the License, or (at your option) any later
8 : version. It is distributed in the hope that it will be useful, but WITHOUT
9 : ANY WARRANTY WHATSOEVER.
10 :
11 : Check the License for details. You should have received a copy of it, along
12 : with the package; see the file 'COPYING'. If not, write to the Free Software
13 : Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */
14 :
15 : /*******************************************************************/
16 : /* */
17 : /* COMPUTATION OF STARK UNITS OF TOTALLY REAL FIELDS */
18 : /* */
19 : /*******************************************************************/
20 : #include "pari.h"
21 : #include "paripriv.h"
22 :
23 : #define DEBUGLEVEL DEBUGLEVEL_stark
24 :
25 : /* ComputeCoeff */
26 : typedef struct {
27 : GEN L0, L1, L11, L2; /* VECSMALL of p */
28 : GEN L1ray, L11ray; /* precomputed isprincipalray(pr), pr | p */
29 : GEN rayZ; /* precomputed isprincipalray(i), i < condZ */
30 : long condZ; /* generates cond(bnr) \cap Z, assumed small */
31 : } LISTray;
32 :
33 : /* Char evaluation */
34 : typedef struct {
35 : long ord;
36 : GEN *val, chi;
37 : } CHI_t;
38 :
39 : /* RecCoeff */
40 : typedef struct {
41 : GEN M, beta, B, U, nB;
42 : long v, G, N;
43 : } RC_data;
44 :
45 : /********************************************************************/
46 : /* Miscellaneous functions */
47 : /********************************************************************/
48 : static GEN
49 18893 : chi_get_c(GEN chi) { return gmael(chi,1,2); }
50 : static long
51 54488 : chi_get_deg(GEN chi) { return itou(gmael(chi,1,1)); }
52 :
53 : /* Compute the image of logelt by character chi, zeta_ord(chi)^n; return n */
54 : static ulong
55 14763 : CharEval_n(GEN chi, GEN logelt)
56 : {
57 14763 : GEN gn = ZV_dotproduct(chi_get_c(chi), logelt);
58 14763 : return umodiu(gn, chi_get_deg(chi));
59 : }
60 : /* Compute the image of logelt by character chi, as a complex number */
61 : static GEN
62 14707 : CharEval(GEN chi, GEN logelt)
63 : {
64 14707 : ulong n = CharEval_n(chi, logelt), d = chi_get_deg(chi);
65 14707 : long nn = Fl_center(n,d,d>>1);
66 14707 : GEN x = gel(chi,2);
67 14707 : x = gpowgs(x, labs(nn));
68 14707 : if (nn < 0) x = conj_i(x);
69 14707 : return x;
70 : }
71 :
72 : /* return n such that C(elt) = z^n */
73 : static ulong
74 644963 : CHI_eval_n(CHI_t *C, GEN logelt)
75 : {
76 644963 : GEN n = ZV_dotproduct(C->chi, logelt);
77 644963 : return umodiu(n, C->ord);
78 : }
79 : /* return C(elt) */
80 : static GEN
81 643227 : CHI_eval(CHI_t *C, GEN logelt)
82 : {
83 643227 : return C->val[CHI_eval_n(C, logelt)];
84 : }
85 :
86 : static void
87 4130 : init_CHI(CHI_t *c, GEN CHI, GEN z)
88 : {
89 4130 : long i, d = chi_get_deg(CHI);
90 4130 : GEN *v = (GEN*)new_chunk(d);
91 4130 : v[0] = gen_1;
92 4130 : if (d != 1)
93 : {
94 4130 : v[1] = z;
95 35511 : for (i=2; i<d; i++) v[i] = gmul(v[i-1], z);
96 : }
97 4130 : c->chi = chi_get_c(CHI);
98 4130 : c->ord = d;
99 4130 : c->val = v;
100 4130 : }
101 : /* as t_POLMOD */
102 : static void
103 2534 : init_CHI_alg(CHI_t *c, GEN CHI) {
104 2534 : long d = chi_get_deg(CHI);
105 : GEN z;
106 2534 : switch(d)
107 : {
108 0 : case 1: z = gen_1; break;
109 945 : case 2: z = gen_m1; break;
110 1589 : default: z = mkpolmod(pol_x(0), polcyclo(d,0));
111 : }
112 2534 : init_CHI(c,CHI, z);
113 2534 : }
114 : /* as t_COMPLEX */
115 : static void
116 1596 : init_CHI_C(CHI_t *c, GEN CHI) {
117 1596 : init_CHI(c,CHI, gel(CHI,2));
118 1596 : }
119 :
120 : typedef struct {
121 : long r; /* rank = lg(gen) */
122 : GEN j; /* current elt is gen[1]^j[1] ... gen[r]^j[r] */
123 : GEN cyc; /* t_VECSMALL of elementary divisors */
124 : } GROUP_t;
125 :
126 : static int
127 684019 : NextElt(GROUP_t *G)
128 : {
129 684019 : long i = 1;
130 684019 : if (G->r == 0) return 0; /* no more elt */
131 755524 : while (++G->j[i] == G->cyc[i]) /* from 0 to cyc[i]-1 */
132 : {
133 72303 : G->j[i] = 0;
134 72303 : if (++i > G->r) return 0; /* no more elt */
135 : }
136 683221 : return i; /* we have multiplied by gen[i] */
137 : }
138 :
139 : /* enumerate all group elements; trivial elt comes last */
140 : GEN
141 44751 : cyc2elts(GEN cyc)
142 : {
143 : long i, n;
144 : GEN z;
145 : GROUP_t G;
146 :
147 44751 : G.cyc = typ(cyc)==t_VECSMALL? cyc: gtovecsmall(cyc);
148 44751 : n = zv_prod(G.cyc);
149 44751 : G.r = lg(cyc)-1;
150 44751 : G.j = zero_zv(G.r);
151 :
152 44751 : z = cgetg(n+1, t_VEC);
153 44751 : gel(z,n) = leafcopy(G.j); /* trivial elt comes last */
154 675045 : for (i = 1; i < n; i++)
155 : {
156 630294 : (void)NextElt(&G);
157 630294 : gel(z,i) = leafcopy(G.j);
158 : }
159 44751 : return z;
160 : }
161 :
162 : /* nchi: a character given by a vector [d, (c_i)], e.g. from char_normalize
163 : * such that chi(x) = e((c . log(x)) / d) where log(x) on bnr.gen */
164 : static GEN
165 3661 : get_Char(GEN nchi, long prec)
166 3661 : { return mkvec2(nchi, rootsof1_cx(gel(nchi,1), prec)); }
167 :
168 : /* prime divisors of conductor */
169 : static GEN
170 448 : divcond(GEN bnr) {GEN bid = bnr_get_bid(bnr); return gel(bid_get_fact(bid),1);}
171 :
172 : /* vector of prime ideals dividing bnr but not bnrc */
173 : static GEN
174 161 : get_prdiff(GEN D, GEN Dc)
175 : {
176 161 : long n, i, l = lg(D);
177 161 : GEN diff = cgetg(l, t_COL);
178 448 : for (n = i = 1; i < l; i++)
179 287 : if (!tablesearch(Dc, gel(D,i), &cmp_prime_ideal)) gel(diff,n++) = gel(D,i);
180 161 : setlg(diff, n); return diff;
181 : }
182 :
183 : #define ch_prec(x) realprec(gel(x,1))
184 : #define ch_C(x) gel(x,1)
185 : #define ch_bnr(x) gel(x,2)
186 : #define ch_3(x) gel(x,3)
187 : #define ch_q(x) gel(x,3)[1]
188 : #define ch_CHI(x) gel(x,4)
189 : #define ch_diff(x) gel(x,5)
190 : #define ch_CHI0(x) gel(x,6)
191 : #define ch_small(x) gel(x,7)
192 : #define ch_comp(x) gel(x,7)[1]
193 : #define ch_phideg(x) gel(x,7)[2]
194 : static long
195 1295 : ch_deg(GEN dtcr) { return chi_get_deg(ch_CHI(dtcr)); }
196 :
197 : /********************************************************************/
198 : /* 1rst part: find the field K */
199 : /********************************************************************/
200 : static GEN AllStark(GEN data, long flag, long prec);
201 :
202 : /* Columns of C [HNF] give the generators of a subgroup of the finite abelian
203 : * group A [ in terms of implicit generators ], compute data to work in A/C:
204 : * 1) order
205 : * 2) structure
206 : * 3) the matrix A ->> A/C
207 : * 4) the subgroup C */
208 : static GEN
209 1316 : InitQuotient(GEN C)
210 : {
211 1316 : GEN U, D = ZM_snfall_i(C, &U, NULL, 1), h = ZV_prod(D);
212 1316 : return mkvec5(h, D, U, C, cyc_normalize(D));
213 : }
214 :
215 : /* lift chi character on A/C [Qt from InitQuotient] to character on A [cyc]*/
216 : static GEN
217 3612 : LiftChar(GEN Qt, GEN cyc, GEN chi)
218 : {
219 3612 : GEN ncyc = gel(Qt,5), U = gel(Qt,3), nchi = char_normalize(chi, ncyc);
220 3612 : GEN c = ZV_ZM_mul(gel(nchi,2), U), d = gel(nchi,1);
221 3612 : return char_denormalize(cyc, d, c);
222 : }
223 :
224 : /* Let C be a subgroup, system of representatives of the quotient */
225 : static GEN
226 329 : subgroup_classes(GEN C)
227 : {
228 329 : GEN U, D = ZM_snfall_i(C, &U, NULL, 1), e = cyc2elts(D);
229 329 : long i, l = lg(e);
230 :
231 329 : if (ZM_isidentity(U))
232 2030 : for (i = 1; i < l; i++) (void)vecsmall_to_vec_inplace(gel(e,i));
233 : else
234 : {
235 14 : GEN Ui = ZM_inv(U,NULL);
236 84 : for (i = 1; i < l; i++) gel(e,i) = ZM_zc_mul(Ui, gel(e,i));
237 : }
238 329 : return e;
239 : }
240 :
241 : /* Let s: A -> B given by [P,cycA,cycB] A and B, compute the kernel of s. */
242 : GEN
243 455 : abmap_kernel(GEN S)
244 : {
245 455 : GEN U, P = gel(S,1), cycA = gel(S,2), DB = diagonal_shallow(gel(S,3));
246 455 : long nA = lg(cycA)-1, rk;
247 :
248 455 : rk = nA + lg(DB) - lg(ZM_hnfall_i(shallowconcat(P, DB), &U, 1));
249 455 : return ZM_hnfmodid(matslice(U, 1,nA, 1,rk), cycA);
250 : }
251 : /* let H be a subgroup of A; return s(H) */
252 : GEN
253 1526 : abmap_subgroup_image(GEN S, GEN H)
254 1526 : { return ZM_hnfmodid(ZM_mul(gel(S,1), H), gel(S,3)); }
255 :
256 : /* Let m and n be two moduli such that n|m and let C be a congruence
257 : group modulo n, compute the corresponding congruence group modulo m
258 : ie the kernel of the map Clk(m) ->> Clk(n)/C */
259 : static GEN
260 455 : ComputeKernel(GEN bnrm, GEN bnrn, GEN dtQ)
261 : {
262 455 : pari_sp av = avma;
263 455 : GEN S = bnrsurjection(bnrm, bnrn);
264 455 : GEN P = ZM_mul(gel(dtQ,3), gel(S,1));
265 455 : return gc_upto(av, abmap_kernel(mkvec3(P, gel(S,2), gel(dtQ,2))));
266 : }
267 :
268 : static long
269 1169 : cyc_is_cyclic(GEN cyc) { return lg(cyc) <= 2 || equali1(gel(cyc,2)); }
270 :
271 : /* Let H be a subgroup of cl(bnr)/sugbroup, return 1 if
272 : cl(bnr)/subgoup/H is cyclic and the signature of the
273 : corresponding field is equal to sig and no finite prime
274 : dividing cond(bnr) is totally split in this field. Return 0
275 : otherwise. */
276 : static long
277 518 : IsGoodSubgroup(GEN H, GEN bnr, GEN map)
278 : {
279 518 : pari_sp av = avma;
280 : GEN S, mod, modH, p1, U, P, PH, bnrH, iH, qH;
281 : long j;
282 :
283 518 : p1 = InitQuotient(H);
284 : /* quotient is non cyclic */
285 518 : if (!cyc_is_cyclic(gel(p1,2))) return gc_long(av,0);
286 :
287 252 : (void)ZM_hnfall_i(shallowconcat(map,H), &U, 0);
288 252 : setlg(U, lg(H));
289 924 : for (j = 1; j < lg(U); j++) setlg(gel(U,j), lg(H));
290 252 : p1 = ZM_hnfmodid(U, bnr_get_cyc(bnr)); /* H as a subgroup of bnr */
291 252 : modH = bnrconductor_raw(bnr, p1);
292 252 : mod = bnr_get_mod(bnr);
293 :
294 : /* is the signature correct? */
295 252 : if (!gequal(gel(modH,2), gel(mod,2))) return gc_long(av, 0);
296 :
297 : /* finite part are the same: OK */
298 182 : if (gequal(gel(modH,1), gel(mod,1))) return gc_long(av, 1);
299 :
300 : /* need to check the splitting of primes dividing mod but not modH */
301 63 : bnrH = Buchray(bnr, modH, nf_INIT);
302 63 : P = divcond(bnr);
303 63 : PH = divcond(bnrH);
304 63 : S = bnrsurjection(bnr, bnrH);
305 : /* H as a subgroup of bnrH */
306 63 : iH = abmap_subgroup_image(S, p1);
307 63 : qH = InitQuotient(iH);
308 203 : for (j = 1; j < lg(P); j++)
309 : {
310 161 : GEN pr = gel(P, j), e;
311 : /* if pr divides modH, it is ramified, so it's good */
312 161 : if (tablesearch(PH, pr, cmp_prime_ideal)) continue;
313 : /* inertia degree of pr in bnr(modH)/H is charorder(cycH, e) */
314 56 : e = ZM_ZC_mul(gel(qH,3), isprincipalray(bnrH, pr));
315 56 : e = ZV_ZV_mod(e, gel(qH,2));
316 56 : if (ZV_equal0(e)) return gc_long(av,0); /* f = 1 */
317 : }
318 42 : return gc_long(av,1);
319 : }
320 :
321 : /* compute list of nontrivial characters trivial on H, modulo complex
322 : * conjugation. If flag is set, impose a nontrivial conductor at infinity */
323 : static GEN
324 399 : AllChars(GEN bnr, GEN dtQ, long flag)
325 : {
326 399 : GEN v, vchi, cyc = bnr_get_cyc(bnr);
327 399 : long n, i, hD = itos(gel(dtQ,1));
328 : hashtable *S;
329 :
330 399 : v = cgetg(hD+1, t_VEC); /* nonconjugate chars */
331 399 : vchi = cyc2elts(gel(dtQ,2));
332 399 : S = hash_create(hD, (ulong(*)(void*))&hash_GEN,
333 : (int(*)(void*,void*))&ZV_equal, 1);
334 4011 : for (i = n = 1; i < hD; i++) /* remove i = hD: trivial char */
335 : { /* lift a character of D in Clk(m) */
336 3612 : GEN F, lchi = LiftChar(dtQ, cyc, zv_to_ZV(gel(vchi,i))), cchi = NULL;
337 :
338 3612 : if (hash_search(S, lchi)) continue;
339 2765 : F = bnrconductor_raw(bnr, lchi);
340 2765 : if (flag && gequal0(gel(F,2))) continue; /* f_oo(chi) trivial ? */
341 :
342 1309 : if (abscmpiu(charorder(cyc,lchi), 2) > 0)
343 : { /* nonreal chi: add its conjugate character to S */
344 847 : cchi = charconj(cyc, lchi);
345 847 : hash_insert(S, cchi, (void*)1);
346 : }
347 1309 : gel(v, n++) = cchi? mkvec3(lchi, F, cchi): mkvec2(lchi, F);
348 : }
349 399 : setlg(v, n); return v;
350 : }
351 :
352 : static GEN InitChar(GEN bnr, GEN CR, long flag, long prec);
353 : static void CharNewPrec(GEN data, long prec);
354 :
355 : /* Given a conductor and a subgroups, return the corresponding complexity and
356 : * precision required using quickpol. Fill data[5] with dataCR */
357 : static long
358 329 : CplxModulus(GEN data, long *newprec)
359 : {
360 329 : long dprec = DEFAULTPREC;
361 329 : pari_sp av = avma;
362 : for (;;)
363 0 : {
364 329 : GEN cpl, pol = AllStark(data, 1, dprec);
365 329 : cpl = RgX_fpnorml2(pol, LOWDEFAULTPREC);
366 329 : dprec = maxss(dprec, nbits2extraprec(gexpo(pol))) + EXTRAPREC64;
367 329 : if (!gequal0(cpl)) { *newprec = dprec; return gexpo(cpl); }
368 0 : set_avma(av);
369 0 : if (DEBUGLEVEL>1) pari_warn(warnprec, "CplxModulus", dprec);
370 0 : CharNewPrec(data, dprec);
371 : }
372 : }
373 :
374 : /* return A \cap B in abelian group defined by cyc. NULL = whole group */
375 : static GEN
376 567 : subgp_intersect(GEN cyc, GEN A, GEN B)
377 : {
378 : GEN H, U;
379 : long k, lH;
380 567 : if (!A) return B;
381 224 : if (!B) return A;
382 224 : H = ZM_hnfall_i(shallowconcat(A,B), &U, 1);
383 224 : setlg(U, lg(A)); lH = lg(H);
384 798 : for (k = 1; k < lg(U); k++) setlg(gel(U,k), lH);
385 224 : return ZM_hnfmodid(ZM_mul(A,U), cyc);
386 : }
387 :
388 : static void CharNewPrec(GEN dataCR, long prec);
389 : /* Let (f,C) be a conductor without infinite part and a congruence group mod f.
390 : * Compute (m,D) such that D is a congruence group of conductor m, f | m,
391 : * divisible by all the infinite places but one, D is a subgroup of index 2 of
392 : * Cm = Ker: Clk(m) -> Clk(f)/C. Consider further the subgroups H of Clk(m)/D
393 : * with cyclic quotient Clk(m)/H such that no place dividing m is totally split
394 : * in the extension KH corresponding to H: we want their intersection to be
395 : * trivial. These H correspond to (the kernels of Galois orbits of) characters
396 : * chi of Clk(m)/D such that chi(log_gen_arch(m_oo)) != 1 and for all pr | m
397 : * we either have
398 : * - chi(log_gen_pr(pr,1)) != 1 [pr | cond(chi) => ramified in KH]
399 : * - or [pr \nmid cond(chi)] chi lifted to Clk(m/pr^oo) is not trivial at pr.
400 : * We want the map from Clk(m)/D given by the vector of such characters to have
401 : * trivial kernel. Return bnr(m), D, Ck(m)/D and Clk(m)/Cm */
402 : static GEN
403 322 : FindModulus(GEN bnr, GEN dtQ, long *newprec)
404 : {
405 322 : const long LIMNORM = 400;
406 322 : long n, i, maxnorm, minnorm, N, pr, rb, iscyc, olde = LONG_MAX;
407 322 : pari_sp av = avma;
408 322 : GEN bnf, nf, f, varch, m, rep = NULL;
409 :
410 322 : bnf = bnr_get_bnf(bnr);
411 322 : nf = bnf_get_nf(bnf);
412 322 : N = nf_get_degree(nf);
413 322 : f = gel(bnr_get_mod(bnr), 1);
414 :
415 : /* if cpl < rb, it is not necessary to try another modulus */
416 322 : rb = expi( powii(mulii(nf_get_disc(nf), ZM_det_triangular(f)),
417 : gmul2n(bnr_get_no(bnr), 3)) );
418 :
419 : /* Initialization of the possible infinite part */
420 322 : varch = cgetg(N+1,t_VEC);
421 1106 : for (i = 1; i <= N; i++)
422 : {
423 784 : GEN a = const_vec(N,gen_1);
424 784 : gel(a, N+1-i) = gen_0;
425 784 : gel(varch, i) = a;
426 : }
427 322 : m = cgetg(3, t_VEC);
428 :
429 : /* Go from minnorm up to maxnorm; if necessary, increase these values.
430 : * If the extension is cyclic then a suitable conductor exists and we go on
431 : * until we find it. Else, stop at norm LIMNORM. */
432 322 : minnorm = 1;
433 322 : maxnorm = 50;
434 322 : iscyc = cyc_is_cyclic(gel(dtQ,2));
435 :
436 322 : if (DEBUGLEVEL>1)
437 0 : err_printf("Looking for a modulus of norm: ");
438 :
439 : for(;;)
440 0 : {
441 322 : GEN listid = ideallist0(nf, maxnorm, 4+8); /* ideals of norm <= maxnorm */
442 322 : pari_sp av1 = avma;
443 1463 : for (n = minnorm; n <= maxnorm; n++, set_avma(av1))
444 : {
445 1463 : GEN idnormn = gel(listid,n);
446 1463 : long nbidnn = lg(idnormn) - 1;
447 1463 : if (DEBUGLEVEL>1) err_printf(" %ld", n);
448 2296 : for (i = 1; i <= nbidnn; i++)
449 : { /* finite part of the conductor */
450 : long s;
451 :
452 1155 : gel(m,1) = idealmul(nf, f, gel(idnormn,i));
453 3213 : for (s = 1; s <= N; s++)
454 : { /* infinite part */
455 : GEN candD, Cm, bnrm;
456 : long lD, c;
457 :
458 2380 : gel(m,2) = gel(varch,s);
459 : /* compute Clk(m), check if m is a conductor */
460 2380 : bnrm = Buchray(bnf, m, nf_INIT);
461 2380 : if (!bnrisconductor(bnrm, NULL)) continue;
462 :
463 : /* compute Im(C) in Clk(m)... */
464 448 : Cm = ComputeKernel(bnrm, bnr, dtQ);
465 : /* ... and its subgroups of index 2 with conductor m */
466 448 : candD = subgrouplist_cond_sub(bnrm, Cm, mkvec(gen_2));
467 448 : lD = lg(candD);
468 455 : for (c = 1; c < lD; c++)
469 : {
470 329 : GEN data, CR, D = gel(candD,c), QD = InitQuotient(D);
471 329 : GEN ord = gel(QD,1), cyc = gel(QD,2), map = gel(QD,3);
472 : long e;
473 :
474 329 : if (!cyc_is_cyclic(cyc)) /* cyclic => suitable, else test */
475 : {
476 77 : GEN lH = subgrouplist(cyc, NULL), IK = NULL;
477 77 : long j, ok = 0;
478 574 : for (j = 1; j < lg(lH); j++)
479 : {
480 567 : GEN H = gel(lH, j), IH = subgp_intersect(cyc, IK, H);
481 : /* if H > IK, no need to test H */
482 567 : if (IK && gidentical(IH, IK)) continue;
483 518 : if (IsGoodSubgroup(H, bnrm, map))
484 : {
485 161 : IK = IH; /* intersection of all good subgroups */
486 161 : if (equalii(ord, ZM_det_triangular(IK))) { ok = 1; break; }
487 : }
488 : }
489 77 : if (!ok) continue;
490 : }
491 322 : CR = InitChar(bnrm, AllChars(bnrm, QD, 1), 0, DEFAULTPREC);
492 322 : data = mkvec4(bnrm, D, subgroup_classes(Cm), CR);
493 322 : if (DEBUGLEVEL>1)
494 0 : err_printf("\nTrying modulus = %Ps and subgroup = %Ps\n",
495 : bnr_get_mod(bnrm), D);
496 322 : e = CplxModulus(data, &pr);
497 322 : if (DEBUGLEVEL>1) err_printf("cpl = 2^%ld\n", e);
498 322 : if (e < olde)
499 : {
500 322 : guncloneNULL(rep); rep = gclone(data);
501 322 : *newprec = pr; olde = e;
502 : }
503 322 : if (olde < rb) goto END; /* OK */
504 0 : if (DEBUGLEVEL>1) err_printf("Trying to find another modulus...");
505 : }
506 : }
507 833 : if (rep) goto END; /* OK */
508 : }
509 : }
510 : /* if necessary compute more ideals */
511 0 : minnorm = maxnorm;
512 0 : maxnorm <<= 1;
513 0 : if (!iscyc && maxnorm > LIMNORM) return NULL;
514 : }
515 322 : END:
516 322 : if (DEBUGLEVEL>1)
517 0 : err_printf("No, we're done!\nModulus = %Ps and subgroup = %Ps\n",
518 0 : bnr_get_mod(gel(rep,1)), gel(rep,2));
519 322 : CharNewPrec(rep, *newprec); return gc_GEN(av, rep);
520 : }
521 :
522 : /********************************************************************/
523 : /* 2nd part: compute W(X) */
524 : /********************************************************************/
525 :
526 : /* find ilambda s.t. Diff*f*ilambda integral and coprime to f
527 : and ilambda >> 0 at foo, fa = factorization of f */
528 : static GEN
529 798 : get_ilambda(GEN nf, GEN fa, GEN foo)
530 : {
531 798 : GEN x, w, E2, P = gel(fa,1), E = gel(fa,2), D = nf_get_diff(nf);
532 798 : long i, l = lg(P);
533 798 : if (l == 1) return gen_1;
534 665 : w = cgetg(l, t_VEC);
535 665 : E2 = cgetg(l, t_COL);
536 1456 : for (i = 1; i < l; i++)
537 : {
538 791 : GEN pr = gel(P,i), t = pr_get_tau(pr);
539 791 : long e = itou(gel(E,i)), v = idealval(nf, D, pr);
540 791 : if (v) { D = idealdivpowprime(nf, D, pr, utoipos(v)); e += v; }
541 791 : gel(E2,i) = stoi(e+1);
542 791 : if (typ(t) == t_MAT) t = gel(t,1);
543 791 : gel(w,i) = gdiv(nfpow(nf, t, stoi(e)), powiu(pr_get_p(pr),e));
544 : }
545 665 : x = mkmat2(P, E2);
546 665 : return idealchinese(nf, mkvec2(x, foo), w);
547 : }
548 : /* compute the list of W(chi) such that Ld(s,chi) = W(chi) Ld(1 - s, chi*),
549 : * for all chi in LCHI. All chi have the same conductor (= cond(bnr)). */
550 : static GEN
551 994 : ArtinNumber(GEN bnr, GEN LCHI, long prec)
552 : {
553 994 : long ic, i, j, nz, nChar = lg(LCHI)-1;
554 : pari_sp av2;
555 : GEN sqrtnc, cond, condZ, cond0, cond1, nf, T, cyc, vN, vB, diff, vt, idh;
556 : GEN zid, gen, z, nchi, indW, W, classe, s0, s, den, ilambda, sarch;
557 : CHI_t **lC;
558 : GROUP_t G;
559 :
560 994 : lC = (CHI_t**)new_chunk(nChar + 1);
561 994 : indW = cgetg(nChar + 1, t_VECSMALL);
562 994 : W = cgetg(nChar + 1, t_VEC);
563 3451 : for (ic = 0, i = 1; i <= nChar; i++)
564 : {
565 2457 : GEN CHI = gel(LCHI,i);
566 2457 : if (chi_get_deg(CHI) <= 2) { gel(W,i) = gen_1; continue; }
567 1596 : ic++; indW[ic] = i;
568 1596 : lC[ic] = (CHI_t*)new_chunk(sizeof(CHI_t));
569 1596 : init_CHI_C(lC[ic], CHI);
570 : }
571 994 : if (!ic) return W;
572 798 : nChar = ic;
573 :
574 798 : nf = bnr_get_nf(bnr);
575 798 : diff = nf_get_diff(nf);
576 798 : T = nf_get_Tr(nf);
577 798 : cond = bnr_get_mod(bnr);
578 798 : cond0 = gel(cond,1); condZ = gcoeff(cond0,1,1);
579 798 : cond1 = gel(cond,2);
580 :
581 798 : sqrtnc = gsqrt(idealnorm(nf, cond0), prec);
582 798 : ilambda = get_ilambda(nf, bid_get_fact(bnr_get_bid(bnr)), cond1);
583 798 : idh = idealmul(nf, ilambda, idealmul(nf, diff, cond0)); /* integral */
584 798 : ilambda = Q_remove_denom(ilambda, &den);
585 798 : z = den? rootsof1_cx(den, prec): NULL;
586 :
587 : /* compute a system of generators of (Ok/cond)^*, we'll make them
588 : * cond1-positive in the main loop */
589 798 : zid = Idealstar(nf, cond0, nf_GEN);
590 798 : cyc = abgrp_get_cyc(zid);
591 798 : gen = abgrp_get_gen(zid);
592 798 : nz = lg(gen) - 1;
593 798 : sarch = nfarchstar(nf, cond0, vec01_to_indices(cond1));
594 :
595 798 : nchi = cgetg(nChar+1, t_VEC);
596 2394 : for (ic = 1; ic <= nChar; ic++) gel(nchi,ic) = cgetg(nz + 1, t_VECSMALL);
597 1631 : for (i = 1; i <= nz; i++)
598 : {
599 833 : if (is_bigint(gel(cyc,i)))
600 0 : pari_err_OVERFLOW("ArtinNumber [conductor too large]");
601 833 : gel(gen,i) = set_sign_mod_divisor(nf, NULL, gel(gen,i), sarch);
602 833 : classe = isprincipalray(bnr, gel(gen,i));
603 2569 : for (ic = 1; ic <= nChar; ic++) {
604 1736 : GEN n = gel(nchi,ic);
605 1736 : n[i] = CHI_eval_n(lC[ic], classe);
606 : }
607 : }
608 :
609 : /* Sum chi(beta) * exp(2i * Pi * Tr(beta * ilambda) where beta
610 : runs through the classes of (Ok/cond0)^* and beta cond1-positive */
611 798 : vt = gel(T,1); /* ( Tr(w_i) )_i */
612 798 : if (typ(ilambda) == t_COL)
613 574 : vt = ZV_ZM_mul(vt, zk_multable(nf, ilambda));
614 : else
615 224 : vt = ZC_Z_mul(vt, ilambda);
616 : /*vt = den . (Tr(w_i * ilambda))_i */
617 798 : G.cyc = gtovecsmall(cyc);
618 798 : G.r = nz;
619 798 : G.j = zero_zv(nz);
620 798 : vN = zero_Flm_copy(nz, nChar);
621 :
622 798 : av2 = avma;
623 798 : vB = const_vec(nz, gen_1);
624 798 : s0 = z? powgi(z, modii(gel(vt,1), den)): gen_1; /* for beta = 1 */
625 798 : s = const_vec(nChar, s0);
626 :
627 53725 : while ( (i = NextElt(&G)) )
628 : {
629 52927 : GEN b = gel(vB,i);
630 52927 : b = nfmuli(nf, b, gel(gen,i));
631 52927 : b = typ(b) == t_COL? FpC_red(b, condZ): modii(b, condZ);
632 106190 : for (j=1; j<=i; j++) gel(vB,j) = b;
633 :
634 225155 : for (ic = 1; ic <= nChar; ic++)
635 : {
636 172228 : GEN v = gel(vN,ic), n = gel(nchi,ic);
637 172228 : v[i] = Fl_add(v[i], n[i], lC[ic]->ord);
638 172788 : for (j=1; j<i; j++) v[j] = v[i];
639 : }
640 :
641 52927 : gel(vB,i) = b = set_sign_mod_divisor(nf, NULL, b, sarch);
642 52927 : if (!z)
643 0 : s0 = gen_1;
644 : else
645 : {
646 52927 : b = typ(b) == t_COL? ZV_dotproduct(vt, b): mulii(gel(vt,1),b);
647 52927 : s0 = powgi(z, modii(b,den));
648 : }
649 225155 : for (ic = 1; ic <= nChar; ic++)
650 : {
651 172228 : GEN v = gel(vN,ic), val = lC[ic]->val[ v[i] ];
652 172228 : gel(s,ic) = gadd(gel(s,ic), gmul(val, s0));
653 : }
654 :
655 52927 : if (gc_needed(av2, 1))
656 : {
657 39 : if (DEBUGMEM > 1) pari_warn(warnmem,"ArtinNumber");
658 39 : (void)gc_all(av2, 2, &s, &vB);
659 : }
660 : }
661 :
662 798 : classe = isprincipalray(bnr, idh);
663 798 : z = powIs(- (lg(gel(sarch,1))-1));
664 :
665 2394 : for (ic = 1; ic <= nChar; ic++)
666 : {
667 1596 : s0 = gmul(gel(s,ic), CHI_eval(lC[ic], classe));
668 1596 : gel(W, indW[ic]) = gmul(gdiv(s0, sqrtnc), z);
669 : }
670 798 : return W;
671 : }
672 :
673 : static GEN
674 721 : AllArtinNumbers(GEN CR, long prec)
675 : {
676 721 : pari_sp av = avma;
677 721 : GEN vChar = gel(CR,1), dataCR = gel(CR,2);
678 721 : long j, k, cl = lg(dataCR) - 1, J = lg(vChar)-1;
679 721 : GEN W = cgetg(cl+1,t_VEC), WbyCond, LCHI;
680 :
681 1638 : for (j = 1; j <= J; j++)
682 : {
683 917 : GEN LChar = gel(vChar,j), ldata = vecpermute(dataCR, LChar);
684 917 : GEN dtcr = gel(ldata,1), bnr = ch_bnr(dtcr);
685 917 : long l = lg(LChar);
686 :
687 917 : if (DEBUGLEVEL>1)
688 0 : err_printf("* Root Number: cond. no %ld/%ld (%ld chars)\n", j, J, l-1);
689 917 : LCHI = cgetg(l, t_VEC);
690 3297 : for (k = 1; k < l; k++) gel(LCHI,k) = ch_CHI0(gel(ldata,k));
691 917 : WbyCond = ArtinNumber(bnr, LCHI, prec);
692 3297 : for (k = 1; k < l; k++) gel(W,LChar[k]) = gel(WbyCond,k);
693 : }
694 721 : return gc_GEN(av, W);
695 : }
696 :
697 : /* compute the constant W of the functional equation of
698 : Lambda(chi). If flag = 1 then chi is assumed to be primitive */
699 : GEN
700 77 : bnrrootnumber(GEN bnr, GEN chi, long flag, long prec)
701 : {
702 77 : pari_sp av = avma;
703 : GEN cyc, W;
704 :
705 77 : if (flag < 0 || flag > 1) pari_err_FLAG("bnrrootnumber");
706 77 : checkbnr(bnr);
707 77 : if (flag)
708 : {
709 0 : cyc = bnr_get_cyc(bnr);
710 0 : if (!char_check(cyc,chi)) pari_err_TYPE("bnrrootnumber [character]", chi);
711 : }
712 : else
713 : {
714 77 : bnr_char_sanitize(&bnr, &chi);
715 77 : cyc = bnr_get_cyc(bnr);
716 : }
717 77 : chi = char_normalize(chi, cyc_normalize(cyc));
718 77 : chi = get_Char(chi, prec);
719 77 : W = ArtinNumber(bnr, mkvec(chi), prec);
720 77 : return gc_GEN(av, gel(W,1));
721 : }
722 :
723 : /********************************************************************/
724 : /* 3rd part: initialize the characters */
725 : /********************************************************************/
726 :
727 : /* Let chi be a character, A(chi) corresponding to the primes dividing diff
728 : * at s = flag. If s = 0, returns [r, A] where r is the order of vanishing
729 : * at s = 0 corresponding to diff. */
730 : static GEN
731 2128 : AChi(GEN dtcr, long *r, long flag, long prec)
732 : {
733 2128 : GEN A, diff = ch_diff(dtcr), bnrc = ch_bnr(dtcr), chi = ch_CHI0(dtcr);
734 2128 : long i, l = lg(diff);
735 :
736 2128 : A = gen_1; *r = 0;
737 2233 : for (i = 1; i < l; i++)
738 : {
739 105 : GEN B, pr = gel(diff,i), z = CharEval(chi, isprincipalray(bnrc, pr));
740 105 : if (flag)
741 0 : B = gsubsg(1, gdiv(z, pr_norm(pr)));
742 105 : else if (gequal1(z))
743 : {
744 21 : B = glog(pr_norm(pr), prec);
745 21 : (*r)++;
746 : }
747 : else
748 84 : B = gsubsg(1, z);
749 105 : A = gmul(A, B);
750 : }
751 2128 : return A;
752 : }
753 : /* simplified version of Achi: return 1 if L(0,chi) = 0 */
754 : static int
755 1071 : L_vanishes_at_0(GEN D)
756 : {
757 1071 : GEN diff = ch_diff(D), bnrc = ch_bnr(D), chi = ch_CHI0(D);
758 1071 : long i, l = lg(diff);
759 1113 : for (i = 1; i < l; i++)
760 : {
761 56 : GEN pr = gel(diff,i);
762 56 : if (!CharEval_n(chi, isprincipalray(bnrc, pr))) return 1;
763 : }
764 1057 : return 0;
765 : }
766 :
767 : static GEN
768 539 : _data3(GEN arch, long r2)
769 : {
770 539 : GEN z = cgetg(4, t_VECSMALL);
771 539 : long i, r1 = lg(arch) - 1, q = 0;
772 1722 : for (i = 1; i <= r1; i++) if (signe(gel(arch,i))) q++;
773 539 : z[1] = q;
774 539 : z[2] = r1 - q;
775 539 : z[3] = r2; return z;
776 : }
777 : static void
778 1603 : ch_get3(GEN dtcr, long *a, long *b, long *c)
779 1603 : { GEN v = ch_3(dtcr); *a = v[1]; *b = v[2]; *c = v[3]; }
780 : /* 2^(2*r2) pi^N */
781 : static GEN
782 714 : get_P(GEN nf, long prec)
783 : {
784 714 : long r2 = nf_get_r2(nf), N = nf_get_degree(nf);
785 714 : GEN P = powru(mppi(prec), N); shiftr_inplace(P, 2*r2); return P;
786 : }
787 : /* sort chars according to conductor */
788 : static GEN
789 392 : sortChars(GEN ch)
790 : {
791 392 : long j, l = lg(ch);
792 392 : GEN F = cgetg(l, t_VEC);
793 1701 : for (j = 1; j < l; j++) gel(F, j) = gmael(ch,j,2);
794 392 : return vec_equiv(F);
795 : }
796 :
797 : /* Given a list [chi, F = cond(chi)] of characters over Cl(bnr), return
798 : * [vChar, dataCR], where vChar contains the equivalence classes of
799 : * characters with the same conductor, and dataCR contains for each character:
800 : * - bnr(F)
801 : * - the constant C(F) [t_REAL]
802 : * - [q, r1 - q, r2, rc] where
803 : * q = number of real places in F
804 : * rc = max{r1 + r2 - q + 1, r2 + q}
805 : * - diff(chi) primes dividing m but not F
806 : * - chi in bnr(m)
807 : * - chi in bnr(F).
808 : * If all is unset, only compute characters s.t. L(chi,0) != 0 */
809 : static GEN
810 392 : InitChar(GEN bnr, GEN ch, long all, long prec)
811 : {
812 392 : GEN bnf = checkbnf(bnr), nf = bnf_get_nf(bnf), mod = bnr_get_mod(bnr);
813 392 : GEN P, dataCR, ncyc, dk = nf_get_disc(nf), vChar = sortChars(ch);
814 392 : long n, l, r2 = nf_get_r2(nf), prec2 = precdbl(prec) + EXTRAPREC64;
815 392 : long lv = lg(vChar);
816 :
817 392 : P = get_P(nf, prec2);
818 392 : ncyc = cyc_normalize(bnr_get_cyc(bnr));
819 :
820 392 : dataCR = cgetg_copy(ch, &l);
821 931 : for (n = 1; n < lv; n++)
822 : {
823 539 : GEN D, bnrc, v = gel(vChar, n); /* indices of chars of given cond */
824 539 : long a, i = v[1], lc = lg(v);
825 539 : GEN F = gmael(ch,i,2);
826 539 : gel(dataCR, i) = D = cgetg(8, t_VEC);
827 539 : ch_C(D) = sqrtr_abs(divir(mulii(dk, ZM_det_triangular(gel(F,1))), P));
828 539 : ch_3(D) = _data3(gel(F,2), r2);
829 539 : if (gequal(F, mod))
830 : {
831 378 : ch_bnr(D) = bnrc = bnr;
832 378 : ch_diff(D) = cgetg(1, t_VEC);
833 : }
834 : else
835 : {
836 161 : ch_bnr(D) = bnrc = Buchray(bnf, F, nf_INIT);
837 161 : ch_diff(D) = get_prdiff(divcond(bnr), divcond(bnrc));
838 : }
839 1848 : for (a = 1; a < lc; a++)
840 : {
841 1309 : long i = v[a];
842 1309 : GEN chi = gmael(ch,i,1);
843 :
844 1309 : if (a > 1) gel(dataCR, i) = D = leafcopy(D);
845 1309 : chi = char_normalize(chi,ncyc);
846 1309 : ch_CHI(D) = get_Char(chi, prec2);
847 1309 : if (bnrc == bnr)
848 1092 : ch_CHI0(D) = ch_CHI(D);
849 : else
850 : {
851 217 : chi = bnrchar_primitive(bnr, chi, bnrc);
852 217 : ch_CHI0(D) = get_Char(chi, prec2);
853 : }
854 : /* set last */
855 1309 : ch_small(D) = mkvecsmall2(all || !L_vanishes_at_0(D),
856 1309 : eulerphiu(itou(gel(chi,1))));
857 : }
858 : }
859 392 : return mkvec2(vChar, dataCR);
860 : }
861 :
862 : /* recompute dataCR with the new precision, in place. Don't modify bnr
863 : * components in place */
864 : static void
865 322 : CharNewPrec(GEN data, long prec)
866 : {
867 322 : long j, l, prec2 = precdbl(prec) + EXTRAPREC64;
868 322 : GEN P, nf, dataCR = gmael(data,4,2), D = gel(dataCR,1);
869 :
870 322 : if (ch_prec(D) >= prec2) return;
871 322 : nf = bnr_get_nf(ch_bnr(D));
872 322 : if (nf_get_prec(nf) < prec) nf = nfnewprec_shallow(nf, prec); /* not prec2 */
873 322 : P = get_P(nf, prec2); l = lg(dataCR);
874 1351 : for (j = 1; j < l; j++)
875 : {
876 : GEN f0, bnr;
877 1029 : D = gel(dataCR,j); f0 = gel(bnr_get_mod(ch_bnr(D)), 1);
878 1029 : ch_C(D) = sqrtr_abs(divir(mulii(nf_get_disc(nf),ZM_det_triangular(f0)), P));
879 1029 : ch_bnr(D) = bnr = shallowcopy(ch_bnr(D));
880 1029 : gel(bnr,1) = shallowcopy(gel(bnr,1)); gmael(bnr,1,7) = nf;
881 1029 : ch_CHI(D) = get_Char(gel(ch_CHI(D),1), prec2);
882 1029 : ch_CHI0(D)= get_Char(gel(ch_CHI0(D),1), prec2);
883 : }
884 : }
885 :
886 : /********************************************************************/
887 : /* 4th part: compute the coefficients an(chi) */
888 : /* */
889 : /* matan entries are arrays of ints containing the coefficients of */
890 : /* an(chi) as a polmod modulo polcyclo(order(chi)) */
891 : /********************************************************************/
892 :
893 : static void
894 1001821 : _0toCoeff(int *rep, long deg)
895 : {
896 : long i;
897 4583479 : for (i=0; i<deg; i++) rep[i] = 0;
898 1001821 : }
899 :
900 : /* transform a polmod into Coeff */
901 : static void
902 397879 : Polmod2Coeff(int *rep, GEN polmod, long deg)
903 : {
904 : long i;
905 397879 : if (typ(polmod) == t_POLMOD)
906 : {
907 293467 : GEN pol = gel(polmod,2);
908 293467 : long d = degpol(pol);
909 :
910 293467 : pol += 2;
911 1266018 : for (i=0; i<=d; i++) rep[i] = itos(gel(pol,i));
912 687949 : for ( ; i<deg; i++) rep[i] = 0;
913 : }
914 : else
915 : {
916 104412 : rep[0] = itos(polmod);
917 112644 : for (i=1; i<deg; i++) rep[i] = 0;
918 : }
919 397879 : }
920 :
921 : /* initialize a deg * n matrix of ints */
922 : static int**
923 4165 : InitMatAn(long n, long deg, long flag)
924 : {
925 : long i, j;
926 4165 : int *a, **A = (int**)pari_malloc((n+1)*sizeof(int*));
927 4165 : A[0] = NULL;
928 6155522 : for (i = 1; i <= n; i++)
929 : {
930 6151357 : a = (int*)pari_malloc(deg*sizeof(int));
931 6151357 : A[i] = a; a[0] = (i == 1 || flag);
932 19974675 : for (j = 1; j < deg; j++) a[j] = 0;
933 : }
934 4165 : return A;
935 : }
936 :
937 : static void
938 6531 : FreeMat(int **A, long n)
939 : {
940 : long i;
941 6170852 : for (i = 0; i <= n; i++)
942 6164321 : if (A[i]) pari_free((void*)A[i]);
943 6531 : pari_free((void*)A);
944 6531 : }
945 :
946 : /* initialize Coeff reduction */
947 : static int**
948 2366 : InitReduction(long d, long deg)
949 : {
950 : long j;
951 2366 : pari_sp av = avma;
952 : int **A;
953 : GEN polmod, pol;
954 :
955 2366 : A = (int**)pari_malloc(deg*sizeof(int*));
956 2366 : pol = polcyclo(d, 0);
957 11165 : for (j = 0; j < deg; j++)
958 : {
959 8799 : A[j] = (int*)pari_malloc(deg*sizeof(int));
960 8799 : polmod = gmodulo(pol_xn(deg+j, 0), pol);
961 8799 : Polmod2Coeff(A[j], polmod, deg);
962 : }
963 :
964 2366 : set_avma(av); return A;
965 : }
966 :
967 : #if 0
968 : void
969 : pan(int **an, long n, long deg)
970 : {
971 : long i,j;
972 : for (i = 1; i <= n; i++)
973 : {
974 : err_printf("n = %ld: ",i);
975 : for (j = 0; j < deg; j++) err_printf("%d ",an[i][j]);
976 : err_printf("\n");
977 : }
978 : }
979 : #endif
980 :
981 : /* returns 0 if c is zero, 1 otherwise. */
982 : static int
983 7661729 : IsZero(int* c, long deg)
984 : {
985 : long i;
986 26145834 : for (i = 0; i < deg; i++)
987 20449437 : if (c[i]) return 0;
988 5696397 : return 1;
989 : }
990 :
991 : /* set c0 <-- c0 * c1 */
992 : static void
993 1511799 : MulCoeff(int *c0, int* c1, int** reduc, long deg)
994 : {
995 : long i,j;
996 : int c, *T;
997 :
998 1511799 : if (IsZero(c0,deg)) return;
999 :
1000 810549 : T = (int*)new_chunk(2*deg);
1001 8556301 : for (i = 0; i < 2*deg; i++)
1002 : {
1003 7745752 : c = 0;
1004 84469968 : for (j = 0; j <= i; j++)
1005 76724216 : if (j < deg && j > i - deg) c += c0[j] * c1[i-j];
1006 7745752 : T[i] = c;
1007 : }
1008 4683425 : for (i = 0; i < deg; i++)
1009 : {
1010 3872876 : c = T[i];
1011 40298546 : for (j = 0; j < deg; j++) c += reduc[j][i] * T[deg+j];
1012 3872876 : c0[i] = c;
1013 : }
1014 : }
1015 :
1016 : /* c0 <- c0 + c1 * c2 */
1017 : static void
1018 6149930 : AddMulCoeff(int *c0, int *c1, int* c2, int** reduc, long deg)
1019 : {
1020 : long i, j;
1021 : pari_sp av;
1022 : int c, *t;
1023 :
1024 6149930 : if (IsZero(c2,deg)) return;
1025 1154783 : if (!c1) /* c1 == 1 */
1026 : {
1027 709114 : for (i = 0; i < deg; i++) c0[i] += c2[i];
1028 291571 : return;
1029 : }
1030 863212 : av = avma;
1031 863212 : t = (int*)new_chunk(2*deg); /* = c1 * c2, not reduced */
1032 6691468 : for (i = 0; i < 2*deg; i++)
1033 : {
1034 5828256 : c = 0;
1035 42776216 : for (j = 0; j <= i; j++)
1036 36947960 : if (j < deg && j > i - deg) c += c1[j] * c2[i-j];
1037 5828256 : t[i] = c;
1038 : }
1039 3777340 : for (i = 0; i < deg; i++)
1040 : {
1041 2914128 : c = t[i];
1042 19931044 : for (j = 0; j < deg; j++) c += reduc[j][i] * t[deg+j];
1043 2914128 : c0[i] += c;
1044 : }
1045 863212 : set_avma(av);
1046 : }
1047 :
1048 : /* evaluate the Coeff. No Garbage collector */
1049 : static GEN
1050 3661174 : EvalCoeff(GEN z, int* c, long deg)
1051 : {
1052 : long i,j;
1053 3661174 : GEN r, e = NULL;
1054 :
1055 : #if 0
1056 : /* standard Horner */
1057 : e = stoi(c[deg - 1]);
1058 : for (i = deg - 2; i >= 0; i--)
1059 : e = gadd(stoi(c[i]), gmul(z, e));
1060 : #else
1061 : /* specific attention to sparse polynomials */
1062 5260114 : for (i = deg-1; i >=0; i=j-1)
1063 : {
1064 12405790 : for (j=i; c[j] == 0; j--)
1065 10806850 : if (j==0)
1066 : {
1067 3000548 : if (!e) return NULL;
1068 311077 : if (i!=j) z = gpowgs(z,i-j+1);
1069 311077 : return gmul(e,z);
1070 : }
1071 1598940 : if (e)
1072 : {
1073 627237 : r = (i==j)? z: gpowgs(z,i-j+1);
1074 627237 : e = gadd(gmul(e,r), stoi(c[j]));
1075 : }
1076 : else
1077 971703 : e = stoi(c[j]);
1078 : }
1079 : #endif
1080 660626 : return e;
1081 : }
1082 :
1083 : /* a2 <- copy the n x m array */
1084 : static void
1085 357308 : CopyCoeff(int** a, int** a2, long n, long m)
1086 : {
1087 : long i,j;
1088 :
1089 5261912 : for (i = 1; i <= n; i++)
1090 : {
1091 4904604 : int *b = a[i], *b2 = a2[i];
1092 19404982 : for (j = 0; j < m; j++) b2[j] = b[j];
1093 : }
1094 357308 : }
1095 :
1096 : static void
1097 357308 : an_AddMul(int **an,int **an2, long np, long n, long deg, GEN chi, int **reduc)
1098 : {
1099 357308 : GEN chi2 = chi;
1100 : long q, qk, k;
1101 357308 : int *c, *c2 = (int*)new_chunk(deg);
1102 :
1103 357308 : CopyCoeff(an, an2, n/np, deg);
1104 357308 : for (q=np;;)
1105 : {
1106 391202 : if (gequal1(chi2)) c = NULL; else { Polmod2Coeff(c2, chi2, deg); c = c2; }
1107 6541132 : for(k = 1, qk = q; qk <= n; k++, qk += q)
1108 6149930 : AddMulCoeff(an[qk], c, an2[k], reduc, deg);
1109 391202 : if (! (q = umuluu_le(q,np, n)) ) break;
1110 :
1111 33894 : chi2 = gmul(chi2, chi);
1112 : }
1113 357308 : }
1114 :
1115 : /* correct the coefficients an(chi) according with diff(chi) in place */
1116 : static void
1117 2366 : CorrectCoeff(GEN dtcr, int** an, int** reduc, long n, long deg)
1118 : {
1119 2366 : pari_sp av = avma;
1120 : long lg, j;
1121 : pari_sp av1;
1122 : int **an2;
1123 : GEN bnrc, diff;
1124 : CHI_t C;
1125 :
1126 2366 : diff = ch_diff(dtcr); lg = lg(diff) - 1;
1127 2366 : if (!lg) return;
1128 :
1129 168 : if (DEBUGLEVEL>2) err_printf("diff(CHI) = %Ps", diff);
1130 168 : bnrc = ch_bnr(dtcr);
1131 168 : init_CHI_alg(&C, ch_CHI0(dtcr));
1132 :
1133 168 : an2 = InitMatAn(n, deg, 0);
1134 168 : av1 = avma;
1135 364 : for (j = 1; j <= lg; j++)
1136 : {
1137 196 : GEN pr = gel(diff,j);
1138 196 : long Np = upr_norm(pr);
1139 196 : GEN chi = CHI_eval(&C, isprincipalray(bnrc, pr));
1140 196 : an_AddMul(an,an2,Np,n,deg,chi,reduc);
1141 196 : set_avma(av1);
1142 : }
1143 168 : FreeMat(an2, n); set_avma(av);
1144 : }
1145 :
1146 : /* compute the coefficients an in the general case */
1147 : static int**
1148 1631 : ComputeCoeff(GEN dtcr, LISTray *R, long n, long deg)
1149 : {
1150 1631 : pari_sp av = avma, av2;
1151 : long i, l;
1152 : int **an, **reduc, **an2;
1153 : GEN L;
1154 : CHI_t C;
1155 :
1156 1631 : init_CHI_alg(&C, ch_CHI(dtcr));
1157 1631 : an = InitMatAn(n, deg, 0);
1158 1631 : an2 = InitMatAn(n, deg, 0);
1159 1631 : reduc = InitReduction(C.ord, deg);
1160 1631 : av2 = avma;
1161 :
1162 1631 : L = R->L1; l = lg(L);
1163 358743 : for (i=1; i<l; i++, set_avma(av2))
1164 : {
1165 357112 : long np = L[i];
1166 357112 : GEN chi = CHI_eval(&C, gel(R->L1ray,i));
1167 357112 : an_AddMul(an,an2,np,n,deg,chi,reduc);
1168 : }
1169 1631 : FreeMat(an2, n);
1170 :
1171 1631 : CorrectCoeff(dtcr, an, reduc, n, deg);
1172 1631 : FreeMat(reduc, deg-1);
1173 1631 : set_avma(av); return an;
1174 : }
1175 :
1176 : /********************************************************************/
1177 : /* 5th part: compute L-functions at s=1 */
1178 : /********************************************************************/
1179 : static void
1180 441 : deg11(LISTray *R, long p, GEN bnr, GEN pr) {
1181 441 : vecsmalltrunc_append(R->L1, p);
1182 441 : vectrunc_append(R->L1ray, isprincipalray(bnr, pr));
1183 441 : }
1184 : static void
1185 24659 : deg12(LISTray *R, long p, GEN bnr, GEN pr) {
1186 24659 : vecsmalltrunc_append(R->L11, p);
1187 24659 : vectrunc_append(R->L11ray, isprincipalray(bnr, pr));
1188 24659 : }
1189 : static void
1190 35 : deg0(LISTray *R, long p) { vecsmalltrunc_append(R->L0, p); }
1191 : static void
1192 26629 : deg2(LISTray *R, long p) { vecsmalltrunc_append(R->L2, p); }
1193 :
1194 : static void
1195 203 : InitPrimesQuad(GEN bnr, ulong N0, LISTray *R)
1196 : {
1197 203 : pari_sp av = avma;
1198 203 : GEN bnf = bnr_get_bnf(bnr), F = gel(bnr_get_mod(bnr), 1);
1199 203 : GEN v, N, nf = bnf_get_nf(bnf), dk = nf_get_disc(nf);
1200 203 : long l = 1 + primepi_upper_bound(N0);
1201 203 : ulong i, p, FZ = itou(gcoeff(F,1,1)), FZ2 = itou(gcoeff(F,2,2));
1202 : forprime_t T;
1203 :
1204 203 : FZ2 = ugcd(FZ, FZ2); /* content(F) */
1205 203 : R->L0 = vecsmalltrunc_init(l);
1206 203 : R->L2 = vecsmalltrunc_init(l); R->condZ = FZ;
1207 203 : R->L1 = vecsmalltrunc_init(l); R->L1ray = vectrunc_init(l);
1208 203 : R->L11= vecsmalltrunc_init(l); R->L11ray= vectrunc_init(l);
1209 203 : N = utoipos(2);
1210 203 : u_forprime_init(&T, 2, N0);
1211 51967 : while ( (p = u_forprime_next(&T)) )
1212 : {
1213 51764 : N[2] = p;
1214 51764 : switch (kroiu(dk, p))
1215 : {
1216 26643 : case -1: /* inert */
1217 26643 : if (FZ % p == 0) deg0(R,p); else deg2(R,p);
1218 26643 : break;
1219 24848 : case 1: /* split */
1220 24848 : if (FZ2 % p == 0) deg0(R,p);
1221 : else
1222 : {
1223 24848 : GEN Lpr = idealprimedec(nf, N);
1224 24848 : if (FZ % p) deg12(R, p, bnr, gel(Lpr,1));
1225 : else
1226 : {
1227 189 : long t = ZC_prdvd(gel(F,2), gel(Lpr,1))? 2: 1;
1228 189 : deg11(R, p, bnr, gel(Lpr,t));
1229 : }
1230 : }
1231 24848 : break;
1232 273 : default: /* ramified */
1233 273 : if (FZ % p == 0)
1234 21 : deg0(R,p);
1235 : else
1236 252 : deg11(R, p, bnr, idealprimedec_galois(nf, N));
1237 273 : break;
1238 : }
1239 : }
1240 : /* precompute isprincipalray(x), x in Z */
1241 203 : v = coprimes_zv(FZ);
1242 203 : R->rayZ = cgetg(FZ, t_VEC);
1243 3934 : for (i = 1; i < FZ; i++)
1244 : {
1245 3731 : N[2] = i;
1246 3731 : gel(R->rayZ,i) = v[i]? isprincipalray(bnr, N): gen_0;
1247 : }
1248 203 : (void)gc_all(av, 7, &(R->L0), &(R->L2), &(R->rayZ),
1249 : &(R->L1), &(R->L1ray), &(R->L11), &(R->L11ray));
1250 203 : }
1251 :
1252 : static void
1253 518 : InitPrimes(GEN bnr, ulong N0, LISTray *R)
1254 : {
1255 518 : GEN bnf = bnr_get_bnf(bnr), cond = gel(bnr_get_mod(bnr), 1);
1256 518 : long p, l, condZ, N = lg(cond)-1;
1257 518 : GEN DL, prime, BOUND, nf = bnf_get_nf(bnf);
1258 : forprime_t T;
1259 :
1260 518 : R->condZ = condZ = itos(gcoeff(cond,1,1));
1261 518 : l = primepi_upper_bound(N0) * N;
1262 518 : DL = cgetg(N+1, t_VEC);
1263 518 : R->L1 = vecsmalltrunc_init(l);
1264 518 : R->L1ray = vectrunc_init(l);
1265 518 : u_forprime_init(&T, 2, N0);
1266 518 : prime = utoipos(2);
1267 518 : BOUND = utoi(N0);
1268 123144 : while ( (p = u_forprime_next(&T)) )
1269 : {
1270 122626 : pari_sp av = avma;
1271 : long j, k, lP;
1272 : GEN P;
1273 122626 : prime[2] = p;
1274 122626 : if (DEBUGLEVEL>1 && (p & 2047) == 1) err_printf("%ld ", p);
1275 122626 : P = idealprimedec_limit_norm(nf, prime, BOUND); lP = lg(P);
1276 244713 : for (j = 1; j < lP; j++)
1277 : {
1278 122087 : GEN pr = gel(P,j), dl = NULL;
1279 122087 : if (condZ % p || !idealval(nf, cond, pr))
1280 : {
1281 121611 : dl = gclone( isprincipalray(bnr, pr) );
1282 121611 : vecsmalltrunc_append(R->L1, upowuu(p, pr_get_f(pr)));
1283 : }
1284 122087 : gel(DL,j) = dl;
1285 : }
1286 122626 : set_avma(av);
1287 244713 : for (k = 1; k < j; k++)
1288 : {
1289 122087 : if (!DL[k]) continue;
1290 121611 : vectrunc_append(R->L1ray, ZC_copy(gel(DL,k)));
1291 121611 : gunclone(gel(DL,k));
1292 : }
1293 : }
1294 518 : }
1295 :
1296 : static GEN /* cf polcoef */
1297 412236 : _sercoeff(GEN x, long n)
1298 : {
1299 412236 : long i = n - valser(x);
1300 412236 : return (i < 0)? gen_0: gel(x,i+2);
1301 : }
1302 :
1303 : static void
1304 412236 : affect_coeff(GEN q, long n, GEN y, long t)
1305 : {
1306 412236 : GEN x = _sercoeff(q,-n);
1307 412236 : if (x == gen_0) gel(y,n) = NULL;
1308 210548 : else { affgr(x, gel(y,n)); shiftr_inplace(gel(y,n), t); }
1309 412236 : }
1310 : /* (x-i)(x-(i+1)) */
1311 : static GEN
1312 105282 : d2(long i) { return deg2pol_shallow(gen_1, utoineg(2*i+1), muluu(i,i+1), 0); }
1313 : /* x-i */
1314 : static GEN
1315 315902 : d1(long i) { return deg1pol_shallow(gen_1, stoi(-i), 0); }
1316 :
1317 : typedef struct {
1318 : GEN c1, aij, bij, cS, cT, powracpi;
1319 : long i0, a,b,c, r, rc1, rc2;
1320 : } ST_t;
1321 :
1322 : /* compute the principal part at the integers s = 0, -1, -2, ..., -i0
1323 : * of Gamma((s+1)/2)^a Gamma(s/2)^b Gamma(s)^c / (s - z) with z = 0 and 1 */
1324 : static void
1325 308 : ppgamma(ST_t *T, long prec)
1326 : {
1327 : GEN G, G1, G2, A, E, O, x, sqpi, aij, bij;
1328 308 : long c = T->c, r = T->r, i0 = T->i0, i, j, s, t, dx;
1329 : pari_sp av;
1330 :
1331 308 : T->aij = aij = cgetg(i0+1, t_VEC);
1332 308 : T->bij = bij = cgetg(i0+1, t_VEC);
1333 105590 : for (i = 1; i <= i0; i++)
1334 : {
1335 : GEN p1, p2;
1336 105282 : gel(aij,i) = p1 = cgetg(r+1, t_VEC);
1337 105282 : gel(bij,i) = p2 = cgetg(r+1, t_VEC);
1338 311400 : for (j=1; j<=r; j++) { gel(p1,j) = cgetr(prec); gel(p2,j) = cgetr(prec); }
1339 : }
1340 308 : av = avma; x = pol_x(0);
1341 308 : sqpi = sqrtr_abs(mppi(prec)); /* Gamma(1/2) */
1342 :
1343 308 : G1 = gexp(integser(psi1series(r-1, 0, prec)), prec); /* Gamma(1 + x) */
1344 308 : G = shallowcopy(G1); setvalser(G,-1); /* Gamma(x) */
1345 :
1346 : /* expansion of log(Gamma(u) / Gamma(1/2)) at u = 1/2 */
1347 308 : G2 = cgetg(r+2, t_SER);
1348 308 : G2[1] = evalsigne(1) | _evalvalser(1) | evalvarn(0);
1349 308 : gel(G2,2) = gneg(gadd(gmul2n(mplog2(prec), 1), mpeuler(prec)));
1350 644 : for (i = 1; i < r; i++) gel(G2,i+2) = mulri(gel(G1,i+2), int2um1(i));
1351 308 : G2 = gmul(sqpi, gexp(G2, prec)); /* Gamma(1/2 + x) */
1352 :
1353 : /* We simplify to get one of the following two expressions
1354 : * if (b > a) : sqrt(Pi)^a 2^{a-au} Gamma(u)^{a+c} Gamma( u/2 )^{|b-a|}
1355 : * if (b <= a): sqrt(Pi)^b 2^{b-bu} Gamma(u)^{b+c} Gamma((u+1)/2)^{|b-a|} */
1356 308 : if (T->b > T->a)
1357 : {
1358 56 : t = T->a; s = T->b; dx = 1;
1359 56 : E = ser_unscale(G, ghalf);
1360 56 : O = gmul2n(gdiv(ser_unscale(G2, ghalf), d1(1)), 1); /* Gamma((x-1)/2) */
1361 : }
1362 : else
1363 : {
1364 252 : t = T->b; s = T->a; dx = 0;
1365 252 : E = ser_unscale(G2, ghalf);
1366 252 : O = ser_unscale(G, ghalf);
1367 : }
1368 : /* (sqrt(Pi) 2^{1-x})^t Gamma(x)^{t+c} */
1369 308 : A = gmul(gmul(powru(gmul2n(sqpi,1), t), gpowgs(G, t+c)),
1370 : gpow(gen_2, RgX_to_ser(gmulgs(x,-t), r+2), prec));
1371 : /* A * Gamma((x - dx + 1)/2)^{s-t} */
1372 308 : E = gmul(A, gpowgs(E, s-t));
1373 : /* A * Gamma((x - dx)/2)^{s-t} */
1374 308 : O = gdiv(gmul(A, gpowgs(O, s-t)), gpowgs(gsubgs(x, 1), t+c));
1375 52949 : for (i = 0; i < i0/2; i++)
1376 : {
1377 52641 : GEN p1, q1, A1 = gel(aij,2*i+1), B1 = gel(bij,2*i+1);
1378 52641 : GEN p2, q2, A2 = gel(aij,2*i+2), B2 = gel(bij,2*i+2);
1379 52641 : long t1 = i * (s+t), t2 = t1 + t;
1380 :
1381 52641 : p1 = gdiv(E, d1(2*i));
1382 52641 : q1 = gdiv(E, d1(2*i+1));
1383 52641 : p2 = gdiv(O, d1(2*i+1));
1384 52641 : q2 = gdiv(O, d1(2*i+2));
1385 155700 : for (j = 1; j <= r; j++)
1386 : {
1387 103059 : affect_coeff(p1, j, A1, t1); affect_coeff(q1, j, B1, t1);
1388 103059 : affect_coeff(p2, j, A2, t2); affect_coeff(q2, j, B2, t2);
1389 : }
1390 52641 : E = gdiv(E, gmul(gpowgs(d1(2*i+1+dx), s-t), gpowgs(d2(2*i+1), t+c)));
1391 52641 : O = gdiv(O, gmul(gpowgs(d1(2*i+2+dx), s-t), gpowgs(d2(2*i+2), t+c)));
1392 : }
1393 308 : set_avma(av);
1394 308 : }
1395 :
1396 : /* chi != 1. Return L(1, chi) if fl & 1, else [r, c] where L(s, chi) ~ c s^r
1397 : * at s = 0. */
1398 : static GEN
1399 1295 : GetValue(GEN dtcr, GEN W, GEN S, GEN T, long fl, long prec)
1400 : {
1401 : GEN cf, z;
1402 : long q, b, c, r;
1403 1295 : int isreal = (ch_deg(dtcr) <= 2);
1404 :
1405 1295 : ch_get3(dtcr, &q, &b, &c);
1406 1295 : if (fl & 1)
1407 : { /* S(chi) + W(chi).T(chi)) / (C(chi) sqrt(Pi)^{r1 - q}) */
1408 196 : cf = gmul(ch_C(dtcr), powruhalf(mppi(prec), b));
1409 :
1410 196 : z = gadd(S, gmul(W, T));
1411 196 : if (isreal) z = real_i(z);
1412 196 : z = gdiv(z, cf);
1413 196 : if (fl & 2) z = gmul(z, AChi(dtcr, &r, 1, prec));
1414 : }
1415 : else
1416 : { /* (W(chi).S(conj(chi)) + T(chi)) / (sqrt(Pi)^q 2^{r1 - q}) */
1417 1099 : cf = gmul2n(powruhalf(mppi(prec), q), b);
1418 :
1419 1099 : z = gadd(gmul(W, conj_i(S)), conj_i(T));
1420 1099 : if (isreal) z = real_i(z);
1421 1099 : z = gdiv(z, cf); r = 0;
1422 1099 : if (fl & 2) z = gmul(z, AChi(dtcr, &r, 0, prec));
1423 1099 : z = mkvec2(utoi(b + c + r), z);
1424 : }
1425 1295 : return z;
1426 : }
1427 :
1428 : /* return the order and the first nonzero term of L(s, chi0)
1429 : at s = 0. If flag != 0, adjust the value to get L_S(s, chi0). */
1430 : static GEN
1431 35 : GetValue1(GEN bnr, long flag, long prec)
1432 : {
1433 35 : GEN bnf = bnr_get_bnf(bnr), nf = bnf_get_nf(bnf);
1434 35 : GEN h = bnf_get_no(bnf), R = bnf_get_reg(bnf);
1435 35 : GEN c = gdivgs(mpmul(h, R), -bnf_get_tuN(bnf));
1436 35 : long r = lg(nf_get_roots(nf)) - 2; /* r1 + r2 - 1 */;
1437 35 : if (flag)
1438 : {
1439 0 : GEN diff = divcond(bnr);
1440 0 : long i, l = lg(diff);
1441 0 : r += l - 1;
1442 0 : for (i = 1; i < l; i++) c = gmul(c, glog(pr_norm(gel(diff,i)), prec));
1443 : }
1444 35 : return mkvec2(utoi(r), c);
1445 : }
1446 :
1447 : /********************************************************************/
1448 : /* 6th part: recover the coefficients */
1449 : /********************************************************************/
1450 : static long
1451 2564 : TestOne(GEN plg, RC_data *d)
1452 : {
1453 2564 : long j, v = d->v;
1454 2564 : GEN z = gsub(d->beta, gel(plg,v));
1455 2564 : if (expo(z) >= d->G) return 0;
1456 7036 : for (j = 1; j < lg(plg); j++)
1457 4902 : if (j != v && mpcmp(d->B, mpabs_shallow(gel(plg,j))) < 0) return 0;
1458 2134 : return 1;
1459 : }
1460 :
1461 : static GEN
1462 412 : chk_reccoeff_init(FP_chk_fun *chk, GEN r, GEN mat)
1463 : {
1464 412 : RC_data *d = (RC_data*)chk->data;
1465 412 : (void)r; d->U = mat; return d->nB;
1466 : }
1467 :
1468 : static GEN
1469 390 : chk_reccoeff(void *data, GEN x)
1470 : {
1471 390 : RC_data *d = (RC_data*)data;
1472 390 : GEN v = gmul(d->U, x), z = gel(v,1);
1473 :
1474 390 : if (!gequal1(z)) return NULL;
1475 390 : *++v = evaltyp(t_COL) | _evallg( lg(d->M) ); /* pop 1st elt */
1476 390 : if (TestOne(gmul(d->M, v), d)) return v;
1477 0 : return NULL;
1478 : }
1479 :
1480 : /* Using Cohen's method */
1481 : static GEN
1482 412 : RecCoeff3(GEN nf, RC_data *d, long prec)
1483 : {
1484 : GEN A, M, nB, cand, p1, B2, C2, tB, beta2, nf2, Bd;
1485 412 : GEN beta = d->beta, B = d->B;
1486 412 : long N = d->N, v = d->v, e, BIG;
1487 412 : long i, j, k, ct = 0, prec2;
1488 412 : FP_chk_fun chk = { &chk_reccoeff, &chk_reccoeff_init, NULL, NULL, 0 };
1489 412 : chk.data = (void*)d;
1490 :
1491 412 : d->G = minss(-10, -prec >> 4);
1492 412 : BIG = maxss(32, -2*d->G);
1493 412 : tB = sqrtnr(real2n(BIG-N,DEFAULTPREC), N-1);
1494 412 : Bd = grndtoi(gmin_shallow(B, tB), &e);
1495 412 : if (e > 0) return NULL; /* failure */
1496 412 : Bd = addiu(Bd, 1);
1497 412 : prec2 = nbits2prec( expi(Bd) + 192 );
1498 412 : prec2 = maxss(precdbl(prec), prec2);
1499 412 : B2 = sqri(Bd);
1500 412 : C2 = shifti(B2, BIG<<1);
1501 :
1502 412 : LABrcf: ct++;
1503 412 : beta2 = gprec_w(beta, prec2);
1504 412 : nf2 = nfnewprec_shallow(nf, prec2);
1505 412 : d->M = M = nf_get_M(nf2);
1506 :
1507 412 : A = cgetg(N+2, t_MAT);
1508 1697 : for (i = 1; i <= N+1; i++) gel(A,i) = cgetg(N+2, t_COL);
1509 :
1510 412 : gcoeff(A, 1, 1) = gadd(gmul(C2, gsqr(beta2)), B2);
1511 1285 : for (j = 2; j <= N+1; j++)
1512 : {
1513 873 : p1 = gmul(C2, gmul(gneg_i(beta2), gcoeff(M, v, j-1)));
1514 873 : gcoeff(A, 1, j) = gcoeff(A, j, 1) = p1;
1515 : }
1516 1285 : for (i = 2; i <= N+1; i++)
1517 2256 : for (j = i; j <= N+1; j++)
1518 : {
1519 1383 : p1 = gen_0;
1520 4443 : for (k = 1; k <= N; k++)
1521 : {
1522 3060 : GEN p2 = gmul(gcoeff(M, k, j-1), gcoeff(M, k, i-1));
1523 3060 : if (k == v) p2 = gmul(C2, p2);
1524 3060 : p1 = gadd(p1,p2);
1525 : }
1526 1383 : gcoeff(A, i, j) = gcoeff(A, j, i) = p1;
1527 : }
1528 :
1529 412 : nB = mului(N+1, B2);
1530 412 : d->nB = nB;
1531 412 : cand = fincke_pohst(A, nB, -1, prec2, &chk);
1532 :
1533 412 : if (!cand)
1534 : {
1535 0 : if (ct > 3) return NULL;
1536 0 : prec2 = precdbl(prec2);
1537 0 : if (DEBUGLEVEL>1) pari_warn(warnprec,"RecCoeff", prec2);
1538 0 : goto LABrcf;
1539 : }
1540 :
1541 412 : cand = gel(cand,1);
1542 412 : if (lg(cand) == 2) return gel(cand,1);
1543 :
1544 217 : if (DEBUGLEVEL>1) err_printf("RecCoeff3: no solution found!\n");
1545 217 : return NULL;
1546 : }
1547 :
1548 : /* Using linear dependence relations */
1549 : static GEN
1550 2156 : RecCoeff2(GEN nf, RC_data *d, long prec)
1551 : {
1552 : pari_sp av;
1553 2156 : GEN vec, M = nf_get_M(nf), beta = d->beta;
1554 2156 : long bit, min, max, lM = lg(M);
1555 :
1556 2156 : d->G = minss(-20, -prec >> 4);
1557 :
1558 2156 : vec = vec_prepend(row(M, d->v), gneg(beta));
1559 2156 : min = (long)prec * 0.75;
1560 2156 : max = (long)prec * 0.98;
1561 2156 : av = avma;
1562 2705 : for (bit = max; bit >= min; bit-=32, set_avma(av))
1563 : {
1564 : long e;
1565 2293 : GEN v = lindep_bit(vec, bit), z = gel(v,1);
1566 2293 : if (!signe(z)) continue;
1567 2174 : *++v = evaltyp(t_COL) | _evallg(lM); /* pop 1st elt */
1568 2174 : v = grndtoi(gdiv(v, z), &e);
1569 2174 : if (e > 0) break;
1570 2174 : if (TestOne(RgM_RgC_mul(M, v), d)) return v;
1571 : }
1572 : /* failure */
1573 412 : return RecCoeff3(nf,d,prec);
1574 : }
1575 :
1576 : /* Attempts to find a polynomial with coefficients in nf such that
1577 : its coefficients are close to those of pol at the place v and
1578 : less than a certain bound at all the other places. This bound is obtained by assuming
1579 : that the roots at the other places are, in absolute values, less than 2 if flag == 0,
1580 : and less than 1 if flag = 1. */
1581 : static GEN
1582 546 : RecCoeff(GEN nf, GEN pol, long v, long flag, long prec)
1583 : {
1584 546 : long j, md, cl = degpol(pol);
1585 546 : pari_sp av = avma;
1586 : RC_data d;
1587 :
1588 : /* if precision(pol) is too low, abort */
1589 3703 : for (j = 2; j <= cl+1; j++)
1590 : {
1591 3157 : GEN t = gel(pol, j);
1592 3157 : if (precision(t) - gexpo(t) < 34) return NULL;
1593 : }
1594 :
1595 546 : md = cl/2;
1596 546 : pol = leafcopy(pol);
1597 :
1598 546 : d.N = nf_get_degree(nf);
1599 546 : d.v = v;
1600 :
1601 2485 : for (j = 1; j <= cl; j++)
1602 : { /* start with the coefficients in the middle,
1603 : since they are the harder to recognize! */
1604 2156 : long cf = md + (j%2? j/2: -j/2);
1605 2156 : GEN t, bound = binomial(utoipos(cl), cf);
1606 :
1607 2156 : if (flag == 0) bound = shifti(bound, cl-cf);
1608 2156 : if (DEBUGLEVEL>1) err_printf("RecCoeff (cf = %ld, B = %Ps)\n", cf, bound);
1609 2156 : d.beta = real_i( gel(pol,cf+2) );
1610 2156 : d.B = bound;
1611 2156 : if (! (t = RecCoeff2(nf, &d, prec)) ) return NULL;
1612 1939 : gel(pol, cf+2) = coltoalg(nf,t);
1613 : }
1614 329 : gel(pol,cl+2) = gen_1;
1615 329 : return gc_GEN(av, pol);
1616 : }
1617 :
1618 : /* an[q * i] *= chi for all (i,p)=1 */
1619 : static void
1620 111303 : an_mul(int **an, long p, long q, long n, long deg, GEN chi, int **reduc)
1621 : {
1622 : pari_sp av;
1623 : long c,i;
1624 : int *T;
1625 :
1626 111303 : if (gequal1(chi)) return;
1627 102549 : av = avma;
1628 102549 : T = (int*)new_chunk(deg); Polmod2Coeff(T,chi, deg);
1629 2158588 : for (c = 1, i = q; i <= n; i += q, c++)
1630 2056039 : if (c == p) c = 0; else MulCoeff(an[i], T, reduc, deg);
1631 102549 : set_avma(av);
1632 : }
1633 : /* an[q * i] = 0 for all (i,p)=1 */
1634 : static void
1635 100787 : an_set0_coprime(int **an, long p, long q, long n, long deg)
1636 : {
1637 : long c,i;
1638 1215943 : for (c = 1, i = q; i <= n; i += q, c++)
1639 1115156 : if (c == p) c = 0; else _0toCoeff(an[i], deg);
1640 100787 : }
1641 : /* an[q * i] = 0 for all i */
1642 : static void
1643 105 : an_set0(int **an, long p, long n, long deg)
1644 : {
1645 : long i;
1646 60020 : for (i = p; i <= n; i += p) _0toCoeff(an[i], deg);
1647 105 : }
1648 :
1649 : /* compute the coefficients an for the quadratic case */
1650 : static int**
1651 735 : computean(GEN dtcr, LISTray *R, long n, long deg)
1652 : {
1653 735 : pari_sp av = avma, av2;
1654 : long i, p, q, condZ, l;
1655 : int **an, **reduc;
1656 : GEN L, chi, chi1;
1657 : CHI_t C;
1658 :
1659 735 : init_CHI_alg(&C, ch_CHI(dtcr));
1660 735 : condZ= R->condZ;
1661 :
1662 735 : an = InitMatAn(n, deg, 1);
1663 735 : reduc = InitReduction(C.ord, deg);
1664 735 : av2 = avma;
1665 :
1666 : /* all pr | p divide cond */
1667 735 : L = R->L0; l = lg(L);
1668 840 : for (i=1; i<l; i++) an_set0(an,L[i],n,deg);
1669 :
1670 : /* 1 prime of degree 2 */
1671 735 : L = R->L2; l = lg(L);
1672 100064 : for (i=1; i<l; i++, set_avma(av2))
1673 : {
1674 99329 : p = L[i];
1675 99329 : if (condZ == 1) chi = C.val[0]; /* 1 */
1676 99175 : else chi = CHI_eval(&C, gel(R->rayZ, p%condZ));
1677 99329 : chi1 = chi;
1678 99329 : for (q=p;;)
1679 : {
1680 100787 : an_set0_coprime(an, p,q,n,deg); /* v_p(q) odd */
1681 100787 : if (! (q = umuluu_le(q,p, n)) ) break;
1682 :
1683 4614 : an_mul(an,p,q,n,deg,chi,reduc);
1684 4614 : if (! (q = umuluu_le(q,p, n)) ) break;
1685 1458 : chi = gmul(chi, chi1);
1686 : }
1687 : }
1688 :
1689 : /* 1 prime of degree 1 */
1690 735 : L = R->L1; l = lg(L);
1691 2415 : for (i=1; i<l; i++, set_avma(av2))
1692 : {
1693 1680 : p = L[i];
1694 1680 : chi = CHI_eval(&C, gel(R->L1ray,i));
1695 1680 : chi1 = chi;
1696 1680 : for(q=p;;)
1697 : {
1698 7760 : an_mul(an,p,q,n,deg,chi,reduc);
1699 7760 : if (! (q = umuluu_le(q,p, n)) ) break;
1700 6080 : chi = gmul(chi, chi1);
1701 : }
1702 : }
1703 :
1704 : /* 2 primes of degree 1 */
1705 735 : L = R->L11; l = lg(L);
1706 92469 : for (i=1; i<l; i++, set_avma(av2))
1707 : {
1708 : GEN ray1, ray2, chi11, chi12, chi2;
1709 :
1710 91734 : p = L[i]; ray1 = gel(R->L11ray,i); /* use pr1 pr2 = (p) */
1711 91734 : if (condZ == 1)
1712 112 : ray2 = ZC_neg(ray1);
1713 : else
1714 91622 : ray2 = ZC_sub(gel(R->rayZ, p%condZ), ray1);
1715 91734 : chi11 = CHI_eval(&C, ray1);
1716 91734 : chi12 = CHI_eval(&C, ray2);
1717 :
1718 91734 : chi1 = gadd(chi11, chi12);
1719 91734 : chi2 = chi12;
1720 91734 : for(q=p;;)
1721 : {
1722 98929 : an_mul(an,p,q,n,deg,chi1,reduc);
1723 98929 : if (! (q = umuluu_le(q,p, n)) ) break;
1724 7195 : chi2 = gmul(chi2, chi12);
1725 7195 : chi1 = gadd(chi2, gmul(chi1, chi11));
1726 : }
1727 : }
1728 :
1729 735 : CorrectCoeff(dtcr, an, reduc, n, deg);
1730 735 : FreeMat(reduc, deg-1);
1731 735 : set_avma(av); return an;
1732 : }
1733 :
1734 : /* return the vector of A^i/i for i = 1...n */
1735 : static GEN
1736 231 : mpvecpowdiv(GEN A, long n)
1737 : {
1738 231 : pari_sp av = avma;
1739 : long i;
1740 231 : GEN v = powersr(A, n);
1741 231 : GEN w = cgetg(n+1, t_VEC);
1742 231 : gel(w,1) = rcopy(gel(v,2));
1743 368368 : for (i=2; i<=n; i++) gel(w,i) = divru(gel(v,i+1), i);
1744 231 : return gc_upto(av, w);
1745 : }
1746 :
1747 : static void GetST0(GEN bnr, GEN *pS, GEN *pT, GEN CR, long prec);
1748 : /* allocate memory for GetST answer */
1749 : static void
1750 427 : ST_alloc(GEN *pS, GEN *pT, long l, long prec)
1751 : {
1752 : long j;
1753 427 : *pS = cgetg(l, t_VEC);
1754 427 : *pT = cgetg(l, t_VEC);
1755 1932 : for (j = 1; j < l; j++)
1756 : {
1757 1505 : gel(*pS,j) = cgetc(prec);
1758 1505 : gel(*pT,j) = cgetc(prec);
1759 : }
1760 427 : }
1761 :
1762 : /* compute S and T for the quadratic case. The following cases are:
1763 : * 1) bnr complex;
1764 : * 2) bnr real and no infinite place divide cond_chi (TODO);
1765 : * 3) bnr real and one infinite place divide cond_chi;
1766 : * 4) bnr real and both infinite places divide cond_chi (TODO) */
1767 : static void
1768 238 : QuadGetST(GEN bnr, GEN *pS, GEN *pT, GEN CR, long prec)
1769 : {
1770 : pari_sp av, av1, av2;
1771 : long ncond, n, j, k, n0;
1772 238 : GEN vChar = gel(CR,1), dataCR = gel(CR,2), S, T, an, cs, N0, C;
1773 : LISTray LIST;
1774 :
1775 : /* initializations */
1776 238 : ST_alloc(pS, pT, lg(dataCR), prec); T = *pT; S = *pS;
1777 238 : av = avma;
1778 238 : ncond = lg(vChar)-1;
1779 238 : C = cgetg(ncond+1, t_VEC);
1780 238 : N0 = cgetg(ncond+1, t_VECSMALL);
1781 238 : cs = cgetg(ncond+1, t_VECSMALL);
1782 238 : n0 = 0;
1783 469 : for (j = 1; j <= ncond; j++)
1784 : {
1785 266 : GEN dtcr = gel(dataCR, mael(vChar,j,1)), c = ch_C(dtcr);
1786 : long r1, r2;
1787 :
1788 266 : gel(C,j) = c;
1789 266 : nf_get_sign(bnr_get_nf(ch_bnr(dtcr)), &r1, &r2);
1790 266 : if (r1 == 2) /* real quadratic */
1791 : {
1792 252 : cs[j] = 2 + ch_q(dtcr);
1793 252 : if (cs[j] == 2 || cs[j] == 4)
1794 : { /* NOT IMPLEMENTED YET */
1795 35 : GetST0(bnr, pS, pT, CR, prec);
1796 35 : return;
1797 : }
1798 : /* FIXME: is this value of N0 correct for the general case ? */
1799 217 : N0[j] = (long)prec * 0.35 * gtodouble(c);
1800 : }
1801 : else /* complex quadratic */
1802 : {
1803 14 : cs[j] = 1;
1804 14 : N0[j] = (long)prec * 0.7 * gtodouble(c);
1805 : }
1806 231 : if (n0 < N0[j]) n0 = N0[j];
1807 : }
1808 203 : if (DEBUGLEVEL>1) err_printf("N0 = %ld\n", n0);
1809 203 : InitPrimesQuad(bnr, n0, &LIST);
1810 :
1811 203 : av1 = avma;
1812 : /* loop over conductors */
1813 434 : for (j = 1; j <= ncond; j++)
1814 : {
1815 231 : GEN c0 = gel(C,j), c1 = divur(1, c0), c2 = divur(2, c0);
1816 231 : GEN ec1 = mpexp(c1), ec2 = mpexp(c2), LChar = gel(vChar,j);
1817 : GEN vf0, vf1, cf0, cf1;
1818 231 : const long nChar = lg(LChar)-1, NN = N0[j];
1819 :
1820 231 : if (DEBUGLEVEL>1)
1821 0 : err_printf("* conductor no %ld/%ld (N = %ld)\n\tInit: ", j,ncond,NN);
1822 231 : if (realprec(ec1) > prec) ec1 = rtor(ec1, prec);
1823 231 : if (realprec(ec2) > prec) ec2 = rtor(ec2, prec);
1824 231 : switch(cs[j])
1825 : {
1826 14 : case 1:
1827 14 : cf0 = gen_1;
1828 14 : cf1 = c0;
1829 14 : vf0 = mpveceint1(rtor(c1, prec), ec1, NN);
1830 14 : vf1 = mpvecpowdiv(invr(ec1), NN); break;
1831 :
1832 217 : case 3:
1833 217 : cf0 = sqrtr(mppi(prec));
1834 217 : cf1 = gmul2n(cf0, 1);
1835 217 : cf0 = gmul(cf0, c0);
1836 217 : vf0 = mpvecpowdiv(invr(ec2), NN);
1837 217 : vf1 = mpveceint1(rtor(c2, prec), ec2, NN); break;
1838 :
1839 0 : default:
1840 0 : cf0 = cf1 = NULL; /* FIXME: not implemented */
1841 0 : vf0 = vf1 = NULL;
1842 : }
1843 973 : for (k = 1; k <= nChar; k++)
1844 : {
1845 742 : long u = LChar[k], d, c;
1846 742 : GEN dtcr = gel(dataCR, u), z, s, t;
1847 : int **matan;
1848 :
1849 742 : if (!ch_comp(dtcr)) continue;
1850 735 : if (DEBUGLEVEL>1) err_printf("\tchar no: %ld (%ld/%ld)\n", u,k,nChar);
1851 735 : d = ch_phideg(dtcr);
1852 735 : z = gel(ch_CHI(dtcr), 2); s = t = gen_0; av2 = avma;
1853 735 : matan = computean(gel(dataCR,u), &LIST, NN, d);
1854 1255374 : for (n = 1, c = 0; n <= NN; n++)
1855 1254639 : if ((an = EvalCoeff(z, matan[n], d)))
1856 : {
1857 330118 : s = gadd(s, gmul(an, gel(vf0,n)));
1858 330118 : t = gadd(t, gmul(an, gel(vf1,n)));
1859 330118 : if (++c == 256) { (void)gc_all(av2,2, &s,&t); c = 0; }
1860 : }
1861 735 : affgc(gmul(cf0, s), gel(S,u));
1862 735 : affgc(gmul(cf1, conj_i(t)), gel(T,u));
1863 735 : FreeMat(matan,NN); set_avma(av2);
1864 : }
1865 231 : if (DEBUGLEVEL>1) err_printf("\n");
1866 231 : set_avma(av1);
1867 : }
1868 203 : set_avma(av);
1869 : }
1870 :
1871 : /* s += t*u. All 3 of them t_REAL, except we allow s or u = NULL (for 0) */
1872 : static GEN
1873 51886310 : _addmulrr(GEN s, GEN t, GEN u)
1874 : {
1875 51886310 : if (u)
1876 : {
1877 51618378 : GEN v = mulrr(t, u);
1878 51618378 : return s? addrr(s, v): v;
1879 : }
1880 267932 : return s;
1881 : }
1882 : /* s += t. Both real, except we allow s or t = NULL (for exact 0) */
1883 : static GEN
1884 105518127 : _addrr(GEN s, GEN t)
1885 105518127 : { return t? (s? addrr(s, t): t) : s; }
1886 :
1887 : /* S & T for the general case. This is time-critical: optimize */
1888 : static void
1889 521409 : get_cS_cT(ST_t *T, long n)
1890 : {
1891 : pari_sp av;
1892 : GEN csurn, nsurc, lncsurn, A, B, s, t, Z, aij, bij;
1893 : long i, j, r, i0;
1894 :
1895 521409 : if (gel(T->cS,n)) return;
1896 :
1897 244167 : av = avma;
1898 244167 : aij = T->aij; i0= T->i0;
1899 244167 : bij = T->bij; r = T->r;
1900 244167 : Z = cgetg(r+1, t_VEC);
1901 244167 : gel(Z,1) = NULL; /* unused */
1902 :
1903 244167 : csurn = divru(T->c1, n);
1904 244167 : nsurc = invr(csurn);
1905 244167 : lncsurn = logr_abs(csurn);
1906 :
1907 244167 : if (r > 1)
1908 : {
1909 243992 : gel(Z,2) = lncsurn; /* r >= 2 */
1910 248087 : for (i = 3; i <= r; i++)
1911 4095 : gel(Z,i) = divru(mulrr(gel(Z,i-1), lncsurn), i-1);
1912 : /* Z[i] = ln^(i-1)(c1/n) / (i-1)! */
1913 : }
1914 :
1915 : /* i = i0 */
1916 244167 : A = gel(aij,i0); t = _addrr(NULL, gel(A,1));
1917 244167 : B = gel(bij,i0); s = _addrr(NULL, gel(B,1));
1918 492254 : for (j = 2; j <= r; j++)
1919 : {
1920 248087 : s = _addmulrr(s, gel(Z,j),gel(B,j));
1921 248087 : t = _addmulrr(t, gel(Z,j),gel(A,j));
1922 : }
1923 52392813 : for (i = i0 - 1; i > 1; i--)
1924 : {
1925 52148646 : A = gel(aij,i); if (t) t = mulrr(t, nsurc);
1926 52148646 : B = gel(bij,i); if (s) s = mulrr(s, nsurc);
1927 77595627 : for (j = odd(i)? T->rc2: T->rc1; j > 1; j--)
1928 : {
1929 25446981 : s = _addmulrr(s, gel(Z,j),gel(B,j));
1930 25446981 : t = _addmulrr(t, gel(Z,j),gel(A,j));
1931 : }
1932 52148646 : s = _addrr(s, gel(B,1));
1933 52148646 : t = _addrr(t, gel(A,1));
1934 : }
1935 : /* i = 1 */
1936 244167 : A = gel(aij,1); if (t) t = mulrr(t, nsurc);
1937 244167 : B = gel(bij,1); if (s) s = mulrr(s, nsurc);
1938 244167 : s = _addrr(s, gel(B,1));
1939 244167 : t = _addrr(t, gel(A,1));
1940 492254 : for (j = 2; j <= r; j++)
1941 : {
1942 248087 : s = _addmulrr(s, gel(Z,j),gel(B,j));
1943 248087 : t = _addmulrr(t, gel(Z,j),gel(A,j));
1944 : }
1945 244167 : s = _addrr(s, T->b? mulrr(csurn, gel(T->powracpi,T->b+1)): csurn);
1946 244167 : if (!s) s = gen_0;
1947 244167 : if (!t) t = gen_0;
1948 244167 : gel(T->cS,n) = gclone(s);
1949 244167 : gel(T->cT,n) = gclone(t); set_avma(av);
1950 : }
1951 :
1952 : static void
1953 497 : clear_cScT(ST_t *T, long N)
1954 : {
1955 497 : GEN cS = T->cS, cT = T->cT;
1956 : long i;
1957 1643058 : for (i=1; i<=N; i++)
1958 1642561 : if (cS[i]) {
1959 244167 : gunclone(gel(cS,i));
1960 244167 : gunclone(gel(cT,i)); gel(cS,i) = gel(cT,i) = NULL;
1961 : }
1962 497 : }
1963 :
1964 : static void
1965 308 : init_cScT(ST_t *T, GEN dtcr, long N, long prec)
1966 : {
1967 308 : ch_get3(dtcr, &T->a, &T->b, &T->c);
1968 308 : T->rc1 = T->a + T->c;
1969 308 : T->rc2 = T->b + T->c;
1970 308 : T->r = maxss(T->rc2+1, T->rc1); /* >= 2 */
1971 308 : ppgamma(T, prec);
1972 308 : clear_cScT(T, N);
1973 308 : }
1974 :
1975 : /* return a t_REAL */
1976 : static GEN
1977 518 : zeta_get_limx(long r1, long r2, long bit)
1978 : {
1979 518 : pari_sp av = avma;
1980 : GEN p1, p2, c0, c1, A0;
1981 518 : long r = r1 + r2, N = r + r2;
1982 :
1983 : /* c1 = N 2^(-2r2 / N) */
1984 518 : c1 = mulrs(powrfrac(real2n(1, DEFAULTPREC), -2*r2, N), N);
1985 :
1986 518 : p1 = powru(Pi2n(1, DEFAULTPREC), r - 1);
1987 518 : p2 = mulir(powuu(N,r), p1); shiftr_inplace(p2, -r2);
1988 518 : c0 = sqrtr( divrr(p2, powru(c1, r+1)) );
1989 :
1990 518 : A0 = logr_abs( gmul2n(c0, bit) ); p2 = divrr(A0, c1);
1991 518 : p1 = divrr(mulur(N*(r+1), logr_abs(p2)), addsr(2*(r+1), gmul2n(A0,2)));
1992 518 : return gc_uptoleaf(av, divrr(addrs(p1, 1), powruhalf(p2, N)));
1993 : }
1994 : /* N_0 = floor( C_K / limx ). Large */
1995 : static long
1996 637 : zeta_get_N0(GEN C, GEN limx)
1997 : {
1998 : long e;
1999 637 : pari_sp av = avma;
2000 637 : GEN z = gcvtoi(gdiv(C, limx), &e); /* avoid truncation error */
2001 637 : if (e >= 0 || is_bigint(z))
2002 0 : pari_err_OVERFLOW("zeta_get_N0 [need too many primes]");
2003 637 : return gc_long(av, itos(z));
2004 : }
2005 :
2006 : static GEN
2007 1897 : eval_i(long r1, long r2, GEN limx, long i)
2008 : {
2009 1897 : GEN t = powru(limx, i);
2010 1897 : if (!r1) t = mulrr(t, powru(mpfactr(i , DEFAULTPREC), r2));
2011 1897 : else if (!r2) t = mulrr(t, powru(mpfactr(i/2, DEFAULTPREC), r1));
2012 : else {
2013 0 : GEN u1 = mpfactr(i/2, DEFAULTPREC);
2014 0 : GEN u2 = mpfactr(i, DEFAULTPREC);
2015 0 : if (r1 == r2) t = mulrr(t, powru(mulrr(u1,u2), r1));
2016 0 : else t = mulrr(t, mulrr(powru(u1,r1), powru(u2,r2)));
2017 : }
2018 1897 : return t;
2019 : }
2020 :
2021 : /* "small" even i such that limx^i ( (i\2)! )^r1 ( i! )^r2 > B. */
2022 : static long
2023 189 : get_i0(long r1, long r2, GEN B, GEN limx)
2024 : {
2025 189 : long imin = 1, imax = 1400;
2026 196 : while (mpcmp(eval_i(r1,r2,limx, imax), B) < 0) { imin = imax; imax *= 2; }
2027 1890 : while(imax - imin >= 4)
2028 : {
2029 1701 : long m = (imax + imin) >> 1;
2030 1701 : if (mpcmp(eval_i(r1,r2,limx, m), B) >= 0) imax = m; else imin = m;
2031 : }
2032 189 : return imax & ~1; /* make it even */
2033 : }
2034 : /* limx = zeta_get_limx(r1, r2, bit), a t_REAL */
2035 : static long
2036 189 : zeta_get_i0(long r1, long r2, long bit, GEN limx)
2037 : {
2038 189 : pari_sp av = avma;
2039 189 : GEN B = gmul(sqrtr( divrr(powrs(mppi(DEFAULTPREC), r2-3), limx) ),
2040 : gmul2n(powuu(5, r1), bit + r2));
2041 189 : return gc_long(av, get_i0(r1, r2, B, limx));
2042 : }
2043 :
2044 : static void
2045 189 : GetST0(GEN bnr, GEN *pS, GEN *pT, GEN CR, long prec)
2046 : {
2047 : pari_sp av, av1, av2;
2048 : long n, j, k, jc, n0, prec2, i0, r1, r2, ncond;
2049 189 : GEN nf = bnr_get_nf(bnr);
2050 189 : GEN vChar = gel(CR,1), dataCR = gel(CR,2), N0, C, an, limx, S, T;
2051 : LISTray LIST;
2052 : ST_t cScT;
2053 :
2054 189 : ST_alloc(pS, pT, lg(dataCR), prec); T = *pT; S = *pS;
2055 189 : av = avma;
2056 189 : nf_get_sign(nf,&r1,&r2);
2057 189 : ncond = lg(vChar)-1;
2058 189 : C = cgetg(ncond+1, t_VEC);
2059 189 : N0 = cgetg(ncond+1, t_VECSMALL);
2060 189 : n0 = 0;
2061 189 : limx = zeta_get_limx(r1, r2, prec);
2062 497 : for (j = 1; j <= ncond; j++)
2063 : {
2064 308 : GEN dtcr = gel(dataCR, mael(vChar,j,1)), c = ch_C(dtcr);
2065 308 : gel(C,j) = c;
2066 308 : N0[j] = zeta_get_N0(c, limx);
2067 308 : if (n0 < N0[j]) n0 = N0[j];
2068 : }
2069 189 : cScT.i0 = i0 = zeta_get_i0(r1, r2, prec, limx);
2070 189 : if (DEBUGLEVEL>1) err_printf("i0 = %ld, N0 = %ld\n",i0, n0);
2071 189 : InitPrimes(bnr, n0, &LIST);
2072 189 : prec2 = precdbl(prec) + EXTRAPREC64;
2073 189 : cScT.powracpi = powersr(sqrtr(mppi(prec2)), r1);
2074 189 : cScT.cS = cgetg(n0+1, t_VEC);
2075 189 : cScT.cT = cgetg(n0+1, t_VEC);
2076 794107 : for (j=1; j<=n0; j++) gel(cScT.cS,j) = gel(cScT.cT,j) = NULL;
2077 :
2078 189 : av1 = avma;
2079 497 : for (jc = 1; jc <= ncond; jc++)
2080 : {
2081 308 : GEN LChar = gel(vChar,jc);
2082 308 : long nChar = lg(LChar)-1, N = N0[jc];
2083 :
2084 : /* Can discard completely a conductor if all chars satisfy L(0,chi) = 0
2085 : * Not sure whether this is possible. */
2086 308 : if (DEBUGLEVEL>1)
2087 0 : err_printf("* conductor no %ld/%ld (N = %ld)\n\tInit: ", jc,ncond,N);
2088 :
2089 308 : cScT.c1 = gel(C,jc);
2090 308 : init_cScT(&cScT, gel(dataCR, LChar[1]), N, prec2);
2091 308 : av2 = avma;
2092 875 : for (k = 1; k <= nChar; k++)
2093 : {
2094 567 : long d, c, u = LChar[k];
2095 567 : GEN dtcr = gel(dataCR, u), z, s, t;
2096 : int **matan;
2097 :
2098 567 : if (!ch_comp(dtcr)) continue;
2099 560 : if (DEBUGLEVEL>1) err_printf("\tchar no: %ld (%ld/%ld)\n", u,k,nChar);
2100 560 : z = gel(ch_CHI(dtcr), 2);
2101 560 : d = ch_phideg(dtcr); s = t = gen_0;
2102 560 : matan = ComputeCoeff(dtcr, &LIST, N, d);
2103 2094167 : for (n = 1, c = 0; n <= N; n++)
2104 2093607 : if ((an = EvalCoeff(z, matan[n], d)))
2105 : {
2106 521409 : get_cS_cT(&cScT, n);
2107 521409 : s = gadd(s, gmul(an, gel(cScT.cS,n)));
2108 521409 : t = gadd(t, gmul(an, gel(cScT.cT,n)));
2109 521409 : if (++c == 256) { (void)gc_all(av2,2, &s,&t); c = 0; }
2110 : }
2111 560 : affgc(s, gel(S,u));
2112 560 : affgc(conj_i(t), gel(T,u));
2113 560 : FreeMat(matan, N); set_avma(av2);
2114 : }
2115 308 : if (DEBUGLEVEL>1) err_printf("\n");
2116 308 : set_avma(av1);
2117 : }
2118 189 : clear_cScT(&cScT, n0);
2119 189 : set_avma(av);
2120 189 : }
2121 :
2122 : static void
2123 392 : GetST(GEN bnr, GEN *pS, GEN *pT, GEN CR, long prec)
2124 : {
2125 392 : if (nf_get_degree(bnr_get_nf(bnr)) == 2)
2126 238 : QuadGetST(bnr, pS, pT, CR, prec);
2127 : else
2128 154 : GetST0(bnr, pS, pT, CR, prec);
2129 392 : }
2130 :
2131 : /*******************************************************************/
2132 : /* */
2133 : /* Class fields of real quadratic fields using Stark units */
2134 : /* */
2135 : /*******************************************************************/
2136 : /* compute the Hilbert class field using genus class field theory when
2137 : the exponent of the class group is exactly 2 (trivial group not covered) */
2138 : /* Cf Herz, Construction of class fields, LNM 21, Theorem 1 (VII-6) */
2139 : static GEN
2140 14 : GenusFieldQuadReal(GEN disc)
2141 : {
2142 14 : GEN T = NULL, p0 = NULL, P = gel(Z_factor(disc), 1);
2143 14 : long i, i0 = 0, l = lg(P);
2144 :
2145 42 : for (i = 1; i < l; i++)
2146 : {
2147 35 : GEN p = gel(P,i);
2148 35 : if (mod4(p) == 3) { p0 = p; i0 = i; break; }
2149 : }
2150 14 : l--; /* remove last prime */
2151 14 : if (i0 == l) l--; /* ... remove p0 and last prime */
2152 49 : for (i = 1; i < l; i++)
2153 : {
2154 35 : GEN p = gel(P,i), d, t;
2155 35 : if (i == i0) continue;
2156 28 : if (absequaliu(p, 2))
2157 14 : switch (mod32(disc))
2158 : {
2159 14 : case 8: d = gen_2; break;
2160 0 : case 24: d = shifti(p0, 1); break;
2161 0 : default: d = p0; break;
2162 : }
2163 : else
2164 14 : d = (mod4(p) == 1)? p: mulii(p0, p);
2165 28 : t = mkpoln(3, gen_1, gen_0, negi(d)); /* x^2 - d */
2166 28 : T = T? ZX_composedsum(T, t): t;
2167 : }
2168 14 : return polredbest(T, 0);
2169 : }
2170 : static GEN
2171 406 : GenusFieldQuadImag(GEN disc)
2172 : {
2173 406 : GEN T = NULL, P = gel(absZ_factor(disc), 1);
2174 406 : long i, n = lg(P)-1;
2175 1183 : for (i = 1; i < n; i++) /* remove last prime */
2176 : {
2177 777 : GEN p = gel(P,i), d, t;
2178 777 : if (absequaliu(p, 2))
2179 231 : switch (mod32(disc))
2180 : {
2181 56 : case 24: d = gen_2; break; /* disc = 8 mod 32 */
2182 42 : case 8: d = gen_m2; break; /* disc =-8 mod 32 */
2183 133 : default: d = gen_m1; break;
2184 : }
2185 : else
2186 546 : d = (mod4(p) == 1)? p: negi(p);
2187 777 : t = mkpoln(3, gen_1, gen_0, negi(d)); /* x^2 - d */
2188 777 : T = T? ZX_composedsum(T, t): t;
2189 : }
2190 406 : return polredbest(T, 0);
2191 : }
2192 :
2193 : /* if flag = 1, computes a fast and crude approximation of the trace of the Stark unit
2194 : if flag = 2, computes the Stark unit */
2195 : static GEN
2196 658 : AllStark(GEN data, long flag, long newprec)
2197 : {
2198 658 : const long BND = 300;
2199 658 : long cl, i, j, cpt = 0, N, h, v, n, r1, r2, den;
2200 : pari_sp av, av2;
2201 : int **matan;
2202 658 : GEN bnr = gel(data,1), nf = bnr_get_nf(bnr), p1, p2, S, T;
2203 658 : GEN CR = gel(data,4), dataCR = gel(CR,2);
2204 : GEN polrelnum, polrel, Lp, W, vzeta, C, cond1, L1, an;
2205 : LISTray LIST;
2206 : pari_timer ti;
2207 :
2208 658 : nf_get_sign(nf, &r1,&r2);
2209 658 : N = nf_get_degree(nf);
2210 658 : cond1 = gel(bnr_get_mod(bnr), 2);
2211 :
2212 658 : v = 1;
2213 1372 : while (gequal1(gel(cond1,v))) v++;
2214 658 : cl = lg(dataCR)-1;
2215 658 : h = itos(ZM_det_triangular(gel(data,2))) >> 1;
2216 :
2217 658 : LABDOUB:
2218 658 : if (DEBUGLEVEL) timer_start(&ti);
2219 658 : av = avma;
2220 658 : W = AllArtinNumbers(CR, newprec);
2221 658 : if (DEBUGLEVEL) timer_printf(&ti,"Compute W");
2222 658 : Lp = cgetg(cl + 1, t_VEC);
2223 658 : if (flag != 1)
2224 : {
2225 329 : GetST(bnr, &S, &T, CR, newprec);
2226 329 : if (DEBUGLEVEL) timer_printf(&ti, "S&T");
2227 1400 : for (i = 1; i <= cl; i++)
2228 : {
2229 1071 : GEN chi = gel(dataCR, i), vv = gen_0;
2230 1071 : if (ch_comp(chi))
2231 1057 : vv = gel(GetValue(chi, gel(W,i), gel(S,i), gel(T,i), 2, newprec), 2);
2232 1071 : gel(Lp, i) = vv;
2233 : }
2234 : }
2235 : else
2236 : { /* compute a crude approximation of the result */
2237 329 : C = cgetg(cl + 1, t_VEC);
2238 1400 : for (i = 1; i <= cl; i++) gel(C,i) = ch_C(gel(dataCR, i));
2239 329 : n = zeta_get_N0(vecmax(C), zeta_get_limx(r1, r2, newprec));
2240 329 : if (n > BND) n = BND;
2241 329 : if (DEBUGLEVEL) err_printf("N0 in QuickPol: %ld \n", n);
2242 329 : InitPrimes(bnr, n, &LIST);
2243 :
2244 329 : L1 = cgetg(cl+1, t_VEC);
2245 : /* use L(1) = sum (an / n) */
2246 1400 : for (i = 1; i <= cl; i++)
2247 : {
2248 1071 : GEN dtcr = gel(dataCR,i);
2249 1071 : long d = ch_phideg(dtcr);
2250 1071 : matan = ComputeCoeff(dtcr, &LIST, n, d);
2251 1071 : av2 = avma;
2252 1071 : p1 = real_0(newprec); p2 = gel(ch_CHI(dtcr), 2);
2253 313999 : for (j = 1; j <= n; j++)
2254 312928 : if ( (an = EvalCoeff(p2, matan[j], d)) )
2255 120176 : p1 = gadd(p1, gdivgu(an, j));
2256 1071 : gel(L1,i) = gc_upto(av2, p1);
2257 1071 : FreeMat(matan, n);
2258 : }
2259 329 : p1 = gmul2n(powruhalf(mppi(newprec), N-2), 1);
2260 :
2261 1400 : for (i = 1; i <= cl; i++)
2262 : {
2263 : long r;
2264 1071 : GEN WW, A = AChi(gel(dataCR,i), &r, 0, newprec);
2265 1071 : WW = gmul(gel(C,i), gmul(A, gel(W,i)));
2266 1071 : gel(Lp,i) = gdiv(gmul(WW, conj_i(gel(L1,i))), p1);
2267 : }
2268 : }
2269 :
2270 658 : p1 = gel(data,3);
2271 658 : den = (flag == 0) ? 2*h: h;
2272 658 : if (flag == 2)
2273 7 : vzeta = cgetg(2*h + 1, t_VEC);
2274 : else
2275 651 : vzeta = cgetg(h + 1,t_VEC);
2276 4228 : for (i = 1; i <= h; i++)
2277 : {
2278 3570 : GEN z = gen_0, sig = gel(p1,i);
2279 18172 : for (j = 1; j <= cl; j++)
2280 : {
2281 14602 : GEN dtcr = gel(dataCR,j), CHI = ch_CHI(dtcr);
2282 14602 : GEN t = mulreal(gel(Lp,j), CharEval(CHI, sig));
2283 14602 : if (chi_get_deg(CHI) != 2) t = gmul2n(t, 1); /* character not real */
2284 14602 : z = gadd(z, t);
2285 : }
2286 3570 : z = gdivgu(z, den);
2287 3570 : if (flag == 2)
2288 : {
2289 77 : gel(vzeta, i) = gexp(gmul2n(z,1), newprec);
2290 77 : gel(vzeta, i+h) = ginv(gel(vzeta,i));
2291 : }
2292 : /* if flag == 0, we first try with the square-root of the Stark unit */
2293 3493 : else gel(vzeta,i) = gmul2n(gcosh(z, newprec), 1);
2294 : }
2295 658 : polrelnum = roots_to_pol(vzeta, 0);
2296 658 : if (DEBUGLEVEL)
2297 : {
2298 0 : if (DEBUGLEVEL>1) {
2299 0 : err_printf("polrelnum = %Ps\n", polrelnum);
2300 0 : err_printf("zetavalues = %Ps\n", vzeta);
2301 0 : if (flag == 0)
2302 0 : err_printf("Checking the square-root of the Stark unit...\n");
2303 : }
2304 0 : timer_printf(&ti, "Compute %s", flag? "quickpol": "polrelnum");
2305 : }
2306 658 : if (flag == 1) return gc_GEN(av, polrelnum);
2307 : /* try to recognize this polynomial */
2308 329 : polrel = RecCoeff(nf, polrelnum, v, flag, newprec);
2309 :
2310 : /* if this doesn't work, maybe the Stark unit is not a square */
2311 329 : if (!polrel && flag == 0)
2312 : {
2313 217 : if (DEBUGLEVEL)
2314 : {
2315 0 : if (DEBUGLEVEL>1) {
2316 0 : err_printf("It's not a square...\n");
2317 0 : err_printf("polrelnum = %Ps\n", polrelnum);
2318 : }
2319 0 : timer_printf(&ti, "Compute polrelnum");
2320 : }
2321 1512 : for (j = 1; j <= h; j++)
2322 1295 : gel(vzeta,j) = gsubgs(gsqr(gel(vzeta,j)), 2);
2323 217 : polrelnum = roots_to_pol(vzeta, 0);
2324 :
2325 217 : polrel = RecCoeff(nf, polrelnum, v, 0, newprec);
2326 : }
2327 329 : if (!polrel) /* FAILED */
2328 : {
2329 0 : const long EXTRA_BITS = 64;
2330 : long incr_pr;
2331 0 : if (++cpt >= 3) pari_err_PREC( "stark (computation impossible)");
2332 : /* estimate needed precision */
2333 0 : incr_pr = gprecision(polrelnum) - gexpo(polrelnum);
2334 0 : if (incr_pr < 0) incr_pr = -incr_pr + EXTRA_BITS;
2335 0 : newprec += nbits2extraprec(maxss(3*EXTRA_BITS, cpt*incr_pr));
2336 0 : if (DEBUGLEVEL) pari_warn(warnprec, "AllStark", newprec);
2337 0 : CharNewPrec(data, newprec);
2338 0 : nf = bnr_get_nf(ch_bnr(gel(dataCR,1)));
2339 0 : goto LABDOUB;
2340 : }
2341 :
2342 329 : if (DEBUGLEVEL) {
2343 0 : if (DEBUGLEVEL>1) err_printf("polrel = %Ps\n", polrel);
2344 0 : timer_printf(&ti, "Recpolnum");
2345 : }
2346 329 : return gc_GEN(av, polrel);
2347 : }
2348 :
2349 : /********************************************************************/
2350 : /* Main functions */
2351 : /********************************************************************/
2352 : static GEN
2353 0 : bnrstark_cyclic(GEN bnr, GEN dtQ, long prec)
2354 : {
2355 0 : GEN v, vH, cyc = gel(dtQ,2), U = gel(dtQ,3), M = ZM_inv(U, NULL);
2356 0 : long i, j, l = lg(M);
2357 :
2358 : /* M = indep. generators of Cl_f/subgp, restrict to cyclic components */
2359 0 : vH = cgetg(l, t_VEC);
2360 0 : for (i = j = 1; i < l; i++)
2361 : {
2362 0 : if (is_pm1(gel(cyc,i))) break;
2363 0 : gel(vH, j++) = ZM_hnfmodid(vecsplice(M,i), cyc);
2364 : }
2365 0 : setlg(vH, j); v = cgetg(l, t_VEC);
2366 0 : for (i = 1; i < j; i++) gel(v,i) = bnrstark(bnr, gel(vH,i), prec);
2367 0 : return v;
2368 : }
2369 : GEN
2370 203 : bnrstark(GEN bnr, GEN subgrp, long prec)
2371 : {
2372 : long newprec;
2373 203 : pari_sp av = avma;
2374 : GEN nf, data, dtQ;
2375 :
2376 : /* check the bnr */
2377 203 : checkbnr(bnr); nf = bnr_get_nf(bnr);
2378 203 : if (nf_get_degree(nf) == 1) return galoissubcyclo(bnr, subgrp, 0, 0);
2379 203 : if (!nf_get_varn(nf))
2380 0 : pari_err_PRIORITY("bnrstark", nf_get_pol(nf), "=", 0);
2381 203 : if (nf_get_r2(nf)) pari_err_DOMAIN("bnrstark", "r2", "!=", gen_0, nf);
2382 :
2383 : /* compute bnr(conductor) */
2384 196 : bnr_subgroup_sanitize(&bnr, &subgrp);
2385 196 : if (gequal1(ZM_det_triangular(subgrp))) { set_avma(av); return pol_x(0); }
2386 :
2387 : /* check the class field */
2388 196 : if (!gequal0(gel(bnr_get_mod(bnr), 2)))
2389 7 : pari_err_DOMAIN("bnrstark", "r2(class field)", "!=", gen_0, bnr);
2390 :
2391 : /* find a suitable extension N */
2392 189 : dtQ = InitQuotient(subgrp);
2393 189 : data = FindModulus(bnr, dtQ, &newprec);
2394 189 : if (!data) return gc_upto(av, bnrstark_cyclic(bnr, dtQ, prec));
2395 189 : if (DEBUGLEVEL>1 && newprec > prec)
2396 0 : err_printf("new precision: %ld\n", newprec);
2397 189 : return gc_upto(av, AllStark(data, 0, newprec));
2398 : }
2399 :
2400 : GEN
2401 14 : bnrstarkunit(GEN bnr, GEN subgrp)
2402 : {
2403 : long newprec, deg;
2404 14 : pari_sp av = avma;
2405 : GEN nf, data, dtQ, bnf, bnrf, Cm, candD, D, QD, CR;
2406 :
2407 : /* check the input */
2408 14 : checkbnr(bnr); bnf = bnr_get_bnf(bnr); nf = bnf_get_nf(bnf);
2409 14 : if (!nf_get_varn(nf))
2410 0 : pari_err_PRIORITY("bnrstarkunit", nf_get_pol(nf), "=", 0);
2411 14 : deg = nf_get_degree(nf);
2412 14 : if (deg == 1) pari_err_IMPL("bnrstarkunit for basefield Q");
2413 14 : if (nf_get_r2(nf)) pari_err_DOMAIN("bnrstarkunit", "r2", "!=", gen_0, nf);
2414 14 : bnr_subgroup_sanitize(&bnr, &subgrp);
2415 14 : if (lg(bid_get_archp(bnr_get_bid(bnr)))-1 != deg-1)
2416 7 : pari_err_DOMAIN("bnrstarkunit", "# unramified places", "!=", gen_1, bnr);
2417 7 : bnrf = Buchray(bnf, gel(bnr_get_mod(bnr), 1), nf_INIT);
2418 7 : subgrp = abmap_subgroup_image(bnrsurjection(bnr, bnrf), subgrp);
2419 7 : dtQ = InitQuotient(subgrp);
2420 7 : Cm = ComputeKernel(bnr, bnrf, dtQ);
2421 7 : candD = subgrouplist_cond_sub(bnr, Cm, mkvec(gen_2));
2422 7 : if (lg(candD) != 2) pari_err(e_MISC, "incorrect modulus in bnrstark");
2423 7 : D = gel(candD, 1);
2424 7 : QD = InitQuotient(D);
2425 7 : CR = InitChar(bnr, AllChars(bnr, QD, 1), 0, DEFAULTPREC);
2426 7 : data = mkvec4(bnr, D, subgroup_classes(Cm), CR);
2427 7 : CplxModulus(data, &newprec);
2428 7 : return gc_upto(av, AllStark(data, 2, newprec));
2429 : }
2430 :
2431 : /* For each character of Cl(bnr)/subgp, compute L(1, chi) (or equivalently
2432 : * the first nonzero term c(chi) of the expansion at s = 0).
2433 : * If flag & 1: compute the value at s = 1 (for nontrivial characters),
2434 : * else compute the term c(chi) and return [r(chi), c(chi)] where r(chi) is
2435 : * the order of L(s, chi) at s = 0.
2436 : * If flag & 2: compute the value of the L-function L_S(s, chi) where S is the
2437 : * set of places dividing the modulus of bnr (and the infinite places),
2438 : * else
2439 : * compute the value of the primitive L-function attached to chi,
2440 : * If flag & 4: return also the character */
2441 : GEN
2442 70 : bnrL1(GEN bnr, GEN subgp, long flag, long prec)
2443 : {
2444 : GEN L1, ch, Qt, z;
2445 : long l, h;
2446 70 : pari_sp av = avma;
2447 :
2448 70 : checkbnr(bnr);
2449 70 : if (flag < 0 || flag > 8) pari_err_FLAG("bnrL1");
2450 :
2451 70 : subgp = bnr_subgroup_check(bnr, subgp, NULL);
2452 70 : if (!subgp) subgp = diagonal_shallow(bnr_get_cyc(bnr));
2453 :
2454 70 : Qt = InitQuotient(subgp);
2455 70 : ch = AllChars(bnr, Qt, 0); l = lg(ch);
2456 70 : h = itou(gel(Qt,1));
2457 70 : L1 = cgetg((flag&1)? h: h+1, t_VEC);
2458 70 : if (l > 1)
2459 : {
2460 63 : GEN W, S, T, CR = InitChar(bnr, ch, 1, prec), dataCR = gel(CR,2);
2461 : long i, j;
2462 :
2463 63 : GetST(bnr, &S, &T, CR, prec);
2464 63 : W = AllArtinNumbers(CR, prec);
2465 301 : for (i = j = 1; i < l; i++)
2466 : {
2467 238 : GEN chi = gel(ch,i);
2468 238 : z = GetValue(gel(dataCR,i), gel(W,i), gel(S,i), gel(T,i), flag, prec);
2469 238 : gel(L1,j++) = (flag & 4)? mkvec2(gel(chi,1), z): z;
2470 238 : if (lg(chi) == 4)
2471 : { /* nonreal */
2472 133 : z = conj_i(z);
2473 133 : gel(L1, j++) = (flag & 4)? mkvec2(gel(chi,3), z): z;
2474 : }
2475 : }
2476 : }
2477 70 : if (!(flag & 1))
2478 : { /* trivial character */
2479 35 : z = GetValue1(bnr, flag & 2, prec);
2480 35 : if (flag & 4)
2481 : {
2482 0 : GEN chi = zerovec(lg(bnr_get_cyc(bnr))-1);
2483 0 : z = mkvec2(chi, z);
2484 : }
2485 35 : gel(L1,h) = z;
2486 : }
2487 70 : return gc_GEN(av, L1);
2488 : }
2489 :
2490 : /*******************************************************************/
2491 : /* */
2492 : /* Hilbert and Ray Class field using Stark */
2493 : /* */
2494 : /*******************************************************************/
2495 : /* P in A[x,y], deg_y P < 2, return P0 and P1 in A[x] such that P = P0 + P1 y */
2496 : static void
2497 133 : split_pol_quad(GEN P, GEN *gP0, GEN *gP1)
2498 : {
2499 133 : long i, l = lg(P);
2500 133 : GEN P0 = cgetg(l, t_POL), P1 = cgetg(l, t_POL);
2501 133 : P0[1] = P1[1] = P[1];
2502 1211 : for (i = 2; i < l; i++)
2503 : {
2504 1078 : GEN c = gel(P,i), c0 = c, c1 = gen_0;
2505 1078 : if (typ(c) == t_POL) /* write c = c1 y + c0 */
2506 945 : switch(degpol(c))
2507 : {
2508 0 : case -1: c0 = gen_0; break;
2509 945 : default: c1 = gel(c,3); /* fall through */
2510 945 : case 0: c0 = gel(c,2); break;
2511 : }
2512 1078 : gel(P0,i) = c0; gel(P1,i) = c1;
2513 : }
2514 133 : *gP0 = normalizepol_lg(P0, l);
2515 133 : *gP1 = normalizepol_lg(P1, l);
2516 133 : }
2517 :
2518 : /* k = nf quadratic field, P relative equation of H_k (Hilbert class field)
2519 : * return T in Z[X], such that H_k / Q is the compositum of Q[X]/(T) and k */
2520 : static GEN
2521 133 : makescind(GEN nf, GEN P)
2522 : {
2523 133 : GEN Pp, p, pol, G, L, a, roo, P0,P1, Ny,Try, nfpol = nf_get_pol(nf);
2524 : long i, is_P;
2525 :
2526 133 : P = lift_shallow(P);
2527 133 : split_pol_quad(P, &P0, &P1);
2528 : /* P = P0 + y P1, Norm_{k/Q}(P) = P0^2 + Tr y P0P1 + Ny P1^2, irreducible/Q */
2529 133 : Ny = gel(nfpol, 2);
2530 133 : Try = negi(gel(nfpol, 3));
2531 133 : pol = RgX_add(RgX_sqr(P0), RgX_Rg_mul(RgX_sqr(P1), Ny));
2532 133 : if (signe(Try)) pol = RgX_add(pol, RgX_Rg_mul(RgX_mul(P0,P1), Try));
2533 : /* pol = rnfequation(nf, P); */
2534 133 : G = galoisinit(pol, NULL);
2535 133 : L = gal_get_group(G);
2536 133 : p = gal_get_p(G);
2537 133 : a = FpX_oneroot(nfpol, p);
2538 : /* P mod a prime \wp above p (which splits) */
2539 133 : Pp = FpXY_evalx(P, a, p);
2540 133 : roo = gal_get_roots(G);
2541 133 : is_P = gequal0( FpX_eval(Pp, remii(gel(roo,1),p), p) );
2542 : /* each roo[i] mod p is a root of P or (exclusive) tau(P) mod \wp */
2543 : /* record whether roo[1] is a root of P or tau(P) */
2544 :
2545 1022 : for (i = 1; i < lg(L); i++)
2546 : {
2547 1022 : GEN perm = gel(L,i);
2548 1022 : long k = perm[1]; if (k == 1) continue;
2549 889 : k = gequal0( FpX_eval(Pp, remii(gel(roo,k),p), p) );
2550 : /* roo[k] is a root of the other polynomial */
2551 889 : if (k != is_P)
2552 : {
2553 133 : ulong o = perm_orderu(perm);
2554 133 : if (o != 2) perm = perm_powu(perm, o >> 1);
2555 : /* perm has order two and doesn't belong to Gal(H_k/k) */
2556 133 : return polredbest(galoisfixedfield(G, perm, 1, varn(P)), 0);
2557 : }
2558 : }
2559 0 : pari_err_BUG("makescind");
2560 : return NULL; /*LCOV_EXCL_LINE*/
2561 : }
2562 :
2563 : /* pbnf = NULL if no bnf is needed, f = NULL may be passed for a trivial
2564 : * conductor */
2565 : static void
2566 847 : quadray_init(GEN *pD, GEN *pbnf, long prec)
2567 : {
2568 847 : GEN D = *pD, nf, bnf = NULL;
2569 847 : if (typ(D) == t_INT)
2570 : {
2571 : int isfund;
2572 812 : if (pbnf) {
2573 252 : bnf = Buchall(quadpoly0(D, 1), nf_FORCE, prec);
2574 252 : nf = bnf_get_nf(bnf);
2575 252 : isfund = equalii(D, nf_get_disc(nf));
2576 : }
2577 : else
2578 560 : isfund = Z_isfundamental(D);
2579 812 : if (!isfund) pari_err_DOMAIN("quadray", "isfundamental(D)", "=",gen_0, D);
2580 : }
2581 : else
2582 : {
2583 35 : bnf = checkbnf(D);
2584 35 : nf = bnf_get_nf(bnf);
2585 35 : if (nf_get_degree(nf) != 2)
2586 7 : pari_err_DOMAIN("quadray", "degree", "!=", gen_2, nf_get_pol(nf));
2587 28 : D = nf_get_disc(nf);
2588 : }
2589 833 : if (pbnf) *pbnf = bnf;
2590 833 : *pD = D;
2591 833 : }
2592 :
2593 : /* compute the polynomial over Q of the Hilbert class field of
2594 : Q(sqrt(D)) where D is a positive fundamental discriminant */
2595 : static GEN
2596 147 : quadhilbertreal(GEN D, long prec)
2597 : {
2598 : GEN bnf, bnr, dtQ, data, M;
2599 : long newprec;
2600 : pari_timer T;
2601 :
2602 147 : quadray_init(&D, &bnf, prec);
2603 147 : switch(itou_or_0(cyc_get_expo(bnf_get_cyc(bnf))))
2604 : {
2605 0 : case 1: return pol_x(0);
2606 14 : case 2: return GenusFieldQuadReal(D);
2607 : }
2608 133 : bnr = Buchray(bnf, gen_1, nf_INIT);
2609 133 : M = diagonal_shallow(bnr_get_cyc(bnr));
2610 133 : dtQ = InitQuotient(M);
2611 :
2612 133 : if (DEBUGLEVEL) timer_start(&T);
2613 133 : data = FindModulus(bnr, dtQ, &newprec);
2614 133 : if (DEBUGLEVEL) timer_printf(&T,"FindModulus");
2615 133 : if (!data) return bnrstark_cyclic(bnr, dtQ, prec);
2616 133 : return makescind(bnf_get_nf(bnf), AllStark(data, 0, newprec));
2617 : }
2618 :
2619 : /*******************************************************************/
2620 : /* */
2621 : /* Hilbert and Ray Class field using CM (Schertz) */
2622 : /* */
2623 : /*******************************************************************/
2624 : /* form^2 = 1 ? */
2625 : static int
2626 813 : hasexp2(GEN form)
2627 : {
2628 813 : GEN a = gel(form,1), b = gel(form,2), c = gel(form,3);
2629 813 : return !signe(b) || absequalii(a,b) || equalii(a,c);
2630 : }
2631 : static int
2632 1323 : uhasexp2(GEN form)
2633 : {
2634 1323 : long a = form[1], b = form[2], c = form[3];
2635 1323 : return !b || a == labs(b) || a == c;
2636 : }
2637 :
2638 : GEN
2639 455 : qfbforms(GEN D)
2640 : {
2641 455 : ulong d = itou(D), dover3 = d/3, t, b2, a, b, c, h;
2642 455 : GEN L = cgetg((long)(sqrt((double)d) * log2(d)), t_VEC);
2643 455 : b2 = b = (d&1); h = 0;
2644 455 : if (!b) /* b = 0 treated separately to avoid special cases */
2645 : {
2646 252 : t = d >> 2; /* (b^2 - D) / 4*/
2647 2954 : for (a=1; a*a<=t; a++)
2648 2702 : if (c = t/a, t == c*a) gel(L,++h) = mkvecsmall3(a,0,c);
2649 252 : b = 2; b2 = 4;
2650 : }
2651 : /* now b > 0, b = D (mod 2) */
2652 8078 : for ( ; b2 <= dover3; b += 2, b2 = b*b)
2653 : {
2654 7623 : t = (b2 + d) >> 2; /* (b^2 - D) / 4*/
2655 : /* b = a */
2656 7623 : if (c = t/b, t == c*b) gel(L,++h) = mkvecsmall3(b,b,c);
2657 : /* b < a < c */
2658 1912029 : for (a = b+1; a*a < t; a++)
2659 1904406 : if (c = t/a, t == c*a)
2660 : {
2661 1057 : gel(L,++h) = mkvecsmall3(a, b,c);
2662 1057 : gel(L,++h) = mkvecsmall3(a,-b,c);
2663 : }
2664 : /* a = c */
2665 7623 : if (a * a == t) gel(L,++h) = mkvecsmall3(a,b,a);
2666 : }
2667 455 : setlg(L,h+1); return L;
2668 : }
2669 :
2670 : /* gcd(n, 24) */
2671 : static long
2672 813 : GCD24(long n)
2673 : {
2674 813 : switch(n % 24)
2675 : {
2676 35 : case 0: return 24;
2677 35 : case 1: return 1;
2678 28 : case 2: return 2;
2679 0 : case 3: return 3;
2680 119 : case 4: return 4;
2681 0 : case 5: return 1;
2682 105 : case 6: return 6;
2683 0 : case 7: return 1;
2684 0 : case 8: return 8;
2685 0 : case 9: return 3;
2686 91 : case 10: return 2;
2687 0 : case 11: return 1;
2688 119 : case 12: return 12;
2689 0 : case 13: return 1;
2690 0 : case 14: return 2;
2691 0 : case 15: return 3;
2692 91 : case 16: return 8;
2693 0 : case 17: return 1;
2694 92 : case 18: return 6;
2695 0 : case 19: return 1;
2696 0 : case 20: return 4;
2697 0 : case 21: return 3;
2698 98 : case 22: return 2;
2699 0 : case 23: return 1;
2700 0 : default: return 0;
2701 : }
2702 : }
2703 :
2704 : struct gpq_data {
2705 : long p, q;
2706 : GEN sqd; /* sqrt(D), t_REAL */
2707 : GEN u, D;
2708 : GEN pq, pq2; /* p*q, 2*p*q */
2709 : GEN qfpq ; /* class of \P * \Q */
2710 : };
2711 :
2712 : /* find P and Q two non principal prime ideals (above p <= q) such that
2713 : * cl(P) = cl(Q) if P,Q have order 2 in Cl(K).
2714 : * Ensure that e = 24 / gcd(24, (p-1)(q-1)) = 1 */
2715 : /* D t_INT, discriminant */
2716 : static void
2717 49 : init_pq(GEN D, struct gpq_data *T)
2718 : {
2719 49 : const long Np = 6547; /* N.B. primepi(50000) = 5133 */
2720 49 : const ulong maxq = 50000;
2721 49 : GEN listp = cgetg(Np + 1, t_VECSMALL); /* primes p */
2722 49 : GEN listP = cgetg(Np + 1, t_VEC); /* primeform(p) if of order 2, else NULL */
2723 49 : GEN gcd24 = cgetg(Np + 1, t_VECSMALL); /* gcd(p-1, 24) */
2724 : forprime_t S;
2725 49 : long l = 1;
2726 49 : double best = 0.;
2727 : ulong q;
2728 :
2729 49 : u_forprime_init(&S, 2, ULONG_MAX);
2730 49 : T->D = D;
2731 49 : T->p = T->q = 0;
2732 : for(;;)
2733 1777 : {
2734 : GEN Q;
2735 : long i, gcdq, mod;
2736 : int order2, store;
2737 : double t;
2738 :
2739 1826 : q = u_forprime_next(&S);
2740 1826 : if (best > 0 && q >= maxq)
2741 : {
2742 0 : if (DEBUGLEVEL)
2743 0 : pari_warn(warner,"possibly suboptimal (p,q) for D = %Ps", D);
2744 0 : break;
2745 : }
2746 1826 : if (kroiu(D, q) < 0) continue; /* inert */
2747 890 : Q = qfbred_i(primeform_u(D, q));
2748 890 : if (is_pm1(gel(Q,1))) continue; /* Q | q is principal */
2749 :
2750 813 : store = 1;
2751 813 : order2 = hasexp2(Q);
2752 813 : gcd24[l] = gcdq = GCD24(q-1);
2753 813 : mod = 24 / gcdq; /* mod must divide p-1 otherwise e > 1 */
2754 813 : listp[l] = q;
2755 813 : gel(listP,l) = order2 ? Q : NULL;
2756 813 : t = (q+1)/(double)(q-1);
2757 2129 : for (i = 1; i < l; i++) /* try all (p, q), p < q in listp */
2758 : {
2759 1660 : long p = listp[i], gcdp = gcd24[i];
2760 : double b;
2761 : /* P,Q order 2 => cl(Q) = cl(P) */
2762 1660 : if (order2 && gel(listP,i) && !gequal(gel(listP,i), Q)) continue;
2763 1653 : if (gcdp % gcdq == 0) store = 0; /* already a better one in the list */
2764 1653 : if ((p-1) % mod) continue;
2765 :
2766 344 : b = (t*(p+1)) / (p-1); /* (p+1)(q+1) / (p-1)(q-1) */
2767 344 : if (b > best) {
2768 98 : store = 0; /* (p,q) always better than (q,r) for r >= q */
2769 98 : best = b; T->q = q; T->p = p;
2770 98 : if (DEBUGLEVEL>2) err_printf("p,q = %ld,%ld\n", p, q);
2771 : }
2772 : /* won't improve with this q as largest member */
2773 344 : if (best > 0) break;
2774 : }
2775 : /* if !store or (q,r) won't improve on current best pair, forget that q */
2776 813 : if (store && t*t > best)
2777 119 : if (++l >= Np) pari_err_BUG("quadhilbert (not enough primes)");
2778 813 : if (!best) /* (p,q) with p < q always better than (q,q) */
2779 : { /* try (q,q) */
2780 140 : if (gcdq >= 12 && umodiu(D, q)) /* e = 1 and unramified */
2781 : {
2782 7 : double b = (t*q) / (q-1); /* q(q+1) / (q-1)^2 */
2783 7 : if (b > best) {
2784 7 : best = b; T->q = T->p = q;
2785 7 : if (DEBUGLEVEL>2) err_printf("p,q = %ld,%ld\n", q, q);
2786 : }
2787 : }
2788 : }
2789 : /* If (p1+1)(q+1) / (p1-1)(q-1) <= best, we can no longer improve
2790 : * even with best p : stop */
2791 813 : if ((listp[1]+1)*t <= (listp[1]-1)*best) break;
2792 : }
2793 49 : if (DEBUGLEVEL>1)
2794 0 : err_printf("(p, q) = %ld, %ld; gain = %f\n", T->p, T->q, 12*best);
2795 49 : }
2796 :
2797 : static GEN
2798 4102 : gpq(GEN form, struct gpq_data *T)
2799 : {
2800 4102 : pari_sp av = avma;
2801 4102 : long a = form[1], b = form[2], c = form[3], p = T->p, q = T->q;
2802 : GEN form2, w, z;
2803 4102 : int fl, real = 0;
2804 :
2805 4102 : form2 = qfbcomp_i(T->qfpq, mkqfb(stoi(a), stoi(-b), stoi(c), T->D));
2806 : /* form2 and form yield complex conjugate roots : only compute for the
2807 : * lexicographically smallest of the 2 */
2808 4102 : fl = cmpis(gel(form2,1), a);
2809 4102 : if (fl <= 0)
2810 : {
2811 2156 : if (fl < 0) return NULL;
2812 210 : fl = cmpis(gel(form2,2), b);
2813 210 : if (fl <= 0)
2814 : {
2815 147 : if (fl < 0) return NULL;
2816 : /* form == form2 : real root */
2817 84 : real = 1;
2818 : }
2819 : }
2820 :
2821 2093 : if (p == 2) { /* (a,b,c) = (1,1,0) mod 2 ? */
2822 203 : if (a % q == 0 && (a & b & 1) && !(c & 1))
2823 : { /* apply S : make sure that (a,b,c) represents odd values */
2824 0 : lswap(a,c); b = -b;
2825 : }
2826 : }
2827 2093 : if (a % p == 0 || a % q == 0)
2828 : { /* apply T^k, look for c' = a k^2 + b k + c coprime to N */
2829 595 : while (c % p == 0 || c % q == 0)
2830 : {
2831 98 : c += a + b;
2832 98 : b += a << 1;
2833 : }
2834 497 : lswap(a, c); b = -b; /* apply S */
2835 : }
2836 : /* now (a,b,c) ~ form and (a,pq) = 1 */
2837 :
2838 : /* gcd(2a, u) = 2, w = u mod 2pq, -b mod 2a */
2839 2093 : w = Z_chinese(T->u, stoi(-b), T->pq2, utoipos(a << 1));
2840 2093 : z = double_eta_quotient(utoipos(a), w, T->D, T->p, T->q, T->pq, T->sqd);
2841 2093 : if (real && typ(z) == t_COMPLEX) z = gcopy(gel(z, 1));
2842 2093 : return gc_upto(av, z);
2843 : }
2844 :
2845 : /* returns an equation for the Hilbert class field of Q(sqrt(D)), D < 0
2846 : * fundamental discriminant */
2847 : static GEN
2848 462 : quadhilbertimag(GEN D)
2849 : {
2850 : GEN L, P, Pi, Pr, qfp, u;
2851 : long h, i, prec;
2852 : struct gpq_data T;
2853 : pari_timer ti;
2854 :
2855 462 : if (DEBUGLEVEL>1) timer_start(&ti);
2856 462 : if (lgefint(D) == 3)
2857 462 : switch (D[2]) { /* = |D|; special cases where e > 1 */
2858 7 : case 3:
2859 : case 4:
2860 : case 7:
2861 : case 8:
2862 : case 11:
2863 : case 19:
2864 : case 43:
2865 : case 67:
2866 7 : case 163: return pol_x(0);
2867 : }
2868 455 : L = qfbforms(D);
2869 455 : h = lg(L)-1;
2870 455 : if (! (h & (h - 1))) /* power of 2 */
2871 : { /* check whether > |Cl|/2 elements have order <= 2 ==> 2-elementary */
2872 413 : long lim = (h>>1) + 1;
2873 1729 : for (i=1; i <= lim; i++)
2874 1323 : if (!uhasexp2(gel(L,i))) break;
2875 413 : if (i > lim) return GenusFieldQuadImag(D);
2876 : }
2877 49 : if (DEBUGLEVEL>1) timer_printf(&ti,"class number = %ld",h);
2878 49 : init_pq(D, &T);
2879 49 : qfp = primeform_u(D, T.p);
2880 49 : T.pq = muluu(T.p, T.q);
2881 49 : T.pq2 = shifti(T.pq,1);
2882 49 : if (T.p == T.q)
2883 : {
2884 0 : GEN qfbp2 = qfbcompraw(qfp, qfp);
2885 0 : u = gel(qfbp2,2);
2886 0 : T.u = modii(u, T.pq2);
2887 0 : T.qfpq = qfbred_i(qfbp2);
2888 : }
2889 : else
2890 : {
2891 49 : GEN qfq = primeform_u(D, T.q), bp = gel(qfp,2), bq = gel(qfq,2);
2892 49 : T.u = Z_chinese(bp, bq, utoipos(T.p << 1), utoipos(T.q << 1));
2893 : /* T.u = bp (mod 2p), T.u = bq (mod 2q) */
2894 49 : T.qfpq = qfbcomp_i(qfp, qfq);
2895 : }
2896 : /* u modulo 2pq */
2897 49 : prec = LOWDEFAULTPREC;
2898 49 : Pr = cgetg(h+1,t_VEC);
2899 49 : Pi = cgetg(h+1,t_VEC);
2900 : for(;;)
2901 14 : {
2902 63 : long ex, exmax = 0, r1 = 0, r2 = 0;
2903 63 : pari_sp av0 = avma;
2904 63 : T.sqd = sqrtr_abs(itor(D, prec));
2905 4165 : for (i=1; i<=h; i++)
2906 : {
2907 4102 : GEN s = gpq(gel(L,i), &T);
2908 4102 : if (DEBUGLEVEL>3) err_printf("%ld ", i);
2909 4102 : if (!s) continue;
2910 2093 : if (typ(s) != t_COMPLEX) gel(Pr, ++r1) = s; /* real root */
2911 2009 : else gel(Pi, ++r2) = s;
2912 2093 : ex = gexpo(s); if (ex > 0) exmax += ex;
2913 : }
2914 63 : if (DEBUGLEVEL>1) timer_printf(&ti,"roots");
2915 63 : setlg(Pr, r1+1);
2916 63 : setlg(Pi, r2+1);
2917 63 : P = roots_to_pol_r1(shallowconcat(Pr,Pi), 0, r1);
2918 63 : P = grndtoi(P,&exmax);
2919 63 : if (DEBUGLEVEL>1) timer_printf(&ti,"product, error bits = %ld",exmax);
2920 63 : if (exmax <= -10) break;
2921 14 : set_avma(av0); prec += nbits2extraprec(DEFAULTPREC + exmax);
2922 14 : if (DEBUGLEVEL) pari_warn(warnprec,"quadhilbertimag",prec);
2923 : }
2924 49 : return P;
2925 : }
2926 :
2927 : GEN
2928 574 : quadhilbert(GEN D, long prec)
2929 : {
2930 574 : pari_sp av = avma;
2931 574 : GEN d = D;
2932 574 : quadray_init(&d, NULL, 0);
2933 973 : return gc_upto(av, signe(d)>0? quadhilbertreal(D,prec)
2934 413 : : quadhilbertimag(d));
2935 : }
2936 :
2937 : /* return a vector of all roots of 1 in bnf [not necessarily quadratic] */
2938 : static GEN
2939 70 : getallrootsof1(GEN bnf)
2940 : {
2941 70 : GEN T, u, nf = bnf_get_nf(bnf), tu;
2942 70 : long i, n = bnf_get_tuN(bnf);
2943 :
2944 70 : if (n == 2) {
2945 56 : long N = nf_get_degree(nf);
2946 56 : return mkvec2(scalarcol_shallow(gen_m1, N),
2947 : scalarcol_shallow(gen_1, N));
2948 : }
2949 14 : tu = poltobasis(nf, bnf_get_tuU(bnf));
2950 14 : T = zk_multable(nf, tu);
2951 14 : u = cgetg(n+1, t_VEC); gel(u,1) = tu;
2952 56 : for (i=2; i <= n; i++) gel(u,i) = ZM_ZC_mul(T, gel(u,i-1));
2953 14 : return u;
2954 : }
2955 : /* assume bnr has the right conductor */
2956 : static GEN
2957 70 : get_lambda(GEN bnr)
2958 : {
2959 70 : GEN bnf = bnr_get_bnf(bnr), nf = bnf_get_nf(bnf), pol = nf_get_pol(nf);
2960 70 : GEN f = gel(bnr_get_mod(bnr), 1), labas, lamodf, u;
2961 70 : long a, b, f2, i, lu, v = varn(pol);
2962 :
2963 70 : f2 = 2 * itos(gcoeff(f,1,1));
2964 70 : u = getallrootsof1(bnf); lu = lg(u);
2965 238 : for (i=1; i<lu; i++)
2966 168 : gel(u,i) = ZC_hnfrem(gel(u,i), f); /* roots of 1, mod f */
2967 70 : if (DEBUGLEVEL>1)
2968 0 : err_printf("quadray: looking for [a,b] != unit mod 2f\n[a,b] = ");
2969 168 : for (a=0; a<f2; a++)
2970 2576 : for (b=0; b<f2; b++)
2971 : {
2972 2478 : GEN la = deg1pol_shallow(stoi(a), stoi(b), v); /* ax + b */
2973 2478 : if (umodiu(gnorm(mkpolmod(la, pol)), f2) != 1) continue;
2974 224 : if (DEBUGLEVEL>1) err_printf("[%ld,%ld] ",a,b);
2975 :
2976 224 : labas = poltobasis(nf, la);
2977 224 : lamodf = ZC_hnfrem(labas, f);
2978 469 : for (i=1; i<lu; i++)
2979 399 : if (ZV_equal(lamodf, gel(u,i))) break;
2980 224 : if (i < lu) continue; /* la = unit mod f */
2981 70 : if (DEBUGLEVEL)
2982 : {
2983 0 : if (DEBUGLEVEL>1) err_printf("\n");
2984 0 : err_printf("lambda = %Ps\n",la);
2985 : }
2986 70 : return labas;
2987 : }
2988 0 : pari_err_BUG("get_lambda");
2989 : return NULL;/*LCOV_EXCL_LINE*/
2990 : }
2991 :
2992 : static GEN
2993 8778 : to_approx(GEN nf, GEN a)
2994 : {
2995 8778 : GEN M = nf_get_M(nf);
2996 8778 : return gadd(gel(a,1), gmul(gcoeff(M,1,2),gel(a,2)));
2997 : }
2998 : /* Z-basis for a (over C) */
2999 : static GEN
3000 4354 : get_om(GEN nf, GEN a) {
3001 4354 : return mkvec2(to_approx(nf,gel(a,2)),
3002 4354 : to_approx(nf,gel(a,1)));
3003 : }
3004 :
3005 : /* Compute all elts in class group G = [|G|,c,g], c=cyclic factors, g=gens.
3006 : * Set list[j + 1] = g1^e1...gk^ek where j is the integer
3007 : * ek + ck [ e(k-1) + c(k-1) [... + c2 [e1]]...] */
3008 : static GEN
3009 70 : getallelts(GEN bnr)
3010 : {
3011 : GEN nf, C, c, g, list, pows, gk;
3012 : long lc, i, j, no;
3013 :
3014 70 : nf = bnr_get_nf(bnr);
3015 70 : no = itos( bnr_get_no(bnr) );
3016 70 : c = bnr_get_cyc(bnr);
3017 70 : g = bnr_get_gen_nocheck(bnr); lc = lg(c)-1;
3018 70 : list = cgetg(no+1,t_VEC);
3019 70 : gel(list,1) = matid(nf_get_degree(nf)); /* (1) */
3020 70 : if (!no) return list;
3021 :
3022 70 : pows = cgetg(lc+1,t_VEC);
3023 70 : c = leafcopy(c); settyp(c, t_VECSMALL);
3024 140 : for (i=1; i<=lc; i++)
3025 : {
3026 70 : long k = itos(gel(c,i));
3027 70 : c[i] = k;
3028 70 : gk = cgetg(k, t_VEC); gel(gk,1) = gel(g,i);
3029 4284 : for (j=2; j<k; j++)
3030 4214 : gel(gk,j) = idealmoddivisor(bnr, idealmul(nf, gel(gk,j-1), gel(gk,1)));
3031 70 : gel(pows,i) = gk; /* powers of g[i] */
3032 : }
3033 :
3034 70 : C = cgetg(lc+1, t_VECSMALL); C[1] = c[lc];
3035 70 : for (i=2; i<=lc; i++) C[i] = C[i-1] * c[lc-i+1];
3036 : /* C[i] = c(k-i+1) * ... * ck */
3037 : /* j < C[i+1] <==> j only involves g(k-i)...gk */
3038 70 : i = 1;
3039 4354 : for (j=1; j < C[1]; j++)
3040 4284 : gel(list, j+1) = gmael(pows,lc,j);
3041 70 : while(j<no)
3042 : {
3043 : long k;
3044 : GEN a;
3045 0 : if (j == C[i+1]) i++;
3046 0 : a = gmael(pows,lc-i,j/C[i]);
3047 0 : k = j%C[i] + 1;
3048 0 : if (k > 1) a = idealmoddivisor(bnr, idealmul(nf, a, gel(list,k)));
3049 0 : gel(list, ++j) = a;
3050 : }
3051 70 : return list;
3052 : }
3053 :
3054 : /* x quadratic integer (approximate), recognize it. If error return NULL */
3055 : static GEN
3056 4424 : findbezk(GEN nf, GEN x)
3057 : {
3058 4424 : GEN a,b, M = nf_get_M(nf), u = gcoeff(M,1,2);
3059 : long ea, eb;
3060 :
3061 : /* u t_COMPLEX generator of nf.zk, write x ~ a + b u, a,b in Z */
3062 4424 : b = grndtoi(mpdiv(imag_i(x), gel(u,2)), &eb);
3063 4424 : if (eb > -20) return NULL;
3064 4424 : a = grndtoi(mpsub(real_i(x), mpmul(b,gel(u,1))), &ea);
3065 4424 : if (ea > -20) return NULL;
3066 4424 : return signe(b)? coltoalg(nf, mkcol2(a,b)): a;
3067 : }
3068 :
3069 : static GEN
3070 70 : findbezk_pol(GEN nf, GEN x)
3071 : {
3072 70 : long i, lx = lg(x);
3073 70 : GEN y = cgetg(lx,t_POL);
3074 4494 : for (i=2; i<lx; i++)
3075 4424 : if (! (gel(y,i) = findbezk(nf,gel(x,i))) ) return NULL;
3076 70 : y[1] = x[1]; return y;
3077 : }
3078 :
3079 : /* P approximation computed at initial precision prec. Compute needed prec
3080 : * to know P with 1 word worth of trailing decimals */
3081 : static long
3082 0 : get_prec(GEN P, long prec)
3083 : {
3084 0 : long k = gprecision(P);
3085 0 : if (k == 3) return precdbl(prec); /* approximation not trustworthy */
3086 0 : k = prec - k; /* lost precision when computing P */
3087 0 : if (k < 0) k = 0;
3088 0 : k += nbits2prec(gexpo(P) + 128);
3089 0 : if (k <= prec) k = precdbl(prec); /* dubious: old prec should have worked */
3090 0 : return k;
3091 : }
3092 :
3093 : /* Compute data for ellphist */
3094 : static GEN
3095 4354 : ellphistinit(GEN om, long prec)
3096 : {
3097 4354 : GEN res,om1b,om2b, om1 = gel(om,1), om2 = gel(om,2);
3098 :
3099 4354 : if (gsigne(imag_i(gdiv(om1,om2))) < 0) { swap(om1,om2); om = mkvec2(om1,om2); }
3100 4354 : om1b = conj_i(om1);
3101 4354 : om2b = conj_i(om2); res = cgetg(4,t_VEC);
3102 4354 : gel(res,1) = gdivgu(elleisnum(om,2,prec),12);
3103 4354 : gel(res,2) = gdiv(PiI2(prec), gmul(om2, imag_i(gmul(om1b,om2))));
3104 4354 : gel(res,3) = om2b; return res;
3105 : }
3106 :
3107 : /* Computes log(phi^*(z,om)), using res computed by ellphistinit */
3108 : static GEN
3109 8708 : ellphist(GEN om, GEN res, GEN z, long prec)
3110 : {
3111 8708 : GEN u = imag_i(gmul(z, gel(res,3)));
3112 8708 : GEN zst = gsub(gmul(u, gel(res,2)), gmul(z,gel(res,1)));
3113 8708 : return gsub(ellsigma(om,z,1,prec),gmul2n(gmul(z,zst),-1));
3114 : }
3115 :
3116 : /* Computes phi^*(la,om)/phi^*(1,om) where (1,om) is an oriented basis of the
3117 : ideal gf*gc^{-1} */
3118 : static GEN
3119 4354 : computeth2(GEN om, GEN la, long prec)
3120 : {
3121 4354 : GEN p1,p2,res = ellphistinit(om,prec);
3122 :
3123 4354 : p1 = gsub(ellphist(om,res,la,prec), ellphist(om,res,gen_1,prec));
3124 4354 : p2 = imag_i(p1);
3125 4354 : if (gexpo(real_i(p1)) > 20 || gexpo(p2) > minss(prec,realprec(p2)) - 10)
3126 0 : return NULL;
3127 4354 : return gexp(p1,prec);
3128 : }
3129 :
3130 : /* Computes P_2(X)=polynomial in Z_K[X] closest to prod_gc(X-th2(gc)) where
3131 : the product is over the ray class group bnr.*/
3132 : static GEN
3133 70 : computeP2(GEN bnr, long prec)
3134 : {
3135 70 : long clrayno, i, first = 1;
3136 70 : pari_sp av=avma, av2;
3137 70 : GEN listray, P0, P, lanum, la = get_lambda(bnr);
3138 70 : GEN nf = bnr_get_nf(bnr), f = gel(bnr_get_mod(bnr), 1);
3139 70 : listray = getallelts(bnr);
3140 70 : clrayno = lg(listray)-1; av2 = avma;
3141 70 : PRECPB:
3142 70 : if (!first)
3143 : {
3144 0 : if (DEBUGLEVEL) pari_warn(warnprec,"computeP2",prec);
3145 0 : nf = gc_GEN(av2, nfnewprec_shallow(bnr_get_nf(bnr),prec));
3146 : }
3147 70 : first = 0; lanum = to_approx(nf,la);
3148 70 : P = cgetg(clrayno+1,t_VEC);
3149 4424 : for (i=1; i<=clrayno; i++)
3150 : {
3151 4354 : GEN om = get_om(nf, idealdiv(nf,f,gel(listray,i)));
3152 4354 : GEN s = computeth2(om,lanum,prec);
3153 4354 : if (!s) { prec = precdbl(prec); goto PRECPB; }
3154 4354 : gel(P,i) = s;
3155 : }
3156 70 : P0 = roots_to_pol(P, 0);
3157 70 : P = findbezk_pol(nf, P0);
3158 70 : if (!P) { prec = get_prec(P0, prec); goto PRECPB; }
3159 70 : return gc_GEN(av, P);
3160 : }
3161 :
3162 : #define nexta(a) (a>0 ? -a : 1-a)
3163 : static GEN
3164 49 : do_compo(GEN A0, GEN B)
3165 : {
3166 49 : long a, i, l = lg(B), v = fetch_var_higher();
3167 : GEN A, z;
3168 : /* now v > x = pol_x(0) > nf variable */
3169 49 : B = leafcopy(B); setvarn(B, v);
3170 210 : for (i = 2; i < l; i++) gel(B,i) = monomial(gel(B,i), l-i-1, 0);
3171 : /* B := x^deg(B) B(v/x) */
3172 49 : A = A0 = leafcopy(A0); setvarn(A0, v);
3173 56 : for (a = 0;; a = nexta(a))
3174 : {
3175 56 : if (a) A = RgX_translate(A0, stoi(a));
3176 56 : z = resultant(A,B); /* in variable 0 */
3177 56 : if (issquarefree(z)) break;
3178 : }
3179 49 : (void)delete_var(); return z;
3180 : }
3181 : #undef nexta
3182 :
3183 : static GEN
3184 14 : galoisapplypol(GEN nf, GEN s, GEN x)
3185 : {
3186 14 : long i, lx = lg(x);
3187 14 : GEN y = cgetg(lx,t_POL);
3188 :
3189 56 : for (i=2; i<lx; i++) gel(y,i) = galoisapply(nf,s,gel(x,i));
3190 14 : y[1] = x[1]; return y;
3191 : }
3192 : /* x quadratic, write it as ua + v, u,v rational */
3193 : static GEN
3194 70 : findquad(GEN a, GEN x, GEN p)
3195 : {
3196 : long tu, tv;
3197 70 : pari_sp av = avma;
3198 : GEN u,v;
3199 70 : if (typ(x) == t_POLMOD) x = gel(x,2);
3200 70 : if (typ(a) == t_POLMOD) a = gel(a,2);
3201 70 : u = poldivrem(x, a, &v);
3202 70 : u = simplify_shallow(u); tu = typ(u);
3203 70 : v = simplify_shallow(v); tv = typ(v);
3204 70 : if (!is_scalar_t(tu)) pari_err_TYPE("findquad", u);
3205 70 : if (!is_scalar_t(tv)) pari_err_TYPE("findquad", v);
3206 70 : x = deg1pol(u, v, varn(a));
3207 70 : if (typ(x) == t_POL) x = gmodulo(x,p);
3208 70 : return gc_upto(av, x);
3209 : }
3210 : static GEN
3211 14 : findquad_pol(GEN p, GEN a, GEN x)
3212 : {
3213 14 : long i, lx = lg(x);
3214 14 : GEN y = cgetg(lx,t_POL);
3215 84 : for (i=2; i<lx; i++) gel(y,i) = findquad(a, gel(x,i), p);
3216 14 : y[1] = x[1]; return y;
3217 : }
3218 : /* m is 3, 4 or 12 */
3219 : static GEN
3220 35 : compocyclo(GEN D, long m)
3221 35 : { return do_compo(quadhilbertimag(D), polcyclo(m,0)); }
3222 : /* m is prime or 4 * prime */
3223 : static GEN
3224 14 : compocyclop(GEN nf, long m)
3225 : {
3226 14 : GEN sb,a,b,s,p1,p2,p3,res,polL,polLK,nfL, D = nf_get_disc(nf);
3227 : long ell,vx;
3228 :
3229 14 : p1 = quadhilbertimag(D);
3230 14 : p2 = polcyclo(m,0);
3231 14 : ell = odd(m)? m: (m>>2); /* prime */
3232 14 : if (absequalui(ell,D)) /* ell = |D| */
3233 : {
3234 0 : p2 = gcoeff(nffactor(nf,p2),1,1);
3235 0 : return do_compo(p1,p2);
3236 : }
3237 14 : if (ell%4 == 3) ell = -ell;
3238 : /* nf = K = Q(a), L = K(b) quadratic extension = Q(t) */
3239 14 : polLK = quadpoly_i(stoi(ell)); /* relative polynomial */
3240 14 : res = rnfequation2(nf, polLK);
3241 14 : vx = nf_get_varn(nf);
3242 14 : polL = gsubst(gel(res,1),0,pol_x(vx)); /* = charpoly(t) */
3243 14 : a = gsubst(lift_shallow(gel(res,2)), 0,pol_x(vx));
3244 14 : b = gsub(pol_x(vx), gmul(gel(res,3), a));
3245 14 : nfL = nfinit(polL, DEFAULTPREC);
3246 14 : p1 = gcoeff(nffactor(nfL,p1),1,1);
3247 14 : p2 = gcoeff(nffactor(nfL,p2),1,1);
3248 14 : p3 = do_compo(p1,p2); /* relative equation over L */
3249 : /* compute non trivial s in Gal(L / K) */
3250 14 : sb= gneg(gadd(b, RgX_coeff(polLK,1))); /* s(b) = Tr(b) - b */
3251 14 : s = gadd(pol_x(vx), gsub(sb, b)); /* s(t) = t + s(b) - b */
3252 14 : p3 = gmul(p3, galoisapplypol(nfL, s, p3));
3253 14 : return findquad_pol(nf_get_pol(nf), a, p3);
3254 : }
3255 :
3256 : /* I integral ideal in HNF. (x) = I, x small in Z ? */
3257 : static long
3258 119 : isZ(GEN I)
3259 : {
3260 119 : GEN x = gcoeff(I,1,1);
3261 119 : if (signe(gcoeff(I,1,2)) || !equalii(x, gcoeff(I,2,2))) return 0;
3262 105 : return is_bigint(x)? -1: itos(x);
3263 : }
3264 :
3265 : /* Treat special cases directly. return NULL if not special case */
3266 : static GEN
3267 119 : treatspecialsigma(GEN bnr)
3268 : {
3269 119 : GEN bnf = bnr_get_bnf(bnr), nf = bnf_get_nf(bnf);
3270 119 : GEN f = gel(bnr_get_mod(bnr), 1), D = nf_get_disc(nf);
3271 : GEN p1, p2;
3272 119 : long Ds, fl, tryf, i = isZ(f);
3273 :
3274 119 : if (i == 1) return quadhilbertimag(D); /* f = 1 */
3275 :
3276 119 : if (absequaliu(D,3)) /* Q(j) */
3277 : {
3278 0 : if (i == 4 || i == 5 || i == 7) return polcyclo(i,0);
3279 0 : if (!absequaliu(gcoeff(f,1,1),9) || !absequaliu(Z_content(f),3)) return NULL;
3280 : /* f = P_3^3 */
3281 0 : p1 = mkpolmod(bnf_get_tuU(bnf), nf_get_pol(nf));
3282 0 : return gadd(pol_xn(3,0), p1); /* x^3+j */
3283 : }
3284 119 : if (absequaliu(D,4)) /* Q(i) */
3285 : {
3286 14 : if (i == 3 || i == 5) return polcyclo(i,0);
3287 14 : if (i != 4) return NULL;
3288 0 : p1 = mkpolmod(bnf_get_tuU(bnf), nf_get_pol(nf));
3289 0 : return gadd(pol_xn(2,0), p1); /* x^2+i */
3290 : }
3291 105 : Ds = smodis(D,48);
3292 105 : if (i)
3293 : {
3294 91 : if (i==2 && Ds%16== 8) return compocyclo(D, 4);
3295 84 : if (i==3 && Ds% 3== 1) return compocyclo(D, 3);
3296 70 : if (i==4 && Ds% 8== 1) return compocyclo(D, 4);
3297 63 : if (i==6 && Ds ==40) return compocyclo(D,12);
3298 56 : return NULL;
3299 : }
3300 :
3301 14 : p1 = gcoeff(f,1,1); /* integer > 0 */
3302 14 : tryf = itou_or_0(p1); if (!tryf) return NULL;
3303 14 : p2 = gcoeff(f,2,2); /* integer > 0 */
3304 14 : if (is_pm1(p2)) fl = 0;
3305 : else {
3306 0 : if (Ds % 16 != 8 || !absequaliu(Z_content(f),2)) return NULL;
3307 0 : fl = 1; tryf >>= 1;
3308 : }
3309 14 : if (tryf <= 3 || umodiu(D, tryf) || !uisprime(tryf)) return NULL;
3310 14 : if (fl) tryf <<= 2;
3311 14 : return compocyclop(nf, tryf);
3312 : }
3313 :
3314 : GEN
3315 161 : quadray(GEN D, GEN f, long prec)
3316 : {
3317 161 : GEN bnr, y, bnf, H = NULL;
3318 161 : pari_sp av = avma;
3319 :
3320 161 : if (isint1(f)) return quadhilbert(D, prec);
3321 126 : if (typ(D) == t_INT && typ(f) != t_INT)
3322 0 : pari_err_TYPE("quadray [conductor]", f);
3323 126 : quadray_init(&D, &bnf, prec);
3324 126 : bnr = Buchray(bnf, f, nf_INIT|nf_GEN);
3325 126 : if (is_pm1(bnr_get_no(bnr))) { set_avma(av); return pol_x(0); }
3326 126 : if (signe(D) > 0)
3327 7 : y = bnrstark(bnr, H, prec);
3328 : else
3329 : {
3330 119 : bnr_subgroup_sanitize(&bnr, &H);
3331 119 : y = treatspecialsigma(bnr);
3332 119 : if (!y) y = computeP2(bnr, prec);
3333 : }
3334 126 : return gc_upto(av, y);
3335 : }
|
