Karim Belabas on Wed, 02 Jun 2004 19:20:05 +0200 |
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Re: Bug#40: bnrinit() bug |
* Igor Schein [2004-05-31 07:48]: > Package: pari > Version: 2.2.8 (development CHANGES-1.944) > Severity: normal > > \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ > realprecision = 28 significant digits > seriesprecision = 16 significant terms > format = g0.28 > > parisize = 8000000, primelimit = 500000 > ? bnrinit(bnfinit(y^16-232*y^14+17564*y^12-592696*y^10+10090294*y^8-87937112*y^6+356253116*y^4-482477960*y^2+143400625),60,1); > *** bnrinit: impossible inverse modulo: Mod(5, 300). > \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ Fixed in CVS. A typo in recent primedec() code [ some computation mod p, should have been mod p^2 ]. I have added some missing garbage collection as well. Note to myself: bnrinit(,,1) insists on finding generators as ideals with the right "signature", which is a very bad idea. It would be (much) better to represent an element of Cl_f(K) by a collection of signs at the infinite places of the divisor f, and an ideal coprime to the finite part of f [ in compact representation, e.g a partial factorisation into principal ideals arising from successive products and LLL reductions ]. And the code would be simpler. This would break backward compatibility in a serious way though. In the same way as using compact representations for isprincipal() output or fundamental units would. Cheers, Karim. > P.S. > > How come the first 3 default lines are indented, then a blank line, > then an unindented line with 2 defaults on it? A bit of a visual > dissonance. History [ there were no "defaults" up to PARI 1.39.16 (released as 1.900 !) ]. These 3 lines don't serve any real purpose: -- one can query them individually, or ask for the values of all defaults -- among the defaults, these 3 are not especially useful on startup, and they can't be set via the command line (contrary to the other 2). I have removed them to reduce screen clutter. -- Karim Belabas Tel: (+33) (0)1 69 15 57 48 Dep. de Mathematiques, Bat. 425 Fax: (+33) (0)1 69 15 60 19 Universite Paris-Sud http://www.math.u-psud.fr/~belabas/ F-91405 Orsay (France) http://pari.math.u-bordeaux.fr/ [PARI/GP]