Re: nffactor() slowdown

[Igor Schein <igor@txc.com>]

On Wed, Jun 19, 2002 at 05:33:58PM +0200, Karim BELABAS wrote:
> On Tue, 18 Jun 2002, Igor Schein wrote:
> > I compared nffactor's speed between 2.2.3 and 2.2.4, and latter
> > is on average 10-25% slower on the type of polynomials I tried - large
> > Galois polynomials over cyclotomic or quarternion fields.
> 
> (hence totally split polynomials ?)
> 
> Does nfroots suffer from the same problem ?

No, they are not split at all, in fact nfroots() outputs [].

> 
> Can you post a few representative examples ?

You can use this one, after the bug is fixed, or any of the 2 I've
posted during the last week on the list:

? nffactor(nfinit(polcyclo(13,y)),x^72-291*x^70+168*x^69+40380*x^68-48588*x^67-3528919*x^66+6672120*x^65+215657160*x^64-575538144*x^63-9642387423*x^62+34735086786*x^61+318475831783*x^60-1543992152304*x^59-7526047084203*x^58+51709921323996*x^57+110268119466273*x^56-1306863903654948*x^55-197687339387338*x^54+24340617020480994*x^53-37674206381844006*x^52-309388136734870296*x^51+1097175021601270233*x^50+1965430743178095924*x^49-17057741307681944498*x^48+12695705864721864408*x^47+149941210123858078557*x^46-449449010694960248724*x^45-360137445013361079753*x^44+4743771886303072354536*x^43-7957480107528139931362*x^42-20006312987061736459890*x^41+103127662005251951018025*x^40-57922725775374790826892*x^39-575374977336477060878406*x^38+1141042155363070337681952*x^37+2107623272811930164219492*x^36-8555883275792119671168984*x^35-6622038332271478648217502*x^34+67788499073804904961005264*x^33-62194621346216574281355513*x^32-298503076979390816950994616*x^31+935868776923024509133161567*x^30-602191893688026944562387144*x^29-2378403718028116295265005703*x^28+7144715267789671188060423636*x^27-8264313767410946129053876314*x^26-2988303993119955116599622124*x^25+36320303706133493815706370331*x^24-93405543373036036850518472592*x^23+137892731303549623166716872621*x^22-73374564495372153466268524626*x^21-180690507689854149951443988039*x^20+506199649638427572646328975856*x^19-511453665473658325356669209047*x^18-183193264910244539106552118338*x^17+1423840911419731272911578335897*x^16-2367314022969857609246689985844*x^15+2236677523353346112926136338695*x^14-1548489683091587051973217338168*x^13+2105049137205776145162583648404*x^12-4754348311294629767834593856064*x^11+7567806891220394207855512254933*x^10-7605431066578089163623568649610*x^9+3882625664788999249342771140339*x^8+1356469287400668040516453202076*x^7-3841355512345259545848813224621*x^6+2330504083587501732658867007532*x^5-169172628407290891217225606775*x^4-398965703199322569698936377044*x^3+198978398979453484569202793808*x^2-60597282938946837445378411698*x+12280639561039083425818958713)
  ***   bug in LLL_cmbf [no factor], please report

Thanks

Igor