|Bill Allombert on Sat, 18 Dec 2010 17:39:37 +0100|
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|Re: weird behaviour of rnfequation|
On Wed, Dec 15, 2010 at 05:25:38PM +0100, Luis Felipe Tabera Alonso wrote: > Hi all, > > I have encounter the following behaviour in pari with the version that comes > with sage. I have confirmed that this happens in pari/gp stable as released by > Debian (2.3.5) and with the development version downloaded from the web (2.4.3 > (alpha)), both 64 bits. > > The problem is the following, I have the following dummy rnfequation: > > ? f = (y^17-1)/(y-1); > ? g = Mod(1,f)*x+Mod(y^6,f); > ? rnfequation(f,g,1); > *** rnfequation: the PARI stack overflows ! > current stack size: 8000000 (7.629 Mbytes) > [hint] you can increase GP stack with allocatemem() Hello Luis, This is certainly a bug. rnfequation use a modular algorithm to compute rnfequation(f,g,1) which unfortunately diverge here. I have recorded this issue in our bug tracking system as bug number 1151 <http://pari.math.u-bordeaux.fr/cgi-bin/bugreport.cgi?bug=1151> so we do not forget about it. Cheers, Bill.