Ilya Zakharevich on Sun, 29 Sep 2002 00:32:58 -0700

[Date Prev] [Date Next] [Thread Prev] [Thread Next] [Date Index] [Thread Index]

Re: extreme behavior of nfsubfields()

On Sun, Sep 29, 2002 at 03:27:34AM -0400, Igor Schein wrote:
> Hi,
> I need to find a degree-27 subfield of a non-Galois degree-81
> polynomial.  When I run nfsubfields(), it returns "too many blocks".
> So I increased the value of oldllist inside choose_prime() from 10^6
> to 5*10^7, and ran gp with 2048MB stack on 32bit Linux.  In a few
> seconds, I saw the screen filled with "***   bug in  ***   bug in  ***
> bug in  *** bug in  ***   bug in  ***   bug in  ***".   If I reduce
> stack size to 1900MB, I'm getting a nicer "not enough memory".  When I
> tried the same on 32bit Solaris with 2048MB stack, the session just
> died with SEGV.  I'll see what happens with 64bit binary, but I'm
> skeptical.

Another reference point: I was very careful with trying to make the
prime limit to be 4G on 32-bit machines (as opposed to 2G).  However,
my tests were misbehaving.  gdb was just dying when I tried to debug
it (on linux).  Which is surprising since one does not need a lot of
memory to store all the primes up to 4G.

At some moment I may try to debug in on 32-bit Solaris...