A quick look at your output suggest that the division poly code is
getting into an infite recursion -- if so, that would explain running
out of memory.  I will look into it.

John Cremona

On Jun 23, 2:17 pm, adam mohamed <[email protected]> wrote:
> Hi All,
>
>  I solve the problem with the memory, thanks to William. But, now when I
> impose some strict conditions so that I have to toss say 100 times in order
> to hope for some curves to pop up,  I am getting different kind of errors. I
> have attached the code and the error message I got hereby. Maybe my code is
> too naive that why I am having this problem.
>
> What I don't get is why the code seems to do well when the conditions are
> less restrictive but once I change a little bit, them Sage is not happy!
> Maybe one has to implement Reinier algorithms in order to avoid  these kind
> of problems. Is this doable in Sage now?
>
> Best wishes,
>
> Adam
>
> On Tue, Jun 23, 2009 at 1:14 PM, John Cremona <[email protected]>wrote:
>
>
>
> > On Jun 22, 7:59 pm, adam mohamed <[email protected]> wrote:
> > >  Hi,
>
> > >  Thanks for the very quick response. I will try that tomorrow. Now  I
> > > understand the problem that we met when running the same code in  a linux
> > > machine.
> > >  I am doing this search for cryptographic applications, so I am dealing
> > with
> > > primes from the size of 170 bit Length.
> > > I would like the 2-sylow of E( F_p)  to be  Z/4Z and #E( F_p) = 4*L  with
> > > L  prime.
>
> > > Reinier Broker did his PhD about EC with prescribed order and we will
> > would
> > > like to find out if his algorithms have been implemented in Sage?
>
> > Hello Adam,
>
> > No, as far as I know Sage has nothing implemented for finding curves
> > with prescribed order or structure.
>
> > John
>
> > > Regards,
>
> > > Adam
>
> > > On Mon, Jun 22, 2009 at 6:31 PM, William Stein <[email protected]> wrote:
>
> > > > On Mon, Jun 22, 2009 at 5:35 PM, harivola<[email protected]
>
> > > > wrote:
>
> > > > > Hi all,
>
> > > > >  I am running a small script on a windows xp machine and some time I
> > > > > am getting this error message:
> > > > >  /usr/local/sage/local/bin/sage-sage: line 348: 19954 Killed
> > > > >  python "$@"
>
> > > > You're probably running out of memory (=RAM).  Try editing the file
> > > > sage_vmx.vmx and increase the amount of RAM that is made available to
> > > > the vmware machine running Sage.  The default amount is very small.
>
> > > > > I don't get the meaning of that. By the way, does someone know an
> > > > > efficient way in Sage to search for EC with prescribed order ( I need
> > > > > curves over a big prime field with rational points of order 4 and
> > > > > cofactor 4 ). Thanks.
>
> > > > Be way more precise.  How big is "big prime field"? Do you want
> > > > #E(F_p) = 4*n with n odd?  Do you require that #E(E_p)[2] = 4 too?
>
> > > > William
>
> > > > > Best wishes
>
> > > > --
> > > > William Stein
> > > > Associate Professor of Mathematics
> > > > University of Washington
> > > >http://wstein.org
>
>
>
>  full_output.txt
> 42KViewDownload
>
>  test_ell.sage
> 2KViewDownload
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