On Nov 28, 2:34 pm, "William Stein" <[EMAIL PROTECTED]> wrote:
> On Nov 27, 2007 4:21 PM, mabshoff
>
>
>
> <[EMAIL PROTECTED]> wrote:
>
> > Hello folks,
>
> > somewhere since 2.8.3 we introduced a new bug that seems to affect
> > computing the power of matrices when the entries are multivariate
> > polynomials with rational coefficients:
>
> > [EMAIL PROTECTED] sage-2.8.14$ ./sage
> > ----------------------------------------------------------------------
> > | SAGE Version 2.8.14, Release Date: 2007-11-24 |
> > | Type notebook() for the GUI, and license() for information. |
> > ----------------------------------------------------------------------
>
> > sage: R.<x,y>=MPolynomialRing(QQ,2)
> > sage: A = matrix([[Integer(1),x], [y,Integer(1)]])
> > sage: A
>
> > [1 x]
> > [y 1]
> > sage: A*A
>
> > [x*y + 1 2*x]
> > [ 2*y x*y + 1]
> > sage: A**2
>
> > ------------------------------------------------------------
> > Unhandled SIGSEGV: A segmentation fault occured in SAGE.
> > This probably occured because a *compiled* component
> > of SAGE has a bug in it (typically accessing invalid memory)
> > or is not properly wrapped with _sig_on, _sig_off.
> > You might want to run SAGE under gdb with 'sage -gdb' to debug this.
> > SAGE will now terminate (sorry).
> > ------------------------------------------------------------
>
> I cannot replicate this on either sage.math or osx 10.5 intel:
>
> [EMAIL PROTECTED]:~$ sage
> ----------------------------------------------------------------------
> | SAGE Version 2.8.14, Release Date: 2007-11-24 |
> | Type notebook() for the GUI, and license() for information. |
> ----------------------------------------------------------------------
>
> sage: sage: R.<x,y>=MPolynomialRing(QQ,2)
> sage: sage: A = matrix([[Integer(1),x], [y,Integer(1)]])
> sage: A
>
> [1 x]
> [y 1]
> sage: A*A
>
> [x*y + 1 2*x]
> [ 2*y x*y + 1]
> sage: A**2
>
> [x*y + 1 2*x]
> [ 2*y x*y + 1]
>
> keyah:~ was$ sage
> ----------------------------------------------------------------------
> | SAGE Version 2.8.14, Release Date: 2007-11-24 |
> | Type notebook() for the GUI, and license() for information. |
> ----------------------------------------------------------------------
>
> sage: sage: R.<x,y>=MPolynomialRing(QQ,2)
> sage: sage: A = matrix([[Integer(1),x], [y,Integer(1)]])
> sage: A^3
>
> [ 3*x*y + 1 x^2*y + 3*x]
> [x*y^2 + 3*y 3*x*y + 1]
> sage: A^2
>
> [x*y + 1 2*x]
> [ 2*y x*y + 1]
> sage: A
>
> [1 x]
> [y 1]
> sage: A**2
>
> [x*y + 1 2*x]
> [ 2*y x*y + 1]
>
> -----
>
> Your subject line suggests maybe this is a solaris-only issue? Is
> that the case?
Yep.
> If so, what does "sage -gdb" have to say about it?
>
I get a pretty bt that point to __cmp__ in libSingular. Notice that it
depends on the coefficient ring, i.e. mv polynomials over ZZ are fine,
QQ not so much. I am currently building 2.8.14 on Linux PPC under
Linux because I suspect endianess issues and I have valgrind there
also to investigate.
I am doing "real" work right now, but I should be done with that in
8-10 hours ;). Once I am done I will get back to Sage and open ticket
for all the issues I have uncovered during the port. I have 2.8.14 on
neron in /tmp. You need to set LD_LIBRRAY_PATH to my 4.2.1-2 gcc to
play with it.
I also created http://wiki.sagemath.org/solaris to keep track of the
port.
> William
Cheers,
Michael
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