On 25 nov, 09:34, Florent Hivert <florent.hiv...@lri.fr> wrote:
> Hi Burcin,
>
>
>
>
>
>
>
>
>
> > Your example was trying to multiply two instances of the class bla.
> > Here is what I guess you meant to write:
>
> > sage: m1 = bla()
> > sage: m2 = bla()
> > sage: a, b = x.ind[m1],2*x.ind[m2]
> > Traceback (most recent call last)
> > <snip>
> > in sage.symbolic.expression.Expression._add_
> > (sage/symbolic/expression.cpp:11082)()
>
> > TypeError: unsupported operand type(s) for -: 'bla' and 'bla'
>
> > Note that it is trying to subtract the objects. Probably trying to
> > check equality. :)
>
> Of course ! I should had figured out it !
>
>
>
>
>
>
>
>
>
> > > WTF ! Why is it adding or multiplying my indices for nothing ! It is
> > > a problem of Ginac ? of the wrapper ? or behind the chair and the
> > > screen ?
>
> > Here is the backtrace:
>
> > Breakpoint 2, GiNaC::numeric::sub (this=0x7fffffffb4a0, other=...)
> > at numeric.cpp:1745
> > 1745 {
> > (gdb) call this->dbgprint()
> > <class '__main__.bla'>
> > (gdb) call other.dbgprint()
> > <class '__main__.bla'>
> > (gdb) bt
> > #0 GiNaC::numeric::sub (this=0x7fffffffb4a0, other=...) at numeric.cpp:1745
> > #1 0x00007fffd687c599 in GiNaC::operator- (lh=<value optimized out>,
> > rh=<value optimized out>) at operators.cpp:97
> > #2 0x00007fffd6879226 in GiNaC::numeric::compare_same_type (this=0x4796060,
> > other=...) at numeric.cpp:1700
> > #3 0x00007fffd67ca25a in compare (this=0x3d9cd10, other=...) at ex.h:339
> > #4 GiNaC::idx::compare_same_type (this=0x3d9cd10, other=...) at idx.cpp:278
> > #5 0x00007fffd6ce0aad in compare (this=<value optimized out>,
> > other=<value optimized out>)
> > at /home/burcin/sage/sage-4.7.2/local/include/pynac/ex.h:339
> > #6 GiNaC::container<std::vector>::compare_same_type (
> > this=<value optimized out>, other=<value optimized out>)
> > at /home/burcin/sage/sage-4.7.2/local/include/pynac/container.h:625
> > #7 0x00007fffd67b5f5e in compare (this=0x45508e0, lh=<value optimized out>,
> > rh=...) at ex.h:339
> > #8 GiNaC::expairseq::construct_from_2_ex (this=0x45508e0,
> > lh=<value optimized out>, rh=...) at expairseq.cpp:887
> > #9 0x00007fffd6771beb in GiNaC::add::add (this=0x45508e0, lh=..., rh=...)
> > at add.cpp:70
> > #10 0x00007fffd687c46c in exadd (lh=..., rh=...) at operators.cpp:42
> > #11 GiNaC::operator+ (lh=..., rh=...) at operators.cpp:69
> > #12 0x00007fffd644e489 in
> > __pyx_f_4sage_8symbolic_10expression_10Expression__add_
> > (__pyx_v_left=0x4757050, __pyx_v_right=0x4757d40,
>
> I should really learn how to debug those. Is
> http://wiki.cython.org/DebuggingTechniques
> the best starting point. Any suggestions ?
Don't know that page, but any tuto on gdb should do.
I guess yo have to start sage inside gdb with:
"./sage -gdb"
Then you add some breakpoints where you want:
Press CTRL+C to get inside gdb and type
"break [...]"
where ... is typically GiNaC::numeric::add or ...::compare_same_type
(you should get some completion in gdb anyway).
bt or backtrace gives you the backtrace.
>
> > In English: it tries to normalize the resulting expression in
> > construct_from_2_ex(). This means checking if the two arguments are equal.
> > Going through idx::compare_same type(), it ends up in
> > numeric::compare_same_type(). Here is the code for that function:
>
> > int numeric::compare_same_type(const basic &other) const
> > {
> > GINAC_ASSERT(is_exactly_a<numeric>(other));
> > const numeric &o = static_cast<const numeric &>(other);
> > int cmpval = (real() - o.real()).csgn();
> > if (cmpval != 0)
> > return cmpval;
> > return (imag() - o.imag()).csgn();
> > }
>
> > We should change this somehow. Maybe we could try PyObject_Compare and fall
> > back to this if it fails.
>
> Looks to me like a solution. Does it mean patch GiNaC at sage level or at
> PyNaC level ?
I guess it would be at the pynac level.
Have a look at the numeric.cpp file.
>
> > Comments?
>
> Is there a way to tell, at the Ginac/C++ level, if an object is a standard
> GiNaC one or an abject wrapping a Python object ?
I guess Burcin could answer that question :)
By the way, this is kind of bad (even if you should not try that kind
of things normally...):
sage: x = polygen(RR)
sage: y = SR._force_pyobject(x)
sage: y._cmp_(3)
BOUM! (i.e. SIGSEGV)
This is on my 4.7.1.rc1 with plenty of patches, surely a custom pynac
and so oon, but I guess a vanilla installation would do the same.
I'll try to have a look at this, but have to build Sage 4.7.2 on the
machine I can access this week-end first and apply the patches.
>
> Florent
--
To post to this group, send an email to sage-devel@googlegroups.com
To unsubscribe from this group, send an email to
sage-devel+unsubscr...@googlegroups.com
For more options, visit this group at http://groups.google.com/group/sage-devel
URL: http://www.sagemath.org
