On 26 nov, 21:01, Jean-Pierre Flori <jpfl...@gmail.com> wrote:
> On 25 nov, 09:34, Florent Hivert <florent.hiv...@lri.fr> wrote:
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> > 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 ?
>
> > > 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 ?
>
> > > 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 ?
>
> If I understand correctly, the numeric class is more or less a wrapper
> for the Number_t class.
> In the Number_T class there are a Value var and a Type var you could
> use to make such a decision.
>
> For the original problem, I guess it's up to Burcin to make the
> decision.
> I guess we should modify numeric::compare_same_type to call a
> corresponding method in the Number_T.
> This could call PyObject_Compare as Burcin suggest or one of the
> operator<=.
I implemented a small Number_T::compare_same_type function which seems
to fix the above situation (you can add things indexed by bla
objects), but it could also have broke everything else.
A patch to apply agains pynac is available at
http://www.infres.enst.fr/~flori/sage/cst.patch.
It touches numeric.cpp and numeric.h
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> > Florent
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