Hi Jason, On 10 Dez., 19:34, Jason Grout <jason-s...@creativetrax.com> wrote: > I think you misunderstood the post. They *can* be inherited. The point > is that "according to the Python/C API docs [3], either all of __hash__, > __cmp__, and __richcmp__ are inherited, or none are. " > > In our case, since none of these three is defined in > vector_rational_dense, they are all inherited from free_module_element.
Yep, that's where my search ended as well, a bit later today. > I inserted > > print "_cmp_c_impl in vector_rational_dense.pyx" > > in the vector_rational_dense.pyx _cmp_c_impl function. I inserted > > print "_cmp_c_impl in FreeModuleElement (free_module_element.pyx)" > > in the free_module_element.pyx _cmp_c_impl function, and > > print "__richcmp__ in FreeModuleElement (free_module_element.pyx)" > > in the free_module_element.pyx __richcmp__ function. Then I get the > following: > > sage: v = vector(QQ, [0,0,0,0]) > sage: w = vector(QQ, [-1,3/2,0,0]) > sage: cm = sage.structure.element.get_coercion_model(); cm > <sage.structure.coerce.CoercionModel_cache_maps object at 0x101f686b0> > sage: cm.explain(v,w,operator.eq) > Identical parents, arithmetic performed immediately. > Result lives in Vector space of dimension 4 over Rational Field > Vector space of dimension 4 over Rational Field > sage: v==w > __richcmp__ in FreeModuleElement (free_module_element.pyx) > False > sage: cmp(v,w) > __richcmp__ in FreeModuleElement (free_module_element.pyx) > __richcmp__ in FreeModuleElement (free_module_element.pyx) > __richcmp__ in FreeModuleElement (free_module_element.pyx) > 1 > > So I see that it is the free module element class (the superclass of > vector_rational_dense) has the __richcmp__ function defined, and it > calls the special FreeModuleElement._cmp_same_ambient_c function. So we > are not using the coercion system, nor are we using the > vector_rational_dense function, in either of the above calls. Hence, in a nutshell, the module elements are not conformal to what *should* be done: They have their own custom __richcmp__ method, rather than copying the default one from Element; and the _cmp_c_impl method, that is supposed to implement comparison, is actually not called. Currently, I work on coercion of modules. So, probably this is something I'll take care of. Cheers, Simon -- 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
