I can confirm that changing in sage.matrix.matrix_generic_dense.Matrix_generic_dense._multiply_classical the line from left._entries[m+k]._mul_ to just left._entries[m+k]* , the code works as expected. So the problem is probably the _mul_.
I think this is a general problem that was not discovered before: as far as I can see, it's legal for element types to have a cdef _mul_. However, in the matrix code, I think it ends up being looked up as a python method. I'm not sure that matrix elements always have to inherit from Element, so I'm not sure a cython typecast to it is warranted. Changing to "*" and just let the coercion framework figure it out is definitely valid, but it should be checked if that brings a performance penalty. Someone should make a ticket and alert the coercion gurus to it. On Thursday, 6 March 2025 at 16:30:27 UTC-8 Nils Bruin wrote: > It's probably a matter that ExteriorAlgebraElement has a "cdef _mul_" now. > That means in cython code it can access the method if it has enough type > information. That's probably why `p*p` works. It looks like in > sage.matrix.matrix_generic_dense.Matrix_generic_dense._multiply_classical > not enough type info is available on left._entries[m+k] to look up this > _mul_ . It may be that the correct typecast, something like "(<Element> > left._entries[m+k])" perhaps, does the trick. Or perhaps _mul_ is supposed > to be "def" or "cpdef". I doubt the latter, though, since for the most > part, multiplication seems to work: the coercion framework can figure out > how to do it: > > sage: coercion_model.bin_op(p,p,operator.mul) > 0 > > it makes sense that matrix multiplication takes a shortcut to avoid the > overhead of the coercion framework. But perhaps it doesn't have enough type > info. > > On Thursday, 6 March 2025 at 15:43:02 UTC-8 Seth Chaiken wrote: > >> In Sage 10.4, >> Ext=ExteriorAlgebra(QQ,['p']) >> Ext.inject_variables() >> Mp = matrix(1,1,[[p]]) >> Mp[0,0]*Mp[0,0] >> -> 0 >> Mp*Mp >> FAILS! >> (This did work in an older version.) >> >> --------------------------------------------------------------------------- >> TypeError Traceback (most recent call last) Cell In[10], line 1 ----> 1 >> Mp*Mp File /data/Software/Sage/sage/src/sage/structure/element.pyx:4116, >> in sage.structure.element.Matrix.__mul__() 4114 # better be square for >> the product to be defined. 4115 if (<Matrix>left)._nrows == >> (<Matrix>left)._ncols: -> 4116 return >> (<Matrix>left)._matrix_times_matrix_(<Matrix>right) 4117 else: 4118 >> parent = (<Matrix>left)._parent File >> /data/Software/Sage/sage/src/sage/matrix/matrix0.pyx:5675, in >> sage.matrix.matrix0.Matrix._matrix_times_matrix_() 5673 return >> self._multiply_strassen(right) 5674 else: -> 5675 return >> self._multiply_classical(right) 5676 5677 cdef bint >> _will_use_strassen(self, Matrix right) except -2: File >> /data/Software/Sage/sage/src/sage/matrix/matrix_generic_dense.pyx:323, >> in >> sage.matrix.matrix_generic_dense.Matrix_generic_dense._multiply_classical >> () 321 m = i*snc 322 for k in range(snc): --> 323 z += >> left._entries[m+k]._mul_(right._entries[k*nc+j]) 324 v[p] = z 325 p += 1 >> TypeError: 'NotImplementedType' object is not callable >> > -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To view this discussion visit https://groups.google.com/d/msgid/sage-support/ca04d82d-89a3-4c48-b0d3-029ba624a71an%40googlegroups.com.
