Comment #3 on issue 2222 by [email protected]: Matrix([Matrix, ...]) should check the row length of empty matrices
http://code.google.com/p/sympy/issues/detail?id=2222
We should only allow Matrix*Matrix work if the number of columns of the first one is equal to the number of rows in the second one (one or more of the dimensions is 0).
Guys, just forget about programming stuff for a moment and try to think about math: whatever you do with a zero-column/row matrix (I wonder whether such objects are allowed to exist at all and it probably would be better to raise an exception in this place) the result will be the same. In other words, one can substitute with no harm a matrix with one of the dimensions equal to zero with 0 (from math point of view of course). Thus, here is a list of solution I see (in a preferable order): * rise NonintegerNumberOfDimensionException; * set all dimensions to 0 once one of them is 0; * treat such objects like 0 or Null. PS. I do not insist on any of the above points and thus feel free to point any weaknesses of the above thoughts. -- You received this message because you are subscribed to the Google Groups "sympy-issues" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/sympy-issues?hl=en.
