On Sat, May 30, 2015 at 6:23 PM, Charles R Harris <[email protected] > wrote:
> The problem arises when multiplying a stack of matrices times a vector. > PEP465 defines this as appending a '1' to the dimensions of the vector and > doing the defined stacked matrix multiply, then removing the last dimension > from the result. Note that in the middle step we have a stack of matrices > and after removing the last dimension we will still have a stack of > matrices. What we want is a stack of vectors, but we can't have those with > our conventions. This makes the result somewhat unexpected. How should we > resolve this? I think that before tackling the @ operator, we should implement the pure dot of stacks of matrices and dot of stacks of vectors generalized ufuncs. The first will have a 2d "core" and the second - 1d. Let's tentatively call them matmul and vecmul. Hopefully matrix vector product can be reduced to the vecmul, but I have not fully figured this out. If not - we may need the third ufunc. Once we have these ufuncs, we can decide what @ operator should do in terms of them and possibly some axes manipulation.
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