On 24/03/07, Travis Oliphant <[EMAIL PROTECTED]> wrote: > My opinion is that a 1-d array in matrix-multiplication should always be > interpreted as a row vector. Is this not what is currently done? If > not, then it is a bug in my mind.
An alternative approach, in line with the usual usage, is that a vector should be interpreted as a row vector or a column vector as necessary to make the expression work out. Of course this can be ambiguous if there's no matrices in the expression, but that's not relevant here. Certainly the *result* of such an operation should be a matrix, not a vector, of the shape that would naturally result. So mat(eye(2))*ones(2) should realize that the operation doesn't make sense if it's a row vector, convert it to a column vector, do the multiplication, and return a column vector. (Which is not what it does now, it seems.) Note that taking a vector and left-multiplying it by a matrix is a very natural operation that won't work any more if you treat all vectors as if they were row vectors. Are there instances where this makes matrix multiplication non-associative? Where it is surprising? I've never used numpy's matrices, so this is more here to make sure we consider all the alternatives. Anne _______________________________________________ Numpy-discussion mailing list Numpy-discussion@scipy.org http://projects.scipy.org/mailman/listinfo/numpy-discussion