On Mon, Jun 6, 2016 at 9:35 AM, Sebastian Berg <sebast...@sipsolutions.net> wrote:
> On So, 2016-06-05 at 19:20 -0600, Charles R Harris wrote: > > > > > > On Sun, Jun 5, 2016 at 6:41 PM, Stephan Hoyer <sho...@gmail.com> > > wrote: > > > If possible, I'd love to add new functions for "generalized ufunc" > > > linear algebra, and then deprecate (or at least discourage) using > > > the older versions with inferior broadcasting rules. Adding a new > > > keyword arg means we'll be stuck with an awkward API for a long > > > time to come. > > > > > > There are three types of matrix/vector products for which ufuncs > > > would be nice: > > > 1. matrix-matrix product (covered by matmul) > > > 2. matrix-vector product > > > 3. vector-vector (inner) product > > > > > > It's straightful to implement either of the later two options by > > > inserting dummy dimensions and then calling matmul, but that's a > > > pretty awkward API, especially for inner products. Unfortunately, > > > we already use the two most obvious one word names for vector inner > > > products (inner and dot). But on the other hand, one word names are > > > not very descriptive, and the short name "dot" probably mostly > > > exists because of the lack of an infix operator. > > > > > > So I'll start by throwing out some potential new names: > > > > > > For matrix-vector products: > > > matvecmul (if it's worth making a new operator) > > > > > > For inner products: > > > vecmul (similar to matmul, but probably too ambiguous) > > > dot_product > > > inner_prod > > > inner_product > > > > > I was using mulmatvec, mulvecmat, mulvecvec back when I was looking > > at this. I suppose the mul could also go in the middle, or maybe > > change it to x and put it in the middle: matxvec, vecxmat, vecxvec. > > > > Were not some of this part of the gufunc linalg functions and we just > removed it because we were not sure about the API? Not sure anymore, > but might be worth to have a look. > We have from numpy.core.umath_tests import inner1d which does vectorized vector-vector multiplication, but it's undocumented. There is also a matrix_multiply in that same module that does the obvious thing. And when gufuncs were introduced in linalg, there were a bunch of functions doing all sorts of operations without intermediate storage, e.g. sum3(a, b, c) -> a + b + c, that were removed before merging the PR. Wasn't involved at the time, so not sure what the rationale was. Since we are at it, should quadratic/bilinear forms get their own function too? That is, after all, what the OP was asking for. Jaime -- (\__/) ( O.o) ( > <) Este es Conejo. Copia a Conejo en tu firma y ayúdale en sus planes de dominación mundial.
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