URGENT: MatrixProduct.scala is missing Matrix * col and row * Matrix

[johnynek]

WTF?

Someone should quickly add something like:

mat * (col.toMatrix(true)).getCol(true)

((row.toMatrix(true)) * mat).getRow(true)

That should be in before the next release. A fancier algorithm could possibly improve this when the vectors are really small.

[ccsevers]

I started on this earlier today, should have something once I get out of meetings.

[joshdevins]

Glad I mentioned something on the mailing list ;) @ccsevers do you have a repo/branch I can clone?

[ccsevers]

I put up a new branch in my fork called vector_implicits. Let me write a couple tests and I'll open a pull request.

I added row_Mat, Mat_col, vec+vec, vec-vec, vec hProd vec and col * row (outer product, dangerous).

[johnynek]

Sweet, Chris.

Outer-product is interesting. One idea I had for outer-product was to make a separate class for it, and not actually materialize the result. Since:
|v><u| * |w><x| = <u|w>* |v><x|, and similarly with multiplying by matrices, you can avoid the materialization for a long time.

We can add outer-product now (people should just be careful), but it might be interesting to think of these algebraic optimizations that a Matrix aware scheduler can do.