Chris Marshall <[email protected]> wrote:

> Well, if I cared about optimizing the matmul
> performance, I would put in an optimized kernel
> for that.

I wonder if there are any PDL users who care about matrix mult. I see a
lot of astronomy people on this list. Not a lot of matrix mult in
astronomy AFAIK.


> Well, I took a look at out default matrix multiply
> in Primitive.pm.  This is the kernel:
> 
>    $a->dummy(1)->inner($b->xchg(0,1)->dummy(2),$c);
> 
> so you can see that the kernel is an inner product
> operation so that the total op count is something
> like:
> 
>    O(N**3) memory ops
>    O(N**3) float ops

Interesting. I have a couple of dumb questions:

1) Why is that O(N**3) memory ops? I'm not very versed with PDL, but it
looks to me that ->dummy() and ->xchg() should not cost any memory. Is
there a reason why ->inner() costs extra memory?


2) Where can I find Primitive.pm? I just downloaded the
sources from git and I can't find it:

% git clone git://pdl.git.sourceforge.net/gitroot/pdl/pdl PDL
% cd PDL
% find . -name Primitive.pm


Daniel.

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