Re: Vector sum

Am 19.07.2025 um 16:51 schrieb Anton Ertl:

minforth <minforth@gmx.net> writes:

Am 19.07.2025 um 12:18 schrieb Anton Ertl:
>

One way to deal with all that would be to have a long-vector stack and
have something like my vector wordset
<https://github.com/AntonErtl/vectors>, where the sum of a vector
would be a word that is implemented in some lower-level way (e.g.,
assembly language); the sum of a vector is actually a planned, but not
yet existing feature of this wordset.
>

>
Not wanting to sound negative, but who in practice adds up long
vectors, apart from testing compilers and fp-arithmetic?

 Everyone who does dot-products.
 

Dot products, on the other hand, are fundamental for many linear
algebra algorithms, eg. matrix multiplication and AI.

 If I add a vector-sum word
 df+red ( dfv -- r )
\ r is the sum of the elements of dfv
 to the vector wordset, then the dot-product is:
 : dot-product ( dfv1 dfv2 -- r )
   df*v df+red ;

Sure, slow hand is not just for guitar players.
With FMA, one could traverse the vectors in one go.
https://docs.nvidia.com/cuda/floating-point/index.html

Concerning matrix multiplication, while you can use the dot-product
for it, there are many other ways to do it, and some are more
efficient (although, admittedly, I have not used pairwise addition for
these ways).

There are tons of algorithms depending on various matrix properties.
Then, given a desktop and a fat CPU, LAPACK et al. are your friends.
Embedded or special CPU .. is a different story.