no vector = vector*vector in BLAS? 
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 no vector = vector*vector in BLAS?

Hi,

I am wondering why there is no
res(1:1000) = v1(1:1000) * v2(1:1000)
subroutine in the BLAS set...

_gbmv could be used with kl = ku = 0, but seems to
be much slower than the f90 construct above.

any hints?

thanks
juergen



Sat, 22 Feb 2003 21:06:31 GMT  
 no vector = vector*vector in BLAS?

Quote:
>I am wondering why there is no
>res(1:1000) = v1(1:1000) * v2(1:1000)
>subroutine in the BLAS set...

>_gbmv could be used with kl = ku = 0, but seems to
>be much slower than the f90 construct above.

>any hints?

I think because the BLAS were intended to provide
operations that were useful in the solution of sets of
linear equations, and this element-by-element
multiply does not fall into that category.

Element-by-element multiply and an operation to
set all the elements of a vector to a single value
have been the "BLAS-like" routines I have needed most.
I have constructed fortran versions by modifying the
reference BLAS routines, and hoped the compilers
could optimize them reasonably.  So far I have not
found that they are dominating the run times of any
of my programs.

-George.



Sun, 23 Feb 2003 00:07:50 GMT  
 
 [ 2 post ] 

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