Re: Instructions for Installing BLAS and LAPACK library on Octave 5.2.0

On Tuesday, 29 September 2020, Nicholas Jankowski <[email protected]>
wrote:

>
>>>    - Downloading Octave 5.2.0-64 bit executable from the official GNU
>>>    Octave website(https://www.gnu.org/software/octave/download.html#
>>>    ms-windows) for Win 10
>>>    - Installing the same and checking with the default OPENBLAS library.
>>>    - Assigning the value for the environment variable  OPENBLAS_NUM_THREADS
>>>    = "the number of processors we need to utilize"
>>>    -
>>>
>>>
>> The second step is not necessary. Otherwise yes.
>>
>> Ian
>>
>
>  Do you mean the installing or assigning step?
>
> My apologies. I was away from my desk any failed to give the question my
full attention.

Install ( of course), but the default installation does result in
libopenblas.dll being copied to libblass.dll so that "checking with the
default OPENBLAS library" is not necessary.

In my default config zip install, OPENBLAS_NUM_THREADS was empty.  I set it
> to different values from 1-4 since I have a 4 core machine, and didn't
> notice any real difference running that test routine you posted.  i
> extended the 1e8 to 2e8 and 1e9 to get meaningful runtimes, but there
> seemed to be no difference changing the value of that option.  in all cases
> multiple cores were taxed on execution.  It's a managed machine so I don't
> have Process Explorer to actually verify the thread count, so maybe other
> things are happening that I'm not noticing.
>

I have the same result. I have task manager and whatever the value of
OPENBLAS_NUM_THREADS the execution time is the same and the cpu utilisation
peaks at the same level so it would appear the environment variable is
being ignored. I will investigate further as my system uses this,
succesfully I believe!

Cheers Ian