OpenBLAS

OpenBLAS

[Federico Beffa]

Hi,

I'm wondering why our OpenBLAS package is built with the flag
"NO_LAPACK=1". It is my understanding that with this optional flag
OpenBLAS doesn't include LAPACK, while without this flag and by
default it does include the LAPACK functions.  In the latter case
OpenBLAS could be used by a larger number of packages which do require
LAPACK functions.

https://github.com/xianyi/OpenBLAS/issues/203

Regards,
Fede

Re: OpenBLAS

[Pjotr Prins]

On Sat, Oct 08, 2016 at 10:13:39PM +0200, Federico Beffa wrote:
> Hi,
> 
> I'm wondering why our OpenBLAS package is built with the flag
> "NO_LAPACK=1". It is my understanding that with this optional flag
> OpenBLAS doesn't include LAPACK, while without this flag and by
> default it does include the LAPACK functions.  In the latter case
> OpenBLAS could be used by a larger number of packages which do require
> LAPACK functions.
> 
> https://github.com/xianyi/OpenBLAS/issues/203

NO_LAPACK=0 does not use external libs. NO_LAPACK=1 uses external
liblapack. They both cover LAPACK functionality.

NO_LAPACK=1 is the conservative choice - it still is what most
software has been developed against today.

OpenBLAS has merged LAPACK code and they have been changing things,
claiming their version is better performing. But since it is less well
tested, new bugs are quite possible. I have hit at least one OpenBLAS
bug, so far.

Personally I think we should have both options in Guix, but we should
probably keep defaulting to NO_LAPACK=1.

Pj.

Re: OpenBLAS

[Federico Beffa]

On Sun, Oct 9, 2016 at 2:19 PM, Pjotr Prins <pjotr.public12@thebird.nl> wrote:
> On Sat, Oct 08, 2016 at 10:13:39PM +0200, Federico Beffa wrote:
>> Hi,
>>
>> I'm wondering why our OpenBLAS package is built with the flag
>> "NO_LAPACK=1". It is my understanding that with this optional flag
>> OpenBLAS doesn't include LAPACK, while without this flag and by
>> default it does include the LAPACK functions.  In the latter case
>> OpenBLAS could be used by a larger number of packages which do require
>> LAPACK functions.
>>
>> https://github.com/xianyi/OpenBLAS/issues/203
>
> NO_LAPACK=0 does not use external libs. NO_LAPACK=1 uses external
> liblapack. They both cover LAPACK functionality.
>
> NO_LAPACK=1 is the conservative choice - it still is what most
> software has been developed against today.
>
> OpenBLAS has merged LAPACK code and they have been changing things,
> claiming their version is better performing. But since it is less well
> tested, new bugs are quite possible. I have hit at least one OpenBLAS
> bug, so far.

Thanks for the info.  OpenBLAS is now around since several years and
has gained in popularity. I'm sure that any bug report will be
addressed timely.

In any case, I find that with "NO_LAPACK=1" hmatrix can't use it
http://hackage.haskell.org/package/hmatrix

>
> Personally I think we should have both options in Guix, but we should
> probably keep defaulting to NO_LAPACK=1.

For the moment I will use LAPACK.  If your proposal will happen I will switch.

Thanks for the reply,
Fede