[Insight-developers] Thread-safety issues - netlib

[Luis Ibanez]

Hi Kris,

Thanks for pointing us to ATLAS,

It may actually be a good option, since its license
is a BSD-style just like the ITK one:

http://math-atlas.sourceforge.net/devel/atlas_contrib/node5.html



    Regards,


       Luis


--------------------------
Kris Thielemans wrote:

> Hi
> 
> I have no idea how much effort all this involves, but I wonder if it
> wouldn't be worth it converting to ATLAS
> (http://math-atlas.sourceforge.net), at least, if it supports enough of
> LAPACK for your purposes. From their web-page:
> 
> What LAPACK routines does ATLAS provide?
> The only way to be sure you have the most up-to-date list is to examine the
> source in ATLAS/interfaces/lapack/F77/src/. It is pretty much a foregone
> conclusion that any documentation, this page included, will eventually
> become out of date. ATLAS3.6 provided C and Fortran77 interfaces to these
> routines: 
> [S,D,C,Z]GESV
> [S,D,C,Z]GETRF
> [S,D,C,Z]GETRS
> [S,D,C,Z]GETRI
> [S,D,C,Z]TRTRI
> [S,D,C,Z]POSV
> [S,D,C,Z]POTRF
> [S,D,C,Z]POTRS
> [S,D,C,Z]POTRI
> [S,D,C,Z]LAUUM 
> 
> Is ATLAS thread safe?
> It should be completely safe to call any ATLAS routine from a threaded code.
> There are no global variables, or other shared information between routines.
> Probably the best idea is to say "yes" to threading in config, even if you
> wish to do the threading yourself. That way, the ATLAS lib will be compiled
> with the threading flags. Then, simply link to the serial interface so that
> ATLAS doesn't do the threading. If you want ATLAS to do the threading as
> well, simply link to the threaded interface.
> 
> Can I vary the number of threads ATLAS uses dynamically?
> No. The maximum number of threads to use is determined at compile time.
> ATLAS will never use more than this, but may use less if the problem sizes
> are too small to get speedup from the additional parallelism.
> 
> 
> All the best
> 
> Kris Thielemans
> 
> Hammersmith Imanet, part of GE Healthcare Cyclotron Building Hammersmith
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