[MITgcm-support] why gsl in some opt files but not others

[Constantinos Evangelinos]

I had forgotten to respond to this:

On Thursday 16 October 2008 05:26:48 pm David Hebert wrote:

> I am attempting to compile code on CRAY XT4 that has both Portland Group
> and Pathscale compilers. I have noticed that in the linux_amd64_pathf90 opt
> file there are flags for gnu scientific library (gsl), but not for
> linux_amd64_pgf90. Is there a reason for this? 

I never got round to updating the optfiles for pgf90

> Do both methods use gsl? 

To use GSL with a recent version of the code you need to add -gsl to the 
genmake2 line and already have GSLLIB and GSLINC defined to be 
the "-Lgsllibdir -lgsl etc." and "-Igslincdir" strings appropriate for your 
system.

> Is  
> there an option to use local scientific/math libraries, such as AMD core
> math libraries available on this particular system?

No - we don't use any BLAS or LAPACK within MITgcm (and FFTs only rarely) so 
it is irrelevant. GSL is not used to provide math library support - it is 
used to provide fine grained control over floating point precision and 
floating point exception trap management (so you can stop the moment a NaN is 
produced). For details look at:
http://www.gnu.org/software/gsl/manual/html_node/Setting-up-your-IEEE-environment.html

Constantinos
-- 
Dr. Constantinos Evangelinos
Department of Earth, Atmospheric and Planetary Sciences
Massachusetts Institute of Technology