[gmx-users] Re: Blue Gene Compile - GROMACS 4

[Mark Abraham]

Mike Hanby wrote:
> Howdy,
> 
>  
> 
> I'm looking at compiling Gromacs 4 for the Blue Gene/L and am stuck at
> the compilation of the prerequisite FFTW 3.1.3.
> 
>  
> 
> If anyone out there has successfully cross compiled FFTW and Gromacs for
> the Blue Gene, would you mind sharing your settings used to run the
> ./configure scripts?
> 
>  
> 
> I'm getting "cannot compute sizeof (unsigned int)" which tells me I'm
> not giving it enough information for the cross compilation.

There's two key components: using the BG/L cross compilers (blrts_xlc 
and blrts_xlf) and letting configure know that you are using cross 
compilers, so that its tests are constructed using successful 
compilation, not successful execution.

I've successfully used

#!/bin/bash

CFLAGS="-O5 -qbgl -qarch=440d 
-qcache=level=1:type=i:size=32:line=32:assoc=64:cost=8 
-qcache=level=1:type=d:size=32:line=32:assoc=64:cost=8 
-qcache=level=2:type=c:size=4096:line=128:assoc=8:cost=40 -qnoautoconfig 
-qfloat=norngchk -qhot -qignerrno"

./configure CC=blrts_xlc --host=powerpc --build=ppc64

Note that some of those compiler flags are probably redundant, and you 
should read up on whether you actually want them all.

Mark