open TELEMAC-MASCARET The mathematically superior suite of solvers

Hi,

Just out of curiosity, in configuring my systel.cfg I can chose between :

gfortran -c -g -fconvert=big-endian -frecord-marker=4 <mods> <incs> <f95name>

OR

gfortran -c -O3 -fopenmp -fconvert=big-endian -frecord-marker=4 <mods> <incs> <f95name>

OR

gfortran -cpp -c -O2 -fconvert=big-endian -frecord-marker=4 <mods> <incs> <f95name>

What does it change?

Cheers,
Alexis

Hello Alexis,

Some pointers from my experience:

1. -cpp should go only to cmd_obj_c:. It is a pre processor flag required for compiling nestor.
2. -O3 & -O2 are optimization flags. O3 is supposed to generate faster code than O2 but at the potential expense of precision and stability. It also takes more time to compile.
3. -g enables flags to generate code that it makes debugging easier. When using this flag, no optimizations are made and the code runs slower.
4. -fopenmp is a flag that I have yet to find a reasonable explenation for its use in Telemac. As far as I know OpenMP deals with multithreading/shared memory but Telemac is an MPI/distributed memory application.

Best Regards,
Costas