Update compiler version and optimized compiler options for ORCHIDEE at curie

[jgipsl]

It has been decided for the coupled model IPSLCM6 to update the compiler version and add new optimization options at curie to have better performances.

LMDZ and the platform group have proposed to

• change compiler version to intel/17.0.2.174 at Curie
• change option -fp-model precise into -fp-model fast=2
• add optimization option -axAVX,SSE4.2

[jgipsl]

Test with ORCHIDEE in offline mode shows that :

• option -fp-model fast=2 gives non reproducibly results which can change quite a lot. => Option -fp-model fast=2 should never be used with ORCHIDEE.
• option -axAVX,SSE4.2 do not give any gain in time. => This option will not be used.
• changing version of compiler from intel/14.0.3.174 into intel/17.0.2.174 gives no change in results. => The compiler can be changed. This is done loading corresponding module before compiling the model.

Note that changing the compiler version for the compilation, necessits the same version of intel during execution. The version of the compiler will be checked by libIGCM and corresponding module intel will be loaded. Not yet done. It is recommended to continue with the current default intel compiler until libIGCM can handle both environments.