Two modes of parallelisation, both working on a field-per-field basis, were developed concurrently for OASIS3, one by IPSL finalized by CERFACS, and one by CMCC. These modes allows different OASIS3 processes to treat different subsets of coupling fields. These parallelisation modes can be applied with any number of OASIS3 processes; they are in fact only limited by the number of coupling fields exchanged within the coupled model.
With both modes, OASIS3 log file (i.e. cplout_x) and auxiliary files for transformations EXTRAP/NINENN, INTERP/SURFMESH and INTERP/GAUSSIAN ( i.e. mweights_x, nweights_x, gweights_x, anaisout_x, see 7.5.1) , and for SCRIPR (see 7.5.3) are suffixed with the number of the corresponding OASIS3 process performing the transformation. This is done automatically by the OASIS3 process when the file is created by OASIS3 or has to do so by the user if he provides the file before hand.
Note that if the CPP keys use_oasis_para or use_oasis_cmcc_para are not activate, these new parallelisation modes have no impact on the use of OASIS3. Here are the details on the two modes.