README_collective.md

Collective communications in Heat equation solver

Utilize collective communication in heat equation code.

1. Replace the individual sends and receives in the routine average (in fortran/utilities.F90 or in cpp/utilities.cpp) with appropriate collective communication.
2. Replace the individual sends and receives in the routine read_field (in fortran/io.F90 or in cpp/io.cpp) with appropriate collective communication. Note that the code needs to be run with the initial data read from an input file (found under the common directory), i.e.

srun ./heat_mpi bottle_dat

3. Is it possible to use collective communications also in the routine write_field (in fortran/io.F90 or in cpp/io.cpp)?

Note that either the base exercise or exercise with MPI_Sendrecv needs to be completed for this exercise.