mpi_cpp openMPI c++ MPI data Type C data Type MPI_BYTE 8 binary digits MPI_CHAR char MPI_UNSIGNED_CHAR unsigned char MPI_SHORT signed short int MPI_UNSIGNED_SHORT unsigned short int MPI_INT signed int MPI_UNSIGNED unsigned int MPI_LONG signed long int MPI_UNSIGNED_LONG unsigned long int MPI_FLOAT float MPI_DOUBLE double etc. MPI_PACKED define your own with Operation Description Datatype MPI_MAX maximum integer,float MPI_MIN minimum integer,float MPI_SUM sum integer,float MPI_PROD product integer,float MPI_LAND logical AND integer MPI_BAND bit-wise AND integer,MPI_BYTE MPI_LOR logical OR integer MPI_BOR bit-wise OR integer,MPI_BYTE MPI_LXOR logical XOR integer MPI_BXOR bit-wise XOR integer,MPI_BYTE MPI_MAXLOC max value and location float MPI_MINLOC min value and location float