Details of Message Passing

For a Communication to Succeed

• Sender must specify a valid destination rank
• Receiver must specify a valid source rank
• The communicator must be the same
• Tags must match
• Receiver's buffer must be large enough

MPI Basic Datatypes - C

MPI Data type	C Data Type
MPI_CHAR	signed char
MPI_SHORT	signed short int
MPI_INT	signed int
MPI_LONG	signed long int
MPI_UNSIGNED_CHAR	unsigned char
MPI_UNISGNED_SHORT	unsigned short int
MPI_UNSIGNED_INT	unsigned int
MPI_UNSIGNED_LONG	unsigned long int
MPI_FLOAT	float
MPI_DOUBLE	double
MPI_LONG_DOUBLE	long double
MPI_BYTE
MPI_PACKED

MPI Basic Datatypes Fortran

MPI Data type	Fortran Data Type
MPI_INTEGER	INTEGER
MPI_REAL	REAL
MPI_DOUBLE_PRECISION	DOUBLE PRECISION
MPI_COMPLEX	COMPLEX
MPI_LOGICAL	LOGICAL
MPI_BYTE
MPI_PACKED