MPI Programming and Subroutine Reference

Appendix I. Predefined Datatypes

The following is a list of the various predefined MPI datatypes by category that you can use with MPI.

Special Purpose

Datatype	Description
MPI_LB	Explicit lower bound marker
MPI_UB	Explicit upper bound marker
MPI_BYTE	Untyped byte data
MPI_PACKED	Packed data (byte)

For C Language Bindings

Datatype	Description
MPI_CHAR	8-bit character
MPI_UNSIGNED_CHAR	8-bit unsigned character
MPI_SIGNED_CHAR	8-bit signed character
MPI_SHORT	16-bit integer
MPI_INT	32-bit integer
MPI_LONG	32-bit integer
MPI_UNSIGNED_SHORT	16-bit unsigned integer
MPI_UNSIGNED	32-bit unsigned integer
MPI_UNSIGNED_LONG	32-bit unsigned integer
MPI_FLOAT	32-bit floating point
MPI_DOUBLE	64-bit floating point
MPI_LONG_DOUBLE	64-bit floating point
MPI_UNSIGNED_LONG_LONG	64-bit unsigned integer
MPI_LONG_LONG_INT	64-bit integer
MPI_WCHAR	Wide (16-bit) unsigned character

For FORTRAN Language Bindings

Datatype	Description
MPI_INTEGER1	8 bit integer
MPI_INTEGER2	16 bit integer
MPI_INTEGER4	32 bit integer
MPI_INTEGER	32 bit integer
MPI_INTEGER8	64 bit integer
MPI_REAL4	32 bit floating point
MPI_REAL	32 bit floating point
MPI_REAL8	64 bit floating point
MPI_DOUBLE_PRECISION	64 bit floating point
MPI_REAL16	128 bit floating point
MPI_COMPLEX8	32 bit float real, 32 bit float imag.
MPI_COMPLEX	32 bit float real, 32 bit float imag.
MPI_COMPLEX16	64 bit float real, 64 bit float imag.
MPI_DOUBLE_COMPLEX	64 bit float real, 64 bit float imag.
MPI_COMPLEX32	128 bit float real, 128 bit float imag.
MPI_LOGICAL1	8 bit logical
MPI_LOGICAL2	16 bit logical
MPI_LOGICAL4	32 bit logical
MPI_LOGICAL	32 bit logical
MPI_LOGICAL8	64 bit logical
MPI_CHARACTER	8 bit character

For Reduction Functions (C Reduction Types)

Datatype	Description
MPI_FLOAT_INT	{MPI_FLOAT, MPI_INT}
MPI_DOUBLE_INT	{MPI_DOUBLE, MPI_INT}
MPI_LONG_INT	{MPI_LONG, MPI_INT}
MPI_2INT	{MPI_INT, MPI_INT}
MPI_SHORT_INT	{MPI_SHORT, MPI_INT}
MPI_LONG_DOUBLE_INT	{MPI_LONG_DOUBLE, MPI_INT}

For Reduction Functions (FORTRAN Reduction Types)

Datatype	Description
MPI_2REAL	{MPI_REAL, MPI_REAL}
MPI_2DOUBLE_PRECISION	{MPI_DOUBLE_PRECISION, MPI_DOUBLE_PRECISION}
MPI_2INTEGER	{MPI_INTEGER, MPI_INTEGER}
MPI_2COMPLEX	{MPI_COMPLEX, MPI_COMPLEX}