To be used for MPI_REDUCE, MPI_ALLREDUCE, MPI_REDUCE_SCATTER, and MPI_SCAN
There are a number of predefined reduction operations for use with MPI_ALLREDUCE, MPI_EXSCAN, MPI_REDUCE, MPI_REDUCE_SCATTER, and MPI_SCAN.
To invoke a predefined operation, place any of the following reductions in variable op.
- Operation
- Description
- MPI_BAND
- bitwise AND
- MPI_BOR
- bitwise OR
- MPI_BXOR
- bitwise XOR
- MPI_LAND
- logical AND
- MPI_LOR
- logical OR
- MPI_LXOR
- logical XOR
- MPI_MAX
- maximum value
- MPI_MAXLOC
- maximum value and location
- MPI_MIN
- minimum value
- MPI_MINLOC
- minimum value and location
- MPI_PROD
- product
- MPI_REPLACE
- f(a,b) = b (the current value in the target memory is replaced by the value supplied by the origin)
- MPI_SUM
- sum
MPI_Op_create
int MPI_Op_create( MPI_User_function *function, int commute, MPI_Op *op );source
MPI DATA types
- Data type
- Description
- MPI_BYTE
- Untyped byte data
- MPI_LB
- Explicit lower bound marker
- MPI_PACKED
- Packed data (byte)
- MPI_UB
- Explicit upper bound marker
Data types for C language bindings
- Data type
- Description
- MPI_CHAR
- 8-bit character
- MPI_DOUBLE
- 64-bit floating point
- MPI_FLOAT
- 32-bit floating point
- MPI_INT
- 32-bit integer
- MPI_LONG
- 32-bit integer
- MPI_LONG_DOUBLE
- 64-bit floating point
- MPI_LONG_LONG
- 64-bit integer
- MPI_LONG_LONG_INT
- 64-bit integer
- MPI_SHORT
- 16-bit integer
- MPI_SIGNED_CHAR
- 8-bit signed character
- MPI_UNSIGNED
- 32-bit unsigned integer
- MPI_UNSIGNED_CHAR
- 8-bit unsigned character
- MPI_UNSIGNED_LONG
- 32-bit unsigned integer
- MPI_UNSIGNED_LONG_LONG
- 64-bit unsigned integer
- MPI_UNSIGNED_SHORT
- 16-bit unsigned integer
- MPI_WCHAR
- Wide (16-bit) unsigned character
Example to write a distributed 2D array
