Constants
Meaning of MPIs defined constants
Data types
Note that the Fortran types should only be used in Fortran programs,
and the C types should only be used in C programs. For example,
it is in error to use MPI_INT for a Fortran INTEGER.
Datatypes are of type MPI_Datatype in C and of tyep INTEGER in Fortran.
C datatypes
- MPI_CHAR
- char
- MPI_BYTE
- See standard; like unsigned char
- MPI_SHORT
- short
- MPI_INT
- int
- MPI_LONG
- long
- MPI_FLOAT
- float
- MPI_DOUBLE
- double
- MPI_UNSIGNED_CHAR
- unsigned char
- MPI_UNSIGNED_SHORT
- unsigned short
- MPI_UNSIGNED
- unsigned int
- MPI_UNSIGNED_LONG
- unsigned long
- MPI_LONG_DOUBLE
- long double (some systems may not implement)
- MPI_LONG_LONG_INT
- long long (some systems may not implement)
The following are datatypes for the MPI functions MPI_MAXLOC and
MPI_MINLOC.
- MPI_FLOAT_INT
-
struct { float, int }
- MPI_LONG_INT
-
struct { long, int }
- MPI_DOUBLE_INT
-
struct { double, int }
- MPI_SHORT_INT
-
struct { short, int }
- MPI_2INT
-
struct { int, int }
- MPI_LONG_DOUBLE_INT
-
struct { long double, int }; this
is an OPTIONAL type, and may be set to NULL
Note that there is no MPI_LONG_LONG_INT type corresponding to
a struct { long long, int }.
Special datatypes for C and Fortran
- MPI_PACKED
- For MPI_Pack and MPI_Unpack
- MPI_UB
- For MPI_Type_struct; an upper-bound indicator
- MPI_LB
- For MPI_Type_struct; a lower-bound indicator
Fortran datatypes
- MPI_REAL
- REAL
- MPI_INTEGER
- INTEGER
- MPI_LOGICAL
- LOGICAL
- MPI_DOUBLE_PRECISION
- DOUBLE PRECISION
- MPI_COMPLEX
- COMPLEX
- MPI_DOUBLE_COMPLEX
- complex*16 (or complex*32) where supported.
The following datatypes are optional
- MPI_INTEGER1
- integer*1 if supported
- MPI_INTEGER2
- integer*2 if supported
- MPI_INTEGER4
- integer*4 if supported
- MPI_REAL4
- real*4 if supported
- MPI_REAL8
- real*8 if supported
The following are datatypes for the MPI functions MPI_MAXLOC and
MPI_MINLOC. In Fortran, these datatype always consist of
two elements of the same Fortran type.
- MPI_2INTEGER
- INTEGER,INTEGER
- MPI_2REAL
- REAL, REAL
- MPI_2DOUBLE_PRECISION
- DOUBLE PRECISION, DOUBLE PRECISION
- MPI_2COMPLEX
- COMPLEX, COMPLEX
- MPI_2DOUBLE_COMPLEX
- complex*16, complex*16
Communicators
Communicators are of type MPI_Comm in C and INTEGER in Fortran
- MPI_COMM_WORLD
- Contains all of the processes
- MPI_COMM_SELF
- Contains only the calling process
Groups
Groups are of type MPI_Group in C and INTEGER in Fortran
- MPI_GROUP_EMPTY
- A group containing no members.
Results of the compare operations
- MPI_IDENT
- Identical
- MPI_CONGRUENT
- (only for MPI_COMM_COMPARE) The groups are identical
- MPI_SIMILAR
- Same members, but in a different order
- MPI_UNEQUAL
- Different
Collective operations
The collective combination operations (MPI_REDUCE, MPI_ALLREDUCE,
MPI_REDUCE_SCATTER, and MPI_SCAN) take a combination operation.
This operation is of type MPI_Op in C and of type INTEGER in Fortran.
The predefined operations are
- MPI_MAX
- return the maximum
- MPI_MIN
- return the minumum
- MPI_SUM
- return the sum
- MPI_PROD
- return the product
- MPI_LAND
- return the logical and
- MPI_BAND
- return the bitwise and
- MPI_LOR
- return the logical or
- MPI_BOR
- return the bitwise of
- MPI_LXOR
- return the logical exclusive or
- MPI_BXOR
- return the bitwise exclusive or
- MPI_MINLOC
- return the minimum and the location (actually, the value of
the second element of the structure where the minimum of
the first is found)
- MPI_MAXLOC
- return the maximum and the location
Notes on collective operations
The reduction functions (MPI_Op) do not return an error value. As a result,
if the functions detect an error, all they can do is either call MPI_Abort
or silently skip the problem. Thus, if you change the error handler from
MPI_ERRORS_ARE_FATAL to something else, for example, MPI_ERRORS_RETURN,
then no error may be indicated.
The reason for this is the performance problems in ensuring that
all collective routines return the same error value.
Note that not all datatypes are valid for these functions. For example,
MPI_COMPLEX is not valid for MPI_MAX and MPI_MIN. In addition, the MPI
1.1 standard did not include the C types MPI_CHAR and MPI_UNSIGNED_CHAR
among the lists of arithmetic types for operations like MPI_SUM. However,
since the C type char is an integer type (like short), it should have been
included. The MPI Forum will probably include char and unsigned char
as a clarification to MPI 1.1; until then, users are advised that MPI
implementations may not accept MPI_CHAR and MPI_UNSIGNED_CHAR as valid
datatypes for MPI_SUM, MPI_PROD, etc. MPICH does allow these datatypes.
Permanent key values
These are the same in C and Fortran
- MPI_TAG_UB
- Largest tag value
- MPI_HOST
- Rank of process that is host, if any
- MPI_IO
- Rank of process that can do I/O
- MPI_WTIME_IS_GLOBAL
- Has value 1 if MPI_WTIME is globally synchronized.
Null objects
- MPI_COMM_NULL
- Null communicator
- MPI_OP_NULL
- Null operation
- MPI_GROUP_NULL
- Null group
- MPI_DATATYPE_NULL
- Null datatype
- MPI_REQUEST_NULL
- Null request
- MPI_ERRHANDLER_NULL
- Null error handler
Predefined Constants
- MPI_MAX_PROCESSOR_NAME
- Maximum length of name returned by
MPI_GET_PROCESSOR_NAME
- MPI_MAX_ERROR_STRING
- Maximum length of string return by
MPI_ERROR_STRING
- MPI_UNDEFINED
- Used by many routines to indicated undefined or unknown
integer value
- MPI_UNDEFINED_RANK
- Unknown rank
- MPI_KEYVAL_INVALID
- Special keyval that may be used to detect uninitialized
keyvals.
- MPI_BSEND_OVERHEAD
- Add this to the size of a MPI_BSEND buffer for each
outstanding message
- MPI_PROC_NULL
- This rank may be used to send or receive from no-one.
- MPI_ANY_SOURCE
- In a receive, accept a message from anyone.
- MPI_ANY_TAG
- In a receive, accept a message with any tag value.
- MPI_BOTTOM
- May be used to indicate the bottom of the address space
Topology types
- MPI_GRAPH
- General graph
- MPI_CART
- Cartesian grid
MPI Status
The MPI_Status datatype is a structure. The three elements for use
by programmers are
- MPI_SOURCE
- Who sent the message
- MPI_TAG
- What tag the message was sent with
- MPI_ERROR
- Any error return
Special MPI types and functions
- MPI_Aint
- C type that holds any valid address.
- MPI_Handler_function
- C function for handling errors (see
MPI_Errhandler_create) .
- MPI_User_function
- C function to combine values (see collective operations
and MPI_Op_create)
- MPI_Copy_function
- Function to copy attributes (see MPI_Keyval_create)
- MPI_NULL_COPY_FN
- Predefined copy function
- MPI_Delete_function
- Function to delete attributes (see MPI_Keyval_create)
- MPI_NULL_DELETE_FN
- Predefined delete function
- MPI_DUP_FN
- Predefined duplication function
- MPI_ERRORS_ARE_FATAL
- Error handler that forces exit on error
- MPI_ERRORS_RETURN
- Error handler that returns error codes (as value of
MPI routine in C and through last argument in Fortran)
MPI Error classes
- MPI_SUCCESS
- Successful return code
- MPI_ERR_BUFFER
- Invalid buffer pointer
- MPI_ERR_COUNT
- Invalid count argument
- MPI_ERR_TYPE
- Invalid datatype argument
- MPI_ERR_TAG
- Invalid tag argument
- MPI_ERR_COMM
- Invalid communicator
- MPI_ERR_RANK
- Invalid rank
- MPI_ERR_ROOT
- Invalid root
- MPI_ERR_GROUP
- Null group passed to function
- MPI_ERR_OP
- Invalid operation
- MPI_ERR_TOPOLOGY
- Invalid topology
- MPI_ERR_DIMS
- Illegal dimension argument
- MPI_ERR_ARG
- Invalid argument
- MPI_ERR_UNKNOWN
- Unknown error
- MPI_ERR_TRUNCATE
- message truncated on receive
- MPI_ERR_OTHER
- Other error; use Error_string
- MPI_ERR_INTERN
- internal error code
- MPI_ERR_IN_STATUS
- Look in status for error value
- MPI_ERR_PENDING
- Pending request
- MPI_ERR_REQUEST
- illegal mpi_request handle
- MPI_ERR_LASTCODE
- Last error code -- always at end
Location:/home/MPI/mansrc/mpiconsts.txt