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 type INTEGER in Fortran.

C Datatypes

MPI_CHAR	char
MPI_SIGNED_CHAR	char, same as MPI_CHAR
MPI_UNSIGNED_CHAR	unsigned char
MPI_WCHAR	wchar_t, wide character
MPI_BYTE	See standard; like unsigned char
MPI_SHORT	short
MPI_INT	int
MPI_LONG	long
MPI_FLOAT	float
MPI_DOUBLE	double
MPI_UNSIGNED_SHORT	unsigned short
MPI_UNSIGNED	unsigned int
MPI_UNSIGNED_LONG	unsigned long
MPI_LONG_DOUBLE	long double (supported by csWMPI II, however some systems may not implement)
MPI_LONG_LONG	a long long int (a 64 bit signed integer, __int64 in Windows)

The following are datatypes for the MPI function where MPI_MAXLOC and MPI_MINLOC are used:

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 }

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).
MPI_INTEGER1	integer*1
MPI_INTEGER2	integer*2
MPI_INTEGER4	integer*4
MPI_REAL4	real*4
MPI_REAL8	real*8
MPI_CHARACTER	character

The following are datatypes for MPI function where MPI_MAXLOC and MPI_MINLOC are used. 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

Subarray and darray constructors

For the MPI_Type_create_darray and MPI_Type_create_subarray function:

MPI_ORDER_C	Row-major order
MPI_ORDER_FORTRAN	Column-major order
MPI_DISTRIBUTE_BLOCK	Block distribution
MPI_DISTRIBUTE_CYCLIC	Cyclic distribution
MPI_DISTRIBUTE_NONE	Dimension not distributed
MPI_DISTRIBUTE_DFLT_DARG	Default distribution

Special Datatypes

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
MPI_DATATYPE_NULL	Null datatype

Communicators are of type MPI_Comm in C and INTEGER in Fortran. The following table lists predefined communicators:

MPI_COMM_WORLD	Contains all processes started by the same operation (by the operating system or by another csWMPI II application) as this caller.
MPI_COMM_SELF	Contains only the calling process
MPI_COMM_NULL	Null communicator

Predefined Attributes

Predefined attribute on MPI_COMM_WORLD. They can be obtained through MPI_Attr_get:

MPI_UNIVERSE_SIZE	Supported for compatibility reasons. csWMPI II licenses do not limit the number of processes but the number of CPUs, thus the value assigned to this attribute is high.
MPI_APPNUM	Always 0.

Topology Types

MPI_GRAPH	General graph
MPI_CART	Cartesian grid

Groups are of type MPI_Group in C and INTEGER in Fortran. The following table lists the predefined groups:

MPI_GROUP_EMPTY	A group containing no members.
MPI_GROUP_NULL	Null group

Possible results of group 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

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 the following:

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
MPI_REPLACE	replaces the current value of the target memory by the value supplied by the origin, for MPI_Accumulate.
MPI_OP_NULL	Null operation

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.

Info objects are of the type MPI_Info in C and INTEGER in Fortran. They contain (key, value) pairs. It is an opaque object created, accessed, and deleted through the following functions: MPI_Info_create, MPI_Info_set, MPI_Info_delete, MPI_Info_get, MPI_Info_get_valuelen, MPI_Info_get_nkeys, MPI_Info_get_nthkey, MPI_Info_dup, and MPI_Info_free.

For a list of info keys recognized by csWMPI II refer to Recognized Info Keys in the User Guide section.

Predefined info object:

MPI_INFO_NULL

Null info object

Files are of type MPI_File in C and INTEGER in Fortran. Predefined file object:

MPI_FILE_NULL

Null file

File Access Modes

MPI_MODE_RDONLY	Read only
MPI_MODE_WRONLY	Write only
MPI_MODE_RDWR	Reading and writing
MPI_MODE_CREATE	Create file if it does not exist
MPI_MODE_DELETE_ON_CLOSE	delete the file on close
MPI_MODE_SEQUENTIAL	file will only be accessed sequentially
MPI_MODE_EXCL	error if file already exists
MPI_MODE_APPEND	set initial position of all file pointers to the end of file
MPI_MODE_UNIQUE_OPEN	file will not be concurrently opened elsewhere

File Seek Modes

MPI_SEEK_SET	Seek to offset (MPI_File_seek and MPI_File_seek_shared)
MPI_SEEK_CUR	Seek to current position + offset (MPI_File_seek and MPI_File_seek_shared)
MPI_SEEK_END	Seek to the end of file + offset (MPI_File_seek and MPI_File_seek_shared)

Windows are of type MPI_Win in C and INTEGER in Fortran. Predefined window object:

MPI_WIN_NULL

Null window

Lock Types

MPI_LOCK_SHARED	A shared lock on a window (MPI_Win_lock)
MPI_LOCK_EXCLUSIVE	An exclusive lock on a window (MPI_Win_lock)

Window Hints

MPI_MODE_NOCHECK	The matching calls to MPI_Win_post have already been completed on all target processes (MPI_Win_start)
MPI_MODE_NOSTORE	The local window was not updated by local stores (MPI_Win_create)
MPI_MODE_NOPUT	The local window was not updated by put or accumulate calls (MPI_Win_fence)
MPI_MODE_NOPRECEDE	The fence does not complete any sequence of locally issued RMA calls (MPI_Win_fence)
MPI_MODE_NOSUCCEED	The fence does start any sequence of locally issued RMA calls(MPI_Win_fence)

The MPI_Status 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

One of the following special constants can be used as parameter in case the status should be ignored a MPI function:

MPI_STATUS_IGNORE	Reference constant specifying csWMPI II can ignore the status object.
MPI_STATUSES_IGNORE	Reference constant specifying csWMPI II can ignore the array of status objects.

The MPI_Request are opaque objects. Nonblocking communications use request objects to identify communication operations and link the posting operation to the completion operation.

Null object:

MPI_REQUEST_NULL

Null request

Error handlers are associeated at each process with each communicator, file, or window object. The following table lists predefined error handlers:

MPI_ERRORS_ARE_FATAL	In case an error occurs all processes are aborted.
MPI_ERRORS_RETURN	In case an error occurs it is returned to the user.
MPI_ERRHANDLER_NULL	Null error handler

MPI_SUCCESS	No error
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_WIN	invalid win argument
MPI_ERR_BASE	invalid base argument
MPI_ERR_SIZE	invalid size argument
MPI_ERR_DISP	invalid disp argument
MPI_ERR_LOCKTYPE	invalid locktype argument
MPI_ERR_ASSERT	invalid assert argument
MPI_ERR_RMA_CONFLICT	conflicting accesses to window
MPI_ERR_RMA_SYNC	wrong synchronization of RMA calls
MPI_ERR_PORT	Named port does not exist (or has been closed)
MPI_ERR_NAME	Service name does not exist
MPI_ERR_SERVICE	Service not registered
MPI_ERR_ACCESS	Permission denied
MPI_ERR_AMODE	Error related to the acess mode
MPI_ERR_BAD_FILE	Invalid file name
MPI_ERR_CONVERSION	An error occured in a user supplied data conversion function
MPI_ERR_DUP_DATAREP	Datarep already exists with this name
MPI_ERR_FILE	Invalid file handle
MPI_ERR_FILE_EXISTS	File exists
MPI_ERR_FILE_IN_USE	File operation cannot be completed, the file is in use by another process
MPI_ERR_IO	Other I/O Error
MPI_ERR_NO_SPACE	Not enough Space
MPI_ERR_NO_SUCH_FILE	File does not exists
MPI_ERR_NOT_SAME	Collective argument no identical on all processes or collective routines called in a different order by diferent processes
MPI_ERR_QUOTA	Quota exceeded
MPI_ERR_READ_ONLY	Read only file in this system
MPI_ERR_UNSUPPORTED_DATAREP	Unsupported datarep passed to MPI_FILE_SET_VIEW
MPI_ERR_UNSUPPORTED_OPERATION	Unsupported operation
MPI_ERR_NO_MEM	Memory exhausted
MPI_ERR_LASTCODE	Last error code

csWMPI II is thread-compliant, which means that multiple threads are allowed to call to MPI functions concurrently. It is recommended that each thread uses a unique communicator.

The following constants can be used for MPI_Init_thread.

MPI_THREAD_SINGLE	Single-threaded application
MPI_THREAD_FUNNELED	Only the main thread of an application will call MPI functions
MPI_THREAD_SERIALIZED	Only one thread will make an MPI call at a time
MPI_THREAD_MULTIPLE	Multiple thread may call MPI functions concurrently

MPI_MAX_PROCESSOR_NAME	Maximum length of name returned by MPI_GET_PROCESSOR_NAME
MPI_MAX_ERROR_STRING	Maximum length of string returned by MPI_ERROR_STRING
MPI_MAX_OBJECT_NAME	Maximum length of object name strings
MPI_MAX_PORT_NAME	Maximum length of a port name supplied by csWMPI II.
MPI_MAX_SERVICE_NAME	Maximum length of a service name
MPI_MAX_INFO_KEY	Maximum length of an info key name
MPI_MAX_INFO_VAL	Maximum length of an info key value
MPI_MAX_DATAREP_STRING	Maximum length a data representation 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_ROOT	Special value supplied by the root process of a (rooted) extended collective operation over an inter-communicator.
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
MPI_IN_PLACE	Reference constant specifying that the same communication buffer should be used for sending and receiving data. Applicable to some collective operations.
MPI_ERRCODES_IGNORE	Reference constant specifying csWMPI II can ignore the array of error codes in MPI_Comm_spawn_multiple.
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.
MPI_Aint	Address argument representing an absolute address in the calling program
MPI_Fint	Datatype for C and C++ which matches the size of a Fortran INTEGER
MPI_Offset	Offset into a file.