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Constants(3) - Constants - Meaning of MPI s defined constants - man 3 Constants

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Constants(3)                          MPI                         Constants(3)



NAME
       Constants -  Meaning of MPI s defined constants

DATA TYPES
       Note  that  the  Fortran types should only be used in(1,8) Fortran programs,
       and the C types should only be used in(1,8) C programs.  For example, it  is
       in(1,8)  error(8,n)  to use MPI_INT for a Fortran INTEGER.  Datatypes are of type
       MPI_Datatype in(1,8) C and of tyep INTEGER in(1,8) 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(7,n,1 builtins) 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(3,n) supported
       MPI_INTEGER2
              - integer*2 if(3,n) supported
       MPI_INTEGER4
              - integer*4 if(3,n) supported
       MPI_REAL4
              - real*4 if(3,n) supported
       MPI_REAL8
              - real*8 if(3,n) 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(1,8) C and INTEGER in(1,8) 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(1,8) C and INTEGER in(1,8) 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(1,8) 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(1,8) C and of type INTEGER in(1,8) 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(8,n) value.  As  a
       result,  if(3,n)  the  functions  detect an error(8,n), all they can do is either
       call MPI_Abort or silently skip the problem.  Thus, if(3,n) you  change  the
       error(8,n) handler from MPI_ERRORS_ARE_FATAL to something else, for example,
       MPI_ERRORS_RETURN , then no error(8,n) may be indicated.

       The reason for this is the performance problems in(1,8)  ensuring  that  all
       collective routines return the same error(8,n) value.

       Note  that  not all datatypes are valid for these functions.  For exam-
       ple, 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(1,5)  are  advised  that  MPI  implementations  may  not  accept(2,8)
       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(1,8) C and Fortran

       MPI_TAG_UB
              - Largest tag value
       MPI_HOST
              - Rank of process that is host(1,5), if(3,n) any
       MPI_IO - Rank of process that can do I/O
       MPI_WTIME_IS_GLOBAL
              - Has value 1 if(3,n) 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(8,n) 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(3,n) return by MPI_ERROR_STRING

       MPI_UNDEFINED
              - Used by many routines to indicated undefined or unknown  inte-
              ger value
       MPI_UNDEFINED_RANK
              - Unknown rank
       MPI_KEYVAL_INVALID
              -  Special  keyval that may be used to detect uninitialized key-
              vals.
       MPI_BSEND_OVERHEAD
              - Add this to the size of a MPI_BSEND buffer for each  outstand-
              ing message
       MPI_PROC_NULL
              - This rank may be used to send(2,n) or receive from no-one.
       MPI_ANY_SOURCE
              - In a receive, accept(2,8) a message from anyone.
       MPI_ANY_TAG
              - In a receive, accept(2,8) 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(8,n) 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(3,n,1 builtins) on error(8,n)
       MPI_ERRORS_RETURN
              - Error handler that returns error(8,n) codes (as value of  MPI  rou-
              tine in(1,8) C and through last argument in(1,8) 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(8,n)
       MPI_ERR_TRUNCATE
              - message truncated on receive
       MPI_ERR_OTHER
              - Other error(8,n); use Error_string
       MPI_ERR_INTERN
              - internal error(8,n) code
       MPI_ERR_IN_STATUS
              - Look in(1,8) status for error(8,n) value
       MPI_ERR_PENDING
              - Pending request
       MPI_ERR_REQUEST
              - illegal mpi_request handle
       MPI_ERR_LASTCODE
              - Last error(8,n) code -- always at end



LOCATION
       /home/MPI/mansrc/mpiconsts.txt



                                   5/27/2004                      Constants(3)

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