MPITypeindexed(3OpenMPI) MPITypeindexed(3OpenMPI)

NAME
       MMPPIITTyyppeeiinnddeexxeedd - Creates an indexed datatype.


SSYYNNTTAAXX
CC SSyynnttaaxx
       #include 
       int MPITypeindexed(int count, int *arrayofblocklengths,
            int *arrayofdisplacements, MPIDatatype oldtype,
            MPIDatatype *newtype)


FFoorrttrraann SSyynnttaaxx
       INCLUDE 'mpif.h'
       MPITYPEINDEXED(COUNT, ARRAYOFBLOCKLENGTHS,
                 ARRAYOFDISPLACEMENTS, OLDTYPE, NEWTYPE, IERROR)
            INTEGER   COUNT, ARRAYOFBLOCKLENGTHS(*)
            INTEGER   ARRAYOFDISPLACEMENTS(*), OLDTYPE, NEWTYPE
            INTEGER   IERROR


CC++++ SSyynnttaaxx
       #include 
       Datatype Datatype::Createindexed(int count,
            const int arrayofblocklengths[],
            const int arrayofdisplacements[]) const


IINNPPUUTT PPAARRAAMMEETTEERRSS
       count     Number  of  blocks - also number of entries in arrayofdis-
                 placements and arrayofblocklengths (nonnegative integer).

       arrayofblocklengths
                 Number of elements per block (array of nonnegative integers).

       arrayofdisplacements
                 Displacement  for  each block, in multiples of oldtype extent
                 (array of integer).

       oldtype   Old datatype (handle).


OOUUTTPPUUTT PPAARRAAMMEETTEERRSS
       newtype   New datatype (handle).

       IERROR    Fortran only: Error status (integer).


DESCRIPTION
       The function MPITypeindexed allows replication  of  an  old  datatype
       into  a  sequence  of  blocks (each block is a concatenation of the old
       datatype), where each block can contain a different  number  of  copies
       and  have  a different displacement. All block displacements are multi-
       ples of the old data type's extent.


       EExxaammppllee:: Let oldtype have type  map  {(double,  0),  (char,  8)},  with
       extent  16.  Let   B  =  (3,  1)  and  let  D  =  (4,  0).   A  call to
       MPITypeindexed(2, B, D, oldtype, newtype)  returns  a  datatype  with
       type map

           {(double, 64), (char, 72), (double, 80), (char, 88),
           (double, 96), (char, 104),
           (double, 0), (char, 8)}

       That is, three copies of the old type starting at displacement 4 x 16 =
       64, and one copy starting at displacement 0.

       In general, assume that oldtype has type map

           {(type(0), disp(0)), ..., (type(n-1), disp(n-1))},

       with extent ex. Let B be the arrayofblocklength argument and D be the
       arrayofdisplacements argument. The newly created datatype has
       n x S ^count-1
           i = 0           B[i]  entries:

           {(type(0), disp(0) + D[0]* ex), ...,
           (type(n-1), disp(n-1) + D[0]* ex), ...,
           (type(0), disp(0) + (D[0] + B[0]-1)* ex), ...,
           (type(n-1), disp(n-1) + (D[0]+ B[0]-1)* ex), ...,
           (type(0), disp(0) + D[count-1]* ex), ...,
           (type(n-1), disp(n-1) + D[count-1]* ex), ...,
           (type(0), disp(0) +  (D[count-1] + B[count-1] -1)* ex), ...,
           (type(n-1), disp(n-1) + (D[count-1] + B[count-1] -1)* ex)}

       A call to MPITypevector(count, blocklength, stride, oldtype, newtype)
       is equivalent to a call to MPITypeindexed(count, B, D, oldtype,  new-
       type) where

           D[j] = j * stride, j = 0,..., count-1

       and

           B[j] = blocklength, j = 0, .., count-1


EERRRROORRSS
       Almost  all MPI routines return an error value; C routines as the value
       of the function and Fortran routines in the last  argument.  C++  func-
       tions  do  not  return  errors.  If the default error handler is set to
       MPI::ERRORSTHROWEXCEPTIONS, then on error the C++ exception mechanism
       will be used to throw an MPI:Exception object.

       Before  the  error  value is returned, the current MPI error handler is
       called. By default, this error handler aborts the MPI job,  except  for
       I/O   function   errors.   The   error  handler  may  be  changed  with
       MPICommseterrhandler; the predefined error handler MPIERRORSRETURN
       may  be  used  to cause error values to be returned. Note that MPI does
       not guarantee that an MPI program can continue past an error.


SEE ALSO
       MPITypecreatehindexed
       MPITypehindexed




Open MPI 1.2                    September 2006      MPITypeindexed(3OpenMPI)