MPI_Type_indexed(3) | Open MPI | MPI_Type_indexed(3) |
MPI_Type_indexed, MPI_Type_create_hindexed - Creates an indexed datatype.
#include <mpi.h> int MPI_Type_indexed(int count, const int array_of_blocklengths[], const int array_of_displacements[], MPI_Datatype oldtype, MPI_Datatype *newtype) int MPI_Type_create_hindexed(int count, const int array_of_blocklengths[], const MPI_Aint array_of_displacements[], MPI_Datatype oldtype, MPI_Datatype *newtype)
USE MPI ! or the older form: INCLUDE 'mpif.h' MPI_TYPE_INDEXED(COUNT, ARRAY_OF_BLOCKLENGTHS, ARRAY_OF_DISPLACEMENTS, OLDTYPE, NEWTYPE, IERROR) INTEGER COUNT, ARRAY_OF_BLOCKLENGTHS(*) INTEGER ARRAY_OF_DISPLACEMENTS(*), OLDTYPE, NEWTYPE INTEGER IERROR MPI_TYPE_CREATE_HINDEXED(COUNT, ARRAY_OF_BLOCKLENGTHS, ARRAY_OF_DISPLACEMENTS, OLDTYPE, NEWTYPE, IERROR) INTEGER COUNT, ARRAY_OF_BLOCKLENGTHS(*) INTEGER OLDTYPE, NEWTYPE INTEGER(KIND=MPI_ADDRESS_KIND) ARRAY_OF_DISPLACEMENTS(*) INTEGER IERROR
USE mpi_f08 MPI_Type_indexed(count, array_of_blocklengths, array_of_displacements, oldtype, newtype, ierror) INTEGER, INTENT(IN) :: count, array_of_blocklengths(count), array_of_displacements(count) TYPE(MPI_Datatype), INTENT(IN) :: oldtype TYPE(MPI_Datatype), INTENT(OUT) :: newtype INTEGER, OPTIONAL, INTENT(OUT) :: ierror MPI_Type_create_hindexed(count, array_of_blocklengths, array_of_displacements, oldtype, newtype, ierror) INTEGER, INTENT(IN) :: count, array_of_blocklengths(count) INTEGER(KIND=MPI_ADDRESS_KIND), INTENT(IN) :: array_of_displacements(count) TYPE(MPI_Datatype), INTENT(IN) :: oldtype TYPE(MPI_Datatype), INTENT(OUT) :: newtype INTEGER, OPTIONAL, INTENT(OUT) :: ierror
#include <mpi.h> Datatype Datatype::Create_indexed(int count, const int array_of_blocklengths[], const int array_of_displacements[]) const Datatype Datatype::Create_hindexed(int count, const int array_of_blocklengths[], const MPI::Aint array_of_displacements[]) const
The function MPI_Type_indexed 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 multiples of the old data type's extent.
Example: Let oldtype have type map {(double, 0), (char, 8)}, with extent 16. Let B = (3, 1) and let D = (4, 0). A call to MPI_Type_indexed(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 array_of_blocklength argument and D
be the array_of_displacements 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 MPI_Type_vector(count, blocklength, stride, oldtype, newtype) is equivalent to a call to MPI_Type_indexed(count, B, D, oldtype, newtype) where
D[j] = j * stride, j = 0,..., count-1 and
B[j] = blocklength, j = 0, .., count-1
The function MPI_Type_create_hindexed is identical to MPI_Type_indexed, except that block displacements in array_of_displacements are specified in bytes, rather than in multiples of the oldtype extent.
Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument. C++ functions do not return errors. If the default error handler is set to MPI::ERRORS_THROW_EXCEPTIONS, 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 MPI_Comm_set_errhandler; the predefined error handler MPI_ERRORS_RETURN 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.
MPI_Type_hindexed
December 18, 2020 | 4.1.0 |