MPI_Type_get_true_extent, MPI_Type_get_true_extent_x − Returns the true lower bound and extent of a data type’s corresponding typemap, ignoring MPI_UB and MPI_LB markers.
#include
<mpi.h>
int MPI_Type_get_true_extent(MPI_Datatype
datatype,
MPI_Aint *true_lb, MPI_Aint *true_extent) |
int MPI_Type_get_true_extent_x(MPI_Datatype datatype,
MPI_Count *true_lb, MPI_Count *true_extent) |
USE MPI
! or the older form: INCLUDE ’mpif.h’
MPI_TYPE_GET_TRUE_EXTENT(DATATYPE, TRUE_LB, TRUE_EXTENT,
IERROR)
INTEGER |
DATATYPE, IERROR | |||
INTEGER(KIND=MPI_ADDRESS_KIND) TRUE_LB, TRUE_EXTENT |
MPI_TYPE_GET_TRUE_EXTENT_X(DATATYPE, TRUE_LB, TRUE_EXTENT, IERROR)
INTEGER |
DATATYPE, IERROR | |||
INTEGER(KIND=MPI_COUNT_KIND) TRUE_LB, TRUE_EXTENT |
USE mpi_f08
MPI_Type_get_true_extent(datatype, true_lb,
true_extent, ierror)
TYPE(MPI_Datatype), INTENT(IN) :: datatype | |
INTEGER(KIND=MPI_ADDRESS_KIND), INTENT(OUT) :: true_lb, true_extent | |
INTEGER, OPTIONAL, INTENT(OUT) :: ierror |
MPI_Type_get_true_extent_x(datatype, true_lb, true_extent, ierror)
TYPE(MPI_Datatype), INTENT(IN) :: datatype | |
INTEGER(KIND = MPI_COUNT_KIND), INTENT(OUT) :: true_lb, true_extent | |
INTEGER, OPTIONAL, INTENT(OUT) :: ierror |
datatype |
Data type for which information is wanted (handle). |
true_lb |
True lower bound of data type (integer). |
true_extent
True size of data type (integer).
IERROR |
Fortran only: Error status (integer). |
The true_lb parameter returns the offset of the lowest unit of store that is addressed by the data type, that is, the lower bound of the corresponding typemap, ignoring MPI_LB markers. The true_extent parameter returns the true size of the data type, that is, the extent of the corresponding typemap, ignoring MPI_LB and MPI_UB markers, and performing no rounding for alignment. For both functions, if either the true_lb or true_extent parameter cannot express the value to be returned (e.g., if the parameter is too small to hold the output value), it is set to MPI_UNDEFINED.
The true_extent is the minimum number of bytes of memory necessary to hold a data type, uncompressed.
See § 4.1.8 of the MPI-3 standard for more detailed definitions of these parameters in relation to the typemap.
The MPI standard prescribes portable Fortran syntax for the TRUE_LB and TRUE_EXTENT arguments only for Fortran 90. FORTRAN 77 users may use the non-portable syntax
MPI_Type_get_true_extent:
INTEGER*MPI_ADDRESS_KIND
TRUE_LB
or
INTEGER*MPI_ADDRESS_KIND TRUE_EXTENT
MPI_Type_get_true_extent_x:
INTEGER*MPI_COUNT_KIND
TRUE_LB
or
INTEGER*MPI_COUNT_KIND TRUE_EXTENT
where MPI_ADDRESS_KIND and MPI_COUNT_KIND are constants defined in mpif.h and give the length of the declared integer in bytes.
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.