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mpi_type_struct(3openmpi) [osx man page]

MPI_Type_struct(3OpenMPI)												 MPI_Type_struct(3OpenMPI)

MPI_Type_struct - Creates a struct data type -- use of this routine is deprecated. SYNTAX
C Syntax #include <mpi.h> int MPI_Type_struct(int count, int *array_of_blocklengths, MPI_Aint *array_of_displacements, MPI_Datatype *array_of_types, MPI_Datatype *newtype) Fortran Syntax INCLUDE 'mpif.h' MPI_TYPE_STRUCT(COUNT, ARRAY_OF_BLOCKLENGTHS, ARRAY_OF_DISPLACEMENTS, ARRAY_OF_TYPES, NEWTYPE, IERROR) INTEGER COUNT, ARRAY_OF_BLOCKLENGTHS(*) INTEGER ARRAY_OF_DISPLACEMENTS(*) INTEGER ARRAY_OF_TYPES(*), NEWTYPE, IERROR INPUT PARAMETERS
count Number of blocks (integer) also number of entries in arrays array_of_types, array_of_displacements, and array_of_blocklengths. array_of_blocklengths Number of elements in each block (array). array_of_displacements Byte displacement of each block (array). array_of_types Type of elements in each block (array of handles to datatype objects). OUTPUT PARAMETERS
newtype New datatype (handle). IERROR Fortran only: Error status (integer). DESCRIPTION
Note that use of this routine is deprecated as of MPI-2. Use MPI_Type_create_struct instead. This deprecated routine is not available in C++. MPI_Type_struct is the most general type constructor. It further generalizes MPI_Type_hindexed in that it allows each block to consist of replications of different datatypes. Example: Let type1 have type map {(double, 0), (char, 8)} with extent 16. Let B = (2, 1, 3), D = (0, 16, 26), and T = (MPI_FLOAT, type1, MPI_CHAR). Then a call to MPI_Type_struct(3, B, D, T, new- type) returns a datatype with type map {(float, 0), (float,4), (double, 16), (char, 24), (char, 26), (char, 27), (char, 28)} That is, two copies of MPI_FLOAT starting at 0, followed by one copy of type1 starting at 16, followed by three copies of MPI_CHAR, start- ing at 26. (We assume that a float occupies 4 bytes.) For more information, see section 3.12.1 of the MPI-1.1 Standard. NOTES
If an upperbound is set explicitly by using the MPI datatype MPI_UB, the corresponding index must be positive. The MPI-1 Standard originally made vague statements about padding and alignment; this was intended to allow the simple definition of struc- tures that could be sent with a count greater than one. For example, struct {int a; char b;} foo; may have sizeof(foo) = sizeof(int) + sizeof(char); defining the extent of a datatype as including an epsilon, which would have allowed an implementation to make the extent an MPI datatype for this structure equal to 2*sizeof(int). However, since different systems might define different paddings, a clarification to the stan- dard made epsilon zero. Thus, if you define a structure datatype and wish to send or receive multiple items, you should explicitly include an MPI_UB entry as the last member of the structure. For example, the following code can be used for the structure foo: blen[0] = 1; indices[0] = 0; oldtypes[0] = MPI_INT; blen[1] = 1; indices[1] = &foo.b - &foo; oldtypes[1] = MPI_CHAR; blen[2] = 1; indices[2] = sizeof(foo); oldtypes[2] = MPI_UB; MPI_Type_struct( 3, blen, indices, oldtypes, &newtype ); ERRORS
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::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. SEE ALSO
MPI_Type_create_struct MPI_Type_create_hindexed Open MPI 1.2 September 2006 MPI_Type_struct(3OpenMPI)
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