.\" Man page generated from reStructuredText. . .TH "MPI_TYPE_CREATE_SUBARRAY" "3" "Feb 06, 2024" "" "Open MPI" . .nr rst2man-indent-level 0 . .de1 rstReportMargin \\$1 \\n[an-margin] level \\n[rst2man-indent-level] level margin: \\n[rst2man-indent\\n[rst2man-indent-level]] - \\n[rst2man-indent0] \\n[rst2man-indent1] \\n[rst2man-indent2] .. .de1 INDENT .\" .rstReportMargin pre: . RS \\$1 . nr rst2man-indent\\n[rst2man-indent-level] \\n[an-margin] . nr rst2man-indent-level +1 .\" .rstReportMargin post: .. .de UNINDENT . RE .\" indent \\n[an-margin] .\" old: \\n[rst2man-indent\\n[rst2man-indent-level]] .nr rst2man-indent-level -1 .\" new: \\n[rst2man-indent\\n[rst2man-indent-level]] .in \\n[rst2man-indent\\n[rst2man-indent-level]]u .. .sp \fI\%MPI_Type_create_subarray\fP — Creates a data type describing an \fIn\fP\-dimensional subarray of an \fIn\fP\-dimensional array. .SH SYNTAX .SS C Syntax .INDENT 0.0 .INDENT 3.5 .sp .nf .ft C #include int MPI_Type_create_subarray(int ndims, const int array_of_sizes[], const int array_of_subsizes[], const int array_of_starts[], int order, MPI_Datatype oldtype, MPI_Datatype *newtype) .ft P .fi .UNINDENT .UNINDENT .SS Fortran Syntax .INDENT 0.0 .INDENT 3.5 .sp .nf .ft C USE MPI ! or the older form: INCLUDE \(aqmpif.h\(aq MPI_TYPE_CREATE_SUBARRAY(NDIMS, ARRAY_OF_SIZES, ARRAY_OF_SUBSIZES, ARRAY_OF_STARTS, ORDER, OLDTYPE, NEWTYPE, IERROR) INTEGER NDIMS, ARRAY_OF_SIZES(*), ARRAY_OF_SUBSIZES(*), ARRAY_OF_STARTS(*), ORDER, OLDTYPE, NEWTYPE, IERROR .ft P .fi .UNINDENT .UNINDENT .SS Fortran 2008 Syntax .INDENT 0.0 .INDENT 3.5 .sp .nf .ft C USE mpi_f08 MPI_Type_create_subarray(ndims, array_of_sizes, array_of_subsizes, array_of_starts, order, oldtype, newtype, ierror) INTEGER, INTENT(IN) :: ndims, array_of_sizes(ndims), array_of_subsizes(ndims), array_of_starts(ndims), order TYPE(MPI_Datatype), INTENT(IN) :: oldtype TYPE(MPI_Datatype), INTENT(OUT) :: newtype INTEGER, OPTIONAL, INTENT(OUT) :: ierror .ft P .fi .UNINDENT .UNINDENT .SH INPUT PARAMETERS .INDENT 0.0 .IP \(bu 2 \fBndims\fP: Number of array dimensions (positive integer). .IP \(bu 2 \fBarray_of_sizes\fP: Number of elements of type \fIoldtype\fP in each dimension of the full array (array of positive integers). .IP \(bu 2 \fBarray_of_subsizes\fP: Number of elements of type \fIoldtype\fP in each dimension of the subarray (array of positive integers). .IP \(bu 2 \fBarray_of_starts\fP: Starting coordinates of the subarray in each dimension (array of nonnegative integers). .IP \(bu 2 \fBorder\fP: Array storage order flag (state). .IP \(bu 2 \fBoldtype\fP: Array element data type (handle). .UNINDENT .SH OUTPUT PARAMETERS .INDENT 0.0 .IP \(bu 2 \fBnewtype\fP: New data type (handle). .IP \(bu 2 \fBierror\fP: Fortran only: Error status (integer). .UNINDENT .SH DESCRIPTION .sp The subarray type constructor creates an MPI data type describing an \fIn\fP\-dimensional subarray of an \fIn\fP\-dimensional array. The subarray may be situated anywhere within the full array, and may be of any nonzero size up to the size of the larger array as long as it is confined within this array. This type constructor facilitates creating file types to access arrays distributed in blocks among processes to a single file that contains the global array. .sp This type constructor can handle arrays with an arbitrary number of dimensions and works for both C\- and Fortran\-ordered matrices (that is, row\-major or column\-major). Note that a C program may use Fortran order and a Fortran program may use C order. .sp The \fIndims\fP parameter specifies the number of dimensions in the full data array and gives the number of elements in \fIarray_of_sizes\fP, \fIarray_of_subsizes\fP, and \fIarray_of_starts\fP\&. .sp The number of elements of type \fIoldtype\fP in each dimension of the \fIn\fP\-dimensional array and the requested subarray are specified by \fIarray_of_sizes\fP and \fIarray_of_subsizes\fP, respectively. For any dimension \fIi\fP, it is erroneous to specify \fIarray_of_subsizes[i]\fP < 1 or \fIarray_of_subsizes[i]\fP > \fIarray of sizes[i]\fP\&. .sp The \fIarray_of_starts\fP contains the starting coordinates of each dimension of the subarray. Arrays are assumed to be indexed starting from zero. For any dimension \fIi\fP, it is erroneous to specify .INDENT 0.0 .INDENT 3.5 .sp .nf .ft C array_of_starts[i] < 0 .ft P .fi .UNINDENT .UNINDENT .sp or .INDENT 0.0 .INDENT 3.5 .sp .nf .ft C array_of_starts[i] > (array_of_sizes[i] \- array_of_subsizes[i]). .ft P .fi .UNINDENT .UNINDENT .sp The \fIorder\fP argument specifies the storage order for the subarray as well as the full array. It must be set to one of the following: .INDENT 0.0 .IP \(bu 2 \fBMPI_ORDER_C\fP: The ordering used by C arrays, (that is, row\-major order) .IP \(bu 2 \fBMPI_ORDER_FORTRAN\fP: The ordering used by Fortran arrays, (that is, column\-major order) .UNINDENT .sp A \fIndims\fP\-dimensional subarray (\fInewtype\fP) with no extra padding can be defined by the function Subarray() as follows: .INDENT 0.0 .INDENT 3.5 .sp .nf .ft C newtype = Subarray(ndims, {size_0, size_1,..., size_ndims\-1}, {subsize_0, subsize_1, ..., subsize_ndims\-1}, {start_0, start_1, ..., start_ndims\-1}, oldtype) .ft P .fi .UNINDENT .UNINDENT .sp Let the typemap of \fIoldtype\fP have the form: .INDENT 0.0 .INDENT 3.5 .sp .nf .ft C {(type_0, disp_0), (type_1, disp_1), ..., (type_n\-1, disp_n\-1)} .ft P .fi .UNINDENT .UNINDENT .sp where type\fIi\fP is a predefined MPI data type, and let \fIex\fP be the extent of \fIoldtype\fP\&. .sp The \fBSubarray()\fP function is defined recursively in three equations on page 72 of the MPI\-2 standard. .sp For an example use of \fI\%MPI_Type_create_subarray\fP in the context of I/O, see Section 9.9.2 of the MPI\-2 standard. .SH NOTES .sp In a Fortran program with arrays indexed starting from 1, if the starting coordinate of a particular dimension of the subarray is \fIn\fP, then the entry in array of starts for that dimension is \fIn\fP\-1. .SH ERRORS .sp Almost all MPI routines return an error value; C routines as the return result of the function and Fortran routines in the last argument. .sp Before the error value is returned, the current MPI error handler associated with the communication object (e.g., communicator, window, file) is called. If no communication object is associated with the MPI call, then the call is considered attached to MPI_COMM_SELF and will call the associated MPI error handler. When MPI_COMM_SELF is not initialized (i.e., before \fI\%MPI_Init\fP/\fI\%MPI_Init_thread\fP, after \fI\%MPI_Finalize\fP, or when using the Sessions Model exclusively) the error raises the initial error handler. The initial error handler can be changed by calling \fI\%MPI_Comm_set_errhandler\fP on MPI_COMM_SELF when using the World model, or the mpi_initial_errhandler CLI argument to mpiexec or info key to \fI\%MPI_Comm_spawn\fP/\fI\%MPI_Comm_spawn_multiple\fP\&. If no other appropriate error handler has been set, then the MPI_ERRORS_RETURN error handler is called for MPI I/O functions and the MPI_ERRORS_ABORT error handler is called for all other MPI functions. .sp Open MPI includes three predefined error handlers that can be used: .INDENT 0.0 .IP \(bu 2 \fBMPI_ERRORS_ARE_FATAL\fP Causes the program to abort all connected MPI processes. .IP \(bu 2 \fBMPI_ERRORS_ABORT\fP An error handler that can be invoked on a communicator, window, file, or session. When called on a communicator, it acts as if \fI\%MPI_Abort\fP was called on that communicator. If called on a window or file, acts as if \fI\%MPI_Abort\fP was called on a communicator containing the group of processes in the corresponding window or file. If called on a session, aborts only the local process. .IP \(bu 2 \fBMPI_ERRORS_RETURN\fP Returns an error code to the application. .UNINDENT .sp MPI applications can also implement their own error handlers by calling: .INDENT 0.0 .IP \(bu 2 \fI\%MPI_Comm_create_errhandler\fP then \fI\%MPI_Comm_set_errhandler\fP .IP \(bu 2 \fI\%MPI_File_create_errhandler\fP then \fI\%MPI_File_set_errhandler\fP .IP \(bu 2 \fI\%MPI_Session_create_errhandler\fP then \fI\%MPI_Session_set_errhandler\fP or at \fI\%MPI_Session_init\fP .IP \(bu 2 \fI\%MPI_Win_create_errhandler\fP then \fI\%MPI_Win_set_errhandler\fP .UNINDENT .sp Note that MPI does not guarantee that an MPI program can continue past an error. .sp See the \fI\%MPI man page\fP for a full list of \fI\%MPI error codes\fP\&. .sp See the Error Handling section of the MPI\-3.1 standard for more information. .SH COPYRIGHT 2003-2024, The Open MPI Community .\" Generated by docutils manpage writer. .