MPI_Iscatterv function

Article
09/14/2018

Syntax

int MPIAPI MPI_Iscatterv(
  _In_opt_  const void         *sendbuf,
  _In_opt_  const int          sendcounts[],
  _In_opt_  const int          displs[],
  _In_            MPI_Datatype sendtype,
  _Out_opt_        void        *recvbuf,
  _In_            int          recvcount,
  _In_            MPI_Datatype recvtype,
  _In_            int          root,
  _In_            MPI_Comm     comm,
  _Out_           MPI_Request  *request
);

Parameters

sendbuf [in, optional]
The pointer to a buffer that contains the data to be sent by the root process.

This parameter is ignored for all non-root processes.

If the comm parameter references an intracommunicator, you can specify an in-place option by specifying MPI_IN_PLACE in the root process. The recvcount and recvtype parameters are ignored. The scattered vector is still considered to contain n segments, where n is the group size; the segment that corresponds to the root process is not moved.
sendcounts[] [in, optional]
The number of elements to send to each process. If sendcounts[i] is zero, the data part of the message for that process is empty.

This parameter is ignored for all non-root processes.
displs[] [in, optional]
The locations of the data to send to each communicator process. Each location in the array is relative to the corresponding element of the sendbuf array.

In the sendbuf, sendcounts, and displs parameter arrays, the nth element of each array refers to the data to be sent to the nth communicator process.

This parameter is significant only at the root process.
sendtype [in]
The data type of each element in the buffer.

This parameter is ignored for all non-root processes.
recvbuf [out, optional]
The pointer to a buffer that contains the data that is received on each process. The number and data type of the elements in the buffer are specified in the recvcount and recvtype parameters.
recvcount [in]
The number of elements in the receive buffer. If the count is zero, the data part of the message is empty.
recvtype [in]
The data type of the elements in the receive buffer.
root [in]
The rank in the sending process within the specified communicator.
comm [in]
The MPI_Comm communicator handle.
request [out]
The MPI_Request handle representing the communication operation.

Return value

Returns MPI_SUCCESS on success. Otherwise, the return value is an error code.

In Fortran, the return value is stored in the IERROR parameter.

Fortran

    MPI_ISCATTERV(SENDBUF, SENDCOUNTS, DISPLS, SENDTYPE, RECVBUF, RECVCOUNT, RECVTYPE, ROOT, COMM, REQUEST, IERROR)
        <type> SENDBUF(*), RECVBUF(*)
        INTEGER SENDCOUNTS(*), DISPLS(*), SENDTYPE, RECVCOUNT, RECVTYPE, ROOT, COMM, REQUEST, IERROR

Remarks

A non-blocking call initiates a collective reduction operation which must be completed in a separate completion call. Once initiated, the operation may progress independently of any computation or other communication at participating processes. In this manner, non-blocking reduction operations can mitigate possible synchronizing eﬀects of reduction operations by running them in the “background.”

All completion calls (e.g., MPI_Wait) are supported for non-blocking reduction operations.

Requirements

Product	Microsoft MPI v7
Header	Mpi.h; Mpif.h
Library	Msmpi.lib
DLL	Msmpi.dll

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