306 lines
10 KiB
Groff
306 lines
10 KiB
Groff
.\" Man page generated from reStructuredText.
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.TH "MPI_IALLGATHERV" "3" "Feb 14, 2025" "" "Open MPI"
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..
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.INDENT 0.0
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.INDENT 3.5
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.UNINDENT
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.UNINDENT
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.sp
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\fI\%MPI_Allgatherv\fP, \fI\%MPI_Iallgatherv\fP, \fI\%MPI_Allgatherv_init\fP \- Gathers data
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from all processes and delivers it to all. Each process may contribute a
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different amount of data.
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.SH SYNTAX
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.SS C Syntax
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.INDENT 0.0
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.INDENT 3.5
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.sp
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.nf
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.ft C
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#include <mpi.h>
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int MPI_Allgatherv(const void *sendbuf, int sendcount,
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MPI_Datatype sendtype, void *recvbuf, const int recvcounts[],
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const int displs[], MPI_Datatype recvtype, MPI_Comm comm)
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int MPI_Iallgatherv(const void *sendbuf, int sendcount,
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MPI_Datatype sendtype, void *recvbuf, const int recvcounts[],
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const int displs[], MPI_Datatype recvtype, MPI_Comm comm,
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MPI_Request *request)
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int MPI_Allgatherv_init(const void *sendbuf, int sendcount,
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MPI_Datatype sendtype, void *recvbuf, const int recvcounts[],
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const int displs[], MPI_Datatype recvtype, MPI_Comm comm,
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MPI_Info info, MPI_Request *request)
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.ft P
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.fi
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.UNINDENT
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.UNINDENT
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.SS Fortran Syntax
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.INDENT 0.0
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.INDENT 3.5
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.sp
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.nf
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.ft C
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USE MPI
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! or the older form: INCLUDE \(aqmpif.h\(aq
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MPI_ALLGATHERV(SENDBUF, SENDCOUNT, SENDTYPE, RECVBUF,
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RECVCOUNT, DISPLS, RECVTYPE, COMM, IERROR)
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<type> SENDBUF(*), RECVBUF(*)
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INTEGER SENDCOUNT, SENDTYPE, RECVCOUNT(*)
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INTEGER DISPLS(*), RECVTYPE, COMM, IERROR
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MPI_IALLGATHERV(SENDBUF, SENDCOUNT, SENDTYPE, RECVBUF,
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RECVCOUNT, DISPLS, RECVTYPE, COMM, REQUEST, IERROR)
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<type> SENDBUF(*), RECVBUF(*)
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INTEGER SENDCOUNT, SENDTYPE, RECVCOUNT(*),
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INTEGER DISPLS(*), RECVTYPE, COMM, REQUEST, IERROR
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MPI_ALLGATHERV_INIT(SENDBUF, SENDCOUNT, SENDTYPE, RECVBUF,
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RECVCOUNT, DISPLS, RECVTYPE, COMM, INFO, REQUEST, IERROR)
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<type> SENDBUF(*), RECVBUF(*)
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INTEGER SENDCOUNT, SENDTYPE, RECVCOUNT(*),
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INTEGER DISPLS(*), RECVTYPE, COMM, INFO, REQUEST, IERROR
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.ft P
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.fi
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.UNINDENT
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.UNINDENT
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.SS Fortran 2008 Syntax
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.INDENT 0.0
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.INDENT 3.5
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.sp
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.nf
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.ft C
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USE mpi_f08
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MPI_Allgatherv(sendbuf, sendcount, sendtype, recvbuf, recvcounts, displs,
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recvtype, comm, ierror)
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TYPE(*), DIMENSION(..), INTENT(IN) :: sendbuf
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TYPE(*), DIMENSION(..) :: recvbuf
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INTEGER, INTENT(IN) :: sendcount, recvcounts(*), displs(*)
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TYPE(MPI_Datatype), INTENT(IN) :: sendtype, recvtype
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TYPE(MPI_Comm), INTENT(IN) :: comm
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INTEGER, OPTIONAL, INTENT(OUT) :: ierror
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MPI_Iallgatherv(sendbuf, sendcount, sendtype, recvbuf, recvcounts, displs,
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recvtype, comm, request, ierror)
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TYPE(*), DIMENSION(..), INTENT(IN), ASYNCHRONOUS :: sendbuf
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TYPE(*), DIMENSION(..), ASYNCHRONOUS :: recvbuf
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INTEGER, INTENT(IN) :: sendcount
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INTEGER, INTENT(IN), ASYNCHRONOUS :: recvcounts(*), displs(*)
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TYPE(MPI_Datatype), INTENT(IN) :: sendtype, recvtype
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TYPE(MPI_Comm), INTENT(IN) :: comm
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TYPE(MPI_Request), INTENT(OUT) :: request
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INTEGER, OPTIONAL, INTENT(OUT) :: ierror
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MPI_Allgatherv_init(sendbuf, sendcount, sendtype, recvbuf, recvcounts, displs,
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recvtype, comm, info, request, ierror)
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TYPE(*), DIMENSION(..), INTENT(IN), ASYNCHRONOUS :: sendbuf
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TYPE(*), DIMENSION(..), ASYNCHRONOUS :: recvbuf
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INTEGER, INTENT(IN) :: sendcount
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INTEGER, INTENT(IN), ASYNCHRONOUS :: recvcounts(*), displs(*)
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TYPE(MPI_Datatype), INTENT(IN) :: sendtype, recvtype
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TYPE(MPI_Comm), INTENT(IN) :: comm
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TYPE(MPI_Info), INTENT(IN) :: info
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TYPE(MPI_Request), INTENT(OUT) :: request
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INTEGER, OPTIONAL, INTENT(OUT) :: ierror
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.ft P
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.fi
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.UNINDENT
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.UNINDENT
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.SH INPUT PARAMETERS
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.INDENT 0.0
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.IP \(bu 2
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\fBsendbuf\fP: Starting address of send buffer (choice).
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.IP \(bu 2
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\fBsendcount\fP: Number of elements in send buffer (integer).
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.IP \(bu 2
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\fBsendtype\fP: Datatype of send buffer elements (handle).
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.IP \(bu 2
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\fBrecvcount\fP: Integer array (of length group size) containing the number of elements that are received from each process.
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.IP \(bu 2
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\fBdispls\fP: Integer array (of length group size). Entry i specifies the displacement (relative to recvbuf) at which to place the incoming data from process i.
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.IP \(bu 2
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\fBrecvtype\fP: Datatype of receive buffer elements (handle).
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.IP \(bu 2
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\fBcomm\fP: Communicator (handle).
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.IP \(bu 2
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\fBinfo\fP: Info (handle, persistent only).
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.UNINDENT
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.SH OUTPUT PARAMETERS
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.INDENT 0.0
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.IP \(bu 2
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\fBrecvbuf\fP: Address of receive buffer (choice).
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.IP \(bu 2
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\fBrequest\fP: Request (handle, non\-blocking only).
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.IP \(bu 2
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\fBierror\fP: Fortran only: Error status (integer).
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.UNINDENT
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.SH DESCRIPTION
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.sp
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\fI\%MPI_Allgatherv\fP is similar to \fI\%MPI_Allgather\fP in that all processes gather
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data from all other processes, except that each process can send a
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different amount of data. The block of data sent from the jth process is
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received by every process and placed in the jth block of the buffer
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\fIrecvbuf.\fP
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.sp
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The type signature associated with sendcount, sendtype, at process j
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must be equal to the type signature associated with recvcounts[j],
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recvtype at any other process.
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.sp
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The outcome is as if all processes executed calls to
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.INDENT 0.0
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.INDENT 3.5
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.sp
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.nf
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.ft C
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MPI_Allgatherv(sendbuf, sendcount, sendtype, recvbuf, recvcount,
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displs,recvtype,root,comm);
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// for root = 0 , ..., n\-1.
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.ft P
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.fi
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.UNINDENT
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.UNINDENT
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.sp
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The rules for correct usage of \fI\%MPI_Allgatherv\fP
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are easily found from the corresponding rules for \fI\%MPI_Gatherv\fP\&.
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.SH USE OF IN-PLACE OPTION
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.sp
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When the communicator is an intracommunicator, you can perform an
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all\-gather operation in\-place (the output buffer is used as the input
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buffer). Use the variable MPI_IN_PLACE as the value of \fIsendbuf\fP\&. In
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this case, \fIsendcount\fP and \fIsendtype\fP are ignored. The input data of
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each process is assumed to be in the area where that process would
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receive its own contribution to the receive buffer. Specifically, the
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outcome of a call to \fI\%MPI_Allgatherv\fP that used the in\-place option is
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identical to the case in which all processes executed \fIn\fP calls to
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.INDENT 0.0
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.INDENT 3.5
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.sp
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.nf
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.ft C
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MPI_Allgatherv ( MPI_IN_PLACE, 0, MPI_DATATYPE_NULL, recvbuf,
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recvcounts, displs, recvtype, root, comm );
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// for root =0, ... , n\-1.
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.ft P
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.fi
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.UNINDENT
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.UNINDENT
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.sp
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Note that MPI_IN_PLACE is a special kind of value; it has the same
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restrictions on its use as MPI_BOTTOM.
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.sp
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Because the in\-place option converts the receive buffer into a
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send\-and\-receive buffer, a Fortran binding that includes INTENT must
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mark these as INOUT, not OUT.
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.SH WHEN COMMUNICATOR IS AN INTER-COMMUNICATOR
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.sp
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When the communicator is an inter\-communicator, the gather operation
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occurs in two phases. The data is gathered from all the members of the
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first group, concatenated, and received by all the members of the second
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group. Then the data is gathered from all the members of the second
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group, concatenated, and received by all the members of the first. The
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send buffer arguments in the one group must be consistent with the
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receive buffer arguments in the other group, and vice versa. The
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operation must exhibit symmetric, full\-duplex behavior.
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.SH ERRORS
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.sp
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Almost all MPI routines return an error value; C routines as the return result
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of the function and Fortran routines in the last argument.
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.sp
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Before the error value is returned, the current MPI error handler associated
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with the communication object (e.g., communicator, window, file) is called.
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If no communication object is associated with the MPI call, then the call is
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considered attached to MPI_COMM_SELF and will call the associated MPI error
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handler. When MPI_COMM_SELF is not initialized (i.e., before
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\fI\%MPI_Init\fP/\fI\%MPI_Init_thread\fP, after \fI\%MPI_Finalize\fP, or when using the Sessions
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Model exclusively) the error raises the initial error handler. The initial
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error handler can be changed by calling \fI\%MPI_Comm_set_errhandler\fP on
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MPI_COMM_SELF when using the World model, or the mpi_initial_errhandler CLI
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argument to mpiexec or info key to \fI\%MPI_Comm_spawn\fP/\fI\%MPI_Comm_spawn_multiple\fP\&.
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If no other appropriate error handler has been set, then the MPI_ERRORS_RETURN
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error handler is called for MPI I/O functions and the MPI_ERRORS_ABORT error
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handler is called for all other MPI functions.
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.sp
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Open MPI includes three predefined error handlers that can be used:
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.INDENT 0.0
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.IP \(bu 2
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\fBMPI_ERRORS_ARE_FATAL\fP
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Causes the program to abort all connected MPI processes.
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.IP \(bu 2
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\fBMPI_ERRORS_ABORT\fP
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An error handler that can be invoked on a communicator,
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window, file, or session. When called on a communicator, it
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acts as if \fI\%MPI_Abort\fP was called on that communicator. If
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called on a window or file, acts as if \fI\%MPI_Abort\fP was called
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on a communicator containing the group of processes in the
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corresponding window or file. If called on a session,
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aborts only the local process.
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.IP \(bu 2
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\fBMPI_ERRORS_RETURN\fP
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Returns an error code to the application.
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.UNINDENT
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.sp
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MPI applications can also implement their own error handlers by calling:
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.INDENT 0.0
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.IP \(bu 2
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\fI\%MPI_Comm_create_errhandler\fP then \fI\%MPI_Comm_set_errhandler\fP
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.IP \(bu 2
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\fI\%MPI_File_create_errhandler\fP then \fI\%MPI_File_set_errhandler\fP
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.IP \(bu 2
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\fI\%MPI_Session_create_errhandler\fP then \fI\%MPI_Session_set_errhandler\fP or at \fI\%MPI_Session_init\fP
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.IP \(bu 2
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\fI\%MPI_Win_create_errhandler\fP then \fI\%MPI_Win_set_errhandler\fP
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.UNINDENT
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.sp
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Note that MPI does not guarantee that an MPI program can continue past
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an error.
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.sp
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See the \fI\%MPI man page\fP for a full list of \fI\%MPI error codes\fP\&.
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.sp
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See the Error Handling section of the MPI\-3.1 standard for
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more information.
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.sp
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\fBSEE ALSO:\fP
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.INDENT 0.0
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.INDENT 3.5
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.INDENT 0.0
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.IP \(bu 2
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\fI\%MPI_Gatherv\fP
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.IP \(bu 2
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\fI\%MPI_Allgather\fP
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.UNINDENT
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.UNINDENT
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.UNINDENT
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.SH COPYRIGHT
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2003-2025, The Open MPI Community
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.\" Generated by docutils manpage writer.
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.
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