119 строки
3.4 KiB
Plaintext
119 строки
3.4 KiB
Plaintext
.\" Copyright 2010 Cisco Systems, Inc. All rights reserved.
|
|
.\" Copyright 2006-2008 Sun Microsystems, Inc.
|
|
.\" Copyright (c) 1996 Thinking Machines Corporation
|
|
.TH MPI_Bsend 3 "#OMPI_DATE#" "#PACKAGE_VERSION#" "#PACKAGE_NAME#"
|
|
.SH NAME
|
|
\fBMPI_Bsend\fP \- Basic send with user-specified buffering.
|
|
|
|
.SH SYNTAX
|
|
.ft R
|
|
.SH C Syntax
|
|
.nf
|
|
#include <mpi.h>
|
|
int MPI_Bsend(void \fI*buf\fP, int\fI count\fP, MPI_Datatype\fI datatype\fP,
|
|
int\fI dest\fP, int\fI tag\fP, MPI_Comm\fI comm\fP)
|
|
|
|
.fi
|
|
.SH Fortran Syntax
|
|
.nf
|
|
INCLUDE 'mpif.h'
|
|
MPI_BSEND(\fIBUF\fP,\fI COUNT\fP,\fIDATATYPE\fP,\fI DEST\fP,\fI TAG\fP,\fI COMM\fP,\fI IERROR\fP)
|
|
<type> \fIBUF\fP(*)
|
|
INTEGER \fICOUNT\fP,\fI DATATYPE\fP,\fI DEST\fP,\fI TAG\fP,\fI COMM\fP,\fI IERROR\fP
|
|
|
|
.fi
|
|
.SH C++ Syntax
|
|
.nf
|
|
#include <mpi.h>
|
|
void Comm::Bsend(const void* \fIbuf\fP, int \fIcount\fP, const
|
|
Datatype& \fIdatatype\fP, int \fIdest\fP, int \fItag\fP) const
|
|
|
|
.fi
|
|
.SH Java Syntax
|
|
.nf
|
|
import mpi.*;
|
|
void MPI.COMM_WORLD.Bsend(Object \fIbuf\fP, int \fIoffset\fP, int \fIcount\fP,
|
|
MPI.Datatype \fIdatatype\fP, int \fIdest\fP, int \fItag\fP)
|
|
|
|
.fi
|
|
.SH INPUT PARAMETERS
|
|
.ft R
|
|
.TP 1i
|
|
buf
|
|
Initial address of send buffer (choice).
|
|
.TP 1i
|
|
offset
|
|
Offset of starting point in buffer (Java-only).
|
|
.TP 1i
|
|
count
|
|
Number of entries in send buffer (nonnegative integer).
|
|
.TP 1i
|
|
datatype
|
|
Datatype of each send buffer element (handle).
|
|
.TP 1i
|
|
dest
|
|
Rank of destination (integer).
|
|
.TP 1i
|
|
tag
|
|
Message tag (integer).
|
|
.TP 1i
|
|
comm
|
|
Communicator (handle).
|
|
|
|
.SH OUTPUT PARAMETER
|
|
.ft R
|
|
.TP 1i
|
|
IERROR
|
|
Fortran only: Error status (integer).
|
|
|
|
.SH DESCRIPTION
|
|
.ft R
|
|
MPI_Bsend performs a buffered-mode, blocking send.
|
|
|
|
.SH NOTES
|
|
.ft R
|
|
This send is provided as a convenience function; it allows the user to send messages without worrying about where they are buffered (because the user must have provided buffer space with MPI_Buffer_attach).
|
|
.sp
|
|
In deciding how much buffer space to allocate, remember that the buffer space
|
|
is not available for reuse by subsequent \fIMPI_Bsend\fPs unless you are certain
|
|
that the message
|
|
has been received (not just that it should have been received). For example,
|
|
this code does not allocate enough buffer space:
|
|
.nf
|
|
|
|
MPI_Buffer_attach( b, n*sizeof(double) + MPI_BSEND_OVERHEAD );
|
|
for (i=0; i<m; i++) {
|
|
MPI_Bsend( buf, n, MPI_DOUBLE, ... );
|
|
}
|
|
|
|
.fi
|
|
because only enough buffer space is provided for a single send, and the
|
|
loop may start a second
|
|
.I MPI_Bsend
|
|
before the first is done making use of the
|
|
buffer.
|
|
|
|
In C, you can
|
|
force the messages to be delivered by
|
|
MPI_Buffer_detach( &b, &n );
|
|
MPI_Buffer_attach( b, n );
|
|
(The
|
|
.I MPI_Buffer_detach
|
|
will not complete until all buffered messages are
|
|
delivered.)
|
|
|
|
|
|
.SH 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++ 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.
|
|
.sp
|
|
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.
|
|
|
|
.SH SEE ALSO
|
|
.ft R
|
|
.nf
|
|
MPI_Buffer_attach
|
|
MPI_Ibsend
|
|
MPI_Bsend_init
|
|
|