1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
|
.. _mpi_isendrecv_replace:
MPI_Isendrecv_replace
=====================
.. include_body
:ref:`MPI_Isendrecv_replace` |mdash| Sends and receives a message using a single
buffer.
SYNTAX
------
C Syntax
^^^^^^^^
.. code-block:: c
#include <mpi.h>
int MPI_Isendrecv_replace(void *buf, int count, MPI_Datatype datatype,
int dest, int sendtag, int source, int recvtag, MPI_Comm comm,
MPI_Request *request)
Fortran Syntax
^^^^^^^^^^^^^^
.. code-block:: fortran
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_ISENDRECV_REPLACE(BUF, COUNT, DATATYPE, DEST, SENDTAG, SOURCE,
RECVTAG, COMM, REQUEST, IERROR)
<type> BUF(*)
INTEGER COUNT, DATATYPE, DEST, SENDTAG
INTEGER SOURCE, RECVTAG, COMM
INTEGER REQUEST, IERROR
Fortran 2008 Syntax
^^^^^^^^^^^^^^^^^^^
.. code-block:: fortran
USE mpi_f08
MPI_Isendrecv_replace(buf, count, datatype, dest, sendtag, source, recvtag,
comm, request, ierror)
TYPE(*), DIMENSION(..) :: buf
INTEGER, INTENT(IN) :: count, dest, sendtag, source, recvtag
TYPE(MPI_Datatype), INTENT(IN) :: datatype
TYPE(MPI_Comm), INTENT(IN) :: comm
TYPE(MPI_Request) :: request
INTEGER, OPTIONAL, INTENT(OUT) :: ierror
INPUT/OUTPUT PARAMETER
----------------------
* ``buf``: Initial address of send and receive buffer (choice).
INPUT PARAMETERS
----------------
* ``count``: Number of elements in send and receive buffer (integer).
* ``datatype``: Type of elements to send and receive (handle).
* ``dest``: Rank of destination (integer).
* ``sendtag``: Send message tag (integer).
* ``source``: Rank of source (integer).
* ``recvtag``: Receive message tag (integer).
* ``comm``: Communicator (handle).
OUTPUT PARAMETERS
-----------------
* ``request``: Communication request (handle).
* ``ierror``: Fortran only: Error status (integer).
DESCRIPTION
-----------
The non-blocking send-receive operations combine in one call the sending
of a message to one destination and the receiving of another message,
from another process. The two (source and destination) are possibly the
same. A send-receive operation is useful for executing a shift operation
across a chain of processes. The send-receive operation can be used in
conjunction with the functions described in the "Process Topologies"
chapter of the MPI Standard in order to perform shifts on various
logical topologies. Also, a send-receive operation is useful for
implementing remote procedure calls.
A message sent by a send-receive operation can be received by a regular
receive operation or probed by a probe operation; a send-receive
operation can receive a message sent by a regular send operation.
:ref:`MPI_Isendrecv_replace` executes a non-blocking send and receive. The same
buffer is used both for the send and for the receive, so that the
message sent is replaced by the message received.
A non-blocking send-receive request can be determined to be completed by
calling the :ref:`MPI_Wait`, :ref:`MPI_Waitany`, :ref:`MPI_Test`, or :ref:`MPI_Testany` with the
request returned by this function.
ERRORS
------
.. include:: ./ERRORS.rst
.. seealso::
* :ref:`MPI_Isendrecv`
* :ref:`MPI_Sendrecv`
* :ref:`MPI_Sendrecv_replace`
|
