/*@
MPI_Sendrecv - Sends and receives a message
Input Parameters:
+ sendbuf - initial address of send buffer (choice)
. sendcount - number of elements in send buffer (integer)
. sendtype - type of elements in send buffer (handle)
. dest - rank of destination (integer)
. sendtag - send tag (integer)
. recvcount - number of elements in receive buffer (integer)
. recvtype - type of elements in receive buffer (handle)
. source - rank of source (integer)
. recvtag - receive tag (integer)
- comm - communicator (handle)
Output Parameters:
+ recvbuf - initial address of receive buffer (choice)
- status - status object (Status). This refers to the receive operation.
.N fortran
.N Errors
.N MPI_SUCCESS
.N MPI_ERR_COMM
.N MPI_ERR_COUNT
.N MPI_ERR_TYPE
.N MPI_ERR_TAG
.N MPI_ERR_RANK
@*/
EXPORT_MPI_API int MPI_Sendrecv( void *sendbuf, int sendcount, MPI_Datatype sendtype,
int dest, int sendtag,
void *recvbuf, int recvcount, MPI_Datatype recvtype,
int source, int recvtag, MPI_Comm comm, MPI_Status *status )
{
MPI_Status __status;
int mpi_errno = MPI_SUCCESS;
MPI_Status status_array[2];
MPI_Request req[2];
MPIR_ERROR_DECL;
struct MPIR_COMMUNICATOR *comm_ptr;
static char myname[] = "MPI_SENDRECV";
if(status == MPI_STATUS_IGNORE) status = &__status;
/* Let the Isend/Irecv check arguments */
/* Comments on this:
We can probably do an Irecv/Send/Wait on Irecv (blocking send)
but what we really like to do is "send if odd, recv if even,
followed by send if even, recv if odd". We can't do that,
because we don't require that these match up in any particular
way (that is, there is no way to assert the "parity" of the
partners). Note that the IBM "mp_bsendrecv" DOES require that
only mp_bsendrecv be used.
Should there be a send/recv bit in the send mode?
Note that in this implementation, if the error handler is "return",
these will return the error to the caller. If the handler causes
an abort or message, then that will occur in the called routine.
Thus, this code need not call the error handler AGAIN.
*/
comm_ptr = MPIR_GET_COMM_PTR(comm);
MPIR_TEST_MPI_COMM(comm,comm_ptr,comm_ptr,myname);
MPIR_ERROR_PUSH(comm_ptr);
MPIR_CALL_POP(MPI_Irecv ( recvbuf, recvcount, recvtype,
source, recvtag, comm, &req[1] ),comm_ptr,myname);
MPIR_CALL_POP(MPI_Isend ( sendbuf, sendcount, sendtype, dest,
sendtag, comm, &req[0] ),comm_ptr,myname);
/* FPRINTF( stderr, "[%d] Starting waitall\n", MPIR_tid );*/
mpi_errno = MPI_Waitall( 2, req, status_array );
/* We don't use MPIR_CALL_POP because we want to convert
error in status to the direct error */
/* MPIR_CALL_POP(MPI_Waitall ( 2, req, status_array ),comm_ptr,myname); */
MPIR_ERROR_POP(comm_ptr);
/*FPRINTF( stderr, "[%d] Ending waitall\n", MPIR_tid );*/
if (mpi_errno == MPI_ERR_IN_STATUS) {
if (status_array[0].MPI_ERROR) mpi_errno = status_array[0].MPI_ERROR;
if (status_array[1].MPI_ERROR) mpi_errno = status_array[1].MPI_ERROR;
}
(*status) = status_array[1];
MPIR_RETURN(comm_ptr,mpi_errno,myname);
}
/*@
MPI_Intercomm_create - Creates an intercommuncator from two intracommunicators
Input Paramters:
+ local_comm - Local (intra)communicator
. local_leader - Rank in local_comm of leader (often 0)
. peer_comm - Remote communicator
. remote_leader - Rank in peer_comm of remote leader (often 0)
- tag - Message tag to use in constructing intercommunicator; if multiple
'MPI_Intercomm_creates' are being made, they should use different tags (more
precisely, ensure that the local and remote leaders are using different
tags for each 'MPI_intercomm_create').
Output Parameter:
. comm_out - Created intercommunicator
Notes:
The MPI 1.1 Standard contains two mutually exclusive comments on the
input intracommunicators. One says that their repective groups must be
disjoint; the other that the leaders can be the same process. After
some discussion by the MPI Forum, it has been decided that the groups must
be disjoint. Note that the `reason` given for this in the standard is
`not` the reason for this choice; rather, the `other` operations on
intercommunicators (like 'MPI_Intercomm_merge') do not make sense if the
groups are not disjoint.
.N fortran
Algorithm:
+ 1) Allocate a send context, an inter-coll context, and an intra-coll context
. 2) Send "send_context" and lrank_to_grank list from local comm group
if I''m the local_leader.
. 3) If I''m the local leader, then wait on the posted sends and receives
to complete. Post the receive for the remote group information and
wait for it to complete.
. 4) Broadcast information received from the remote leader.
. 5) Create the inter_communicator from the information we now have.
- An inter-communicator ends up with three levels of communicators.
The inter-communicator returned to the user, a "collective"
inter-communicator that can be used for safe communications between
local & remote groups, and a collective intra-communicator that can
be used to allocate new contexts during the merge and dup operations.
For the resulting inter-communicator, 'comm_out'
.vb
comm_out = inter-communicator
comm_out->comm_coll = "collective" inter-communicator
comm_out->comm_coll->comm_coll = safe collective intra-communicator
.ve
.N Errors
.N MPI_SUCCESS
.N MPI_ERR_COMM
.N MPI_ERR_TAG
.N MPI_ERR_EXHAUSTED
.N MPI_ERR_RANK
.seealso: MPI_Intercomm_merge, MPI_Comm_free, MPI_Comm_remote_group,
MPI_Comm_remote_size
@*/
EXPORT_MPI_API int MPI_Intercomm_create ( MPI_Comm local_comm, int local_leader,
MPI_Comm peer_comm, int remote_leader, int tag,
MPI_Comm *comm_out )
{
int local_size, local_rank, peer_size, peer_rank;
int remote_size;
int mpi_errno = MPI_SUCCESS;
MPIR_CONTEXT context, send_context;
struct MPIR_GROUP *remote_group_ptr;
struct MPIR_COMMUNICATOR *new_comm, *local_comm_ptr, *peer_comm_ptr;
MPI_Request req[6];
MPI_Status status[6];
MPIR_ERROR_DECL;
static char myname[]="MPI_INTERCOMM_CREATE";
TR_PUSH(myname);
local_comm_ptr = MPIR_GET_COMM_PTR(local_comm);
#ifndef MPIR_NO_ERROR_CHECKING
/* Check for valid arguments to function */
MPIR_TEST_MPI_COMM(local_comm,local_comm_ptr,local_comm_ptr,myname);
MPIR_TEST_SEND_TAG(tag);
if (mpi_errno)
return MPIR_ERROR(local_comm_ptr, mpi_errno, myname );
#endif
if (local_comm == MPI_COMM_NULL) {
mpi_errno = MPIR_Err_setmsg( MPI_ERR_COMM, MPIR_ERR_LOCAL_COMM, myname,
"Local communicator must not be MPI_COMM_NULL", (char *)0 );
return MPIR_ERROR( local_comm_ptr, mpi_errno, myname );
}
(void) MPIR_Comm_size ( local_comm_ptr, &local_size );
(void) MPIR_Comm_rank ( local_comm_ptr, &local_rank );
if ( local_leader == local_rank ) {
/* Peer_comm need be valid only at local_leader */
peer_comm_ptr = MPIR_GET_COMM_PTR(peer_comm);
if ((MPIR_TEST_COMM_NOTOK(peer_comm,peer_comm_ptr) ||
(peer_comm == MPI_COMM_NULL))) {
mpi_errno = MPIR_Err_setmsg( MPI_ERR_COMM, MPIR_ERR_PEER_COMM,
myname, "Peer communicator is not valid",
(char *)0 );
return MPIR_ERROR( local_comm_ptr, mpi_errno, myname );
}
(void) MPIR_Comm_size ( peer_comm_ptr, &peer_size );
(void) MPIR_Comm_rank ( peer_comm_ptr, &peer_rank );
if (((peer_rank == MPI_UNDEFINED) && (mpi_errno = MPI_ERR_RANK)))
return MPIR_ERROR( local_comm_ptr, mpi_errno, myname );
if (((remote_leader >= peer_size) && (mpi_errno = MPI_ERR_RANK)) ||
((remote_leader < 0) && (mpi_errno = MPI_ERR_RANK))) {
mpi_errno = MPIR_Err_setmsg( MPI_ERR_RANK, MPIR_ERR_REMOTE_RANK,
myname,
"Error specifying remote_leader",
"Error specifying remote_leader; value %d not between 0 and %d", remote_leader, peer_size );
return MPIR_ERROR( local_comm_ptr, mpi_errno, myname );
}
}
if (((local_leader >= local_size) && (mpi_errno = MPI_ERR_RANK)) ||
((local_leader < 0) && (mpi_errno = MPI_ERR_RANK))) {
mpi_errno = MPIR_Err_setmsg( MPI_ERR_RANK, MPIR_ERR_LOCAL_RANK,
myname,
"Error specifying local_leader",
"Error specifying local_leader; value %d not in between 0 and %d", local_leader, local_size );
return MPIR_ERROR( local_comm_ptr, mpi_errno, myname );
}
/* Allocate send context, inter-coll context and intra-coll context */
MPIR_Context_alloc ( local_comm_ptr, 3, &context );
/* If I'm the local leader, then exchange information */
if (local_rank == local_leader) {
MPIR_ERROR_PUSH(peer_comm_ptr);
/* Post the receives for the information from the remote_leader */
/* We don't post a receive for the remote group yet, because we */
/* don't know how big it is yet. */
MPIR_CALL_POP(MPI_Irecv (&remote_size, 1, MPI_INT, remote_leader, tag,
peer_comm, &(req[2])),peer_comm_ptr,myname);
MPIR_CALL_POP(MPI_Irecv (&send_context, 1, MPIR_CONTEXT_TYPE,
remote_leader,tag, peer_comm, &(req[3])),
peer_comm_ptr,myname);
/* Send the lrank_to_grank table of the local_comm and an allocated */
/* context. Currently I use multiple messages to send this info. */
/* Eventually, this will change(?) */
MPIR_CALL_POP(MPI_Isend (&local_size, 1, MPI_INT, remote_leader, tag,
peer_comm, &(req[0])),peer_comm_ptr,myname);
MPIR_CALL_POP(MPI_Isend (&context, 1, MPIR_CONTEXT_TYPE, remote_leader,
tag, peer_comm, &(req[1])),peer_comm_ptr,myname);
/* Wait on the communication requests to finish */
MPIR_CALL_POP(MPI_Waitall ( 4, req, status ),peer_comm_ptr,myname);
/* We now know how big the remote group is, so create it */
remote_group_ptr = MPIR_CreateGroup ( remote_size );
remote_group_ptr->self =
(MPI_Group) MPIR_FromPointer( remote_group_ptr );
/* Post the receive for the group information */
MPIR_CALL_POP(MPI_Irecv (remote_group_ptr->lrank_to_grank, remote_size,
MPI_INT, remote_leader, tag, peer_comm,
&(req[5])),peer_comm_ptr,myname);
/* Send the local group info to the remote group */
MPIR_CALL_POP(MPI_Isend (local_comm_ptr->group->lrank_to_grank, local_size,
MPI_INT, remote_leader, tag, peer_comm,
&(req[4])),peer_comm_ptr,myname);
/* wait on the send and the receive for the group information */
MPIR_CALL_POP(MPI_Waitall ( 2, &(req[4]), &(status[4]) ),peer_comm_ptr,
myname);
MPIR_ERROR_POP(peer_comm_ptr);
/* Now we can broadcast the group information to the other local comm */
/* members. */
MPIR_ERROR_PUSH(local_comm_ptr);
MPIR_CALL_POP(MPI_Bcast(&remote_size,1,MPI_INT,local_rank,local_comm),
local_comm_ptr,myname);
MPIR_CALL_POP(MPI_Bcast(remote_group_ptr->lrank_to_grank, remote_size,
MPI_INT, local_rank, local_comm),local_comm_ptr,
myname);
MPIR_ERROR_POP(local_comm_ptr);
}
/* Else I'm just an ordinary comm member, so receive the bcast'd */
/* info about the remote group */
else {
MPIR_ERROR_PUSH(local_comm_ptr);
MPIR_CALL_POP(MPI_Bcast(&remote_size, 1, MPI_INT, local_leader,
local_comm),local_comm_ptr,myname);
/* We now know how big the remote group is, so create it */
remote_group_ptr = MPIR_CreateGroup ( remote_size );
remote_group_ptr->self =
(MPI_Group) MPIR_FromPointer( remote_group_ptr );
/* Receive the group info */
MPIR_CALL_POP(MPI_Bcast(remote_group_ptr->lrank_to_grank, remote_size,
MPI_INT, local_leader, local_comm),
local_comm_ptr,myname );
MPIR_ERROR_POP(local_comm_ptr);
}
MPIR_ERROR_PUSH(local_comm_ptr);
/* Broadcast the send context */
MPIR_CALL_POP(MPI_Bcast(&send_context, 1, MPIR_CONTEXT_TYPE,
local_leader, local_comm),local_comm_ptr,myname);
MPIR_ERROR_POP(local_comm_ptr);
/* We all now have all the information necessary, start building the */
/* inter-communicator */
MPIR_ALLOC(new_comm,NEW(struct MPIR_COMMUNICATOR),local_comm_ptr,
MPI_ERR_EXHAUSTED,myname );
MPIR_Comm_init( new_comm, local_comm_ptr, MPIR_INTER );
*comm_out = new_comm->self;
new_comm->group = remote_group_ptr;
MPIR_Group_dup( local_comm_ptr->group, &(new_comm->local_group) );
new_comm->local_rank = new_comm->local_group->local_rank;
new_comm->lrank_to_grank = new_comm->group->lrank_to_grank;
new_comm->np = new_comm->group->np;
new_comm->send_context = send_context;
new_comm->recv_context = context;
new_comm->comm_name = 0;
if ((mpi_errno = MPID_CommInit( local_comm_ptr, new_comm )) )
return mpi_errno;
(void) MPIR_Attr_create_tree ( new_comm );
/* Build the collective inter-communicator */
MPIR_Comm_make_coll( new_comm, MPIR_INTER );
MPIR_Comm_make_onesided( new_comm, MPIR_INTER );
/* Build the collective intra-communicator. Note that we require
an intra-communicator for the "coll_comm" so that MPI_COMM_DUP
can use it for some collective operations (do we need this
for MPI-2 with intercommunicator collective?)
Note that this really isn't the right thing to do; we need to replace
*all* of the Mississippi state collective code.
*/
MPIR_Comm_make_coll( new_comm->comm_coll, MPIR_INTRA );
#if 0
MPIR_Comm_make_coll( new_comm->comm_onesided, MPIR_INTRA );
#endif
/* Remember it for the debugger */
MPIR_Comm_remember ( new_comm );
TR_POP;
return (mpi_errno);
}
/*@
MPI_Bsend - Basic send with user-specified buffering
Input Parameters:
+ buf - initial address of send buffer (choice)
. count - number of elements in send buffer (nonnegative integer)
. datatype - datatype of each send buffer element (handle)
. dest - rank of destination (integer)
. tag - message tag (integer)
- comm - communicator (handle)
Notes:
This send is provided as a convenience function; it allows the user to
send messages without worring about where they are buffered (because the
user `must` have provided buffer space with 'MPI_Buffer_attach').
In deciding how much buffer space to allocate, remember that the buffer space
is not available for reuse by subsequent 'MPI_Bsend's 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
.vb
MPI_Buffer_attach( b, n*sizeof(double) + MPI_BSEND_OVERHEAD );
for (i=0; i<m; i++) {
MPI_Bsend( buf, n, MPI_DOUBLE, ... );
}
.ve
because only enough buffer space is provided for a single send, and the
loop may start a second 'MPI_Bsend' before the first is done making use of the
buffer.
In C, you can
force the messages to be delivered by
.vb
MPI_Buffer_detach( &b, &n );
MPI_Buffer_attach( b, n );
.ve
(The 'MPI_Buffer_detach' will not complete until all buffered messages are
delivered.)
.N fortran
.N Errors
.N MPI_SUCCESS
.N MPI_ERR_COMM
.N MPI_ERR_COUNT
.N MPI_ERR_TYPE
.N MPI_ERR_RANK
.N MPI_ERR_TAG
.seealso: MPI_Buffer_attach, MPI_Ibsend, MPI_Bsend_init
@*/
int MPI_Bsend(
void *buf,
int count,
MPI_Datatype datatype,
int dest,
int tag,
MPI_Comm comm )
{
MPI_Request handle;
MPI_Status status;
int mpi_errno = MPI_SUCCESS;
struct MPIR_COMMUNICATOR *comm_ptr;
MPIR_ERROR_DECL;
static char myname[] = "MPI_BSEND";
disableSignal();
TR_PUSH(myname);
if (dest != MPI_PROC_NULL)
{
/* We should let Ibsend find the errors, but
we will soon add a special case for faster Bsend and we'll
need these tests then
*/
comm_ptr = MPIR_GET_COMM_PTR(comm);
#ifndef MPIR_NO_ERROR_CHECKING
MPIR_TEST_MPI_COMM(comm,comm_ptr,comm_ptr,myname);
MPIR_TEST_COUNT(count);
MPIR_TEST_SEND_TAG(tag);
MPIR_TEST_SEND_RANK(comm_ptr,dest);
if (mpi_errno) {
revertSignal();
return MPIR_ERROR(comm_ptr, mpi_errno, myname );
}
#endif
/*
? BsendDatatype?
MPID_BsendContig( comm, buf, len, src_lrank, tag, context_id,
dest_grank, msgrep, &mpi_errno );
if (!mpi_errno) return MPI_SUCCESS;
if (mpi_errno != MPIR_ERR_MAY_BLOCK)
return MPIR_ERROR( comm, mpi_errno, myname );
*/
MPIR_ERROR_PUSH(comm_ptr);
/* We don't use MPIR_CALL_POP so that we can free the handle */
handle = MPI_REQUEST_NULL;
if ((mpi_errno = MPI_Ibsend( buf, count, datatype, dest, tag, comm,
&handle ))) {
MPIR_ERROR_POP(comm_ptr);
if (handle != MPI_REQUEST_NULL)
MPID_SendFree( handle );
revertSignal();
return MPIR_ERROR(comm_ptr,mpi_errno,myname);
}
/* This Wait only completes the transfer of data into the
buffer area. The test/wait in util/bsendutil.c completes
the actual transfer
*/
MPIR_CALL_POP(MPI_Wait( &handle, &status ),comm_ptr,myname);
MPIR_ERROR_POP(comm_ptr);
}
TR_POP;
revertSignal();
return mpi_errno;
}
