+1
FWIW, the trivial patch below does not make the test run because
MPI_DATATYPE_NULL is not commited.
also, FWIW, this simple test case fails with both OpenMPI and MPICH
(and i expected it to work with MPICH)
/*
* This is a dumb example that sendrecv to/from self
* with MPI_DATATYPE_NULL and a zero count
*/
#include <stdio.h>
#include <mpi.h>
int main (int argc, char *argv[]) {
MPI_Init(&argc, &argv);
MPI_Sendrecv(NULL, 0, MPI_DATATYPE_NULL, 0, 0,
NULL, 0, MPI_DATATYPE_NULL, 0, 0,
MPI_COMM_SELF, MPI_STATUS_IGNORE);
MPI_Finalize();
return 0;
}
Cheers,
Gilles
diff --git a/ompi/mpi/c/bindings.h b/ompi/mpi/c/bindings.h
index 12e29cb..42d3705 100644
--- a/ompi/mpi/c/bindings.h
+++ b/ompi/mpi/c/bindings.h
@@ -10,6 +10,8 @@
* Copyright (c) 2004-2005 The Regents of the University of California.
* All rights reserved.
* Copyright (c) 2010 Cisco Systems, Inc. All rights reserved.
+ * Copyright (c) 2016 Research Organization for Information Science
+ * and Technology (RIST). All rights reserved.
* $COPYRIGHT$
*
* Additional copyrights may follow
@@ -45,7 +47,7 @@ BEGIN_C_DECLS
#define OMPI_CHECK_DATATYPE_FOR_SEND( RC, DDT, COUNT ) \
do { \
/* (RC) = MPI_SUCCESS; */ \
- if( NULL == (DDT) || MPI_DATATYPE_NULL == (DDT) ) (RC) =
MPI_ERR_TYPE; \
+ if( NULL == (DDT) || ((MPI_DATATYPE_NULL == (DDT)) && (0 <
(COUNT))) ) (RC) = MPI_ERR_TYPE; \
else if( (COUNT) < 0 ) (RC) = MPI_ERR_COUNT; \
else if( !opal_datatype_is_committed(&((DDT)->super)) ) (RC)
= MPI_ERR_TYPE; \
else if( !opal_datatype_is_valid(&((DDT)->super)) ) (RC) =
MPI_ERR_TYPE; \
@@ -54,7 +56,7 @@ BEGIN_C_DECLS
#define OMPI_CHECK_DATATYPE_FOR_RECV( RC, DDT, COUNT ) \
do { \
/* (RC) = MPI_SUCCESS; */ \
- if( NULL == (DDT) || MPI_DATATYPE_NULL == (DDT) ) (RC) =
MPI_ERR_TYPE; \
+ if( NULL == (DDT) || ((MPI_DATATYPE_NULL == (DDT)) && (0 <
(COUNT))) ) (RC) = MPI_ERR_TYPE; \
else if( (COUNT) < 0 ) (RC) = MPI_ERR_COUNT; \
else if( !opal_datatype_is_committed(&((DDT)->super)) ) (RC)
= MPI_ERR_TYPE; \
/* XXX Fix flags else if( ompi_datatype_is_overlapped((DDT))
) (RC) = MPI_ERR_TYPE; */ \
@@ -64,7 +66,7 @@ BEGIN_C_DECLS
#define OMPI_CHECK_DATATYPE_FOR_ONE_SIDED( RC, DDT, COUNT )
\
do {
\
/*(RC) = MPI_SUCCESS; */
\
- if( NULL == (DDT) || MPI_DATATYPE_NULL == (DDT) ) (RC) =
MPI_ERR_TYPE; \
+ if( NULL == (DDT) || ((MPI_DATATYPE_NULL == (DDT)) && (0 <
(COUNT))) ) (RC) = MPI_ERR_TYPE; \
else if( (COUNT) < 0 ) (RC) = MPI_ERR_COUNT;
\
else if( !opal_datatype_is_committed(&((DDT)->super)) ) (RC)
= MPI_ERR_TYPE; \
else if( opal_datatype_is_overlapped(&((DDT)->super)) ) (RC)
= MPI_ERR_TYPE; \
On Wed, Jan 13, 2016 at 11:06 AM, George Bosilca <bosi...@icl.utk.edu> wrote:
> As JH mentioned the examples are not normative. The type MPI_DATATYPE_NULL
> is not part of the MPI predefined datatypes, and as such is not expected to
> be a commited datatype, thus improper for communications (even when the
> count is 0).
>
> George.
>
>
> On Tue, Jan 12, 2016 at 8:25 PM, Jim Edwards <jedwa...@ucar.edu> wrote:
>>
>> Hi Gilles,
>>
>> I think that your conversation with Jeff pretty much covered it but
>> your understanding of my original problem is correct.
>> Thanks for the prompt response and the PR.
>>
>> On Tue, Jan 12, 2016 at 5:59 PM, Jeff Hammond <jeff.scie...@gmail.com>
>> wrote:
>>>
>>> Consider MPI_Get_accumulate with op=MPI_NO_OP, which is used to achieve
>>> atomic Get. Obviously, one does not want to allocate and describe a source
>>> buffer that will not be touched by this. This is a case like MPI_Alltoallw
>>> where (NULL,0,MPI_DATATYPE_NULL) needs to work at participating processes.
>>>
>>> Best,
>>>
>>> Jeff
>>>
>>> On Tue, Jan 12, 2016 at 4:46 PM, Gilles Gouaillardet
>>> <gilles.gouaillar...@gmail.com> wrote:
>>>>
>>>> Thanks Jeff,
>>>>
>>>> i could not find anything in the standard that says this is an invalid
>>>> usage ... so i can only agree this is a bug.
>>>>
>>>> fwiw, example 4.23 is working fine with OpenMPI
>>>> but that is a different case : with MPI_Gather and friends, recv stuff
>>>> is irrelevant on non root task.
>>>> in the case of MPI_Alltoallw and friends, no parameter is ignored.
>>>>
>>>> fortunatly, the fix is pretty trivial, so i will make a PR from now
>>>>
>>>> Cheers,
>>>>
>>>> Gilles
>>>>
>>>>
>>>> On Wed, Jan 13, 2016 at 9:37 AM, Jeff Hammond <jeff.scie...@gmail.com>
>>>> wrote:
>>>> > Example 4.23 of MPI 3.1 (it is hardly a new example, but may have a
>>>> > different number in older versions) demonstrates the use of
>>>> > (buffer=NULL,count=0,type=MPI_DATATYPE_NULL). While examples in the
>>>> > MPI
>>>> > standard are not normative text, this is certainly a valid use of MPI.
>>>> > I
>>>> > can't find a citation where it says explicitly that this is correct,
>>>> > but it
>>>> > follows logically from other text.
>>>> >
>>>> > The MPICH macro MPIR_ERRTEST_USERBUFFER that is used through the code
>>>> > to
>>>> > test for valid user buffers begins with "if (count > 0..." and thus
>>>> > does
>>>> > concern itself with the type or buffer pointer when count=0.
>>>> > Furthermore,
>>>> > this macro is redundantly protected with a count>0 check when used in
>>>> > MPI_Alltoallw (and other collectives).
>>>> >
>>>> > Best,
>>>> >
>>>> > Jeff
>>>> >
>>>> >
>>>> > On Tue, Jan 12, 2016 at 4:18 PM, Gilles Gouaillardet
>>>> > <gil...@rist.or.jp>
>>>> > wrote:
>>>> >>
>>>> >> Hi Jim,
>>>> >>
>>>> >> can you please confirm my understanding is correct :
>>>> >>
>>>> >> - OpenMPI does *not* accept MPI_DATATYPE_NULL as an input of
>>>> >> MPI_Alltoallw
>>>> >> - mpich does accept MPI_DATATYPE_NULL as an input of MPI_Alltoallw
>>>> >> *if*
>>>> >> the corresponding count *is* zero
>>>> >> - mpich does *not* accept MPI_DATATYPE_NULL as an input of
>>>> >> MPI_Alltoallw
>>>> >> *if* the corresponding count is *not* zero
>>>> >>
>>>> >> So you are considering as a bug the fact OpenMPI does not accept
>>>> >> MPI_DATATYPE_NULL *with* a zero count.
>>>> >>
>>>> >> am i correct ?
>>>> >>
>>>> >> Cheers,
>>>> >>
>>>> >> Gilles
>>>> >>
>>>> >>
>>>> >> On 1/13/2016 8:27 AM, Jim Edwards wrote:
>>>> >>
>>>> >> Hi,
>>>> >>
>>>> >> I am using OpenMPI-1.8.3 built with gcc 4.8.3
>>>> >> and I am using an MPI_Alltoallw call to perform
>>>> >> an all to some (or some to all) communication.
>>>> >>
>>>> >> In the case in which my task is not sending (or receiving) any data I
>>>> >> set
>>>> >> the
>>>> >> datatype for that send or recv buffer to MPI_DATATYPE_NULL - this
>>>> >> works fine with other mpi libraries but fails in openmpi. If I set
>>>> >> the datatype to something else say MPI_CHAR - it works fine. I
>>>> >> think
>>>> >> that this is a bug in open-mpi - would you agree?
>>>> >>
>>>> >>
>>>> >>
>>>> >>
>>>> >> --
>>>> >> Jim Edwards
>>>> >>
>>>> >> CESM Software Engineer
>>>> >> National Center for Atmospheric Research
>>>> >> Boulder, CO
>>>> >>
>>>> >>
>>>> >> _______________________________________________
>>>> >> users mailing list
>>>> >> us...@open-mpi.org
>>>> >> Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users
>>>> >> Link to this post:
>>>> >> http://www.open-mpi.org/community/lists/users/2016/01/28249.php
>>>> >>
>>>> >>
>>>> >>
>>>> >> _______________________________________________
>>>> >> users mailing list
>>>> >> us...@open-mpi.org
>>>> >> Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users
>>>> >> Link to this post:
>>>> >> http://www.open-mpi.org/community/lists/users/2016/01/28250.php
>>>> >
>>>> >
>>>> >
>>>> >
>>>> > --
>>>> > Jeff Hammond
>>>> > jeff.scie...@gmail.com
>>>> > http://jeffhammond.github.io/
>>>> >
>>>> > _______________________________________________
>>>> > users mailing list
>>>> > us...@open-mpi.org
>>>> > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users
>>>> > Link to this post:
>>>> > http://www.open-mpi.org/community/lists/users/2016/01/28251.php
>>>> _______________________________________________
>>>> users mailing list
>>>> us...@open-mpi.org
>>>> Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users
>>>> Link to this post:
>>>> http://www.open-mpi.org/community/lists/users/2016/01/28252.php
>>>
>>>
>>>
>>>
>>> --
>>> Jeff Hammond
>>> jeff.scie...@gmail.com
>>> http://jeffhammond.github.io/
>>>
>>> _______________________________________________
>>> users mailing list
>>> us...@open-mpi.org
>>> Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users
>>> Link to this post:
>>> http://www.open-mpi.org/community/lists/users/2016/01/28253.php
>>
>>
>>
>>
>> --
>> Jim Edwards
>>
>> CESM Software Engineer
>> National Center for Atmospheric Research
>> Boulder, CO
>>
>> _______________________________________________
>> users mailing list
>> us...@open-mpi.org
>> Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users
>> Link to this post:
>> http://www.open-mpi.org/community/lists/users/2016/01/28254.php
>
>
>
> _______________________________________________
> users mailing list
> us...@open-mpi.org
> Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users
> Link to this post:
> http://www.open-mpi.org/community/lists/users/2016/01/28255.php
