So just to be clear, the C interface for MPI_Testsome is:
int MPI_Testsome(int incount, MPI_Request requests[],
int *outcount, int indices[],
MPI_Status statuses[]);
And your R call is:
mpi_errhandler(MPI_Testsome(countn, request, &INTEGER(indices)[0],
&INTEGER(indices)[1], status));
I'm assuming request is an MPI_Request object. And integer(indices)[0] is
where you want the outcount to go, and then integer(indices)[1] through
[value_of_outcount] is where you want the indices to go, right?
If so, then yes, that looks proper.
You'll probably need to look into what's happening in the R wrapper as to why
you're not getting the right answers, sorry.
(and yes, the values in the indices[] array should be between 0 and (incount-1))
On Mar 21, 2014, at 12:01 PM, Ross Boylan <[email protected]> wrote:
> On Fri, 2014-03-21 at 14:11 +0000, Jeff Squyres (jsquyres) wrote:
>> Is that C or R code?
> C.
>>
>> If it's R, I think the next step would be to check the R wrapper for
>> MPI_Testsome and see what is actually being returned by OMPI in C before it
>> gets converted to R. I'm afraid I don't know R, so I can't really comment
>> on the syntax / correctness of your code snipit.
>>
>> If it's C -- which I don't think it is, but it *could* be...? -- I would
>> need to understand your syntax in calling MPI_Testsome better; e.g., what's
>> &INTEGER(foo)[x]?
> allocVector(INTSXP, countn+1) allocates an R vector of integers.
> INTEGER(indices) returns the data portion of that structure, where the
> actual integers go. The &...[0] get the address of the first location.
> PROTECT keeps things from being garbage-collected by R.
>
> The allocation of indices is a cheat: the first location is used for the
> outcount, and the following locations get the actual indices.
>
> status is a pointer to an array of MPI status objects,
>
> The indices should be small integers, shouldn't they? I'm also getting
> some large values back.
>
> Ross
>>
>> On Mar 20, 2014, at 8:39 PM, Ross Boylan <[email protected]> wrote:
>>
>>> MPI_Testsome seems to have returned successfully, with a positive outcount,
>>> and yet given me a negative index, -4432. Can anyone help me understand
>>> what's going on?
>>>
>>> The call is from R, and so there might be a translation issue. My first
>>> thought was that it might be 32 vs 64 bit integers, but both OMPI and R
>>> seem to be using the C int type for the integers.
>>>
>>> Here's the inner call:
>>>
>>> SEXP mpi_testsome(SEXP sexp_count){
>>> int countn=INTEGER(sexp_count)[0];
>>> SEXP indices;
>>> PROTECT (indices = allocVector(INTSXP, countn+1));
>>> mpi_errhandler(MPI_Testsome(countn, request, &INTEGER(indices)[0],
>>> &INTEGER(indices)[1], status));
>>> UNPROTECT(1);
>>> return indices;
>>> }
>>>
>>> SEXP is an R structure.
>>>
>>> OMPI 1.7.4.
>>>
>>> Ross Boylan
>>>
>>> _______________________________________________
>>> users mailing list
>>> [email protected]
>>> http://www.open-mpi.org/mailman/listinfo.cgi/users
>>
>>
>
>
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--
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