I'm trying to write a routine which unpicks user defined datatypes
using MPI_Type_get_{envelope,contents}. I'm having a problem that
a derived type returned by a call of MPI_Type_get_contents, when handed
onwards to MPI_Type_get_envelope, causes the system to bomb:
[suse10:15004] *** An error occurred in MPI_Type_get_envelope
[suse10:15004] *** on communicator MPI_COMM_WORLD
[suse10:15004] *** MPI_ERR_INTERN: internal error
[suse10:15004] *** MPI_ERRORS_ARE_FATAL (goodbye)
Close inspection of the MPI2 specification for MPI_Type_get_envelope
does not appear to reveal any limitations on the types or
committedness-state of types that may be passed to MPI_Type_get_envelope.
This is with Open MPI 1.0.1 on SuSE 10.0 (x86), built from source.
This build otherwise appears to work and has run various MPI apps
successfully over the past month.
A test case is attached. What am I doing wrong?
J
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include "mpi.h"
/* Generate a _contiguous type */
static MPI_Datatype tycon_Contiguous ( int count, MPI_Datatype t )
{
MPI_Datatype t2;
int r = MPI_Type_contiguous( count, t, &t2 );
assert(r == MPI_SUCCESS);
return t2;
}
/* Generate a simple 2-element _struct type w/ given tys and
displacements */
static MPI_Datatype tycon_Struct2 ( MPI_Datatype t1, int disp1,
MPI_Datatype t2, int disp2 )
{
int blocklens[2];
MPI_Aint disps[2];
MPI_Datatype tys[2];
MPI_Datatype tres;
int r;
blocklens[0] = blocklens[1] = 1;
disps[0] = disp1;
disps[1] = disp2;
tys[0] = t1;
tys[1] = t2;
r = MPI_Type_struct( 2, blocklens, disps, tys, &tres );
assert(r == MPI_SUCCESS);
return tres;
}
/* Generate a simple struct type, then try to unravel it with
MPI_Type_get_{envelope,contents}. */
int main ( int argc, char** argv )
{
int rank, size, r;
MPI_Datatype t1, t2;
MPI_Init( &argc, &argv );
MPI_Comm_size( MPI_COMM_WORLD, &size );
MPI_Comm_rank( MPI_COMM_WORLD, &rank );
if (rank == 0) {
t1 = tycon_Contiguous(4, MPI_DOUBLE);
/* t1 = {(double,0),(double,8),(double,16),(double,24)} */
t2 = tycon_Struct2(t1, 0, MPI_CHAR, 48);
/* t2 = {(double,0),(double,8),(double,16),(double,24), (char,48)} */
/* Disassemble the struct type (t2). */
int n_ints, n_addrs, n_dtys, combiner;
r = MPI_Type_get_envelope( t2, &n_ints, &n_addrs, &n_dtys, &combiner );
assert(r == MPI_SUCCESS);
assert(n_ints == 3 && n_addrs == 2 && n_dtys == 2);
assert(combiner == MPI_COMBINER_STRUCT);
int* ints = malloc(n_ints * sizeof(int));
MPI_Aint* addrs = malloc(n_addrs * sizeof(MPI_Aint));
MPI_Datatype* dtys = malloc(n_dtys * sizeof(MPI_Datatype));
r = MPI_Type_get_contents( t2, n_ints, n_addrs, n_dtys,
ints, addrs, dtys );
assert(r == MPI_SUCCESS);
/* Peer at the first element of the struct, which is (a copy of)
t1. */
assert(dtys[1] == MPI_CHAR);
printf("before second MPI_Type_get_envelope\n");
/* XXXXXXX this is the call that dies */
r = MPI_Type_get_envelope( dtys[0],
&n_ints, &n_addrs, &n_dtys, &combiner );
/* XXXXXXX we never get here */
printf("after second MPI_Type_get_envelope\n");
assert(r == MPI_SUCCESS);
} /* rank==0 */
MPI_Finalize();
return 0;
}
