The type map is an important but confounding concept in MPI. I would like a routine to display or print a type map for me.
For example (taken from the MPI-3 standard),
MPI_TYPE_CREATE_RESIZED(MPI_INT, -3, 9, type1)
results in the typemap
{(lb_marker, -3), (int, 0), (ub_marker, 6)}.
Use that type again:
MPI_TYPE_CONTIGUOUS(2, type1, type2)
and the typemap is
{(lb_marker, -3), (int, 0), (int,9), (ub_marker, 15)}
I would like a way to display that typemap automatically.
Certainly one could use MPI_Type_get_contents and MPI_Type_get_envelope and recursively descend until hitting the built-in types. This is rather a giant pain and I would have thought 20 years on some tool would exist to do this for me.
Some tools that are promising, but not quite working:
I had found MPImap from ~ 2001 here. First, it needs to be updated for modern Tcl/TK, patched to address some memory errors and after you do that; you get an unresponsive GUI. Instead, I'm looking for a library/routine I can call at run time.
MPIDU_Datatype_deubg is an MPICH specific internal type-dumping routine. It does not display the type map (it does display the dataloop representation, again close)
There once was a debugger called XMPI that lists among its features the ability to display a MPI type map. This debugger appears to be LAM-MPI specific and does not make use of get_contents/ get_envelope.
As Rob Latham said, there isn't good pre-existing solutions. With the help of the links given by tim I created this function available on Github. I took your example for the contiguous + resize test (here) and the output is
contiguous + resize
"(LB, -3), (MPI_INT, 0), (MPI_INT, 9), (UB, 15)"
With this function you just need to do printMapDatatype(mydatatype). I hope this was what you was searching for.
Here is the function, just in case of :
MPI_Aint printdatatype( MPI_Datatype datatype, MPI_Aint prevExtentTot ) {
int *array_of_ints;
MPI_Aint *array_of_adds;
MPI_Datatype *array_of_dtypes;
int num_ints, num_adds, num_dtypes, combiner;
int i, j;
MPI_Type_get_envelope( datatype, &num_ints, &num_adds, &num_dtypes, &combiner );
array_of_ints = (int *) malloc( num_ints * sizeof(int) );
array_of_adds = (MPI_Aint *) malloc( num_adds * sizeof(MPI_Aint) );
array_of_dtypes = (MPI_Datatype *) malloc( num_dtypes * sizeof(MPI_Datatype) );
MPI_Aint extent, subExtent;
MPI_Type_extent(datatype, &extent);
switch (combiner) {
case MPI_COMBINER_NAMED:
// To print the specific type, we can match against the predefined forms.
if (datatype == MPI_BYTE) printf( "(MPI_BYTE, %ld)", prevExtentTot);
else if (datatype == MPI_LB) printf( "(MPI_LB, %ld)", prevExtentTot);
else if (datatype == MPI_PACKED) printf( "(MPI_PACKED, %ld)", prevExtentTot);
else if (datatype == MPI_UB) printf( "(MPI_UB, %ld)", prevExtentTot);
else if (datatype == MPI_CHAR) printf( "(MPI_CHAR, %ld)", prevExtentTot);
else if (datatype == MPI_DOUBLE) printf( "(MPI_DOUBLE, %ld)", prevExtentTot);
else if (datatype == MPI_FLOAT) printf( "(MPI_FLOAT, %ld)", prevExtentTot);
else if (datatype == MPI_INT) printf( "(MPI_INT, %ld)", prevExtentTot );
else if (datatype == MPI_LONG) printf( "(MPI_LONG, %ld)", prevExtentTot);
else if (datatype == MPI_LONG_DOUBLE) printf( "(MPI_LONG_DOUBLE, %ld)", prevExtentTot);
else if (datatype == MPI_LONG_LONG) printf( "(MPI_LONG_LONG, %ld)", prevExtentTot);
else if (datatype == MPI_LONG_LONG_INT) printf( "(MPI_LONG_LONG_INT, %ld)", prevExtentTot);
else if (datatype == MPI_SHORT) printf( "(MPI_SHORT, %ld)", prevExtentTot);
else if (datatype == MPI_SIGNED_CHAR) printf( "(MPI_SIGNED_CHAR, %ld)", prevExtentTot);
else if (datatype == MPI_UNSIGNED) printf( "(MPI_UNSIGNED, %ld)", prevExtentTot);
else if (datatype == MPI_UNSIGNED_CHAR) printf( "(MPI_UNSIGNED_CHAR, %ld)", prevExtentTot);
else if (datatype == MPI_UNSIGNED_LONG) printf( "(MPI_UNSIGNED_LONG, %ld)", prevExtentTot);
else if (datatype == MPI_UNSIGNED_LONG_LONG)printf( "(MPI_UNSIGNED_LONG_LONG, %ld)", prevExtentTot);
else if (datatype == MPI_UNSIGNED_SHORT) printf( "(MPI_UNSIGNED_SHORT, %ld)", prevExtentTot);
else if (datatype == MPI_WCHAR) printf( "(MPI_WCHAR, %ld)", prevExtentTot);
free( array_of_ints );
free( array_of_adds );
free( array_of_dtypes );
return prevExtentTot;
break;
case MPI_COMBINER_DUP:
MPI_Type_get_contents( datatype, num_ints, num_adds, num_dtypes, array_of_ints, array_of_adds, array_of_dtypes );
printdatatype( array_of_dtypes[0], prevExtentTot);
printf(", \n");
break;
case MPI_COMBINER_CONTIGUOUS:
MPI_Type_get_contents( datatype, num_ints, num_adds, num_dtypes, array_of_ints, array_of_adds, array_of_dtypes );
MPI_Type_extent(array_of_dtypes[0], &subExtent); // no need to do in loop because same type
for (i=0; i < array_of_ints[0]; i++) {
prevExtentTot = printdatatype( array_of_dtypes[0], prevExtentTot);
prevExtentTot += subExtent;
printf(", ");
}
break;
case MPI_COMBINER_VECTOR:
MPI_Type_get_contents( datatype, num_ints, num_adds, num_dtypes, array_of_ints, array_of_adds, array_of_dtypes );
MPI_Type_extent(array_of_dtypes[0], &subExtent); // no need to do in loop because same type
printf("[");
for (i = 0; i < array_of_ints[0]; i++) { //count
printf( "BL : %d - ", array_of_ints[1]);
for (j = 0; j < array_of_ints[2]; j++) { // stride
if (j < array_of_ints[1]) { // if in blocklength
prevExtentTot = printdatatype( array_of_dtypes[0], prevExtentTot);
printf(", ");
}
prevExtentTot += subExtent;
}
}
printf("], ");
break;
case MPI_COMBINER_HVECTOR:
case MPI_COMBINER_HVECTOR_INTEGER:{
MPI_Aint backupPrevExtent = prevExtentTot;
MPI_Type_get_contents( datatype, num_ints, num_adds, num_dtypes, array_of_ints, array_of_adds, array_of_dtypes );
MPI_Type_extent(array_of_dtypes[0], &subExtent); // no need to do in loop because same type
printf("[");
for (i = 0; i < array_of_ints[0]; i++) { //count
printf( "BL : %d - ", array_of_ints[1]);
for (j = 0; j < array_of_ints[1]; j++) { // blocklength
prevExtentTot = printdatatype( array_of_dtypes[0], prevExtentTot);
printf(", ");
prevExtentTot += subExtent;
}
prevExtentTot = backupPrevExtent + array_of_adds[0]; // + stride un byte
}
printf("], ");
break;
}
case MPI_COMBINER_INDEXED:{
MPI_Aint tmpPrevExtent;
int count, blocklength;
MPI_Type_get_contents( datatype, num_ints, num_adds, num_dtypes, array_of_ints, array_of_adds, array_of_dtypes );
MPI_Type_extent(array_of_dtypes[0], &subExtent); // no need to do in loop because same type
printf("<");
count = array_of_ints[0];
for (i = 0; i < count; i++) { // count
blocklength = array_of_ints[i + 1]; // array of blocklength
tmpPrevExtent = prevExtentTot;
tmpPrevExtent += array_of_ints[count + 1 + i] * subExtent; // + displacement * size of block
printf( "BL : %d - ", blocklength);
for (j = 0; j < blocklength; j++) { // blocklength
tmpPrevExtent = printdatatype( array_of_dtypes[0], tmpPrevExtent);
printf(", ");
tmpPrevExtent += subExtent;
}
}
printf(">, ");
prevExtentTot = tmpPrevExtent;
break;
}
case MPI_COMBINER_HINDEXED:
case MPI_COMBINER_HINDEXED_INTEGER:{
MPI_Aint tmpPrevExtent;
int count, blocklength;
MPI_Type_get_contents( datatype, num_ints, num_adds, num_dtypes, array_of_ints, array_of_adds, array_of_dtypes );
MPI_Type_extent(array_of_dtypes[0], &subExtent); // no need to do in loop because same type
printf("<");
count = array_of_ints[0];
for (i = 0; i < count; i++) { // count
blocklength = array_of_ints[i + 1]; // array of blocklength
tmpPrevExtent = prevExtentTot;
tmpPrevExtent += array_of_adds[i]; // + displacement in byte
printf( "BL : %d - ", blocklength);
for (j = 0; j < blocklength; j++) {
tmpPrevExtent = printdatatype( array_of_dtypes[0], tmpPrevExtent);
printf(", ");
tmpPrevExtent += subExtent;
}
}
printf(">, ");
prevExtentTot = tmpPrevExtent;
break;
}
case MPI_COMBINER_INDEXED_BLOCK:{
MPI_Aint tmpPrevExtent;
int count;
MPI_Type_get_contents( datatype, num_ints, num_adds, num_dtypes, array_of_ints, array_of_adds, array_of_dtypes );
MPI_Type_extent(array_of_dtypes[0], &subExtent); // no need to do in loop because same type
printf("<");
count = array_of_ints[0];
for (i = 0; i < count; i++) { // count
tmpPrevExtent = prevExtentTot;
tmpPrevExtent += array_of_ints[i + 2] * subExtent; // + displacement * size of block
printf( "BL : %d - ", array_of_ints[i + 1]);
for (j = 0; j < array_of_ints[1]; j++) { // blocklength
tmpPrevExtent = printdatatype( array_of_dtypes[0], tmpPrevExtent);
printf(", ");
tmpPrevExtent += subExtent;
}
}
printf(">, ");
prevExtentTot = tmpPrevExtent;
break;
}
case MPI_COMBINER_STRUCT:
case MPI_COMBINER_STRUCT_INTEGER:{
MPI_Aint tmpPrevExtent;
MPI_Type_get_contents( datatype, num_ints, num_adds, num_dtypes, array_of_ints, array_of_adds, array_of_dtypes );
printf( "{");
for (i = 0; i < array_of_ints[0]; i++) { // count
tmpPrevExtent = prevExtentTot + array_of_adds[i]; // origin + displacement
printf( "BL : %d - ", array_of_ints[i + 1]);
tmpPrevExtent = printdatatype( array_of_dtypes[i], tmpPrevExtent);
tmpPrevExtent += subExtent;
printf(", ");
}
printf("}, ");
prevExtentTot = tmpPrevExtent;
break;
}
case MPI_COMBINER_SUBARRAY:
// I don't know what is interresting to display here...
printf("... subarray not handled ...");
break;
case MPI_COMBINER_DARRAY:
// Same
printf("... darray not handled ...");
break;
case MPI_COMBINER_RESIZED:
MPI_Type_get_contents( datatype, num_ints, num_adds, num_dtypes, array_of_ints, array_of_adds, array_of_dtypes );
prevExtentTot = printdatatype( array_of_dtypes[0], prevExtentTot);
printf(", \n");
break;
default:
printf( "Unrecognized combiner type\n" );
}
free( array_of_ints );
free( array_of_adds );
free( array_of_dtypes );
return prevExtentTot;
}
void printMapDatatype(MPI_Datatype datatype) {
MPI_Aint lb, ub;
MPI_Type_lb(datatype, &lb);
MPI_Type_ub(datatype, &ub);
printf("\"(LB, %ld), ", lb);
printdatatype(datatype, 0);
printf("(UB, %ld)\"\n", ub);
}