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many2many.cpp
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Fri, Nov 1, 08:22

many2many.cpp
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#include "mpi.h"
#include "many2many.h"
#include "irregular.h"
#include "memory.h"
#include "error.h"
#include <map>
#define MAX(A,B) ((A) > (B)) ? (A) : (B)
/* ---------------------------------------------------------------------- */
Many2Many::Many2Many(MPI_Comm caller)
{
comm = caller;
MPI_Comm_rank(comm,&me);
MPI_Comm_size(comm,&nprocs);
memory = new Memory(comm);
error = new Error(comm);
src_own = dest_own = NULL;
src_off = dest_off = NULL;
src_iwork = dest_iwork = NULL;
src_dwork = dest_dwork = NULL;
irregular = NULL;
}
/* ---------------------------------------------------------------------- */
Many2Many::~Many2Many()
{
delete memory;
delete error;
deallocate();
}
/* ----------------------------------------------------------------------
create a many2many pattern, deallocating any previous pattern
each proc will contribute nsrc items with IDs listed in id_src
each proc will receive ndest items with IDs listed in id_dest
only sets up communication via rendezvous algorithm and Irregular class
if id_src does not match id_dest on all procs
------------------------------------------------------------------------- */
void Many2Many::setup(int nsrc, int *id_src, int ndest, int *id_dest)
{
int i,j,isrc,idest,nsend,nrecv;
int *proclist,*work;
std::map<int,int> hash;
std::map<int,int>::iterator loc;
// free any previous many2many info
deallocate();
// allocate on-proc and off-proc index lists
src_own =
(int *) memory->smalloc(nsrc*sizeof(int),"many2many:src_own");
dest_own =
(int *) memory->smalloc(ndest*sizeof(int),"many2many:dest_own");
src_off =
(int *) memory->smalloc(nsrc*sizeof(int),"many2many:src_off");
dest_off =
(int *) memory->smalloc(ndest*sizeof(int),"many2many:dest_off");
// store destination IDs in hash
for (int i = 0; i < ndest; i++)
hash.insert(std::pair<int,int> (id_dest[i],i));
// src_own, dest_own = list of IDs in both src and dest
// nsrc_off = list of IDs in src owned by other procs
nown = nsrc_off = 0;
nsrc_off = 0;
for (i = 0; i < nsrc; i++) {
loc = hash.find(id_src[i]);
if (loc != hash.end()) {
src_own[nown] = i;
dest_own[nown] = loc->second;
nown++;
} else src_off[nsrc_off++] = i;
}
// all done if all procs have one-to-one mapping of src and dest IDs
// else figure out irregular comm needed
int flag = 0;
if (nown == nsrc && nown == ndest) flag = 1;
int flagall;
MPI_Allreduce(&flag,&flagall,1,MPI_INT,MPI_MIN,comm);
if (flagall) return;
// ndest_off = list of IDs in dest owned by other procs
work = (int *) memory->smalloc(ndest*sizeof(int),"many2many:work");
for (i = 0; i < ndest; i++) work[i] = 0;
for (i = 0; i < nown; i++) work[dest_own[i]] = 1;
ndest_off = 0;
for (i = 0; i < ndest; i++)
if (work[i] == 0) dest_off[ndest_off++] = i;
memory->sfree(work);
// realloc off-proc arrays to smaller size
src_off = (int *)
memory->srealloc(src_off,nsrc_off*sizeof(int),"many2many:src_off");
dest_off = (int *)
memory->srealloc(dest_off,ndest_off*sizeof(int),"many2many:dest_off");
// send off-proc src and dest Datums to 3rd-party proc via irregular comm
// proc = ID % nprocs
nsend = nsrc_off + ndest_off;
proclist = new int[nsend];
Datum1 *send1 = new Datum1[nsend];
for (i = 0; i < nsrc_off; i++) {
proclist[i] = id_src[src_off[i]] % nprocs;
send1[i].id = id_src[src_off[i]];
send1[i].proc = me;
send1[i].index = src_off[i];
}
for (i = 0, j = nsrc_off; i < ndest_off; i++, j++) {
proclist[j] = id_dest[dest_off[i]] % nprocs;
send1[j].id = -id_dest[dest_off[i]];
send1[j].proc = me;
send1[j].index = dest_off[i];
}
irregular = new Irregular(comm);
irregular->pattern(nsend,proclist);
nrecv = irregular->size(sizeof(Datum1)) / sizeof(Datum1);
Datum1 *recv1 = new Datum1[nrecv];
irregular->exchange((char *) send1, (char *) recv1);
delete irregular;
delete [] proclist;
// as 3rd-party proc, now have matching pairs of off-proc IDs
// store src IDs (which are positive) in hash
// loop over dest IDs (which are negative) to find matches
// send match info back to src procs via a 2nd irregular comm
nsend = nrecv/2;
proclist = new int[nsend];
Datum2 *send2 = new Datum2[nsend];
nsend = 0;
hash.clear();
for (isrc = 0; isrc < nrecv; isrc++)
if (recv1[isrc].id > 0)
hash.insert(std::pair<int,int> (recv1[isrc].id,isrc));
for (idest = 0; idest < nrecv; idest++)
if (recv1[idest].id < 0) {
loc = hash.find(-recv1[idest].id);
if (loc != hash.end()) {
isrc = loc->second;
proclist[nsend] = recv1[isrc].proc;
send2[nsend].slocal = recv1[isrc].index;
send2[nsend].dlocal = recv1[idest].index;
send2[nsend].dproc = recv1[idest].proc;
nsend++;
} else error->one("Did not receive matching src/dest ID");
}
irregular = new Irregular(comm);
irregular->pattern(nsend,proclist);
nrecv = irregular->size(sizeof(Datum2)) / sizeof(Datum2);
Datum2 *recv2 = new Datum2[nrecv];
irregular->exchange((char *) send2, (char *) recv2);
delete irregular;
delete [] proclist;
// use list of received src->dest Datums to build final irregular commm
// irregular comm will communicate off-proc info from src to dest directly
// work = local indices of dest IDs to send initially
nsend = nrecv;
proclist = new int[nsend];
work = new int[nsend];
for (i = 0; i < nrecv; i++) {
src_off[i] = recv2[i].slocal;
work[i] = recv2[i].dlocal;
proclist[i] = recv2[i].dproc;
}
irregular = new Irregular(comm);
irregular->pattern(nsend,proclist);
// send receiver's local indices
// receiver stores them as indirection list in dest_off
nrecv = irregular->size(sizeof(int)) / sizeof(int);
irregular->exchange((char *) work, (char *) dest_off);
delete [] proclist;
delete [] work;
// create work arrays for data exchange of int/double data
src_iwork =
(int *) memory->smalloc(nsrc_off*sizeof(int),"many2many:src_iwork");
dest_iwork =
(int *) memory->smalloc(ndest_off*sizeof(int),"many2many:dest_iwork");
src_dwork =
(double *) memory->smalloc(nsrc_off*sizeof(double),"many2many:src_dwork");
dest_dwork =
(double *) memory->smalloc(ndest_off*sizeof(double),
"many2many:dest_dwork");
// clean up
delete [] send1;
delete [] recv1;
delete [] send2;
delete [] recv2;
// debug checks for full coverage of srd/dest - can delete eventually
work = new int[MAX(nsrc,ndest)];
for (i = 0; i < nsrc; i++) work[i] = 0;
for (i = 0; i < nown; i++) work[src_own[i]]++;
for (i = 0; i < nsrc_off; i++) work[src_off[i]]++;
for (i = 0; i < nsrc; i++)
if (work[i] != 1) {
char str[128];
sprintf(str,"BAD SRC %d: %d %d\n",me,i,work[i]);
error->one(str);
}
for (i = 0; i < ndest; i++) work[i] = 0;
for (i = 0; i < nown; i++) work[dest_own[i]]++;
for (i = 0; i < ndest_off; i++) work[dest_off[i]]++;
for (i = 0; i < ndest; i++)
if (work[i] != 1) {
char str[128];
sprintf(str,"BAD DEST %d: %d %d\n",me,i,work[i]);
error->one(str);
}
delete [] work;
}
/* ----------------------------------------------------------------------
transfer one src entity to dest entity, matched by IDs in create()
operates on an int vector
------------------------------------------------------------------------- */
void Many2Many::exchange(int *src, int *dest)
{
int i;
// copy on-proc info
for (i = 0; i < nown; i++)
dest[dest_own[i]] = src[src_own[i]];
// communicate off-proc info
// user src_off and dest_off to pack/unpack data
if (irregular) {
int nrecv = irregular->size(sizeof(int)) / sizeof(int);
for (i = 0; i < nsrc_off; i++) src_iwork[i] = src[src_off[i]];
irregular->exchange((char *) src_iwork, (char *) dest_iwork);
for (i = 0; i < ndest_off; i++) dest[dest_off[i]] = dest_iwork[i];
}
}
/* ----------------------------------------------------------------------
transfer one src entity to dest entity, matched by IDs in create()
operates on a double vector
------------------------------------------------------------------------- */
void Many2Many::exchange(double *src, double *dest)
{
int i;
// copy on-proc info
for (int i = 0; i < nown; i++)
dest[dest_own[i]] = src[src_own[i]];
// communicate off-proc info
// user src_off and dest_off to pack/unpack data
if (irregular) {
int nrecv = irregular->size(sizeof(double)) / sizeof(double);
for (i = 0; i < nsrc_off; i++) src_dwork[i] = src[src_off[i]];
irregular->exchange((char *) src_dwork, (char *) dest_dwork);
for (i = 0; i < ndest_off; i++) dest[dest_off[i]] = dest_dwork[i];
}
}
/* ---------------------------------------------------------------------- */
void Many2Many::deallocate()
{
memory->sfree(src_own);
memory->sfree(dest_own);
memory->sfree(src_off);
memory->sfree(dest_off);
memory->sfree(src_iwork);
memory->sfree(dest_iwork);
memory->sfree(src_dwork);
memory->sfree(dest_dwork);
delete irregular;
}

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