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psrs.c
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psrs.c
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#include "psrs.h"
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <time.h>
#include <string.h>
#include <mpi.h>
#include "mpi-printf.h"
#include "seq_sort.h"
void assert_malloc(void *ptr, int _MYPROC) {
if (ptr==NULL) {
fprintf(stderr,"ERROR: PE%2d cannot malloc\n",_MYPROC);
fflush(stderr);
exit(1);
}
}
#define OVERSMP 1
void all_sort_psrs_check_i(int *A, int A_size) {
int i;
int _PROCS, _MYPROC;
MPI_Comm_size(MPI_COMM_WORLD, &_PROCS);
MPI_Comm_rank(MPI_COMM_WORLD, &_MYPROC);
for (i=1 ; i<A_size ; i++)
if (A[i] < A[i-1])
fprintf(stderr,"(PE%3d)ERROR: A[%8d] < A[%8d] (%12d %12d)\n",
_MYPROC, i, i-1, A[i], A[i-1]);
MPI_fprintf(stderr,"HERE CHECKED\n");
}
int *findpos (int *base, int size, int key) {
/* find position of key (or next larger) in sorted array */
int done = 0, *l, *u, *m, *end;
l = base;
u = end = base + size - 1;
while (! done && size > 0) {
m = l + size/2;
if (key == *m)
done = 1;
else {
size /= 2;
if (key > *m)
l = m+1;
else
u = m-1;
}
}
while (m < end && key > *m)
++m;
return (m);
}
int all_sort_psrs_i(int *A, int A_size, int *B) {
int i, B_size;
int
*recv_cnt, /* number of keys to receive from each PN */
*send_cnt, /* number of keys to send to PNs */
*recv_off,
*send_off;
int no_samples, /* number of samples to take from sorted data */
*pivbuffer, /* array of pivots */
pivdist, /* distance between pivots in set of samples */
possmp, /* position of pivot in set of all samples */
**prtbound, /* boundaries for partitioning local data */
*recv_buf, /* incoming data to merge */
*smpbuffer, /* array of local samples */
*smpallbuf, /* array of global samples */
smpdist, /* distance between consecutive samples */
trecv;
MPI_Status stat;
int _PROCS, _MYPROC;
MPI_Comm_size(MPI_COMM_WORLD, &_PROCS);
MPI_Comm_rank(MPI_COMM_WORLD, &_MYPROC);
prtbound = (int **) malloc((_PROCS+1)*sizeof(int *));
assert_malloc(prtbound, _MYPROC);
send_cnt = (int *)malloc(_PROCS*sizeof(int));
assert_malloc(send_cnt, _MYPROC);
send_off = (int *)malloc(_PROCS*sizeof(int));
assert_malloc(send_off, _MYPROC);
recv_off = (int *)malloc(_PROCS*sizeof(int));
assert_malloc(recv_off, _MYPROC);
recv_cnt = (int *)malloc(_PROCS*sizeof(int));
assert_malloc(recv_cnt, _MYPROC);
pivbuffer = (int *)malloc((_PROCS-1)*sizeof(int));
assert_malloc(pivbuffer, _MYPROC);
/* STEP 1 */
fastsort(A, A_size);
/* STEP 2 */
no_samples = OVERSMP*_PROCS - 1;
smpdist = A_size / (no_samples + 1);
smpbuffer = (int *)malloc(no_samples*sizeof(int));
assert_malloc(smpbuffer, _MYPROC);
for (i=0; i<no_samples; i++)
smpbuffer[i] = A[(i+1)*smpdist];
/* STEP 3 */
smpallbuf = (int *)malloc(_PROCS*no_samples*sizeof(int));
assert_malloc(smpallbuf, _MYPROC);
MPI_Gather(smpbuffer, no_samples, MPI_INT,
smpallbuf, no_samples, MPI_INT,
0, MPI_COMM_WORLD);
/* STEP 4 */
fastsort(smpallbuf, _PROCS*no_samples);
if (_MYPROC==0) {
pivdist = _PROCS*no_samples/(_PROCS-1);
possmp = pivdist/2;
for (i=0; i<_PROCS-1; i++) {
pivbuffer[i] = smpallbuf[possmp];
possmp += pivdist;
}
}
/* STEP 5 */
MPI_Bcast(pivbuffer, _PROCS-1, MPI_INT, 0, MPI_COMM_WORLD);
/* STEP 6 */
prtbound[0] = A;
for (i=1; i<_PROCS; i++)
prtbound[i] = findpos (A, A_size, pivbuffer[i-1]);
prtbound[_PROCS] = A + A_size;
free (smpbuffer);
free (smpallbuf);
free (pivbuffer);
/* STEP 7 */
for (i=0; i<_PROCS; i++)
send_cnt[i] = max(0, prtbound[i+1] - 1 - prtbound[i]);
MPI_Alltoall(send_cnt, 1, MPI_INT,
recv_cnt, 1, MPI_INT,
MPI_COMM_WORLD);
send_off[0] = 0;
recv_off[0] = 0;
for (i=1 ; i<_PROCS ; i++) {
send_off[i] = send_off[i-1] + send_cnt[i-1];
recv_off[i] = recv_off[i-1] + recv_cnt[i-1];
}
trecv = recv_off[_PROCS-1] + recv_cnt[_PROCS-1];
if (trecv>0) {
recv_buf = (int *)malloc(trecv*sizeof(int));
assert_malloc(recv_buf, _MYPROC);
}
else {
recv_buf = NULL;
}
MPI_Alltoallv(A, send_cnt, send_off, MPI_INT,
recv_buf, recv_cnt, recv_off, MPI_INT,
MPI_COMM_WORLD);
/* STEP 8 */
#if 0
B_size = trecv;
bcopy(recv_buf, B, B_size*sizeof(int));
fastsort(B, B_size);
#else
{
int **listptr, *listcnt;
int elem, minelem, minlist;
int i, j;
listptr = (int **)malloc(_PROCS * sizeof(int *));
assert_malloc(listptr,_MYPROC);
listcnt = (int *)malloc(_PROCS * sizeof(int));
assert_malloc(listcnt,_MYPROC);
for (i=0 ; i<_PROCS ; i++) {
listptr[i] = recv_buf + recv_off[i];
listcnt[i] = recv_cnt[i];
}
B_size = 0;
while (B_size < trecv) {
minlist = -1;
for (j=0 ; j<_PROCS ; j++) {
if ((listcnt[j] > 0) &&
((minlist<0) || ((elem = *(listptr[j])) < minelem))) {
minlist = j;
minelem = elem;
}
}
B[B_size++] = minelem;
listptr[minlist]++;
listcnt[minlist]--;
}
free(listcnt);
free(listptr);
}
#endif
MPI_Barrier(MPI_COMM_WORLD);
free(recv_buf);
free(recv_off);
free(send_off);
free(send_cnt);
free(recv_cnt);
free(prtbound);
return (B_size);
}