1 files changed, 124 insertions, 0 deletions
diff --git a/benchmarks/CUDA/DG/src/ParallelPairs.c b/benchmarks/CUDA/DG/src/ParallelPairs.c
new file mode 100644
index 0000000..7474c0b
--- /dev/null
+++ b/benchmarks/CUDA/DG/src/ParallelPairs.c
@@ -0,0 +1,124 @@
+#include <strings.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <math.h>
+
+#include "mpi.h"
+
+#define max(a,b)  ( (a>b)?a:b )
+#define min(a,b)  ( (a<b)?a:b )
+
+void ParallelPairs(void *objs, int Nmyobjs, int sizeobj,
+		   int  (*numget)(const void *),
+		   void (*numset)(const void *, int ),
+		   int  (*procget)(const void *),
+		   void (*marry)(const void *, const void *),
+		   int (*compare_objs)(const void *, const void *)){
+
+  char *myobjs = (char*) objs;
+
+  int n, p, sk, cnt, num;
+  int maxind = 0;
+
+  int procid, nprocs;
+  MPI_Comm_rank(MPI_COMM_WORLD, &procid);
+  MPI_Comm_size(MPI_COMM_WORLD, &nprocs);
+
+  /* local sort */
+  qsort(myobjs, Nmyobjs, sizeobj, compare_objs);
+
+  /* TW: homework replace from here --------> */
+  maxind = 0;
+  for(n=0;n<Nmyobjs;++n){
+    num = numget(myobjs+sizeobj*n);
+    maxind = max(maxind, num);
+  }
+
+  int globalmaxind;
+  MPI_Allreduce(&maxind, &globalmaxind, 1, MPI_INT, MPI_MAX, MPI_COMM_WORLD);
+  
+  int binsize = ceil( (double)(globalmaxind)/(double)nprocs ) + 10;
+
+  int *outN = (int*) calloc(nprocs, sizeof(int));
+  int *inN  = (int*) calloc(nprocs, sizeof(int));
+
+  int *cumoutN = (int*) calloc(nprocs, sizeof(int));
+  int *cuminN  = (int*) calloc(nprocs, sizeof(int));
+
+  sk = 0;
+  /* count the number of objs in each bin */
+  int binup = binsize;
+  for(p=0;p<nprocs;++p){
+    while( numget(myobjs+(sk*sizeobj) ) <= binup ){
+      ++(outN[p]);
+      ++sk;
+      if(sk==Nmyobjs){
+	break;
+      }
+    }
+    binup += binsize;
+    if(sk==Nmyobjs){
+      break;
+    }
+  }
+  /* TW: <---------- replace to here */
+
+  /* communicate numbers to be sent to each bin */
+  MPI_Alltoall(outN, 1, MPI_INT, 
+	       inN,  1, MPI_INT, 
+	       MPI_COMM_WORLD);
+
+  /* build incoming buffer */
+  int Notherobjs = 0;
+  for(p=0;p<nprocs;++p)
+    Notherobjs += inN[p];
+
+  for(p=0;p<nprocs;++p){
+    outN[p] *=  sizeobj/sizeof(int);
+    inN[p]  *=  sizeobj/sizeof(int);
+  }
+
+  for(p=1;p<nprocs;++p){
+    cumoutN[p] = cumoutN[p-1]+outN[p-1];
+    cuminN[p]  = cuminN[p-1] + inN[p-1];
+  }
+
+  /* fill up bins of objects from cloud */
+  char *otherobjs = (char*) calloc(Notherobjs*sizeobj, sizeof(char));
+
+  MPI_Alltoallv(myobjs,    outN, cumoutN, MPI_INT,
+		otherobjs, inN,  cuminN,  MPI_INT,
+		MPI_COMM_WORLD);
+
+  /* sort the bin */
+  qsort(otherobjs, Notherobjs, sizeobj, compare_objs);
+
+  /* number unique objs consecutively in each bin */
+  for(n=1;n<Notherobjs;++n){
+    /* match ? */
+    if(!compare_objs(otherobjs+    n*sizeobj, 
+		     otherobjs+(n-1)*sizeobj)){
+      
+      marry(otherobjs+n*sizeobj, otherobjs+(n-1)*sizeobj);
+    }
+  }
+
+  char *outobjs = (char*) calloc(Notherobjs*sizeobj, sizeof(char));
+  sk = 0;
+  for(p=0;p<nprocs;++p)
+    for(n=0;n<Notherobjs;++n)
+      if(procget(otherobjs+n*sizeobj)==p){
+	memcpy(outobjs+sk*sizeobj, otherobjs+n*sizeobj, sizeobj);
+	++sk;
+      }
+
+  /* send results out */
+  MPI_Alltoallv(outobjs,  inN,  cuminN, MPI_INT,
+		 myobjs, outN, cumoutN, MPI_INT,
+		MPI_COMM_WORLD);
+
+
+  free(otherobjs);
+  free(outN); free(inN); free(cumoutN); free(cuminN);
+}
+