added floyd-parallel.cc

git-svn-id: svn://anubis/gvsu@197 45c1a28c-8058-47b2-ae61-ca45b979098e

cs677/hw7/src/floyd-parallel.cc

@@ -0,0 +1,122 @@
+
+/* Josh Holtrop
+ * 2008-10-15
+ * CS 677
+ * Grand Valley State University
+ */
+
+#include <omp.h>
+#include <math.h>
+#include <stdlib.h>
+#include <limits.h>
+#include <stdio.h>
+#include <iostream>
+#include <fstream>
+#include <vector>
+#include <sys/time.h>   /* gettimeofday(), struct timeval */
+using namespace std;
+
+void usage(char * progname);
+int readFile(char * fileName, vector<int> & v);
+void convertToMatrix(const vector<int> & v, int num_verts, int * vals);
+
+void usage(char * progname)
+{
+    cout << "Usage: " << progname << " <adjacency-file>" << endl;
+    exit(42);
+}
+
+int main(int argc, char * argv[])
+{
+    if (argc < 1)
+        usage(argv[0]);
+
+    vector<int> v;
+
+    int num_verts = readFile(argv[1], v);
+    int D[2][num_verts][num_verts];
+    convertToMatrix(v, num_verts, (int *) &D[0]);
+
+    struct timeval before, after;
+    gettimeofday(&before, NULL);        /* Start timing */
+
+    /* Run Floyd's Algorithm on D */
+    for (int k = 1; k <= num_verts; k++)
+    {
+        for (int i = 0; i < num_verts; i++)
+        {
+            for (int j = 0; j < num_verts; j++)
+            {
+                int distWithoutK = D[(k-1) & 1][i][j];
+                int distItoK = D[(k-1) & 1][i][k-1];
+                int distKtoJ = D[(k-1) & 1][k-1][j];
+                int distWithK =
+                    (distItoK == INT_MAX || distKtoJ == INT_MAX)
+                        ? INT_MAX
+                        : distItoK + distKtoJ;
+                D[k & 1][i][j] = min(
+                    distWithoutK,
+                    distWithK
+                );
+            }
+        }
+    }
+
+    gettimeofday(&after, NULL);         /* Stop timing */
+    cout << "Result:" << endl;
+    /* Print out the final matrix */
+    for (int i = 0; i < num_verts; i++)
+    {
+        for (int j = 0; j < num_verts; j++)
+        {
+            if (D[num_verts & 1][i][j] == INT_MAX)
+                printf("-- ");
+            else
+                printf("%2d ", D[num_verts & 1][i][j]);
+        }
+        printf("\n");
+    }
+
+    double time_before = before.tv_sec + before.tv_usec / 1000000.0;
+    double time_after = after.tv_sec + after.tv_usec / 1000000.0;
+    double diff = time_after - time_before;
+    cout << "Elapsed time: " << diff << " seconds." << endl;
+
+    return 0;
+}
+
+int readFile(char * fileName, vector<int> & v)
+{
+    ifstream in(fileName);
+    if (!in.is_open())
+    {
+        cerr << "Error opening " << fileName << endl;
+        return -1;
+    }
+
+    for (;;)
+    {
+        int weight;
+        in >> weight;
+        if (in.eof())
+            break;
+        v.push_back(weight);
+    }
+
+    return (int) sqrt(v.size());
+}
+
+void convertToMatrix(const vector<int> & v, int num_verts, int * vals)
+{
+    int vidx = 0;
+    int (*V)[num_verts][num_verts] = (int (*)[num_verts][num_verts]) vals;
+    for (int i = 0; i < num_verts; i++)
+    {
+        for (int j = 0; j < num_verts; j++)
+        {
+            (*V)[i][j] = v[vidx++];
+            if ((*V)[i][j] == 0)
+                (*V)[i][j] = INT_MAX;
+        }
+    }
+}