Misc

mpi_line/jacobi_mpi_line.c

@@ -10,16 +10,22 @@
 
 #define TAG_BORDER 0
 
-void compute_jacobi(int n, double init_value, double threshold, borders b);
+double **compute_jacobi(int n, double init_value, double threshold, borders b, int *rows, int *iterations);
+
+int rank;
+int numprocs;
 
 int main(int argc, char* argv[]) {
-  int rank, numprocs;
   int n;
   double init_value, threshold;
   double north, south, east, west;
   borders b;
   int config_loaded;
   configuration config;
+  double **x;
+  double startwtime = 0.0, endwtime;
+  int iterations;
+  int rows;
 
   MPI_Init(&argc, &argv);
 
@@ -51,36 +57,48 @@ int main(int argc, char* argv[]) {
   b.south = south;
   b.east = east;
   b.west = west;
- 
-  int rows;
-  if (rank == 0) {
-    rows = n - (n / numprocs) * (numprocs - 1);
-  } else {
-    rows = n / numprocs;
-  }
-  LOG(printf("[Process %d/%d] rows: %d\n", rank, numprocs, rows));
-
-  double **x;
-  double max_diff, global_max_diff, new_x;
-  int i, j, iterations;
-  MPI_Status status;
-  double startwtime = 0.0, endwtime;
 
   if (rank == 0) {
     startwtime = MPI_Wtime();
   }
+ 
+  x = compute_jacobi(n, init_value, threshold, b, &rows, &iterations);
 
+  if (rank == 0) {
+    endwtime = MPI_Wtime();
+    printf("Wall clock time: %fs\n", endwtime - startwtime);
+    printf("Iterations: %d\n", iterations);
+  }
+
+  destroy_matrix(x, rows);
+
+  MPI_Finalize();
+
+  return 0;
+}
+
+double **compute_jacobi(int n, double init_value, double threshold, borders b, int *rows, int *iterations) {
+  double **x;
+  double max_diff, global_max_diff, new_x;
+  int i, j;
+  MPI_Status status;
+
+  if (rank == 0) {
+    *rows = n - (n / numprocs) * (numprocs - 1);
+  } else {
+    *rows = n / numprocs;
+  }
+  LOG(printf("[Process %d/%d] rows: %d\n", rank, numprocs, *rows));
   /* LOG(printf("[Process %d/%d] initializing matrix\n", rank, numprocs)); */
-  
   /* Initialize the matrix */
-  x = create_matrix(rows + 2, n + 2);
+  x = create_matrix(*rows + 2, n + 2);
-  for (i = 0; i < rows + 2; i++) {
+  for (i = 0; i < *rows + 2; i++) {
     for (j = 1; j <= n; j++) {
       x[i][j] = init_value;
     }
   }
   /* Initialize boundary regions */
-  for (i = 0; i < rows + 2; i++) {
+  for (i = 0; i < *rows + 2; i++) {
     x[i][0] = b.west;
     x[i][n + 1] = b.east;
   }
@@ -91,16 +109,16 @@ int main(int argc, char* argv[]) {
   }
   if (rank == numprocs - 1){
     for (i = 1; i < n + 1; i++) {
-      x[rows + 1][i] = b.south;
+      x[*rows + 1][i] = b.south;
     }
   }
   /* LOG(printf("[Process %d/%d] matrix initialized\n", rank, numprocs)); */
   /* Iterative refinement of x until values converge */
-  iterations = 0;
+  *iterations = 0;
   do {
     max_diff = 0;
     global_max_diff = 0;
-    for (i = 1; i <= rows; i++) {
+    for (i = 1; i <= *rows; i++) {
       for (j = 1; j <= n; j++) {
         new_x = 0.25 * (x[i - 1][j] + x[i][j + 1] + x[i + 1][j] + x[i][j - 1]);
         max_diff = (double) fmax(max_diff, fabs(new_x - x[i][j]));
@@ -110,8 +128,8 @@ int main(int argc, char* argv[]) {
     if (rank % 2 == 0) {
       if (rank != numprocs - 1) {
         // Send and receive south border
-        MPI_Send(&x[rows][0], n + 2, MPI_DOUBLE, rank + 1, TAG_BORDER, MPI_COMM_WORLD);
+        MPI_Send(&x[*rows][0], n + 2, MPI_DOUBLE, rank + 1, TAG_BORDER, MPI_COMM_WORLD);
-        MPI_Recv(&x[rows + 1][0], n + 2, MPI_DOUBLE, rank + 1, TAG_BORDER, MPI_COMM_WORLD, &status);
+        MPI_Recv(&x[*rows + 1][0], n + 2, MPI_DOUBLE, rank + 1, TAG_BORDER, MPI_COMM_WORLD, &status);
       }
       if (rank != 0) {
         // Send and receive north border
@@ -124,23 +142,14 @@ int main(int argc, char* argv[]) {
       MPI_Send(&x[1][0], n + 2, MPI_DOUBLE, rank - 1, TAG_BORDER, MPI_COMM_WORLD);
       if (rank != numprocs - 1) {
         // Receive and send south border
-        MPI_Recv(&x[rows + 1][0], n + 2, MPI_DOUBLE, rank + 1, TAG_BORDER, MPI_COMM_WORLD, &status);
+        MPI_Recv(&x[*rows + 1][0], n + 2, MPI_DOUBLE, rank + 1, TAG_BORDER, MPI_COMM_WORLD, &status);
-        MPI_Send(&x[rows][0], n + 2, MPI_DOUBLE, rank + 1, TAG_BORDER, MPI_COMM_WORLD);
+        MPI_Send(&x[*rows][0], n + 2, MPI_DOUBLE, rank + 1, TAG_BORDER, MPI_COMM_WORLD);
       }
     }
     /* LOG(printf("[Process %d/%d] max_diff: %f\n", rank, numprocs, max_diff)); */
     MPI_Allreduce(&max_diff, &global_max_diff, 1, MPI_DOUBLE, MPI_MAX, MPI_COMM_WORLD);
     /* LOG(printf("[Process %d/%d] global_max_diff: %f\n", rank, numprocs, global_max_diff)); */
-    iterations++;
+    (*iterations)++;
   } while (global_max_diff > threshold);
-
+  return x;
-  if (rank == 0) {
-    endwtime = MPI_Wtime();
-    printf("Wall clock time: %fs\n", endwtime - startwtime);
-    printf("Iterations: %d\n", iterations);
-  }
-
-  MPI_Finalize();
-
-  return 0;
 }

sequential/jacobi.conf

@@ -1,7 +1,7 @@
 # Configuration file for the Jacobi project.
 
 # The size of the matrix (borders excluded).
-N 5000
+N 3000
 
 # The value at each border.
 NORTH 0.0

sequential/jacobi_sequential.c

@@ -9,7 +9,7 @@
 #include "../config/config.h"
 #include "../utils/utils.h"
 
-void compute_jacobi(int n, double init_value, double threshold, borders b);
+double **compute_jacobi(int n, double init_value, double threshold, borders b);
 
 int main(int argc, char* argv[]) {
   int numprocs;
@@ -17,6 +17,7 @@ int main(int argc, char* argv[]) {
   configuration config;
   borders b;
   double startwtime = 0.0, endwtime;
+  double **x;
 
   MPI_Init(&argc, &argv);
   MPI_Comm_size(MPI_COMM_WORLD, &numprocs);
@@ -36,17 +37,18 @@ int main(int argc, char* argv[]) {
   b.west = config.west;
 
   startwtime = MPI_Wtime();
-  compute_jacobi(config.n, config.init_value, config.threshold, b);
+  x = compute_jacobi(config.n, config.init_value, config.threshold, b);
 
   endwtime = MPI_Wtime();
   printf("Wall clock time: %fs\n", endwtime - startwtime);
 
+  destroy_matrix(x, config.n + 2);
   MPI_Finalize();
 
   return 0;
 }
 
-void compute_jacobi(int n, double init_value, double threshold, borders b) {
+double **compute_jacobi(int n, double init_value, double threshold, borders b) {
   double **x;
   double max_diff, new_x;
   int i, j;
@@ -76,6 +78,5 @@ void compute_jacobi(int n, double init_value, double threshold, borders b) {
       }
     }
   } while (max_diff > threshold);
-
+  return x;
-  destroy_matrix(x, n + 2);
 }