Create matrix-mult.c

Author: tr3sp4ss3rexe

matrix-mult.c

@@ -0,0 +1,92 @@
+/*
+Simple example of a huge matrix multiplication
+and speeding the process up as much as possible
+by running the main tasks parallelly using threads
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <pthread.h>
+#define SIZE 1024
+
+static double a[SIZE][SIZE];
+static double b[SIZE][SIZE];
+static double c[SIZE][SIZE];
+
+void *initialize_row(void *arg) {
+    int row = *(int *)arg;
+    free(arg);
+
+    for (int j = 0; j < SIZE; j++) {
+        a[row][j] = 1.0;
+        b[row][j] = 1.0;
+    }
+    return NULL;
+}
+
+static void init_matrix() {
+    pthread_t threads[SIZE];
+
+    for (int i = 0; i < SIZE; i++) {
+        int *row = malloc(sizeof(int));
+        *row = i;
+
+        pthread_create(&threads[i], NULL, initialize_row, row);
+    }
+
+    for (int i = 0; i < SIZE; i++) {
+        pthread_join(threads[i], NULL);
+    }
+}
+
+
+static void
+print_matrix(void)
+{
+    int i, j;
+
+    for (i = 0; i < SIZE; i++) {
+        for (j = 0; j < SIZE; j++)
+	        printf(" %7.2f", c[i][j]);
+	    printf("\n");
+    }
+}
+
+
+// using the pthread to make it run parallel 
+void *matmul_rows(void *arg) {
+    int row = *(int *)arg;
+    free(arg);
+
+    for (int j = 0; j < SIZE; j++) {
+        c[row][j] = 0.0;
+        for (int k = 0; k < SIZE; k++) {
+            c[row][j] += a[row][k] * b[k][j];
+        }
+    }
+    return NULL;
+}
+
+static void matmul_para() {
+    pthread_t threads[SIZE];
+
+    for (int i = 0; i < SIZE; i++) {
+        int *row = malloc(sizeof(int));
+        *row = i;
+
+        pthread_create(&threads[i], NULL, matmul_rows, row);
+    }
+
+    for (int i = 0; i < SIZE; i++) {
+        pthread_join(threads[i], NULL);
+    }
+}
+
+
+int
+main(int argc, char **argv)
+{
+    init_matrix();
+    matmul_para();
+    print_matrix();
+}