First Commit

openmp_add.c

@@ -0,0 +1,57 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/time.h>
+#include <omp.h>
+
+#define ARRAY_SIZE 15000576  // 100 million items
+
+double get_time() {
+    struct timeval tv;
+    gettimeofday(&tv, NULL);
+    return tv.tv_sec + tv.tv_usec * 1e-6;
+}
+
+int main() {
+    float *a = (float*)malloc(sizeof(float) * ARRAY_SIZE);
+    float *b = (float*)malloc(sizeof(float) * ARRAY_SIZE);
+    float *c = (float*)malloc(sizeof(float) * ARRAY_SIZE);
+
+    // Initialize arrays (single-threaded)
+    double start = get_time();
+    for (int i = 0; i < ARRAY_SIZE; i++) {
+        a[i] = i;
+        b[i] = i * 2;
+    }
+    double init_time = get_time() - start;
+
+    // Set number of threads
+    omp_set_num_threads(8);
+
+    // Perform the calculation (parallelized with OpenMP)
+    start = get_time();
+    // Try different schedules:
+    // #pragma omp parallel for schedule(static)  // Let the compiler choose chunk size
+    // #pragma omp parallel for schedule(dynamic, 256)  // Dynamic scheduling
+    #pragma omp parallel for schedule(static, 256)  // Smaller chunk size
+    for (int i = 0; i < ARRAY_SIZE; i++) {
+        c[i] = a[i] + b[i];
+    }
+    double calc_time = get_time() - start;
+
+    // Print timing results
+    printf("Array initialization time: %.3f ms\n", init_time * 1000);
+    printf("Calculation time:          %.3f ms\n", calc_time * 1000);
+    printf("Total time:               %.3f ms\n", (init_time + calc_time) * 1000);
+
+    // Print a sample of the result
+    for (int i = 0; i < 10; i++) {
+        printf("c[%d] = %f\n", i, c[i]);
+    }
+
+    // Clean up
+    free(a);
+    free(b);
+    free(c);
+
+    return 0;
+}