init cuda file

djikstra_cuda.cu

+#include <stdio.h>
+#include <stdlib.h>
+#include <limits.h>
+#include <stdbool.h>
+#include <sys/time.h>
+#include <string.h>
+// #include <cuda.h>
+
+#define INFINITY INT_MAX;
+#define MIN(a,b) (((a)<(b))?(a):(b));
+#define MAX(a,b) (((a)>(b))?(a):(b));
+
+void createGraph(int n, int graph[n]){
+    srand(13517032);
+    int val;
+    for(int i=0;i<n;i++){
+        graph[i*n+i] = 0;
+        for(int j=i+1;j<n;j++){
+            val = (rand() % 50) + 1;
+            graph[i*n+j] = val;
+            graph[j*n+i] = val;
+        }
+    }
+}
+
+void printGraph(int n, int graph[n]){
+    for(int i=0;i<n;i++){
+        for(int j=0;j<n;j++){
+            printf("%d ",graph[i*n+j]);
+        }
+        printf("\n");
+    }
+    printf("\n");
+}
+
+__device__ 
+void djikstra(int graph[],int start,int distance[],int visited[],int n,int answer[]){
+
+    int node;
+    int temp_dist;
+    int min_dist[2]; // node and its distance
+    min_dist[0] = -1;
+    min_dist[1] = INFINITY;
+    for(int i = 0;i<n;i++){
+        if(i == start){
+            visited[i] = true;
+            distance[i] = 0;
+        } else{
+            visited[i] = false;
+            distance[i] = graph[start*n+i];
+            if(distance[i] < min_dist[1]){
+                min_dist[1] = distance[i];
+                min_dist[0] = i;
+            }
+        }
+    }
+
+    // initialized distance with a
+    for(int i = 0;i<n+1;i++){
+        node = min_dist[0];
+        visited[node] = true;
+        distance[node] = min_dist[1];
+        min_dist[0] = -1;
+        min_dist[1] = INFINITY;
+        for (int j=0;j<n;j++){
+            if(visited[j] == 0){
+                temp_dist = MIN(distance[node] + graph[node*n+j],distance[j]);
+                if(temp_dist < min_dist[1]){
+                    min_dist[0] = j;
+                    min_dist[1] = temp_dist;
+                }
+                if(distance[j] > temp_dist){
+                    distance[j] = temp_dist;
+                }
+            }
+
+        }
+    }
+    for(int i=0;i<n;i++){
+        answer[start*n+i] = distance[i];
+
+    }
+}
+
+__global__
+void djikstra_cuda(int graph[]int distance[],int visited[],int n,int answer[])
+{
+    int index = blockIdx.x * blockDim.x + threadIdx.x;
+    int stride = blockDim.x * gridDim.x;
+    for (int i = index; i < n; i += stride){
+        djikstra(graph,i,distance,visited[],n,answer);
+  }
+}
+
+int main(int argc, char** argv){
+
+    if (argc != 2){
+        printf("Invalid argument\n./djikstra <number_of_node>\n");
+        return 0;
+    }
+    FILE* output_file; 
+
+    struct timeval st, et;
+    int n = atoi(argv[1]);
+
+    char filename[80];
+    strcpy(filename, "output_");
+    strcat(filename, argv[1]);
+    strcat(filename,".txt");
+    output_file = fopen(filename, "w+");
+
+    int *graph,*distance,*visited, *answer;
+    graph = malloc(n*n*sizeof(int));
+    distance = malloc(n*sizeof(int));
+    visited = malloc(n*sizeof(int));
+    answer = malloc(n*n*sizeof(int));
+    createGraph(n,graph);
+    fprintf(output_file, "GRAPH:\n");
+    for(int i = 0;i<n;i++){
+        for(int j = 0;j<n;j++){
+            fprintf(output_file, "%d ", graph[i*n+j]);
+        }
+        fprintf(output_file, "\n");
+    }
+    fprintf(output_file, "\n\n\n");
+
+    int blockSize = 256;
+    int numBlocks = (n + blockSize - 1) / blockSize;
+
+    gettimeofday(&st,NULL);
+    djikstra_cuda<<<numBlocks, blockSize>>>>(graph,distance,visited,n,answer);
+    gettimeofday(&et,NULL);
+    unsigned long long int elapsed = ((et.tv_sec - st.tv_sec) * 1000000) + (et.tv_usec - st.tv_usec);
+    printf("Djikstra total time: %llu micro seconds\n",elapsed);
+    fprintf(output_file, "Answer:\n");
+    for(int i = 0;i<n;i++){
+        for(int j = 0;j<n;j++){
+            fprintf(output_file, "%d ", answer[i*n+j]);
+        }
+        fprintf(output_file, "\n");
+    }
+    return 0;
+}
+