new functionality

graph.c

@@ -49,5 +49,70 @@ void calculate_distance_matrix(const uint64_t vertex_count, const uint64_t adjac
     }
 }
 
-void calculate_eccentricities(const uint64_t vertex_count, const uint64_t output_arraay[vertex_count]) {
+int get_eccentricities(const uint64_t vertex_count, const uint64_t distance_matrix[vertex_count][vertex_count], uint64_t eccentricities[vertex_count]) {
+    uint64_t eccentricity;
+
+    // set all eccentricities to infinity in case this is a disconnected graph
+    for (uint64_t index = 0; index < vertex_count; index++) {
+        eccentricities[index] = UINT64_MAX;
+    }
+
+    for (uint64_t row_index = 0; row_index < vertex_count; row_index++) {
+        eccentricity = 0;
+
+        for (uint64_t column_index = 0; column_index < vertex_count; column_index++) {
+            if (distance_matrix[row_index][column_index] > eccentricity) {
+                eccentricity = distance_matrix[row_index][column_index];
+            }
+        }
+        // in case of a disconnected graph
+        if (eccentricity == 0) {
+            return 1;
+        }
+        eccentricities[row_index] = eccentricity;
+    }
+
+    return 0;
 }
+
+uint64_t get_radius(const uint64_t vertex_count, const uint64_t eccentricities[vertex_count]) {
+    uint64_t radius = UINT64_MAX;
+
+    for (uint64_t index = 0; index < vertex_count; index++) {
+        if (eccentricities[index] < radius) {
+            radius = eccentricities[index];
+        }
+    }
+
+    return radius;
+}
+
+uint64_t get_diameter(const uint64_t vertex_count, const uint64_t eccentricities[vertex_count]) {
+    uint64_t diamter = 0;
+
+    for (uint64_t index = 0; index < vertex_count; index++) {
+        // in case of a disconnected graph
+        if (eccentricities[index] == UINT64_MAX) {
+            return UINT64_MAX;
+        }
+        if (eccentricities[index] > diamter) {
+            diamter = eccentricities[index];
+        }
+    }
+
+    return diamter;
+}
+
+void get_centre(const uint64_t vertex_count, const uint64_t eccentricities[vertex_count], const uint64_t radius, uint64_t centre[vertex_count]) {
+    for (uint64_t index = 0; index < vertex_count; index++) {
+        centre[index] = 0;
+    }
+
+    for (uint64_t index = 0; index < vertex_count; index++) {
+        if (eccentricities[index] == radius) {
+            centre[index] = 1;
+        }
+    }
+}
+
+

graph.h

@@ -10,4 +10,23 @@ void calculate_distance_matrix(const uint64_t vertex_count,
                               const uint64_t adjacency_matrix[vertex_count][vertex_count],
                               uint64_t distance_matrix[vertex_count][vertex_count]);
 
+// returns 1 if it is a disconnected graph and just in case it was on purpose,
+// all values in eccentricities will be set to UINT64_MAX
+int get_eccentricities(const uint64_t vertex_count,
+                              const uint64_t distance_matrix[vertex_count][vertex_count],
+                              uint64_t eccentricities[vertex_count]);
+
+// returns the radius
+uint64_t get_radius(const uint64_t vertex_count,
+                    const uint64_t eccentricities[vertex_count]);
+
+// returns the diameter
+uint64_t get_diameter(const uint64_t vertex_count,
+                      const uint64_t eccentricities[vertex_count]);
+
+void get_centre(const uint64_t vertex_count,
+                const uint64_t eccentricities[vertex_count],
+                const uint64_t radius,
+                uint64_t centre[vertex_count]);
+
 #endif

main.c

@@ -40,25 +40,48 @@ void benchmark() {
 }
 
 void test() {
-    const uint64_t vertex_count = 5;
+    const uint64_t vertex_count = 7;
     uint64_t adjacency_matrix[vertex_count][vertex_count];
+    uint64_t distance_matrix[vertex_count][vertex_count];
+    uint64_t eccentricities[vertex_count];
+    uint64_t radius, diameter, centre[vertex_count];
 
-    read_csv("csv/graph.csv", vertex_count, vertex_count, adjacency_matrix);
+    read_csv("csv/7n.csv", vertex_count, vertex_count, adjacency_matrix);
 
     puts("G:");
     print_matrix(vertex_count, vertex_count, adjacency_matrix);
     puts("");
 
-    uint64_t distance_matrix[vertex_count][vertex_count];
-
     calculate_distance_matrix(vertex_count, adjacency_matrix, distance_matrix);
 
     puts("distance_matrix:");
     print_matrix(vertex_count, vertex_count, distance_matrix);
     puts("");
+
+    get_eccentricities(vertex_count, distance_matrix, eccentricities);
+
+    puts("eccentricities:");
+    for (uint64_t index = 0; index < vertex_count; index++) {
+        printf("Vertex %lu: %lu, ", index + 1,  eccentricities[index]);
+    }
+    puts("");
+
+    radius = get_radius(vertex_count, eccentricities);
+    diameter = get_diameter(vertex_count, eccentricities);
+    get_centre(vertex_count, eccentricities, radius, centre);
+
+    printf("radius: %lu\n", radius);
+    printf("diameter: %lu\n", diameter);
+    printf("centre: ");
+    for (uint64_t index = 0; index < vertex_count; index++) {
+        if (centre[index] == 1) {
+            printf("Vertex: %lu, ", index);
+        }
+    }
+    puts("");
 }
 
 int main(void) {
-    // test();
-    benchmark();
+    test();
+    // benchmark();
 }