remove old code from samples.c

C/samples.c

@@ -18,18 +18,6 @@ void array_print(float* array, int length)
     printf("\n");
 }
 
-void array_fill(float* array, int length, float item)
-{
-    int i;
-    #pragma omp private(i)
-    {
-        #pragma omp for
-        for (i = 0; i < length; i++) {
-            array[i] = item;
-        }
-    }
-}
-
 float array_sum(float* array, int length)
 {
     float output = 0.0;
@@ -47,159 +35,12 @@ void array_cumsum(float* array_to_sum, float* array_cumsummed, int length)
     }
 }
 
-float rand_float(float to, unsigned int* seed)
+// Split array helpers
-{
-    return ((float)rand_r(seed) / (float)RAND_MAX) * to;
-		// See: <https://stackoverflow.com/questions/43151361/how-to-create-thread-safe-random-number-generator-in-c-using-rand-r>
-		// rand() is not thread-safe, as it relies on (shared) hidden state.
-}
-
-float ur_normal(unsigned int* seed)
-{
-    float u1 = rand_float(1.0, seed);
-    float u2 = rand_float(1.0, seed);
-    float z = sqrtf(-2.0 * log(u1)) * sin(2 * PI * u2);
-    return z;
-}
-
-inline float random_uniform(float from, float to, unsigned int* seed)
-{
-    return ((float) rand_r(seed) / (float)RAND_MAX) * (to - from) + from;
-}
-
-inline float random_normal(float mean, float sigma, unsigned int* seed)
-{
-    return (mean + sigma * ur_normal(seed));
-}
-
-inline float random_lognormal(float logmean, float logsigma, unsigned int* seed)
-{
-    return expf(random_normal(logmean, logsigma, seed));
-}
-
-inline float random_to(float low, float high, unsigned int* seed)
-{
-    const float NORMAL95CONFIDENCE = 1.6448536269514722;
-    float loglow = logf(low);
-    float loghigh = logf(high);
-    float logmean = (loglow + loghigh) / 2;
-    float logsigma = (loghigh - loglow) / (2.0 * NORMAL95CONFIDENCE);
-    return random_lognormal(logmean, logsigma, seed);
-}
-
 int split_array_get_my_length(int index, int total_length, int n_threads)
 {
     return (total_length % n_threads > index ? total_length / n_threads + 1 : total_length / n_threads);
 }
 
-//Old version, don't use it!! Optimized version is called mixture_f. This one is just for display
-/*
-void mixture(float* dists[], float* weights, int n_dists, float* results)
-{
-    float sum_weights = array_sum(weights, n_dists);
-    float* normalized_weights = malloc(n_dists * sizeof(float));
-    for (int i = 0; i < n_dists; i++) {
-        normalized_weights[i] = weights[i] / sum_weights;
-    }
-
-    float* cummulative_weights = malloc(n_dists * sizeof(float));
-    array_cumsum(normalized_weights, cummulative_weights, n_dists);
-
-    //create var holders
-    float p1, p2;
-    int index_found, index_counter, sample_index, i;
-
-    #pragma omp parallel private(i, p1, p2, index_found, index_counter, sample_index)
-    {
-        #pragma omp for
-        for (i = 0; i < N; i++) {
-            p1 = random_uniform(0, 1);
-            p2 = random_uniform(0, 1);
-
-            index_found = 0;
-            index_counter = 0;
-
-            while ((index_found == 0) && (index_counter < n_dists)) {
-                if (p1 < cummulative_weights[index_counter]) {
-                    index_found = 1;
-                } else {
-                    index_counter++;
-                }
-            }
-            if (index_found != 0) {
-                sample_index = (int)(p2 * N);
-                results[i] = dists[index_counter][sample_index];
-            } else
-                printf("This shouldn't be able to happen.\n");
-        }
-    }
-    free(normalized_weights);
-    free(cummulative_weights);
-}
-*/
-void mixture_f(float (*samplers[])(unsigned int* ), float* weights, int n_dists, float** results, int n_threads)
-{
-    float sum_weights = array_sum(weights, n_dists);
-    float* normalized_weights = malloc(n_dists * sizeof(float));
-    for (int i = 0; i < n_dists; i++) {
-        normalized_weights[i] = weights[i] / sum_weights;
-    }
-
-    float* cummulative_weights = malloc(n_dists * sizeof(float));
-    array_cumsum(normalized_weights, cummulative_weights, n_dists);
-
-    //create var holders
-    float p1;
-    int sample_index, i, own_length;
-		unsigned int* seeds[n_threads];
-		for(unsigned int i=0; i<n_threads; i++){
-			seeds[i] = malloc(sizeof(unsigned int));
-			*seeds[i] = i;
-		}
-
-    #pragma omp parallel private(i, p1, sample_index, own_length)
-    {
-        #pragma omp for
-        for (i = 0; i < n_threads; i++) {
-            own_length = split_array_get_my_length(i, N, n_threads);
-            for (int j = 0; j < own_length; j++) {
-                p1 = random_uniform(0, 1, seeds[i]);
-                for (int k = 0; k < n_dists; k++) {
-                    if (p1 < cummulative_weights[k]) {
-                        results[i][j] = samplers[k](seeds[i]);
-                        break;
-                    }
-                }
-            }
-        }
-    }
-    free(normalized_weights);
-    free(cummulative_weights);
-		for(unsigned int i=0; i<n_threads; i++){
-			free(seeds[i]);
-		}
-}
-
-float sample_0(unsigned int* seed)
-{
-    return 0;
-}
-
-float sample_1(unsigned int* seed)
-{
-    return 1;
-}
-
-float sample_few(unsigned int* seed)
-{
-    return random_to(1, 3, seed);
-}
-
-float sample_many(unsigned int* seed)
-{
-    return random_to(2, 10, seed);
-}
-
 void split_array_allocate(float** meta_array, int length, int divide_into)
 {
     int own_length;
@@ -239,13 +80,119 @@ float split_array_sum(float** meta_array, int length, int divided_into)
     return output;
 }
 
+// Distribution & sampling functions
+
+float rand_float(float to, unsigned int* seed)
+{
+    return ((float)rand_r(seed) / (float)RAND_MAX) * to;
+		// See: <https://stackoverflow.com/questions/43151361/how-to-create-thread-safe-random-number-generator-in-c-using-rand-r> for why to use rand_r: 
+		// rand() is not thread-safe, as it relies on (shared) hidden state.
+}
+
+float ur_normal(unsigned int* seed)
+{
+    float u1 = rand_float(1.0, seed);
+    float u2 = rand_float(1.0, seed);
+    float z = sqrtf(-2.0 * log(u1)) * sin(2 * PI * u2);
+    return z;
+}
+
+inline float random_uniform(float from, float to, unsigned int* seed)
+{
+    return ((float) rand_r(seed) / (float)RAND_MAX) * (to - from) + from;
+}
+
+inline float random_normal(float mean, float sigma, unsigned int* seed)
+{
+    return (mean + sigma * ur_normal(seed));
+}
+
+inline float random_lognormal(float logmean, float logsigma, unsigned int* seed)
+{
+    return expf(random_normal(logmean, logsigma, seed));
+}
+
+inline float random_to(float low, float high, unsigned int* seed)
+{
+    const float NORMAL95CONFIDENCE = 1.6448536269514722;
+    float loglow = logf(low);
+    float loghigh = logf(high);
+    float logmean = (loglow + loghigh) / 2;
+    float logsigma = (loghigh - loglow) / (2.0 * NORMAL95CONFIDENCE);
+    return random_lognormal(logmean, logsigma, seed);
+}
+
+// Mixture function
+void mixture(float (*samplers[])(unsigned int* ), float* weights, int n_dists, float** results, int n_threads)
+{
+	  // You can see a simpler version of this function in the git history
+		// or in C-02-better-algorithm-one-thread/
+    float sum_weights = array_sum(weights, n_dists);
+    float* normalized_weights = malloc(n_dists * sizeof(float));
+    for (int i = 0; i < n_dists; i++) {
+        normalized_weights[i] = weights[i] / sum_weights;
+    }
+
+    float* cummulative_weights = malloc(n_dists * sizeof(float));
+    array_cumsum(normalized_weights, cummulative_weights, n_dists);
+
+    //create var holders
+    float p1;
+    int sample_index, i, own_length;
+		unsigned int* seeds[n_threads];
+		for(unsigned int i=0; i<n_threads; i++){
+			seeds[i] = malloc(sizeof(unsigned int));
+			*seeds[i] = i;
+		}
+
+    #pragma omp parallel private(i, p1, sample_index, own_length)
+    {
+        #pragma omp for
+        for (i = 0; i < n_threads; i++) {
+            own_length = split_array_get_my_length(i, N, n_threads);
+            for (int j = 0; j < own_length; j++) {
+                p1 = random_uniform(0, 1, seeds[i]);
+                for (int k = 0; k < n_dists; k++) {
+                    if (p1 < cummulative_weights[k]) {
+                        results[i][j] = samplers[k](seeds[i]);
+                        break;
+                    }
+                }
+            }
+        }
+    }
+    free(normalized_weights);
+    free(cummulative_weights);
+		for(unsigned int i=0; i<n_threads; i++){
+			free(seeds[i]);
+		}
+}
+
+// Functions used for the BOTEC.
+// Their type has to be the same, as we will be passing them around.
+
+float sample_0(unsigned int* seed)
+{
+    return 0;
+}
+
+float sample_1(unsigned int* seed)
+{
+    return 1;
+}
+
+float sample_few(unsigned int* seed)
+{
+    return random_to(1, 3, seed);
+}
+
+float sample_many(unsigned int* seed)
+{
+    return random_to(2, 10, seed);
+}
+
 int main()
 {
-    //initialize randomness
-    srand(time(NULL));
-    
-		// clock_t start, end;
-		// start = clock();
     
 		// Toy example
 		// Declare variables in play
@@ -266,16 +213,10 @@ int main()
 		float weights[] = { 1 - p_c, p_c / 2, p_c / 4, p_c / 4 };
 		float (*samplers[])(unsigned int* ) = { sample_0, sample_1, sample_few, sample_many };
 
-		mixture_f(samplers, weights, n_dists, dist_mixture, n_threads);
+		mixture(samplers, weights, n_dists, dist_mixture, n_threads);
 		printf("Sum(dist_mixture, N)/N = %f\n", split_array_sum(dist_mixture, N, n_threads) / N);
 		// array_print(dist_mixture[0], N);
 		split_array_free(dist_mixture, n_threads);
 		
-		// end = clock();
-		// printf("Time (ms): %f\n", ((double)(end - start)) / (CLOCKS_PER_SEC) * 1000);
-		// ^ Will only measure how long it takes the inner main to run, not the whole program, 
-		// including e.g., loading the program into memory or smth.
-		// Also CLOCKS_PER_SEC in POSIX is a constant equal to 1000000.
-		// See: https://stackoverflow.com/questions/10455905/why-is-clocks-per-sec-not-the-actual-number-of-clocks-per-second
     return 0;
 }