commit 03421f953b6aac6086c4a6531ce87fdc0d78faad
parent 160e8241088e8afbc5c8db2529e6a058f51f72db
Author: NunoSempere <nuno.sempere@protonmail.com>
Date: Mon, 29 May 2023 19:55:57 -0400
add one-threaded C example
Diffstat:
3 files changed, 189 insertions(+), 7 deletions(-)
diff --git a/C-optimized/makefile b/C-optimized/makefile
@@ -12,6 +12,9 @@ CC=gcc
SRC=samples.c
OUTPUT=out/samples
+SRC_ONE_THREAD=./samples-one-thread.c
+OUTPUT_ONE_THREAD=out/samples-one-thread
+
## Dependencies
# Has no dependencies
MATH=-lm
@@ -30,24 +33,20 @@ FORMATTER=clang-format -i -style=$(STYLE_BLUEPRINT)
## make build
build: $(SRC)
$(CC) $(OPTIMIZED) $(DEBUG) $(SRC) $(OPENMP) $(MATH) -o $(OUTPUT)
-
-#fast: Has been removed, compilation of "build" is very fast and it outputs optimized code by default
+ $(CC) $(OPTIMIZED) $(DEBUG) $(SRC_ONE_THREAD) $(OPENMP) $(MATH) -o $(OUTPUT_ONE_THREAD)
format: $(SRC)
$(FORMATTER) $(SRC)
run: $(SRC) $(OUTPUT)
OMP_NUM_THREADS=1 ./$(OUTPUT)
-
-multi: $(SRC) $(OUTPUT)
- OMP_NUM_THREADS=1 ./$(OUTPUT) && echo
- OMP_NUM_THREADS=2 ./$(OUTPUT) && echo
- OMP_NUM_THREADS=4 ./$(OUTPUT)
+ ./$(OUTPUT_ONE_THREAD)
time:
OMP_NUM_THREADS=1 /bin/time -f "Time: %es" ./$(OUTPUT) && echo
OMP_NUM_THREADS=2 /bin/time -f "Time: %es" ./$(OUTPUT) && echo
OMP_NUM_THREADS=4 /bin/time -f "Time: %es" ./$(OUTPUT) && echo
+ /bin/time -f "Time: %es" ./$(OUTPUT_ONE_THREAD) && echo
linux-install:
sudo apt-get install libomp-dev
diff --git a/C-optimized/out/samples-one-thread b/C-optimized/out/samples-one-thread
Binary files differ.
diff --git a/C-optimized/samples-one-thread.c b/C-optimized/samples-one-thread.c
@@ -0,0 +1,183 @@
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+const float PI = 3.14159265358979323846;
+
+#define N 1000000
+
+//Array helpers
+
+void array_print(float* array, int length)
+{
+ for (int i = 0; i < length; i++) {
+ printf("item[%d] = %f\n", i, array[i]);
+ }
+ printf("\n");
+}
+
+void array_fill(float* array, int length, float item)
+{
+ int i;
+ {
+ for (i = 0; i < length; i++) {
+ array[i] = item;
+ }
+ }
+}
+
+float array_sum(float* array, int length)
+{
+ float output = 0.0;
+ for (int i = 0; i < length; i++) {
+ output += array[i];
+ }
+ return output;
+}
+
+void array_cumsum(float* array_to_sum, float* array_cumsummed, int length)
+{
+ array_cumsummed[0] = array_to_sum[0];
+ for (int i = 1; i < length; i++) {
+ array_cumsummed[i] = array_cumsummed[i - 1] + array_to_sum[i];
+ }
+}
+
+float rand_float(float to)
+{
+ return ((float)rand() / (float)RAND_MAX) * to;
+}
+
+float ur_normal()
+{
+ float u1 = rand_float(1.0);
+ float u2 = rand_float(1.0);
+ float z = sqrtf(-2.0 * log(u1)) * sin(2 * PI * u2);
+ return z;
+}
+
+inline float random_uniform(float from, float to)
+{
+ return ((float)rand() / (float)RAND_MAX) * (to - from) + from;
+}
+
+inline float random_normal(float mean, float sigma)
+{
+ return (mean + sigma * ur_normal());
+}
+
+inline float random_lognormal(float logmean, float logsigma)
+{
+ return expf(random_normal(logmean, logsigma));
+}
+
+inline float random_to(float low, float high)
+{
+ 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);
+}
+
+void array_random_to(float* array, int length, float low, float high)
+{
+ int i;
+ #pragma omp private(i)
+ {
+ #pragma omp for
+ for (i = 0; i < length; i++) {
+ array[i] = random_to(low, high);
+ }
+ }
+}
+
+void mixture(float (*samplers[])(void), float* weights, int n_dists, float* results, int results_length)
+{
+ 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;
+
+ {
+ for (int i = 0; i < results_length; i++) {
+ p1 = random_uniform(0, 1);
+ for (int j = 0; j < n_dists; j++) {
+ if (p1 < cummulative_weights[j]) {
+ results[i] = samplers[j]();
+ break;
+ }
+ }
+ }
+ }
+ free(normalized_weights);
+ free(cummulative_weights);
+}
+
+float sample_0()
+{
+ return 0;
+}
+
+float sample_1()
+{
+ return 1;
+}
+
+float sample_few()
+{
+ return random_to(1, 3);
+}
+
+float sample_many()
+{
+ return random_to(2, 10);
+}
+
+int main()
+{
+ //initialize randomness
+ srand(1);
+
+ // clock_t start, end;
+ // start = clock();
+
+ // Toy example
+ // Declare variables in play
+ float p_a, p_b, p_c;
+ // printf("Max threads: %d\n", n_threads);
+ // omp_set_num_threads(n_threads);
+
+ // Initialize variables
+ p_a = 0.8;
+ p_b = 0.5;
+ p_c = p_a * p_b;
+
+ // Generate mixture
+ int n_dists = 4;
+ float weights[] = { 1 - p_c, p_c / 2, p_c / 4, p_c / 4 };
+ float (*samplers[])(void) = { sample_0, sample_1, sample_few, sample_many };
+
+ float* results = malloc(N * sizeof(float));
+ mixture(samplers, weights, n_dists, results, N);
+ printf("Sum(dist_mixture, N)/N = %f\n", array_sum(results, N) / N);
+ // array_print(dist_mixture[0], N);
+
+ // end = clock();
+ // printf("Time (ms): %f\n", ((double)(end - start)) / (CLOCKS_PER_SEC * 10) * 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;
+}
