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// SPDX-License-Identifier: GPL-3.0-or-later
// Copyright 2020 Florian Fischer
#include <assert.h>
#include <math.h>
#include <pthread.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "pso.h"
#include "problems.h"
// defaults
static size_t problem = 0;
static size_t dimensions = 2;
static size_t threads = 1;
static size_t num_particles = 100;
static size_t iterations = 100;
static double a = 0.72984;
static double b_loc = 1.496172;
static double b_glob = 1.496172;
static particle_t** particles;
static vec_t* p_glob;
static double p_glob_val;
static pthread_barrier_t iteration_barrier;
static pthread_barrier_t p_glob_barrier;
static void* thread_func(void* arg) {
size_t tid = (size_t)arg;
size_t particles_per_thread = num_particles / threads;
size_t first_particle = tid * particles_per_thread;
size_t last_particle = first_particle + particles_per_thread;
init_random();
// iteration loop
for (size_t iteration = 0; iteration < iterations; ++iteration) {
// particle loop
for (size_t i = first_particle; i < last_particle; ++i) {
step(a, b_loc, b_glob, particles[i], p_glob);
evaluate_particle(particles[i], problems[problem].func);
}
pthread_barrier_wait(&iteration_barrier);
if (tid == 0) {
// update p_glob
vec_t* optimum_location;
find_min(particles, num_particles, &optimum_location, &p_glob_val);
copy_vec(optimum_location, p_glob);
// reset barrier
pthread_barrier_destroy(&iteration_barrier);
pthread_barrier_init(&iteration_barrier, NULL, threads);
}
// wait till p_glob is updated
pthread_barrier_wait(&p_glob_barrier);
if (tid == 0) {
// reset barrier
pthread_barrier_destroy(&p_glob_barrier);
pthread_barrier_init(&p_glob_barrier, NULL, threads);
}
}
return NULL;
}
int main(int argc, char* argv[]) {
// TODO: read parameters from command line
for(size_t i = 1; i < argc; i += 2) {
if (strcmp(argv[i], "-p") == 0) {
num_particles = atol(argv[i + 1]);
} else if (strcmp(argv[i], "-i") == 0) {
iterations = atol(argv[i + 1]);
} else if (strcmp(argv[i], "-t") == 0) {
threads = atol(argv[i + 1]);
} else if (strcmp(argv[i], "-f") == 0) {
problem = atol(argv[i + 1]);
} else if (strcmp(argv[i], "-b") == 0) {
b_loc = strtod(argv[i + 1], NULL);
b_glob = b_loc;
} else if (strcmp(argv[i], "-a") == 0) {
a = strtod(argv[i + 1], NULL);
} else if (strcmp(argv[i], "-h") == 0) {
printf("Usage: %s [OPTIONS]\n", argv[0]);
printf("OPTIONS:\n");
printf("\t -p number of particles\n");
printf("\t -h print this help and exit\n");
printf("\t -t number of threads\n");
printf("\t -i iterations\n");
printf("\t -f the function to optimize\n");
printf("\t 0 - sphere function\n");
printf("\t 1 - rosenbrock function\n");
printf("\t 2 - rastrigin function\n");
printf("\t 3 - schwefel function\n");
printf("\t -a the a parameter\n");
printf("\t -b the b parameter\n");
exit(1);
}
}
assert(num_particles % threads == 0);
assert(problem < NUM_PROBLEMS);
printf("threads: %ld, particles: %ld, iterations: %ld, function: %s\n",
threads, num_particles, iterations, problems[problem].name);
printf("a: %lf, b_loc: %lf b_glob: %lf\n",
a, b_loc, b_glob);
pthread_t *threads_array = check_malloc(sizeof(pthread_t*) * threads);
if (pthread_barrier_init(&iteration_barrier, NULL, threads) != 0) {
perror("pthread_barrier_init");
exit(1);
}
if (pthread_barrier_init(&p_glob_barrier, NULL, threads) != 0) {
perror("pthread_barrier_init");
exit(1);
}
init_random();
particles = check_malloc(sizeof(particle_t*) * num_particles);
for (size_t i = 0; i < num_particles; ++i) {
particles[i] = new_particle(dimensions, problems[problem].interval);
}
vec_t* optimum_location;
find_min(particles, num_particles, &optimum_location, &p_glob_val);
p_glob = new_vec(dimensions);
copy_vec(optimum_location, p_glob);
for (size_t i = 0; i < threads; ++i) {
if (pthread_create(&threads_array[i], NULL, thread_func, (void*)i) != 0) {
perror("pthread_create");
exit(1);
}
}
for (size_t i = 0; i < threads; ++i) {
if (pthread_join(threads_array[i], NULL) != 0) {
perror("pthread_join");
exit(1);
}
}
printf("Found optimum %g at ", p_glob_val);
print_vec(p_glob);
printf(" after step %ld\n", iterations);
for (size_t i = 0; i < num_particles; ++i) {
destroy_particle(particles[i]);
}
free(particles);
free(threads_array);
return 0;
}
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