Make some changes

- Add new programs
- Add command line args
- Add Usage to guide user on how to use programs

src/phase_transition.cpp

@@ -0,0 +1,84 @@
+/** @file phase_transition.cpp
+ *
+ *  @author Cory Alexander Balaton (coryab)
+ *  @author Janita Ovidie Sandtrøen Willumsen (janitaws)
+ *
+ *  @version 1.0
+ *
+ *  @brief Sweep over different temperatures and generate data.
+ *
+ *  @details This program takes in 4 arguments: the start temperature,
+ *  the end temperature, the amount of temperature points to simulate, and
+ *  the amount of monte carlo samples to collect, in that order.
+ *
+ *  @bug No known bugs
+ * */
+#include "data_type.hpp"
+#include "monte_carlo.hpp"
+#include "utils.hpp"
+
+#include <getopt.h>
+#include <omp.h>
+#include <string>
+
+void usage(std::string filename)
+{
+    std::cout << "Usage: " << filename
+              << " <start temperature> <end temperature> <lattice size> "
+                 "<points> <cycles> <burn-in-time> <output file>\n\n"
+              << "\t[ -h | --help ]\n";
+    exit(-1);
+}
+
+/** @brief The main function
+ *
+ *  */
+int main(int argc, char **argv)
+{
+    // Command options
+    struct option long_options[] = {{"help", 0, 0, 0}, {NULL, 0, NULL, 0}};
+
+    int option_index = -1;
+    int c;
+
+    while (true) {
+        c = getopt_long(argc, argv, "h", long_options, &option_index);
+
+        if (c == -1)
+            break;
+
+        switch (c) {
+        case 0:
+            switch (option_index) {
+            case 0: // Not a mistake. This just goes to the default.
+            default:
+                usage(argv[0]);
+            }
+            break;
+        case 'h':
+        default:
+            usage(argv[0]);
+        }
+    }
+    // Check that the number of arguments is at least 8.
+    if (argc < 8) {
+        usage(argv[0]);
+    }
+
+    // Timing variables
+    double t0, t1;
+    t0 = omp_get_wtime();
+
+    // Define/initialize variables
+    double start = atof(argv[1]), end = atof(argv[2]);
+    int points = atoi(argv[3]), cycles = atoi(argv[5]), L = atoi(argv[4]),
+        burn_in_time = atoi(argv[6]), N = L * L;
+    std::string outfile = argv[7];
+
+    montecarlo::phase_transition(L, start, end, points, cycles,
+                                 montecarlo::mcmc_parallel, outfile);
+
+    t1 = omp_get_wtime();
+
+    std::cout << "Time: " << t1 - t0 << " seconds\n";
+}