MC-pi test, Missing #include in diceforge_core

include/diceforge_core.h

@@ -4,6 +4,7 @@
 #include <limits>
 #include <iostream>
 #include <cmath>
+#include <algorithm>
 #include <vector>
 
 namespace DiceForge

testing/test_montecarlo.cpp

@@ -0,0 +1,56 @@
+#include "diceforge.h"
+#include <time.h>
+#include <fstream>
+
+int main(int argc, char const *argv[])
+{
+    DiceForge::XORShift rng = DiceForge::XORShift(time(NULL));
+    std::ofstream f_out = std::ofstream("pi_out.dat");
+    std::ofstream f_in = std::ofstream("pi_in.dat");
+
+    if (argc < 2)
+    {
+        std::cout << "Enter number of points to generate!" << std::endl;
+        return -1;
+    }
+
+    int num_samples = atoi(argv[1]);
+    int inside = 0;
+
+    for (int i = 0; i < num_samples; i++)
+    {
+        double x = rng.next_in_crange(0, 1);
+        double y = rng.next_in_crange(0, 1);
+
+        if (x*x + y*y <= 1)
+        {
+            inside++;
+
+            if (i % 1000 == 0)
+                f_in << x << " " << y << std::endl;
+        }
+        else
+        {
+            if (i % 1000 == 0)   
+                f_out << x << " " << y << std::endl;
+        }
+    }
+
+    f_out.close();
+    f_in.close();
+
+    double pi = 4 * double(inside)/num_samples;
+
+    std::cout << "pi = " << pi << std::endl;
+
+    FILE* gnuplot = popen("gnuplot -persist", "w");
+    fprintf(gnuplot, "set label 'π = %f' at 0.3, 0.3\n", pi);
+    fprintf(gnuplot, "set label 'samples = %d' at 0.3, 0.35\n", num_samples);
+    fprintf(gnuplot, "f(x) = sqrt(1 - x*x)\n");
+    fprintf(gnuplot, "set xrange [0:1]\n");    
+    fprintf(gnuplot, "plot f(x) title 'unit quarter circle' with l, 'pi_out.dat' title '(showing 1 out of every 1000 points)' pt 6 ps 0.2," \
+    "'pi_in.dat' title '' pt 7 ps 0.2\n");
+    fclose(gnuplot);
+
+    return 0;
+}