Initial data commit

Task/Monte-Carlo-methods/Java/monte-carlo-methods-2.java

@@ -0,0 +1,44 @@
+package montecarlo;
+
+import java.util.stream.IntStream;
+import java.util.stream.DoubleStream;
+
+import static java.lang.Math.random;
+import static java.lang.Math.hypot;
+import static java.lang.System.out;
+
+public interface MonteCarlo {
+  public static void main(String... arguments) {
+    IntStream.of(
+      10000,
+      100000,
+      1000000,
+      10000000,
+      100000000
+    )
+      .mapToDouble(MonteCarlo::pi)
+      .forEach(out::println)
+    ;
+  }
+
+  public static double range() {
+    //a square with a side of length 2 centered at 0 has
+    //x and y range of -1 to 1
+    return (random() * 2) - 1;
+  }
+
+  public static double pi(int numThrows){
+    long inCircle = DoubleStream.generate(
+      //distance from (0,0) = hypot(x, y)
+      () -> hypot(range(), range())
+    )
+      .limit(numThrows)
+      .unordered()
+      .parallel()
+      //circle with diameter of 2 has radius of 1
+      .filter(d -> d < 1)
+      .count()
+    ;
+    return (4.0 * inCircle) / numThrows;
+  }
+}