Update all new Tasks

Task/Percolation-Mean-run-density/D/percolation-mean-run-density.d

@@ -0,0 +1,23 @@
+import std.stdio, std.range, std.algorithm, std.random, std.math;
+
+enum n = 100, p = 0.5, t = 500;
+
+double meanRunDensity(in size_t n, in double prob) {
+    return n.iota.map!(_ => uniform01 < prob)
+           .array.uniq.sum / double(n);
+}
+
+void main() {
+    foreach (immutable p; iota(0.1, 1.0, 0.2)) {
+        immutable limit = p * (1 - p);
+        writeln;
+        foreach (immutable n2; iota(10, 16, 2)) {
+            immutable n = 2 ^^ n2;
+            immutable sim = t.iota.map!(_ => meanRunDensity(n, p))
+                            .sum / t;
+            writefln("t=%3d, p=%4.2f, n=%5d, p(1-p)=%5.5f, " ~
+                     "sim=%5.5f, delta=%3.1f%%", t, p, n, limit, sim,
+                     limit ? abs(sim - limit) / limit * 100 : sim*100);
+        }
+    }
+}