update

Task/Evolutionary-algorithm/D/evolutionary-algorithm.d

@@ -0,0 +1,18 @@
+import std.stdio, std.random, std.algorithm, std.range, std.ascii;
+
+enum target = "METHINKS IT IS LIKE A WEASEL"d;
+enum C = 100;  // Number of children in each generation.
+enum P = 0.05; // Mutation probability.
+enum fitness = (dchar[] s) => target.zip(s).count!q{ a[0] != a[1] };
+dchar rnd() { return (uppercase ~ " ")[uniform(0, $)]; }
+enum mut= (dchar[] s) => s.map!(a=> uniform(0,1.) < P ? rnd : a).array;
+
+void main() {
+    auto parent = target.length.iota.map!(_ => rnd).array;
+    for (auto gen = 1; parent != target; gen++) {
+        //parent = parent.repeat(C).map!mut.array.max!(s => s.fitness);
+        parent = parent.repeat(C).map!mut.array
+                 .minPos!((a, b) => a.fitness < b.fitness)[0];
+        writefln("Gen %2d, dist=%2d: %s", gen, parent.fitness, parent);
+    }
+}