RosettaCodeData/Task/Evolutionary-algorithm/D/evolutionary-algorithm-1.d

34 lines
1.1 KiB
D

import std.stdio, std.random, std.algorithm, std.range, std.ascii;
void evolve(string target, double prob=0.05, int C=100) {
auto chars = uppercase ~ " ";
char rndCh() { return chars[uniform(0, $)]; }
void mutate(char[] parent, char[] child) {
foreach (i, ref c; child)
c = uniform(0.0, 1.0) < prob ? rndCh() : parent[i];
}
int fitness(char[] subject, string target) {
return count!q{ a[0] != a[1] }(zip(subject, target));
}
auto parent= map!(i => rndCh())(target).array();
auto best = parent.dup;
auto child = new char[target.length];
int currDist = fitness(parent, target);
for (int gen; currDist > 0; gen++) {
foreach (_; 0 .. C) {
mutate(parent, child);
int dist = fitness(child, target);
if (dist < currDist) {
currDist = dist;
best[] = child[];
}
}
parent = best;
writefln("Generation %2s, dist=%2s: %s", gen, currDist, best);
}
}
void main() {
evolve("METHINKS IT IS LIKE A WEASEL");
}