Data commit

Task/Evolutionary-algorithm/AWK/evolutionary-algorithm.awk

@@ -0,0 +1,62 @@
+#!/bin/awk -f
+function randchar(){
+return substr(charset,randint(length(charset)+1),1)
+}
+function mutate(gene,rate    ,l,newgene){
+newgene = ""
+for (l=1; l < 1+length(gene); l++){
+if (rand() < rate)
+   newgene = newgene randchar()
+else
+   newgene = newgene substr(gene,l,1)
+}
+return newgene
+}
+function fitness(gene,target  ,k,fit){
+fit = 0
+for (k=1;k<1+length(gene);k++){
+if (substr(gene,k,1) == substr(target,k,1)) fit = fit + 1
+}
+return fit
+}
+function randint(n){
+return int(n * rand())
+}
+function evolve(){
+     maxfit = fitness(parent,target)
+     oldfit = maxfit
+     maxj = 0
+     for (j=1; j < D; j++){
+         child[j] = mutate(parent,mutrate)
+         fit[j] = fitness(child[j],target)
+         if (fit[j] > maxfit) {
+            maxfit = fit[j]
+            maxj = j
+            }
+          }
+     if (maxfit > oldfit) parent = child[maxj]
+     }
+
+BEGIN{
+target = "METHINKS IT IS LIKE A WEASEL"
+charset = " ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+mutrate = 0.10
+if (ARGC > 1) mutrate = ARGV[1]
+lenset = length(charset)
+C = 100
+D = C + 1
+parent = ""
+for (j=1; j < length(target)+1; j++) {
+     parent = parent randchar()
+     }
+print "target: " target
+print "fitness of target: " fitness(target,target)
+print "initial parent: " parent
+gens = 0
+while (parent != target){
+      evolve()
+      gens = gens + 1
+      if (gens % 10 == 0) print "after " gens " generations,","new parent: " parent," with fitness: " fitness(parent,target)
+      }
+print "after " gens " generations,"," evolved parent: " parent
+}