Data commit

Task/Evolutionary-algorithm/BBC-BASIC/evolutionary-algorithm.basic

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+      target$ = "METHINKS IT IS LIKE A WEASEL"
+      parent$ = "IU RFSGJABGOLYWF XSMFXNIABKT"
+      mutation_rate = 0.5
+      children% = 10
+
+      DIM child$(children%)
+
+      REPEAT
+        bestfitness = 0
+        bestindex% = 0
+        FOR index% = 1 TO children%
+          child$(index%) = FNmutate(parent$, mutation_rate)
+          fitness = FNfitness(target$, child$(index%))
+          IF fitness > bestfitness THEN
+            bestfitness = fitness
+            bestindex% = index%
+          ENDIF
+        NEXT index%
+
+        parent$ = child$(bestindex%)
+        PRINT parent$
+      UNTIL parent$ = target$
+      END
+
+      DEF FNfitness(text$, ref$)
+      LOCAL I%, F%
+      FOR I% = 1 TO LEN(text$)
+        IF MID$(text$, I%, 1) = MID$(ref$, I%, 1) THEN F% += 1
+      NEXT
+      = F% / LEN(text$)
+
+      DEF FNmutate(text$, rate)
+      LOCAL C%
+      IF rate > RND(1) THEN
+        C% = 63+RND(27)
+        IF C% = 64 C% = 32
+        MID$(text$, RND(LEN(text$)), 1) = CHR$(C%)
+      ENDIF
+      = text$