Initial data commit

Task/Evolutionary-algorithm/FreeBASIC/evolutionary-algorithm.basic

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+' version 01-07-2018
+' compile with: fbc -s console
+
+Randomize Timer
+Const As UInteger children = 100
+Const As Double mutate_rate = 0.05
+
+Function fitness(target As String, tmp As String) As UInteger
+
+    Dim As UInteger x, f
+
+    For x = 0 To Len(tmp) -1
+        If tmp[x] = target[x] Then f += 1
+    Next
+    Return f
+
+End Function
+
+Sub mutate(tmp As String, chars As String, mute_rate As Double)
+
+    If Rnd <= mute_rate Then
+        tmp[Int(Rnd * Len(tmp))] = chars[Int(Rnd * Len(chars))]
+    End If
+
+End Sub
+
+' ------=< MAIN >=------
+
+Dim As String target = "METHINKS IT IS LIKE A WEASEL"
+Dim As String chars  = " ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+Dim As String parent, mutation()
+Dim As UInteger x, iter, f, fit(), best_fit, parent_fit
+
+For x = 1 To Len(target)
+    parent += Chr(chars[Int(Rnd * Len(chars))])
+Next
+
+f = fitness(target, parent)
+parent_fit = f
+best_fit = f
+
+Print "iteration  best fit   Parent"
+Print "=========  ========   ============================"
+Print Using "     ####      ####   ";iter; best_fit;
+Print parent
+
+Do
+    iter += 1
+    ReDim mutation(1 To children),fit(1 To children)
+
+    For x = 1 To children
+        mutation(x) = parent
+        mutate(mutation(x), chars, mutate_rate)
+    Next
+
+    For x = 1 To children
+        If mutation(x) <> parent Then
+            f = fitness(target, mutation(x))
+            If best_fit < f Then
+                best_fit = f
+                fit(x) = f
+            Else
+                fit(x) = parent_fit
+            End If
+        End If
+    Next
+
+    If best_fit > parent_fit Then
+        For x = 1 To children
+            If fit(x) = best_fit Then
+                parent = mutation(x)
+                Print Using "     ####      ####   ";iter; best_fit;
+                Print parent
+            End If
+        Next
+    End If
+
+Loop Until parent = target
+
+' empty keyboard buffer
+While InKey <> "" : Wend
+Print : Print "hit any key to end program"
+Sleep
+End