Minify program after hitting score

grow/definition.go

@@ -65,6 +65,19 @@ func (def *Definition) Grow(statusChan chan<- Status) (*vm.Program, error) {
 			}
 
 			if status.BestScore == status.TargetScore {
+				err = def.minifyProgram(prog)
+				if err != nil {
+					if statusChan != nil {
+						close(statusChan)
+					}
+
+					return nil, err
+				}
+
+				if statusChan != nil {
+					statusChan <- status
+				}
+
 				if statusChan != nil {
 					close(statusChan)
 				}
@@ -106,3 +119,42 @@ func (def *Definition) sumOuts() uint64 {
 
 	return sum
 }
+
+func (def *Definition) minifyProgram(prog *vm.Program) error {
+	for f := 0; f < len(prog.Functions); f++ {
+		err := def.minifyFunction(prog, f)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (def *Definition) minifyFunction(prog *vm.Program, f int) error {
+	baseScore, err := def.score(prog)
+	if err != nil {
+		return err
+	}
+
+	for loop := true; loop; {
+		loop = false
+
+		for i := 0; i < len(prog.Functions[f].Instructions); i++ {
+			origInstructions := prog.Functions[f].Instructions
+			tmp := make([]*vm.Instruction, len(prog.Functions[f].Instructions))
+			copy(tmp, prog.Functions[f].Instructions)
+			prog.Functions[f].Instructions = append(tmp[:i], tmp[i+1:]...)
+
+			newScore, err := def.score(prog)
+			if err == nil && newScore >= baseScore {
+				loop = true
+				break
+			} else {
+				prog.Functions[f].Instructions = origInstructions
+			}
+		}
+	}
+
+	return nil
+}

grow/mutate.go

@@ -1,6 +1,5 @@
 package grow
 
-import "math"
 import "math/rand"
 
 import "github.com/firestuff/subcoding/gen"
@@ -10,7 +9,7 @@ const instructionsPerFunctionMean = 15
 const instrucitonsPerFunctionStdDev = 10
 
 func Mutate(prog *vm.Program) {
-	target := int(math.Max(2, rand.NormFloat64()*instrucitonsPerFunctionStdDev+instructionsPerFunctionMean))
+	target := int(rand.NormFloat64()*instrucitonsPerFunctionStdDev+instructionsPerFunctionMean)
 
 	if len(prog.Functions[0].Instructions) < target {
 		addInstruction(prog, prog.Functions[0])