45 lines
1.2 KiB
Go
45 lines
1.2 KiB
Go
package grow
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import "math/rand"
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import "github.com/firestuff/subcoding/gen"
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import "github.com/firestuff/subcoding/vm"
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const instructionsPerFunctionMean = 15
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const instrucitonsPerFunctionStdDev = 10
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const minifyPeriodMean = 10000
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func Mutate(def *Definition, prog *vm.Program) {
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if rand.Intn(minifyPeriodMean) == 0 {
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def.minifyProgram(prog) // ignore error
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}
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target := int(rand.NormFloat64()*instrucitonsPerFunctionStdDev + instructionsPerFunctionMean)
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if len(prog.Functions[0].Instructions) < target {
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addInstruction(prog, prog.Functions[0])
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} else {
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removeInstruction(prog, prog.Functions[0])
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}
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}
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func addInstruction(prog *vm.Program, fnc *vm.Function) {
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if len(fnc.Instructions) == 0 {
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fnc.Instructions = append(fnc.Instructions, gen.RandInstruction(prog))
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} else {
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i := rand.Intn(len(fnc.Instructions))
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fnc.Instructions = append(fnc.Instructions[:i+1], fnc.Instructions[i:]...)
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fnc.Instructions[i] = gen.RandInstruction(prog)
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}
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}
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func removeInstruction(prog *vm.Program, fnc *vm.Function) {
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if len(fnc.Instructions) == 0 {
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return
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}
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i := rand.Intn(len(fnc.Instructions))
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fnc.Instructions = append(fnc.Instructions[:i], fnc.Instructions[i+1:]...)
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}
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