Gen.hs

{-# LANGUAGE DeriveDataTypeable, FlexibleInstances, MultiParamTypeClasses #-} 
module Gen where

import GenProg
import Data.Generics
import Control.Monad
import Control.Monad.Random

import Logic

data E=Nand E E
        | Const Bit
        | Param
        deriving (Show,Eq,Data,Typeable)

eval :: E -> Bit -> Bit
eval (Nand e1 e2) p=nand (eval e1 p,eval e2 p)
eval (Const b) _=b
eval Param p=p

notFitness :: E -> Double
notFitness e=let
        resF=eval e F
        resT=eval e T
        in if resF==T && resT==F
                then ((realToFrac $ nodes e)*100)
                else 100000000
                
                
instance GenProg (Rand StdGen) E where
  terminal    = do
        r<-getRandomR (0,2)
        return $ [Const T,Const F,Param] !! r
  nonterminal = liftM2 Nand terminal terminal
  
run=let 
        params = defaultEvolParams { fitness = notFitness }
        g = mkStdGen 0
    in cachedBest $ evalRand (evolve params) g