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[11659] | 1 | using System;
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| 2 | using System.Collections.Generic;
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| 3 | using System.Diagnostics;
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| 4 | using System.Linq;
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| 5 | using System.Text;
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| 6 | using System.Text.RegularExpressions;
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| 7 |
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| 8 | namespace HeuristicLab.Problems.GrammaticalOptimization {
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| 9 | // 4-bit even parity
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| 10 | public class EvenParityProblem : IProblem {
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| 11 | // + == OR
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| 12 | // * == AND
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| 13 | private const string grammarString = @"
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| 14 | G(S):
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| 15 | S -> N | N*S | N+S | !S | (S)
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| 16 | N -> a | b | c | d
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| 17 | ";
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| 18 |
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| 19 | private readonly IGrammar grammar;
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| 20 | private readonly ExpressionInterpreter interpreter = new ExpressionInterpreter();
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| 21 | public EvenParityProblem() {
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[11732] | 22 | this.grammar = new Grammar (grammarString);
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[11659] | 23 | }
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| 24 |
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[11732] | 25 | public double BestKnownQuality(int maxLen) {
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[11659] | 26 | // for now only an upper bound is returned, ideally all fitness cases are predicted correctly
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| 27 | return Math.Pow(2, 4);
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| 28 | }
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| 29 |
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| 30 | public IGrammar Grammar {
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| 31 | get { return grammar; }
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| 32 | }
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| 33 |
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| 34 | public double Evaluate(string sentence) {
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| 35 | var vars = new bool[4];
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| 36 | var nCorrect = 0;
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| 37 | for (int b0 = 0; b0 <= 1; b0++)
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| 38 | for (int b1 = 0; b1 <= 1; b1++)
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| 39 | for (int b2 = 0; b2 <= 1; b2++)
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| 40 | for (int b3 = 0; b3 <= 1; b3++) {
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| 41 | vars[0] = b0 > 0;
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| 42 | vars[1] = b1 > 0;
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| 43 | vars[2] = b2 > 0;
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| 44 | vars[3] = b3 > 0;
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| 45 |
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| 46 | var pred = interpreter.Interpret(sentence, vars);
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| 47 | var target = (b0 > 0) ^ (b1 > 0) ^ (b2 > 0) ^ (b3 > 0);
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| 48 | if (pred == target) nCorrect++;
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| 49 | }
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| 50 | return nCorrect;
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| 51 | }
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[11727] | 52 |
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| 53 | public string Hash(string terminalPhrase) {
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| 54 | return terminalPhrase;
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| 55 | }
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[11659] | 56 | }
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| 57 | }
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