[11659] | 1 | using System;
|
---|
| 2 | using System.Collections.Generic;
|
---|
| 3 | using System.Diagnostics.Eventing.Reader;
|
---|
| 4 | using System.Linq;
|
---|
[11832] | 5 | using System.Runtime.CompilerServices;
|
---|
[11659] | 6 | using System.Runtime.Remoting.Messaging;
|
---|
| 7 | using System.Text;
|
---|
| 8 | using System.Threading.Tasks;
|
---|
[11727] | 9 | using HeuristicLab.Common;
|
---|
[11659] | 10 |
|
---|
| 11 | namespace HeuristicLab.Problems.GrammaticalOptimization {
|
---|
| 12 | public class ExpressionInterpreter {
|
---|
[11832] | 13 | private static readonly double[] emptyErc = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
|
---|
| 14 |
|
---|
[11659] | 15 | private string sentence;
|
---|
| 16 | private int syIdx;
|
---|
| 17 | // interprets sentences from L(G(Expr)):
|
---|
| 18 | // Expr -> Term { ('+' | '-' | '^' ) Term }
|
---|
| 19 | // Term -> Fact { ('*' | '/') Fact }
|
---|
[11832] | 20 | // Fact -> '!' Expr | '(' Expr ')' | Var | const
|
---|
[11659] | 21 | // Var -> 'a'..'z'
|
---|
[11832] | 22 | // const -> '0' .. '9'
|
---|
[11659] | 23 |
|
---|
[11832] | 24 | // constants are Koza-style ephemeral random constants (ERC). for now we only allow up to 10 constants.
|
---|
| 25 | // The constant symbols '0' .. '9' are treated as ERC indices
|
---|
| 26 |
|
---|
[11659] | 27 | // for boolean problems the symbol * representes the AND operator, the symbol + represents the OR operator, ! = NOT, ^ = XOR
|
---|
| 28 |
|
---|
| 29 | public bool Interpret(string sentence, bool[] vars) {
|
---|
[11832] | 30 | return Interpret(sentence, vars, emptyErc);
|
---|
| 31 | }
|
---|
| 32 |
|
---|
| 33 | public bool Interpret(string sentence, bool[] vars, double[] erc) {
|
---|
[11659] | 34 | InitLex(sentence);
|
---|
| 35 | var d = new double[vars.Length];
|
---|
| 36 | for (int i = 0; i < vars.Length; i++) d[i] = vars[i] ? 1.0 : 0.0;
|
---|
[11832] | 37 | return !(Expr(d, erc).IsAlmost(0));
|
---|
[11659] | 38 | }
|
---|
| 39 |
|
---|
| 40 | public double Interpret(string sentence, double[] vars) {
|
---|
[11832] | 41 | return Interpret(sentence, vars, emptyErc);
|
---|
| 42 | }
|
---|
| 43 |
|
---|
| 44 | public double Interpret(string sentence, double[] vars, double[] erc) {
|
---|
[11659] | 45 | InitLex(sentence);
|
---|
[11832] | 46 | return Expr(vars, erc);
|
---|
[11659] | 47 | }
|
---|
| 48 |
|
---|
| 49 |
|
---|
| 50 | private void InitLex(string sentence) {
|
---|
| 51 | this.sentence = sentence;
|
---|
| 52 | this.syIdx = 0;
|
---|
| 53 | }
|
---|
| 54 |
|
---|
| 55 | private char CurSy() {
|
---|
| 56 | if (syIdx >= sentence.Length) return '\0';
|
---|
| 57 | return sentence[syIdx];
|
---|
| 58 | }
|
---|
| 59 | private void NewSy() {
|
---|
| 60 | if (syIdx < sentence.Length) syIdx++;
|
---|
| 61 | }
|
---|
| 62 |
|
---|
| 63 | // helper for xor
|
---|
| 64 | private double Not(double x) {
|
---|
| 65 | return x.IsAlmost(0) ? 1.0 : 0.0;
|
---|
| 66 | }
|
---|
| 67 |
|
---|
[11832] | 68 | private double Expr(double[] d, double[] erc) {
|
---|
[11659] | 69 | var r = 0.0;
|
---|
[11832] | 70 | r = Term(d, erc);
|
---|
[11732] | 71 | var curSy = CurSy();
|
---|
| 72 | while (curSy == '+' || curSy == '-' || curSy == '^') {
|
---|
| 73 | if (curSy == '+') {
|
---|
[11659] | 74 | NewSy();
|
---|
[11832] | 75 | r += Expr(d, erc);
|
---|
[11732] | 76 | } else if (curSy == '-') {
|
---|
[11659] | 77 | NewSy();
|
---|
[11832] | 78 | r -= Expr(d, erc);
|
---|
[11732] | 79 | } else {
|
---|
[11659] | 80 | NewSy();
|
---|
[11832] | 81 | var e = Expr(d, erc);
|
---|
[11659] | 82 | r = Not(r) * e + r * Not(e); // xor = (!x AND y) OR (x AND !y)
|
---|
| 83 | }
|
---|
[11732] | 84 | curSy = CurSy();
|
---|
[11659] | 85 | }
|
---|
| 86 | return r;
|
---|
| 87 | }
|
---|
| 88 |
|
---|
[11832] | 89 | private double Term(double[] d, double[] erc) {
|
---|
[11659] | 90 | var r = 0.0;
|
---|
[11832] | 91 | r = Fact(d, erc);
|
---|
[11732] | 92 | var curSy = CurSy();
|
---|
| 93 | while (curSy == '*' || curSy == '/') {
|
---|
| 94 | if (curSy == '*') {
|
---|
[11659] | 95 | NewSy();
|
---|
[11832] | 96 | r *= Term(d, erc);
|
---|
[11732] | 97 | } else {
|
---|
[11659] | 98 | NewSy();
|
---|
[11832] | 99 | r /= Term(d, erc);
|
---|
[11659] | 100 | }
|
---|
[11732] | 101 | curSy = CurSy();
|
---|
[11659] | 102 | }
|
---|
| 103 | return r;
|
---|
| 104 | }
|
---|
| 105 |
|
---|
[11832] | 106 | private double Fact(double[] d, double[] erc) {
|
---|
[11659] | 107 | double r = 0.0;
|
---|
[11732] | 108 | var curSy = CurSy();
|
---|
| 109 | if (curSy == '!') {
|
---|
[11659] | 110 | NewSy();
|
---|
[11832] | 111 | r = Not(Expr(d, erc));
|
---|
[11732] | 112 | } else if (curSy == '(') {
|
---|
[11659] | 113 | NewSy();
|
---|
[11832] | 114 | r = Expr(d, erc);
|
---|
[11659] | 115 | if (CurSy() != ')') throw new ArgumentException();
|
---|
| 116 | NewSy();
|
---|
[11832] | 117 | } else if (curSy >= 'a' && curSy <= 'z') {
|
---|
[11732] | 118 | int o = (byte)curSy - (byte)'a';
|
---|
| 119 | //int o = Convert.ToByte(CurSy()) - Convert.ToByte('a');
|
---|
[11659] | 120 | if (o < 0 || o >= d.Length) throw new ArgumentException();
|
---|
| 121 | r = d[o];
|
---|
| 122 | NewSy();
|
---|
[11832] | 123 | } else /* if (curSy >= '0' && curSy <= '9') */ {
|
---|
| 124 | int o = (byte)curSy - (byte)'0';
|
---|
| 125 | //int o = Convert.ToByte(CurSy()) - Convert.ToByte('a');
|
---|
| 126 | if (o < 0 || o >= 10) throw new ArgumentException();
|
---|
| 127 | r = erc[o];
|
---|
| 128 | NewSy();
|
---|
[11732] | 129 | }
|
---|
| 130 | //} else throw new ArgumentException();
|
---|
[11659] | 131 | return r;
|
---|
| 132 | }
|
---|
| 133 |
|
---|
| 134 | }
|
---|
| 135 | }
|
---|