[26] | 1 | /*************************************************************************/ |
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| 2 | /* */ |
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| 3 | /* Process sets of rules */ |
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| 4 | /* --------------------- */ |
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| 5 | /* */ |
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| 6 | /*************************************************************************/ |
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| 7 | |
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| 8 | |
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| 9 | #include "defns.i" |
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| 10 | #include "types.i" |
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| 11 | #include "extern.i" |
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| 12 | #include "rulex.i" |
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| 13 | |
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| 14 | |
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| 15 | ItemNo *ClassFreq, /* ClassFreq[c] = no. items of class c */ |
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| 16 | *Covered, /* Covered[i] = no. included rules that cover item i */ |
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| 17 | *FalsePos, /* FalsePos[c] = no. false positives from rules |
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| 18 | selected for class c */ |
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| 19 | *NoRule, /* NoRule[c] = no. items covered by no selected rule */ |
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| 20 | |
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| 21 | *Right, /* Right[r] = no. correct rule firings */ |
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| 22 | *Wrong; /* Wrong[r] = no. incorrect rule firings */ |
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| 23 | |
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| 24 | float *Value, /* Value[r] = advantage attributable to rule r or |
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| 25 | realisable if rule r included */ |
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| 26 | SubsetValue, /* value of best class subset so far */ |
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| 27 | CodeWeight; /* multiplying factor for rule encodings */ |
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| 28 | |
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| 29 | Boolean *RuleIn, /* RuleIn[r] = true if rule r included */ |
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| 30 | *Subset, /* best class subset so far */ |
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| 31 | **Match; /* Match[r][i] = true if rule r fires on item i */ |
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| 32 | |
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| 33 | RuleNo *ClassRules; /* list of all rules for current target class */ |
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| 34 | |
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| 35 | ClassNo FocusClass; |
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| 36 | |
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| 37 | |
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| 38 | |
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| 39 | /*************************************************************************/ |
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| 40 | /* */ |
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| 41 | /* Construct an ordered subset (indexed by RuleIndex) of the current */ |
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| 42 | /* set of rules */ |
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| 43 | /* */ |
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| 44 | /*************************************************************************/ |
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| 45 | |
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| 46 | |
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| 47 | ConstructRuleset() |
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| 48 | /* ---------------- */ |
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| 49 | { |
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| 50 | RuleNo r, OldNRules = NRules; |
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| 51 | |
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| 52 | /* Allocate tables */ |
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| 53 | |
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| 54 | Right = (ItemNo *) calloc(NRules+1, sizeof(ItemNo)); |
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| 55 | Wrong = (ItemNo *) calloc(NRules+1, sizeof(ItemNo)); |
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| 56 | |
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| 57 | Value = (float *) calloc(NRules+1, sizeof(float)); |
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| 58 | |
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| 59 | RuleIn = (Boolean *) calloc(NRules+1, sizeof(Boolean)); |
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| 60 | Subset = (Boolean *) malloc((NRules+1) * sizeof(Boolean)); |
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| 61 | |
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| 62 | ClassRules = (RuleNo *) malloc((NRules+1) * sizeof(RuleNo)); |
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| 63 | |
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| 64 | ClassFreq = (ItemNo *) calloc(MaxClass+1, sizeof(ItemNo)); |
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| 65 | |
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| 66 | Covered = (ItemNo *) calloc(MaxItem+1, sizeof(ItemNo)); |
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| 67 | |
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| 68 | Match = (Boolean **) calloc(NRules+1, sizeof(Boolean *)); |
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| 69 | |
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| 70 | FalsePos = (ItemNo *) calloc(MaxClass+1, sizeof(ItemNo)); |
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| 71 | |
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| 72 | NoRule = (ItemNo *) calloc(MaxClass+1, sizeof(ItemNo)); |
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| 73 | |
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| 74 | ForEach(r, 1, NRules) |
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| 75 | { |
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| 76 | Match[r] = (Boolean *) calloc(MaxItem+1, sizeof(Boolean)); |
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| 77 | } |
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| 78 | |
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| 79 | /* Cover each class, then order the classes to give an index of rules */ |
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| 80 | |
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| 81 | InitialiseTables(); |
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| 82 | |
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| 83 | FindRuleCodes(); |
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| 84 | CodeWeight = 0.5; |
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| 85 | |
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| 86 | ForEach(FocusClass, 0, MaxClass) |
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| 87 | { |
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| 88 | CoverClass(); |
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| 89 | } |
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| 90 | |
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| 91 | MakeIndex(); |
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| 92 | FindDefault(); |
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| 93 | |
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| 94 | /* Clear */ |
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| 95 | |
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| 96 | cfree(Value); |
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| 97 | cfree(RuleIn); |
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| 98 | cfree(ClassRules); |
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| 99 | cfree(Subset); |
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| 100 | cfree(Covered); |
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| 101 | cfree(FalsePos); |
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| 102 | cfree(NoRule); |
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| 103 | ForEach(r, 1, OldNRules) |
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| 104 | { |
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| 105 | cfree(Match[r]); |
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| 106 | } |
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| 107 | cfree(Match); |
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| 108 | } |
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| 109 | |
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| 110 | |
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| 111 | |
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| 112 | /*************************************************************************/ |
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| 113 | /* */ |
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| 114 | /* Initialise all tables used in sifting */ |
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| 115 | /* */ |
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| 116 | /*************************************************************************/ |
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| 117 | |
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| 118 | |
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| 119 | InitialiseTables() |
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| 120 | /* ---------------- */ |
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| 121 | { |
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| 122 | ItemNo i; |
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| 123 | RuleNo r; |
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| 124 | ClassNo c; |
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| 125 | float Strength(); |
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| 126 | |
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| 127 | ForEach(r, 1, NRules) |
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| 128 | { |
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| 129 | RuleIn[r] = false; |
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| 130 | Rule[r].Used = Rule[r].Incorrect = 0; |
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| 131 | } |
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| 132 | |
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| 133 | ForEach(c, 0, MaxClass) |
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| 134 | { |
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| 135 | ClassFreq[c] = 0; |
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| 136 | } |
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| 137 | |
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| 138 | ForEach(i, 0, MaxItem) |
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| 139 | { |
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| 140 | ClassFreq[Class(Item[i])]++; |
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| 141 | |
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| 142 | ForEach(r, 1, NRules) |
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| 143 | { |
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| 144 | Match[r][i] = Strength(Rule[r], Item[i]) > 0.1; |
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| 145 | |
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| 146 | if ( Match[r][i] ) |
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| 147 | { |
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| 148 | Rule[r].Used++; |
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| 149 | if ( Class(Item[i]) != Rule[r].Rhs ) Rule[r].Incorrect++; |
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| 150 | } |
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| 151 | } |
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| 152 | } |
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| 153 | } |
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| 154 | |
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| 155 | |
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| 156 | |
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| 157 | /*************************************************************************/ |
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| 158 | /* */ |
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| 159 | /* Select a subset of the rules for class FocusClass */ |
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| 160 | /* */ |
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| 161 | /*************************************************************************/ |
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| 162 | |
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| 163 | |
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| 164 | CoverClass() |
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| 165 | /* ---------- */ |
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| 166 | { |
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| 167 | RuleNo r, RuleCount=0; |
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| 168 | ItemNo i; |
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| 169 | |
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| 170 | Verbosity(1) |
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| 171 | printf("\nClass %s\n-----\nAction Change Value", |
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| 172 | ClassName[FocusClass]); |
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| 173 | |
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| 174 | ForEach(i, 0, MaxItem) |
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| 175 | { |
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| 176 | Covered[i] = 0; |
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| 177 | } |
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| 178 | |
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| 179 | ForEach(r, 1, NRules) |
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| 180 | { |
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| 181 | if ( Rule[r].Rhs == FocusClass ) |
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| 182 | { |
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| 183 | RuleCount++; |
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| 184 | ClassRules[RuleCount] = r; |
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| 185 | } |
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| 186 | } |
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| 187 | |
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| 188 | if ( ! RuleCount ) |
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| 189 | { |
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| 190 | return; |
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| 191 | } |
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| 192 | |
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| 193 | SubsetValue = 1E10; |
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| 194 | |
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| 195 | if ( RuleCount <= 10 ) |
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| 196 | { |
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| 197 | AllCombinations(RuleCount); |
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| 198 | } |
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| 199 | else |
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| 200 | if ( SIMANNEAL ) |
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| 201 | { |
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| 202 | SimAnneal(RuleCount); |
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| 203 | } |
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| 204 | else |
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| 205 | { |
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| 206 | SpotSearch(RuleCount); |
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| 207 | } |
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| 208 | |
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| 209 | memcpy(RuleIn, Subset, NRules+1); |
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| 210 | Verbosity(1) printf("\n\tBest value %.1f\n", SubsetValue); |
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| 211 | } |
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| 212 | |
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| 213 | |
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| 214 | |
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| 215 | /*************************************************************************/ |
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| 216 | /* */ |
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| 217 | /* Try all combinations of rules to find best value */ |
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| 218 | /* */ |
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| 219 | /*************************************************************************/ |
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| 220 | |
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| 221 | |
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| 222 | AllCombinations(NR) |
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| 223 | /* --------------- */ |
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| 224 | RuleNo NR; |
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| 225 | { |
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| 226 | RuleNo r; |
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| 227 | |
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| 228 | if ( ! NR ) |
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| 229 | { |
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| 230 | CalculateValue(); |
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| 231 | } |
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| 232 | else |
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| 233 | { |
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| 234 | r = ClassRules[NR]; |
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| 235 | |
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| 236 | AllCombinations(NR-1); |
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| 237 | |
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| 238 | AddRule(r); |
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| 239 | AllCombinations(NR-1); |
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| 240 | |
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| 241 | DeleteRule(r); |
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| 242 | Verbosity(1) printf("\n"); |
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| 243 | } |
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| 244 | } |
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| 245 | |
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| 246 | |
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| 247 | |
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| 248 | /*************************************************************************/ |
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| 249 | /* */ |
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| 250 | /* Find a good subset by simulated annealing */ |
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| 251 | /* */ |
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| 252 | /*************************************************************************/ |
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| 253 | |
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| 254 | |
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| 255 | SimAnneal(RuleCount) |
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| 256 | /* --------- */ |
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| 257 | RuleNo RuleCount; |
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| 258 | { |
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| 259 | RuleNo r, OutCount; |
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| 260 | short ri, Tries; |
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| 261 | float Temp, Delta; |
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| 262 | Boolean Changed; |
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| 263 | |
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| 264 | /* Keep dropping and adding rules until can't improve */ |
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| 265 | |
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| 266 | for ( Temp = 1000 ; Temp > 0.001 ; Temp *= 0.95 ) |
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| 267 | { |
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| 268 | CalculateValue(); |
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| 269 | |
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| 270 | Verbosity(2) |
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| 271 | { |
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| 272 | OutCount = 0; |
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| 273 | |
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| 274 | ForEach(ri, 1, RuleCount) |
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| 275 | { |
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| 276 | r = ClassRules[ri]; |
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| 277 | |
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| 278 | if ( ! RuleIn[r] ) |
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| 279 | { |
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| 280 | if ( ! (OutCount++ % 3) ) printf("\n\t\t"); |
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| 281 | printf("%d<%d|%d=%.1f> ", r, Right[r], Wrong[r], Value[r]); |
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| 282 | } |
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| 283 | } |
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| 284 | |
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| 285 | printf("\n\n"); |
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| 286 | } |
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| 287 | |
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| 288 | Changed = false; |
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| 289 | |
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| 290 | for ( Tries = 100 ; ! Changed && Tries > 0 ; Tries-- ) |
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| 291 | { |
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| 292 | /* Choose a rule to add or delete */ |
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| 293 | |
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| 294 | ri = RuleCount * Random + 1; |
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| 295 | |
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| 296 | r = ClassRules[ri]; |
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| 297 | |
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| 298 | Delta = ( RuleIn[r] ? -Value[r] : Value[r] ); |
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| 299 | |
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| 300 | if ( Delta > 0 || Random < exp(Delta / Temp) ) |
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| 301 | { |
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| 302 | if ( RuleIn[r] ) |
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| 303 | { |
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| 304 | DeleteRule(r); |
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| 305 | } |
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| 306 | else |
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| 307 | { |
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| 308 | AddRule(r); |
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| 309 | } |
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| 310 | |
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| 311 | Changed = true; |
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| 312 | } |
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| 313 | } |
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| 314 | |
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| 315 | if ( ! Changed ) break; |
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| 316 | } |
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| 317 | |
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| 318 | /* Try to improve best subset so far by hill-climbing */ |
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| 319 | |
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| 320 | Verbosity(1) printf("Polish: "); |
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| 321 | memcpy(RuleIn, Subset, NRules+1); |
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| 322 | HillClimb(RuleCount); |
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| 323 | } |
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| 324 | |
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| 325 | |
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| 326 | |
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| 327 | /*************************************************************************/ |
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| 328 | /* */ |
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| 329 | /* Find a good subset by repeated greedy search */ |
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| 330 | /* */ |
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| 331 | /*************************************************************************/ |
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| 332 | |
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| 333 | |
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| 334 | SpotSearch(RuleCount) |
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| 335 | /* ---------- */ |
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| 336 | RuleNo RuleCount; |
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| 337 | { |
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| 338 | RuleNo r; |
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| 339 | short ri, Trial; |
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| 340 | float ProbIn; |
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| 341 | |
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| 342 | ForEach(Trial, 0, 10) |
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| 343 | { |
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| 344 | Verbosity(1) printf("\n Trial %d:", Trial); |
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| 345 | |
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| 346 | /* Add rules randomly to the initial subset */ |
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| 347 | |
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| 348 | ProbIn = Trial / 10.0; |
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| 349 | ForEach(ri, 1, RuleCount) |
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| 350 | { |
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| 351 | r = ClassRules[ri]; |
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| 352 | RuleIn[r] = Random < ProbIn; |
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| 353 | } |
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| 354 | |
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| 355 | HillClimb(RuleCount); |
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| 356 | } |
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| 357 | } |
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| 358 | |
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| 359 | |
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| 360 | |
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| 361 | /*************************************************************************/ |
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| 362 | /* */ |
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| 363 | /* Improve a subset of rules by adding and deleting rules */ |
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| 364 | /* */ |
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| 365 | /*************************************************************************/ |
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| 366 | |
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| 367 | |
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| 368 | HillClimb(RuleCount) |
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| 369 | /* --------- */ |
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| 370 | RuleNo RuleCount; |
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| 371 | { |
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| 372 | RuleNo r, Bestr; |
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| 373 | short ri, OutCount; |
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| 374 | ItemNo i; |
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| 375 | float Delta, BestDelta; |
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| 376 | |
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| 377 | ForEach(i, 0, MaxItem) |
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| 378 | { |
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| 379 | Covered[i] = 0; |
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| 380 | } |
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| 381 | |
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| 382 | ForEach(ri, 1, RuleCount) |
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| 383 | { |
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| 384 | r = ClassRules[ri]; |
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| 385 | if ( RuleIn[r] ) |
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| 386 | { |
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| 387 | ForEach(i, 0, MaxItem) |
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| 388 | { |
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| 389 | if ( Match[r][i] ) |
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| 390 | { |
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| 391 | Covered[i]++; |
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| 392 | } |
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| 393 | } |
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| 394 | } |
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| 395 | } |
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| 396 | |
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| 397 | /* Add or drop rule with greatest reduction in coding cost */ |
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| 398 | |
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| 399 | while ( true ) |
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| 400 | { |
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| 401 | CalculateValue(); |
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| 402 | |
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| 403 | Verbosity(2) |
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| 404 | { |
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| 405 | OutCount = 0; |
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| 406 | |
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| 407 | ForEach(ri, 1, RuleCount) |
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| 408 | { |
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| 409 | r = ClassRules[ri]; |
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| 410 | |
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| 411 | if ( ! RuleIn[r] ) |
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| 412 | { |
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| 413 | if ( ! (OutCount++ % 3) ) printf("\n\t\t"); |
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| 414 | printf("%d<%d|%d=%.1f> ", r, Right[r], Wrong[r], Value[r]); |
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| 415 | } |
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| 416 | } |
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| 417 | |
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| 418 | printf("\n\n"); |
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| 419 | } |
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| 420 | |
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| 421 | Bestr = BestDelta = 0; |
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| 422 | ForEach(ri, 1, RuleCount) |
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| 423 | { |
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| 424 | r = ClassRules[ri]; |
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| 425 | Delta = ( RuleIn[r] ? -Value[r] : Value[r] ); |
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| 426 | if ( Delta > BestDelta ) |
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| 427 | { |
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| 428 | Bestr = r; |
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| 429 | BestDelta = Delta; |
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| 430 | } |
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| 431 | } |
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| 432 | if ( ! Bestr ) break; |
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| 433 | |
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| 434 | if ( RuleIn[Bestr] ) |
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| 435 | { |
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| 436 | DeleteRule(Bestr); |
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| 437 | } |
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| 438 | else |
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| 439 | { |
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| 440 | AddRule(Bestr); |
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| 441 | } |
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| 442 | } |
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| 443 | } |
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| 444 | |
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| 445 | |
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| 446 | |
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| 447 | /*************************************************************************/ |
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| 448 | /* */ |
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| 449 | /* Find the number of correct and incorrect rule firings for rules */ |
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| 450 | /* for class FocusClass and hence determine the Value of the rules. */ |
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| 451 | /* If best so far, remember. */ |
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| 452 | /* */ |
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| 453 | /*************************************************************************/ |
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| 454 | |
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| 455 | |
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| 456 | CalculateValue() |
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| 457 | /* -------------- */ |
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| 458 | { |
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| 459 | RuleNo r, Selected=0, InCount; |
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| 460 | ItemNo i, Times, FPos=0, FNeg=0, SumCover=0; |
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| 461 | float BaseBits, RuleBits=0, NewBits, ExceptionBits(); |
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| 462 | ClassNo ThisClass; |
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| 463 | Boolean *RuleMatch; |
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| 464 | |
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| 465 | ForEach(i, 0, MaxItem) |
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| 466 | { |
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| 467 | ThisClass = Class(Item[i]); |
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| 468 | |
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| 469 | if ( Covered[i] ) |
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| 470 | { |
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| 471 | SumCover++; |
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| 472 | if( ThisClass != FocusClass ) FPos++; |
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| 473 | } |
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| 474 | else |
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| 475 | if ( ThisClass == FocusClass ) |
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| 476 | { |
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| 477 | FNeg++; |
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| 478 | } |
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| 479 | } |
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| 480 | |
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| 481 | ForEach(r, 1, NRules) |
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| 482 | { |
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| 483 | if ( Rule[r].Rhs == FocusClass ) |
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| 484 | { |
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| 485 | Right[r] = Wrong[r] = 0; |
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| 486 | |
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| 487 | if ( RuleIn[r] ) |
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| 488 | { |
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| 489 | RuleBits += Rule[r].Bits; |
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| 490 | Selected++; |
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| 491 | } |
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| 492 | |
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| 493 | RuleMatch = Match[r]; |
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| 494 | |
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| 495 | ForEach(i, 0, MaxItem) |
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| 496 | { |
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| 497 | if ( RuleMatch[i] && |
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| 498 | ( ! (Times = Covered[i]) || Times == 1 && RuleIn[r] ) ) |
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| 499 | { |
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| 500 | if ( Class(Item[i]) == FocusClass ) |
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| 501 | { |
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| 502 | Right[r]++; |
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| 503 | } |
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| 504 | else |
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| 505 | { |
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| 506 | Wrong[r]++; |
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| 507 | } |
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| 508 | } |
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| 509 | } |
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| 510 | } |
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| 511 | } |
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| 512 | |
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| 513 | RuleBits -= LogFact[Selected]; /* allow for reordering of rules */ |
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| 514 | |
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| 515 | BaseBits = CodeWeight * RuleBits + ExceptionBits(SumCover, FPos, FNeg); |
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| 516 | |
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| 517 | /* From the Right and Wrong of each rule, calculate its value */ |
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| 518 | |
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| 519 | Verbosity(1) |
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| 520 | { |
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| 521 | printf("\t"); |
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| 522 | InCount = -1; |
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| 523 | } |
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| 524 | |
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| 525 | ForEach(r, 1, NRules) |
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| 526 | { |
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| 527 | if ( Rule[r].Rhs == FocusClass ) |
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| 528 | { |
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| 529 | if ( RuleIn[r] ) |
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| 530 | { |
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| 531 | NewBits = ExceptionBits(SumCover-Right[r]-Wrong[r], |
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| 532 | FPos-Wrong[r], FNeg+Right[r]) + |
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| 533 | CodeWeight * |
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| 534 | (RuleBits - Rule[r].Bits + LogItemNo[Selected]); |
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| 535 | Value[r] = NewBits - BaseBits; |
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| 536 | } |
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| 537 | else |
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| 538 | { |
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| 539 | NewBits = ExceptionBits(SumCover+Right[r]+Wrong[r], |
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| 540 | FPos+Wrong[r], FNeg-Right[r]) + |
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| 541 | CodeWeight * |
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| 542 | (RuleBits + Rule[r].Bits - LogItemNo[Selected+1]); |
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| 543 | Value[r] = BaseBits - NewBits; |
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| 544 | } |
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| 545 | |
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| 546 | Verbosity(1) |
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| 547 | { |
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| 548 | if ( RuleIn[r] ) |
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| 549 | { |
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| 550 | if ( ++InCount && ! (InCount % 3) ) printf("\n\t\t"); |
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| 551 | printf("%d[%d|%d=%.1f] ", r, Right[r], Wrong[r], Value[r]); |
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| 552 | } |
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| 553 | } |
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| 554 | } |
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| 555 | } |
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| 556 | |
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| 557 | Verbosity(1) |
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| 558 | { |
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| 559 | printf("\n\t\t%d rules, %d firings: F+=%d, F-=%d, %.1f bits (rules=%.1f)\n", |
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| 560 | Selected, SumCover, FPos, FNeg, BaseBits, RuleBits); |
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| 561 | } |
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| 562 | |
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| 563 | if ( BaseBits < SubsetValue ) |
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| 564 | { |
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| 565 | SubsetValue = BaseBits; |
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| 566 | memcpy(Subset, RuleIn, NRules+1); |
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| 567 | } |
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| 568 | } |
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| 569 | |
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| 570 | |
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| 571 | |
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| 572 | /*************************************************************************/ |
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| 573 | /* */ |
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| 574 | /* Add rule r to the set of included rules and increase the number of */ |
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| 575 | /* rules covering each of the items that fire the rule */ |
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| 576 | /* */ |
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| 577 | /*************************************************************************/ |
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| 578 | |
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| 579 | |
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| 580 | AddRule(r) |
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| 581 | /* ------- */ |
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| 582 | RuleNo r; |
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| 583 | { |
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| 584 | ItemNo i; |
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| 585 | |
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| 586 | RuleIn[r] = true; |
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| 587 | |
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| 588 | ForEach(i, 0, MaxItem) |
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| 589 | { |
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| 590 | if ( Match[r][i] ) |
---|
| 591 | { |
---|
| 592 | Covered[i]++; |
---|
| 593 | } |
---|
| 594 | } |
---|
| 595 | |
---|
| 596 | Verbosity(1) printf("%5d+ %6.1f", r, Value[r]); |
---|
| 597 | } |
---|
| 598 | |
---|
| 599 | |
---|
| 600 | |
---|
| 601 | /*************************************************************************/ |
---|
| 602 | /* */ |
---|
| 603 | /* Delete rule r from the included rules and decrease the number of */ |
---|
| 604 | /* rules covering each of the items covered by the rule */ |
---|
| 605 | /* */ |
---|
| 606 | /*************************************************************************/ |
---|
| 607 | |
---|
| 608 | |
---|
| 609 | DeleteRule(r) |
---|
| 610 | /* ---------- */ |
---|
| 611 | RuleNo r; |
---|
| 612 | { |
---|
| 613 | ItemNo i; |
---|
| 614 | |
---|
| 615 | RuleIn[r] = false; |
---|
| 616 | |
---|
| 617 | ForEach(i, 0, MaxItem) |
---|
| 618 | { |
---|
| 619 | if ( Match[r][i] ) |
---|
| 620 | { |
---|
| 621 | Covered[i]--; |
---|
| 622 | } |
---|
| 623 | } |
---|
| 624 | |
---|
| 625 | Verbosity(1) printf("%5d- %6.1f", r, -Value[r]); |
---|
| 626 | } |
---|
| 627 | |
---|
| 628 | |
---|
| 629 | |
---|
| 630 | /*************************************************************************/ |
---|
| 631 | /* */ |
---|
| 632 | /* Make an index of included rules in RuleIndex. Select first those */ |
---|
| 633 | /* classes whose rules have the fewest false positives. Within a */ |
---|
| 634 | /* class, put rules with higher accuracy ahead. */ |
---|
| 635 | /* */ |
---|
| 636 | /*************************************************************************/ |
---|
| 637 | |
---|
| 638 | |
---|
| 639 | MakeIndex() |
---|
| 640 | /* --------- */ |
---|
| 641 | { |
---|
| 642 | ClassNo c, BestC, Pass; |
---|
| 643 | RuleNo r, BestR, NewNRules = 0; |
---|
| 644 | ItemNo i; |
---|
| 645 | Boolean *Included; |
---|
| 646 | |
---|
| 647 | Included = (Boolean *) calloc(MaxClass+1, sizeof(Boolean)); |
---|
| 648 | RuleIndex = (RuleNo *) calloc(NRules+1, sizeof(RuleNo)); |
---|
| 649 | |
---|
| 650 | Verbosity(1) printf("\nFalsePos Class\n"); |
---|
| 651 | |
---|
| 652 | ForEach(i, 0, MaxItem) |
---|
| 653 | { |
---|
| 654 | Covered[i] = 0; |
---|
| 655 | } |
---|
| 656 | |
---|
| 657 | /* Select the best class to put next */ |
---|
| 658 | |
---|
| 659 | ForEach(Pass, 0, MaxClass) |
---|
| 660 | { |
---|
| 661 | ForEach(c, 0, MaxClass) |
---|
| 662 | { |
---|
| 663 | if ( Included[c] ) continue; |
---|
| 664 | |
---|
| 665 | FalsePos[c] = 0; |
---|
| 666 | |
---|
| 667 | ForEach(i, 0, MaxItem) |
---|
| 668 | { |
---|
| 669 | if ( Covered[i] || Class(Item[i]) == c ) continue; |
---|
| 670 | |
---|
| 671 | ForEach(r, 1, NRules) |
---|
| 672 | { |
---|
| 673 | if ( Rule[r].Rhs == c && RuleIn[r] && Match[r][i] ) |
---|
| 674 | { |
---|
| 675 | FalsePos[c]++; |
---|
| 676 | break; |
---|
| 677 | } |
---|
| 678 | } |
---|
| 679 | } |
---|
| 680 | } |
---|
| 681 | |
---|
| 682 | BestC = -1; |
---|
| 683 | ForEach(c, 0, MaxClass) |
---|
| 684 | { |
---|
| 685 | if ( ! Included[c] && |
---|
| 686 | ( BestC < 0 || FalsePos[c] < FalsePos[BestC] ) ) |
---|
| 687 | { |
---|
| 688 | BestC = c; |
---|
| 689 | } |
---|
| 690 | } |
---|
| 691 | Included[BestC] = true; |
---|
| 692 | |
---|
| 693 | Verbosity(1) |
---|
| 694 | printf("%5d %s\n", FalsePos[BestC], ClassName[BestC]); |
---|
| 695 | |
---|
| 696 | /* Now grab the rules for this class */ |
---|
| 697 | |
---|
| 698 | do |
---|
| 699 | { |
---|
| 700 | BestR = 0; |
---|
| 701 | |
---|
| 702 | /* Find the best rule to put next */ |
---|
| 703 | |
---|
| 704 | ForEach(r, 1, NRules) |
---|
| 705 | { |
---|
| 706 | if ( RuleIn[r] && Rule[r].Rhs == BestC && |
---|
| 707 | ( ! BestR || Rule[r].Error < Rule[BestR].Error ) ) |
---|
| 708 | { |
---|
| 709 | BestR = r; |
---|
| 710 | } |
---|
| 711 | } |
---|
| 712 | |
---|
| 713 | if ( BestR ) |
---|
| 714 | { |
---|
| 715 | RuleIndex[++NewNRules] = BestR; |
---|
| 716 | RuleIn[BestR] = false; |
---|
| 717 | |
---|
| 718 | ForEach(i, 0, MaxItem) |
---|
| 719 | { |
---|
| 720 | Covered[i] |= Match[BestR][i]; |
---|
| 721 | } |
---|
| 722 | } |
---|
| 723 | } while ( BestR ); |
---|
| 724 | } |
---|
| 725 | |
---|
| 726 | NRules = NewNRules; |
---|
| 727 | cfree(Included); |
---|
| 728 | } |
---|
| 729 | |
---|
| 730 | |
---|
| 731 | |
---|
| 732 | /*************************************************************************/ |
---|
| 733 | /* */ |
---|
| 734 | /* Find the default class as the one with most items not covered by */ |
---|
| 735 | /* any rule. Resolve ties in favour of more frequent classes. */ |
---|
| 736 | /* (Note: Covered has been set by MakeIndex.) */ |
---|
| 737 | /* */ |
---|
| 738 | /*************************************************************************/ |
---|
| 739 | |
---|
| 740 | |
---|
| 741 | FindDefault() |
---|
| 742 | /* ----------- */ |
---|
| 743 | { |
---|
| 744 | ClassNo c; |
---|
| 745 | ItemNo i; |
---|
| 746 | |
---|
| 747 | /* Determine uncovered items */ |
---|
| 748 | |
---|
| 749 | ForEach(c, 0, MaxClass) |
---|
| 750 | { |
---|
| 751 | NoRule[c] = 0; |
---|
| 752 | } |
---|
| 753 | |
---|
| 754 | ForEach(i, 0, MaxItem) |
---|
| 755 | { |
---|
| 756 | if ( ! Covered[i] ) |
---|
| 757 | { |
---|
| 758 | NoRule[Class(Item[i])]++; |
---|
| 759 | } |
---|
| 760 | } |
---|
| 761 | |
---|
| 762 | Verbosity(1) |
---|
| 763 | { |
---|
| 764 | printf("\nItems: Uncovered Class\n"); |
---|
| 765 | ForEach(c, 0, MaxClass) |
---|
| 766 | { |
---|
| 767 | printf("%5d %7d %s\n", ClassFreq[c], NoRule[c], ClassName[c]); |
---|
| 768 | } |
---|
| 769 | printf("\n"); |
---|
| 770 | } |
---|
| 771 | |
---|
| 772 | DefaultClass = 0; |
---|
| 773 | ForEach(c, 1, MaxClass) |
---|
| 774 | { |
---|
| 775 | if ( NoRule[c] > NoRule[DefaultClass] || |
---|
| 776 | NoRule[c] == NoRule[DefaultClass] && |
---|
| 777 | ClassFreq[c] > ClassFreq[DefaultClass] ) |
---|
| 778 | { |
---|
| 779 | DefaultClass = c; |
---|
| 780 | } |
---|
| 781 | } |
---|
| 782 | } |
---|
| 783 | |
---|
| 784 | |
---|
| 785 | |
---|
| 786 | /*************************************************************************/ |
---|
| 787 | /* */ |
---|
| 788 | /* Given a rule and a case, determine the strength with which we can */ |
---|
| 789 | /* conclude that the case belongs to the class specified by the rule's */ |
---|
| 790 | /* right-hand side. */ |
---|
| 791 | /* */ |
---|
| 792 | /* If the case doesn't satisfy all the conditions of the rule, */ |
---|
| 793 | /* then this is 0. */ |
---|
| 794 | /* */ |
---|
| 795 | /*************************************************************************/ |
---|
| 796 | |
---|
| 797 | |
---|
| 798 | float Strength(ThisRule, Case) |
---|
| 799 | /* -------- */ |
---|
| 800 | PR ThisRule; |
---|
| 801 | Description Case; |
---|
| 802 | { |
---|
| 803 | short d; |
---|
| 804 | Boolean Satisfies(); |
---|
| 805 | |
---|
| 806 | if ( ThisRule.Error > 0.7 ) return 0.0; |
---|
| 807 | |
---|
| 808 | ForEach(d, 1, ThisRule.Size) |
---|
| 809 | { |
---|
| 810 | if ( ! Satisfies(Case, ThisRule.Lhs[d]) ) |
---|
| 811 | { |
---|
| 812 | return 0.0; |
---|
| 813 | } |
---|
| 814 | } |
---|
| 815 | |
---|
| 816 | return ( 1 - ThisRule.Error ); |
---|
| 817 | } |
---|
| 818 | |
---|
| 819 | |
---|
| 820 | |
---|
| 821 | /*************************************************************************/ |
---|
| 822 | /* */ |
---|
| 823 | /* Determine the number of bits to encode exceptions. Unlike the */ |
---|
| 824 | /* version in the book, this uses an approximate encoding that */ |
---|
| 825 | /* penalizes unbalanced numbers of false positives and false negatives */ |
---|
| 826 | /* as described in my paper at 1995 International Machine Learning */ |
---|
| 827 | /* Conference (published by Morgan Kaufmann). */ |
---|
| 828 | /* */ |
---|
| 829 | /*************************************************************************/ |
---|
| 830 | |
---|
| 831 | |
---|
| 832 | float Biased(N, E, ExpE) |
---|
| 833 | /* ------ */ |
---|
| 834 | int N, E; |
---|
| 835 | float ExpE; |
---|
| 836 | { |
---|
| 837 | float Rate; |
---|
| 838 | |
---|
| 839 | if ( ExpE <= 1E-6 ) |
---|
| 840 | { |
---|
| 841 | return ( E == 0 ? 0.0 : 1E6 ); |
---|
| 842 | } |
---|
| 843 | else |
---|
| 844 | if ( ExpE >= N-1E-6 ) |
---|
| 845 | { |
---|
| 846 | return ( E == N ? 0.0 : 1E6 ); |
---|
| 847 | } |
---|
| 848 | |
---|
| 849 | Rate = ExpE / N; |
---|
| 850 | return -E * Log(Rate) - (N-E) * Log(1-Rate); |
---|
| 851 | } |
---|
| 852 | |
---|
| 853 | |
---|
| 854 | |
---|
| 855 | float ExceptionBits(Fires, FP, FN) |
---|
| 856 | /* ------------- */ |
---|
| 857 | int Fires, FP, FN; |
---|
| 858 | { |
---|
| 859 | if ( Fires > 0.5 * (MaxItem+1) ) |
---|
| 860 | { |
---|
| 861 | return Log(MaxItem+1) |
---|
| 862 | + Biased(Fires, FP, 0.5 * (FP+FN)) |
---|
| 863 | + Biased(MaxItem+1-Fires, FN, (float) FN); |
---|
| 864 | } |
---|
| 865 | else |
---|
| 866 | { |
---|
| 867 | return Log(MaxItem+1) |
---|
| 868 | + Biased(Fires, FP, (float) FP) |
---|
| 869 | + Biased(MaxItem+1-Fires, FN, 0.5 * (FP+FN)); |
---|
| 870 | } |
---|
| 871 | } |
---|
| 872 | |
---|
| 873 | |
---|
| 874 | |
---|
| 875 | /*************************************************************************/ |
---|
| 876 | /* */ |
---|
| 877 | /* Find encoding lengths for all rules */ |
---|
| 878 | /* */ |
---|
| 879 | /*************************************************************************/ |
---|
| 880 | |
---|
| 881 | |
---|
| 882 | FindRuleCodes() |
---|
| 883 | /* ------------- */ |
---|
| 884 | { |
---|
| 885 | RuleNo r; |
---|
| 886 | short d, NCond; |
---|
| 887 | float Bits, CondBits(); |
---|
| 888 | |
---|
| 889 | ForEach(r, 1, NRules) |
---|
| 890 | { |
---|
| 891 | NCond = Rule[r].Size; |
---|
| 892 | Bits = 0; |
---|
| 893 | |
---|
| 894 | ForEach(d, 1, NCond) |
---|
| 895 | { |
---|
| 896 | Bits += CondBits(Rule[r].Lhs[d]); |
---|
| 897 | } |
---|
| 898 | |
---|
| 899 | /* Must encode the number of conditions, but credit the total |
---|
| 900 | encoding by the ways conditions can be reordered */ |
---|
| 901 | |
---|
| 902 | Rule[r].Bits = Bits + LogItemNo[NCond] - LogFact[NCond]; |
---|
| 903 | } |
---|
| 904 | } |
---|
| 905 | |
---|
| 906 | |
---|
| 907 | |
---|
| 908 | /*************************************************************************/ |
---|
| 909 | /* */ |
---|
| 910 | /* Determine the number of bits required to encode a condition */ |
---|
| 911 | /* */ |
---|
| 912 | /*************************************************************************/ |
---|
| 913 | |
---|
| 914 | |
---|
| 915 | float CondBits(C) |
---|
| 916 | /* -------- */ |
---|
| 917 | Condition C; |
---|
| 918 | { |
---|
| 919 | Test t; |
---|
| 920 | Attribute a; |
---|
| 921 | |
---|
| 922 | t = C->CondTest; |
---|
| 923 | a = t->Tested; |
---|
| 924 | |
---|
| 925 | switch ( t->NodeType ) |
---|
| 926 | { |
---|
| 927 | case BrDiscr: /* test of discrete attribute */ |
---|
| 928 | case ThreshContin: /* test of continuous attribute */ |
---|
| 929 | |
---|
| 930 | return AttTestBits/REDUNDANCY + BranchBits[a]; |
---|
| 931 | |
---|
| 932 | case BrSubset: /* subset test on discrete attribute */ |
---|
| 933 | |
---|
| 934 | return AttTestBits/REDUNDANCY + MaxAttVal[a]; |
---|
| 935 | } |
---|
| 936 | } |
---|