[26] | 1 | /*************************************************************************/ |
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| 2 | /* */ |
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| 3 | /* Generate all rulesets from the decision trees */ |
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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 | /*************************************************************************/ |
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| 16 | /* */ |
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| 17 | /* For each tree, form a set of rules and process them, then form a */ |
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| 18 | /* composite set of rules from all of these sets. */ |
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| 19 | /* If there is only one tree, then no composite set is formed. */ |
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| 20 | /* */ |
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| 21 | /* Rulesets are stored in PRSet[0] to PRSet[TRIALS], where */ |
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| 22 | /* PRSet[TRIALS] contains the composite ruleset. */ |
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| 23 | /* */ |
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| 24 | /* On completion, the current ruleset is the composite ruleset (if one */ |
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| 25 | /* has been made), otherwise the ruleset from the single tree. */ |
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| 26 | /* */ |
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| 27 | /*************************************************************************/ |
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| 28 | |
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| 29 | |
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| 30 | GenerateRules() |
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| 31 | /* ------------- */ |
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| 32 | { |
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| 33 | Tree DecisionTree, GetTree(); |
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| 34 | short t=0, RuleSetSpace=0, r; |
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| 35 | |
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| 36 | /* Find bits to encode attributes and branches */ |
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| 37 | |
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| 38 | FindTestCodes(); |
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| 39 | |
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| 40 | /* Now process each decision tree */ |
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| 41 | |
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| 42 | while ( DecisionTree = GetTree(".unpruned") ) |
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| 43 | { |
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| 44 | printf("\n------------------\n"); |
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| 45 | printf("Processing tree %d\n", t); |
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| 46 | |
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| 47 | /* Form a set of rules from the next tree */ |
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| 48 | |
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| 49 | FormRules(DecisionTree); |
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| 50 | |
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| 51 | /* Process the set of rules for this trial */ |
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| 52 | |
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| 53 | ConstructRuleset(); |
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| 54 | |
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| 55 | printf("\nFinal rules from tree %d:\n", t); |
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| 56 | PrintIndexedRules(); |
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| 57 | |
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| 58 | /* Make sure there is enough room for the new ruleset */ |
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| 59 | |
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| 60 | if ( t + 1 >= RuleSetSpace ) |
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| 61 | { |
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| 62 | RuleSetSpace += 10; |
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| 63 | |
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| 64 | if ( RuleSetSpace > 10 ) |
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| 65 | { |
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| 66 | PRSet = (RuleSet *) realloc(PRSet, RuleSetSpace * sizeof(RuleSet)); |
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| 67 | } |
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| 68 | else |
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| 69 | { |
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| 70 | PRSet = (RuleSet *) malloc(RuleSetSpace * sizeof(RuleSet)); |
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| 71 | } |
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| 72 | |
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| 73 | } |
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| 74 | |
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| 75 | PRSet[t].SNRules = NRules; |
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| 76 | PRSet[t].SRule = Rule; |
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| 77 | PRSet[t].SRuleIndex = RuleIndex; |
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| 78 | PRSet[t].SDefaultClass = DefaultClass; |
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| 79 | |
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| 80 | ++t; |
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| 81 | } |
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| 82 | |
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| 83 | if ( ! t ) |
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| 84 | { |
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| 85 | printf("\nERROR: can't find any decision trees\n"); |
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| 86 | exit(1); |
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| 87 | } |
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| 88 | |
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| 89 | TRIALS = t; |
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| 90 | |
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| 91 | /* If there is more than one tree in the trees file, |
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| 92 | make a composite ruleset of the rules from all trees */ |
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| 93 | |
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| 94 | if ( TRIALS > 1 ) |
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| 95 | { |
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| 96 | CompositeRuleset(); |
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| 97 | } |
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| 98 | } |
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| 99 | |
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| 100 | |
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| 101 | |
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| 102 | /*************************************************************************/ |
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| 103 | /* */ |
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| 104 | /* Determine code lengths for attributes and branches */ |
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| 105 | /* */ |
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| 106 | /*************************************************************************/ |
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| 107 | |
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| 108 | |
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| 109 | FindTestCodes() |
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| 110 | /* ------------- */ |
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| 111 | { |
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| 112 | Attribute Att; |
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| 113 | DiscrValue v, V; |
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| 114 | ItemNo i, *ValFreq; |
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| 115 | int PossibleCuts; |
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| 116 | float Sum, SumBranches=0, p; |
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| 117 | void SwapUnweighted(); |
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| 118 | |
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| 119 | BranchBits = (float *) malloc((MaxAtt+1) * sizeof(float)); |
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| 120 | |
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| 121 | ForEach(Att, 0, MaxAtt) |
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| 122 | { |
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| 123 | if ( (V = MaxAttVal[Att]) ) |
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| 124 | { |
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| 125 | ValFreq = (ItemNo *) calloc(V+1, sizeof(ItemNo)); |
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| 126 | |
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| 127 | ForEach(i, 0, MaxItem) |
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| 128 | { |
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| 129 | ValFreq[DVal(Item[i],Att)]++; |
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| 130 | } |
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| 131 | |
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| 132 | Sum = 0; |
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| 133 | ForEach(v, 1, V) |
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| 134 | { |
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| 135 | if ( ValFreq[v] ) |
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| 136 | { |
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| 137 | Sum += (ValFreq[v] / (MaxItem+1.0)) * |
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| 138 | (LogItemNo[MaxItem+1] - LogItemNo[ValFreq[v]]); |
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| 139 | } |
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| 140 | } |
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| 141 | free(ValFreq); |
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| 142 | |
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| 143 | BranchBits[Att] = Sum; |
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| 144 | } |
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| 145 | else |
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| 146 | { |
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| 147 | Quicksort(0, MaxItem, Att, SwapUnweighted); |
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| 148 | |
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| 149 | PossibleCuts = 1; |
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| 150 | ForEach(i, 1, MaxItem) |
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| 151 | { |
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| 152 | if ( CVal(Item[i],Att) > CVal(Item[i-1],Att) ) |
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| 153 | { |
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| 154 | PossibleCuts++; |
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| 155 | } |
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| 156 | } |
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| 157 | |
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| 158 | BranchBits[Att] = PossibleCuts > 1 ? |
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| 159 | 1 + LogItemNo[PossibleCuts] / 2 : 0 ; |
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| 160 | } |
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| 161 | |
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| 162 | SumBranches += BranchBits[Att]; |
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| 163 | } |
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| 164 | |
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| 165 | AttTestBits = 0; |
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| 166 | ForEach(Att, 0, MaxAtt) |
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| 167 | { |
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| 168 | if ( (p = BranchBits[Att] / SumBranches) > 0 ) |
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| 169 | { |
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| 170 | AttTestBits -= p * log(p) / log(2.0); |
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| 171 | } |
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| 172 | } |
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| 173 | } |
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| 174 | |
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| 175 | |
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| 176 | |
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| 177 | /*************************************************************************/ |
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| 178 | /* */ |
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| 179 | /* Exchange items at a and b. Note: unlike the similar routine in */ |
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| 180 | /* buildtree, this does not assume that items have a Weight to be */ |
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| 181 | /* swapped as well! */ |
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| 182 | /* */ |
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| 183 | /*************************************************************************/ |
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| 184 | |
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| 185 | |
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| 186 | void SwapUnweighted(a, b) |
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| 187 | /* -------------- */ |
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| 188 | ItemNo a, b; |
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| 189 | { |
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| 190 | Description Hold; |
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| 191 | |
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| 192 | Hold = Item[a]; |
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| 193 | Item[a] = Item[b]; |
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| 194 | Item[b] = Hold; |
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| 195 | } |
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| 196 | |
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| 197 | |
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| 198 | |
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| 199 | /*************************************************************************/ |
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| 200 | /* */ |
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| 201 | /* Form composite ruleset for all trials */ |
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| 202 | /* */ |
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| 203 | /*************************************************************************/ |
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| 204 | |
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| 205 | |
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| 206 | CompositeRuleset() |
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| 207 | /* ---------------- */ |
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| 208 | { |
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| 209 | RuleNo r; |
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| 210 | short t, ri; |
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| 211 | Boolean NewRule(); |
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| 212 | |
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| 213 | InitialiseRules(); |
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| 214 | |
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| 215 | /* Lump together all the rules from each ruleset */ |
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| 216 | |
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| 217 | ForEach(t, 0, TRIALS-1) |
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| 218 | { |
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| 219 | ForEach(ri, 1, PRSet[t].SNRules) |
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| 220 | { |
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| 221 | r = PRSet[t].SRuleIndex[ri]; |
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| 222 | NewRule(PRSet[t].SRule[r].Lhs, PRSet[t].SRule[r].Size, |
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| 223 | PRSet[t].SRule[r].Rhs, PRSet[t].SRule[r].Error); |
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| 224 | } |
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| 225 | } |
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| 226 | |
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| 227 | /* ... and select a subset in the usual way */ |
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| 228 | |
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| 229 | ConstructRuleset(); |
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| 230 | |
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| 231 | printf("\nComposite ruleset:\n"); |
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| 232 | PrintIndexedRules(); |
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| 233 | |
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| 234 | PRSet[TRIALS].SNRules = NRules; |
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| 235 | PRSet[TRIALS].SRule = Rule; |
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| 236 | PRSet[TRIALS].SRuleIndex = RuleIndex; |
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| 237 | PRSet[TRIALS].SDefaultClass = DefaultClass; |
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| 238 | } |
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