1 | /*************************************************************************/ |
---|
2 | /* */ |
---|
3 | /* Form a set of rules from a decision tree */ |
---|
4 | /* ---------------------------------------- */ |
---|
5 | /* */ |
---|
6 | /*************************************************************************/ |
---|
7 | |
---|
8 | |
---|
9 | #include "defns.i" |
---|
10 | #include "types.i" |
---|
11 | #include "extern.i" |
---|
12 | #include "rulex.i" |
---|
13 | |
---|
14 | |
---|
15 | ItemNo *TargetClassFreq, /* [Boolean] */ |
---|
16 | *Errors, /* [Condition] */ |
---|
17 | *Total; /* [Condition] */ |
---|
18 | |
---|
19 | float *Pessimistic, /* [Condition] */ |
---|
20 | *Actual, /* [Condition] */ |
---|
21 | *CondSigLevel; /* [Condition] */ |
---|
22 | |
---|
23 | Boolean **CondSatisfiedBy, /* [Condition][ItemNo] */ |
---|
24 | *Deleted; /* [Condition] */ |
---|
25 | |
---|
26 | DiscrValue *SingleValue; /* [Attribute] */ |
---|
27 | |
---|
28 | Condition *Stack; |
---|
29 | |
---|
30 | short MaxDisjuncts, |
---|
31 | MaxDepth; |
---|
32 | |
---|
33 | |
---|
34 | |
---|
35 | /*************************************************************************/ |
---|
36 | /* */ |
---|
37 | /* Form a ruleset from decision tree t */ |
---|
38 | /* */ |
---|
39 | /*************************************************************************/ |
---|
40 | |
---|
41 | |
---|
42 | FormRules(t) |
---|
43 | /* ---------- */ |
---|
44 | Tree t; |
---|
45 | { |
---|
46 | short i; |
---|
47 | |
---|
48 | /* Find essential parameters and allocate storage */ |
---|
49 | |
---|
50 | MaxDepth = 0; |
---|
51 | MaxDisjuncts = 0; |
---|
52 | |
---|
53 | TreeParameters(t, 0); |
---|
54 | |
---|
55 | Actual = (float *) calloc(MaxDepth+2, sizeof(float)); |
---|
56 | Total = (ItemNo *) calloc(MaxDepth+2, sizeof(ItemNo)); |
---|
57 | Errors = (ItemNo *) calloc(MaxDepth+2, sizeof(ItemNo)); |
---|
58 | Pessimistic = (float *) calloc(MaxDepth+2, sizeof(float)); |
---|
59 | |
---|
60 | CondSigLevel = (float *) calloc(MaxDepth+2, sizeof(float)); |
---|
61 | |
---|
62 | TargetClassFreq = (ItemNo *) calloc(2, sizeof(ItemNo)); |
---|
63 | |
---|
64 | Deleted = (Boolean *) calloc(MaxDepth+2, sizeof(Boolean)); |
---|
65 | CondSatisfiedBy = (char **) calloc(MaxDepth+2, sizeof(char *)); |
---|
66 | Stack = (Condition *) calloc(MaxDepth+2, sizeof(Condition)); |
---|
67 | |
---|
68 | ForEach(i, 0, MaxDepth+1) |
---|
69 | { |
---|
70 | CondSatisfiedBy[i] = (char *) calloc(MaxItem+1, sizeof(char)); |
---|
71 | Stack[i] = (Condition) malloc(sizeof(struct CondRec)); |
---|
72 | } |
---|
73 | |
---|
74 | SingleValue = (DiscrValue *) calloc(MaxAtt+1, sizeof(DiscrValue)); |
---|
75 | |
---|
76 | InitialiseRules(); |
---|
77 | |
---|
78 | /* Extract and prune disjuncts */ |
---|
79 | |
---|
80 | Scan(t, 0); |
---|
81 | |
---|
82 | /* Deallocate storage */ |
---|
83 | |
---|
84 | ForEach(i, 0, MaxDepth+1) |
---|
85 | { |
---|
86 | cfree(CondSatisfiedBy[i]); |
---|
87 | cfree(Stack[i]); |
---|
88 | } |
---|
89 | cfree(Deleted); |
---|
90 | cfree(CondSatisfiedBy); |
---|
91 | cfree(Stack); |
---|
92 | |
---|
93 | cfree(Actual); |
---|
94 | cfree(Total); |
---|
95 | cfree(Errors); |
---|
96 | cfree(Pessimistic); |
---|
97 | |
---|
98 | cfree(CondSigLevel); |
---|
99 | |
---|
100 | cfree(TargetClassFreq); |
---|
101 | } |
---|
102 | |
---|
103 | |
---|
104 | |
---|
105 | /*************************************************************************/ |
---|
106 | /* */ |
---|
107 | /* Find the maximum depth and the number of leaves in tree t */ |
---|
108 | /* with initial depth d */ |
---|
109 | /* */ |
---|
110 | /*************************************************************************/ |
---|
111 | |
---|
112 | |
---|
113 | TreeParameters(t, d) |
---|
114 | /* --------------- */ |
---|
115 | Tree t; |
---|
116 | short d; |
---|
117 | { |
---|
118 | DiscrValue v; |
---|
119 | |
---|
120 | if ( t->NodeType ) |
---|
121 | { |
---|
122 | ForEach(v, 1, t->Forks) |
---|
123 | { |
---|
124 | TreeParameters(t->Branch[v], d+1); |
---|
125 | } |
---|
126 | } |
---|
127 | else |
---|
128 | { |
---|
129 | /* This is a leaf */ |
---|
130 | |
---|
131 | if ( d > MaxDepth ) MaxDepth = d; |
---|
132 | MaxDisjuncts++; |
---|
133 | } |
---|
134 | } |
---|
135 | |
---|
136 | |
---|
137 | |
---|
138 | /*************************************************************************/ |
---|
139 | /* */ |
---|
140 | /* Extract disjuncts from tree t at depth d, and process them */ |
---|
141 | /* */ |
---|
142 | /*************************************************************************/ |
---|
143 | |
---|
144 | |
---|
145 | Scan(t, d) |
---|
146 | /* ---- */ |
---|
147 | Tree t; |
---|
148 | short d; |
---|
149 | { |
---|
150 | DiscrValue v; |
---|
151 | short i; |
---|
152 | Condition *Term; |
---|
153 | Test x, FindTest(); |
---|
154 | |
---|
155 | if ( t->NodeType ) |
---|
156 | { |
---|
157 | d++; |
---|
158 | |
---|
159 | x = (Test) malloc(sizeof(struct TestRec)); |
---|
160 | x->NodeType = t->NodeType; |
---|
161 | x->Tested = t->Tested; |
---|
162 | x->Forks = t->Forks; |
---|
163 | x->Cut = ( t->NodeType == ThreshContin ? t->Cut : 0 ); |
---|
164 | if ( t->NodeType == BrSubset ) |
---|
165 | { |
---|
166 | x->Subset = (Set *) calloc(t->Forks + 1, sizeof(Set)); |
---|
167 | ForEach(v, 1, t->Forks) |
---|
168 | { |
---|
169 | x->Subset[v] = t->Subset[v]; |
---|
170 | } |
---|
171 | } |
---|
172 | |
---|
173 | Stack[d]->CondTest = FindTest(x); |
---|
174 | |
---|
175 | ForEach(v, 1, t->Forks) |
---|
176 | { |
---|
177 | Stack[d]->TestValue = v; |
---|
178 | Scan(t->Branch[v], d); |
---|
179 | } |
---|
180 | } |
---|
181 | else |
---|
182 | if ( t->Items >= 1 ) |
---|
183 | { |
---|
184 | /* Leaf of decision tree - construct the set of |
---|
185 | conditions associated with this leaf and prune */ |
---|
186 | |
---|
187 | Term = (Condition *) calloc(d+1, sizeof(Condition)); |
---|
188 | ForEach(i, 1, d) |
---|
189 | { |
---|
190 | Term[i] = (Condition) malloc(sizeof(struct CondRec)); |
---|
191 | Term[i]->CondTest = Stack[i]->CondTest; |
---|
192 | Term[i]->TestValue = Stack[i]->TestValue; |
---|
193 | } |
---|
194 | |
---|
195 | PruneRule(Term, d, t->Leaf); |
---|
196 | |
---|
197 | cfree(Term); |
---|
198 | } |
---|
199 | } |
---|