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1 % Here the training data is adapted from Russell95 book. See restaurant.names for description.
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2 % (1) Use infomation-gain as the split testing score, we get the the same decision tree as the book Russell 95 (page 537),
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3 % and the Gain(Patrons) is 0.5409, equal to the result in Page 541 of Russell 95. (see below output trace)
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4 % (Note: the dtree in that book has small compilation error, the Type node is from YES of Hungry node, not NO.)
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5 % (2) Use gain-ratio (Quilan 93), the splitting defavorite attribute with more values. (e.g. the Type attribute here)
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6
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7 dtreeCPD=tree_CPD;
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8
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9 % load data
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10 fname = fullfile(BNT_HOME, 'examples', 'static', 'uci_data', 'restaurant', 'restaurant.data');
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11 data=load(fname);
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12 data=data';
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13
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14 %make the data be BNT compliant (values for discrete nodes are from 1-n, here n is the node size)
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15 % e.g. if the values are [0 1 6], they must be mapping to [1 2 3]
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16 %data=transform_data(data,'tmp.dat',[]); %here no cts nodes
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17
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18 % learn decision tree from data
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19 ns=2*ones(1,11);
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20 ns(5:6)=3;
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21 ns(9:10)=4;
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22 dtreeCPD1=learn_params(dtreeCPD,1:11,data,ns,[]);
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23
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24 % evaluate on data
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25 [score,outputs]=evaluate_tree_performance(dtreeCPD1,1:11,data,ns,[]);
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26 fprintf('Accuracy in training data %6.3f\n',score);
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27
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28 % show decision tree using graphpad
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29
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30
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31
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32 % --------------------------Output trace: using Information-Gain------------------------------
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33 % The splits are Patron, Hungry, Type, Fri/Sat
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34 % *********************************
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35 % Create node 1 split at 5 gain 0.5409 Th 0. Class 1 Cases 12 Error 6
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36 % Create leaf node(onecla) 2. Class 1 Cases 2 Error 0
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37 % Add subtree node 2 to 1. #nodes 2
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38 % Create leaf node(onecla) 3. Class 2 Cases 4 Error 0
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39 % Add subtree node 3 to 1. #nodes 3
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40 % Create node 4 split at 4 gain 0.2516 Th 0. Class 1 Cases 6 Error 2
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41 % Create leaf node(onecla) 5. Class 1 Cases 2 Error 0
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42 % Add subtree node 5 to 4. #nodes 5
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43 % Create node 6 split at 9 gain 0.5000 Th 0. Class 1 Cases 4 Error 2
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44 % Create leaf node(nullset) 7. Father 6 Class 1
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45 % Create node 8 split at 3 gain 1.0000 Th 0. Class 1 Cases 2 Error 1
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46 % Create leaf node(onecla) 9. Class 1 Cases 1 Error 0
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47 % Add subtree node 9 to 8. #nodes 9
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48 % Create leaf node(onecla) 10. Class 2 Cases 1 Error 0
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49 % Add subtree node 10 to 8. #nodes 10
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50 % Add subtree node 8 to 6. #nodes 10
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51 % Create leaf node(onecla) 11. Class 2 Cases 1 Error 0
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52 % Add subtree node 11 to 6. #nodes 11
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53 % Create leaf node(onecla) 12. Class 1 Cases 1 Error 0
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54 % Add subtree node 12 to 6. #nodes 12
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55 % Add subtree node 6 to 4. #nodes 12
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56 % Add subtree node 4 to 1. #nodes 12
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57 % ********************************
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58 %
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59 % Note:
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60 % ***Create node 4 split at 4 gain 0.2516 Th 0. Class 1 Cases 6 Error 2
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61 % This mean we create a new node number 4, it is splitting at the attribute 4, and info-gain is 0.2516,
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62 % "Th 0" means threshhold for splitting continous attribute, "Class 1" means the majority class at node 4 is 1,
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63 % and "Cases 6" means it has 6 cases attached to it, "Error 2" means it has two errors if changing the class lable of
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64 % all the cases in it to the majority class.
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65 % *** Add subtree node 12 to 6. #nodes 12
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66 % It means we add the child node 12 to node 6.
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67 % *** Create leaf node(onecla) 10. Class 2 Cases 1 Error 0
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68 % here 'onecla' means all cases in this node belong to one class, so no need to split further.
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69 % 'nullset' means no training cases belong to this node, we use its parent node majority class as its class
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70 %
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71 %
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72 %
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73 % ---------------Output trace: using GainRatio-----------------------
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74 % The splits are Patron, Hungry, Fri/Sat, Price
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75 %
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76 %
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77 % Create node 1 split at 5 gain 0.3707 Th 0. Class 1 Cases 12 Error 6
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78 % Create leaf node(onecla) 2. Class 1 Cases 2 Error 0
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79 % Add subtree node 2 to 1. #nodes 2
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80 % Create leaf node(onecla) 3. Class 2 Cases 4 Error 0
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81 % Add subtree node 3 to 1. #nodes 3
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82 % Create node 4 split at 4 gain 0.2740 Th 0. Class 1 Cases 6 Error 2
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83 % Create leaf node(onecla) 5. Class 1 Cases 2 Error 0
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84 % Add subtree node 5 to 4. #nodes 5
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85 % Create node 6 split at 3 gain 0.3837 Th 0. Class 1 Cases 4 Error 2
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86 % Create leaf node(onecla) 7. Class 1 Cases 1 Error 0
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87 % Add subtree node 7 to 6. #nodes 7
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88 % Create node 8 split at 6 gain 1.0000 Th 0. Class 2 Cases 3 Error 1
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89 % Create leaf node(onecla) 9. Class 2 Cases 2 Error 0
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90 % Add subtree node 9 to 8. #nodes 9
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91 % Create leaf node(nullset) 10. Father 8 Class 2
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92 % Create leaf node(onecla) 11. Class 1 Cases 1 Error 0
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93 % Add subtree node 11 to 8. #nodes 11
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94 % Add subtree node 8 to 6. #nodes 11
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95 % Add subtree node 6 to 4. #nodes 11
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96 % Add subtree node 4 to 1. #nodes 11
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97 %
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98 %
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