ML.DecTree.DecTree

Package ML :: Package DecTree :: Module DecTree |
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# Source Code for Module ML.DecTree.DecTree

      1  #
      2  #  Copyright (C) 2000-2004  greg Landrum and Rational Discovery LLC
      3  #  All Rights Reserved
      4  #
      5  """ Defines the class _DecTreeNode_, used to represent decision trees
      6
      7    _DecTreeNode_ is derived from _Tree.TreeNode_
      8
      9  """
     10  from ML.DecTree import Tree
     11
     12 -class DecTreeNode(Tree.TreeNode):
     13    """ This is used to represent decision trees
     14
     15     _DecTreeNode_s are simultaneously the roots and branches of decision trees.
     16     Everything is nice and recursive.
     17
     18     _DecTreeNode_s can save the following pieces of internal state, accessible via
     19       standard setter/getter functions:
     20
     21       1) _Examples_: a list of examples which have been classified
     22
     23       2) _BadExamples_: a list of examples which have been misclassified
     24
     25       3) _TrainingExamples_: the list of examples used to train the tree
     26
     27       4) _TestExamples_: the list of examples used to test the tree
     28
     29    """
     30 -  def __init__(self,*args,**kwargs):
     31      apply(Tree.TreeNode.__init__,(self,)+args,kwargs)
     32      self.examples = []
     33      self.badExamples = []
     34      self.trainingExamples = []
     35      self.testExamples = []
     36 -  def ClassifyExample(self,example,appendExamples=0):
     37      """ Recursively classify an example by running it through the tree
     38
     39        **Arguments**
     40
     41          - example: the example to be classified
     42
     43          - appendExamples: if this is nonzero then this node (and all children)
     44            will store the example
     45
     46        **Returns**
     47
     48          the classification of _example_
     49
     50        **NOTE:**
     51          In the interest of speed, I don't use accessor functions
     52          here.  So if you subclass DecTreeNode for your own trees, you'll
     53          have to either include ClassifyExample or avoid changing the names
     54          of the instance variables this needs.
     55
     56      """
     57      if appendExamples:
     58        self.examples.append(example)
     59      if self.terminalNode:
     60        return self.label
     61      else:
     62        val = example[self.label]
     63        return self.children[val].ClassifyExample(example,appendExamples)
     64
     65 -  def AddChild(self,name,label=None,data=None,isTerminal=0):
     66      """ Constructs and adds a child with the specified data to our list
     67
     68        **Arguments**
     69
     70         - name: the name of the new node
     71
     72         - label: the label of the new node (should be an integer)
     73
     74         - data: the data to be stored in the new node
     75
     76         - isTerminal: a toggle to indicate whether or not the new node is
     77           a terminal (leaf) node.
     78
     79        **Returns*
     80
     81          the _DecTreeNode_ which is constructed
     82
     83      """
     84      child = DecTreeNode(self,name,label,data,level=self.level+1,isTerminal=isTerminal)
     85      self.children.append(child)
     86      return child
     87
     88 -  def GetExamples(self):
     89      return self.examples
     90 -  def SetExamples(self,examples):
     91      self.examples = examples
     92
     93 -  def GetBadExamples(self):
     94      return self.badExamples
     95 -  def SetBadExamples(self,examples):
     96      self.badExamples = examples
     97
     98 -  def GetTrainingExamples(self):
     99      return self.trainingExamples
    100 -  def SetTrainingExamples(self,examples):
    101      self.trainingExamples = examples
    102
    103 -  def GetTestExamples(self):
    104      return self.testExamples
    105 -  def SetTestExamples(self,examples):
    106      self.testExamples = examples
    107
    108 -  def ClearExamples(self):
    109      self.examples = []
    110      self.badExamples = []
    111      self.trainingExamples = []
    112      self.testExamples = []
    113      for child in self.GetChildren():
    114        child.ClearExamples()
    115