Changes between Version 38 and Version 39 of Parallel-DT
- Timestamp:
- Jan 18, 2010, 9:33:28 PM (14 years ago)
Legend:
- Unmodified
- Added
- Removed
- Modified
-
Parallel-DT
v38 v39 12 12 * Project Implementation Details: '''[wiki:Details]''' 13 13 14 ''' Serial DT process ''' 14 == Serial DT process == 15 15 Most of the existing induction-based algorithms, also C4.5 that is analysed on this topic, use Hunt's method as the basic algorithm. Here is a recursive description of Hunt's method for constructing a decision tree from a set T of trainning cases with classes denoted {C1, C2, C3, ..., Ck} : 16 16 * ''' Case 1 ''' T contains cases all belonging to a single class Cj. The decision tree for T is a leaf identifying class Cj. … … 24 24 [[Image(Outlook&Humidity.jpg)]] 25 25 26 ''' Parallel approaches ''' 26 == Parallel approaches == 27 27 * '''Syncronous Tree Construction - Depth First Expansion Strategy''' - the one that we implemented 28 28 29 29 In this approach, all processors construct a decision tree syncronously by sending and receiving class distribution information of local data. Major steps for the approach: 30 *30 { 31 31 * select a node to expand according to a decision tree expansion strategy (eg Depth-First or Breadth-First), and call that node as the current node. At the beginning, root node is selected as the current node 32 32 * for each data attribute, collect class distribution information of the local data at the current node … … 34 34 * simultaneously compute the entropy gains of each attribute at each processor and select the best attribute for child node expansion 35 35 * depending on the branching factor of the tree desired, create child nodes for the same number of partitions of attributes values, and split training cases accordingly 36 36 } 37 37 [[Image(SyncronusTreeConstruction-DepthFirstExpansionStrategy.jpg)]] 38 38