Towards the end, pruning becomes slower.

Alpha-Beta Pruning Problem #7 A partial search tree for a two player game is given below. a)Find the best move for the MAX player using the minimax procedure.

b)Using alpha-beta pruning show which parts of the tree do not need to be searched. Indicate where the cuto s occur. MAX MIN. It has 71 leaf nodes. Next, by finding the weakest link, after one step of pruning, the tree is reduced to size 63 (8 leaf nodes are pruned off in one step). Next, five leaf nodes pruned off. From \(T_3\) to \(T_4\), the pruning is significant, 18 leave nodes removed. Towards the end, pruning becomes slower.

Apr 30, 1. Holdout some instances from training data. 2. Calculate misclassification for each of holdout set using the decision tree created. 3. Pruning is done if parent node has errors lesser than child node. After the full grown tree, we make trees out of it by pruning at different levels such that we have tree rolled up to the level of root node stumphaul.bar: Shaily Jain.

stumphaul.bar = which(stumphaul.bardev == min(stumphaul.bardev)) # Size of smallest optimal tree (stumphaul.bar = min(stumphaul.barsize[stumphaul.bar])) ## [1] 27 stumphaul.bar = stumphaul.bar(stumphaul.bar,best=stumphaul.bar) 43/49File Size: KB. Classification/Decision Trees (II) Preliminaries for Pruning I Grow a very large tree T max. 1. Until all terminal nodes are pure (contain only one class) or contain only identical measurement vectors. 2. When the number of data in each terminal node is no greater than a certain threshold, say 5, or even 1.

3. Nov 19, A tree trained on the Titanic data with a min_impurity_decrease parameter of results in this little depth 3 tree with 4 leaf nodes: Even halving the parameter to (now only requiring a 1% improvement in purity) results in this reasonably sized tree with the same depth of 3 and only 1 additional leaf node for a total of 5 stumphaul.barg: min k nodes.

Sep 24, Given a binary tree, a complete path is defined as a path from root to a leaf. The sum of all nodes on that path is defined as the sum of that path. Given a number K, you have to remove (prune the tree) all nodes which don’t lie in any path with sum>=k. Note: A node can be part of multiple stumphaul.barted Reading Time: 3 mins.