Construction of Nearly Optimal Multiway Trees
نویسنده
چکیده
In this paper, the construction of nearly optimal multiway trees for n keys, n key weights, and n + 1 gap weights, is investigated. we present an efficient algorithm for this problem having a time complexity of O(H tn), where H is the height of the resulting tree and t is its order. The algorithm is based on a top down approach. For a given set of keys, we determine a subset of keys that should stay in the root. This leads to equal subproblems of smaller size. For the determination of the root keys, we use a variant of the concave leastweight subsequence problem that can be solved in linear time. Computational experiments have always yielded trees for which the weighted path length is not more than two percent above the optimal weighted path length.
منابع مشابه
Classification Trees With Unbiased Multiway Splits
Two univariate split methods and one linear combination split method are proposed for the construction of classification trees with multiway splits. Examples are given where the trees are more compact and hence easier to interpret than binary trees. A major strength of the univariate split methods is that they have negligible bias in variable selection, both when the variables differ in the num...
متن کاملSelecting Multiway Splits in Decision Trees
Decision trees in which numeric attributes are split several ways are more comprehensible than the usual binary trees because attributes rarely appear more than once in any path from root to leaf. There are efficient algorithms for finding the optimal multiway split for a numeric attribute, given the number of intervals in which it is to be divided. The problem we tackle is how to choose this n...
متن کاملConvergence rate of Bayesian supervised tensor modeling with multiway shrinkage priors
This article studies the convergence rate of the posterior for Bayesian low rank supervised tensor modeling with multiway shrinkage priors. Multiway shrinkage priors constitute a new class of shrinkage prior distributions for tensor parameters in Bayesian low rank supervised tensor modeling to regress a scalar response on a tensor predictor with the primary aim to identify cells in the tensor p...
متن کاملMultiway Iceberg Cubing on Trees
The Star-cubing algorithm performs multiway aggregation on trees but incurs huge memory consumption. We propose a new algorithm MG-cubing that achieves maximal multiway aggregation. Our experiments show that MG-cubing achieves similar and very often better time and memory efficiency than Star-cubing.
متن کاملAlgorithms for Cut Problems on Trees
We study the multicut on trees and the generalized multiway Cut on trees problems. For the multicut on trees problem, we present a parameterized algorithm that runs in time O(ρ), where ρ = √√ 2 + 1 ≈ 1.555 is the positive root of the polynomial x4−2x2−1. This improves the current-best algorithm of Chen et al. that runs in time O(1.619). For the generalized multiway cut on trees problem, we show...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 1997