Hardware implementation of decision tree ensembles

Abstract

In this paper, several hardware architectures for the realization of ensembles of axis-parallel, oblique and nonlinear decision trees (DTs) are presented. Hardware architectures for the implementation of a number of ensemble combination rules are also presented. These architectures are universal and can be used to combine predictions from any type of classifiers, such as decision trees, artificial neural networks (ANNs) and support vector machines (SVMs). Proposed architectures are suitable for the implementation using Field Programmable Gate Arrays (FPGA) and Application Specific Integrated Circuits (ASIC). Experiment results obtained using 29 datasets from the standard UCI Machine Learning Repository database suggest that the FPGA implementations offer significant improvement in the classification time in comparison with the traditional software implementations. Greatest improvement can be achieved using the SP2-P architecture implemented on the FPGA achieving 416.53 times faster classification speed on average, compared with the software implementation. This result has been achieved on the FPGA working at 135.51 MHz on average, which is 33.21 times slower than the operating frequency of the general purpose computer on which the software implementation has been executed. © 2013 World Scientific Publishing Company.