Speed-Up in Test Methods Using Probabilistic Merit Indicators

Abstract

Deterministic test generation methods are time consuming and, this has led to emergence of simulation-based approaches. The basis of simulation-based methods is to propose a number of test vectors, evaluate the efficiency of the proposed vectors, and accept or reject them. In these methods, the efficiency of each test vector is traditionally evaluated based on fault coverage of that vector. In this paper an alternative criterion based on probabilistic simulation approaches is proposed that can be calculated much faster than fault coverage. Statistical evaluations confirm a strong correlation between the proposed measure and fault coverage. The proposed measure can be used in simulation-based and meta-heuristic test generation methods to achieve speedup. In order to indicate efficiency of the proposed probabilistic measure, two test generation methods that utilize this measure are suggested and exploited to generate test for ISCAS85 benchmark circuits. These test generation methods are called PMI_PRUNE and PMI_GA. Our results demonstrate that PMI_PRUNE can achieve up to 21.2x, while the maximum speedup in PMI_GA is 5.0x. The average speedup in PMI_PRUNE and PMI_GA is about 9.6x, and 2.7x respectively.