A new heuristic algorithm for estimating signal and detection probabilities

The problem of computing signal probabilities of digital circuits arises in the context of random testing, pseudorandom testing, and testability analysis. This paper presents a simple but effective algorithm for estimating signal probabilities, which provides significantly better estimates of signal probabilities than the weighted averaging algorithm and most importantly is linear in the product of circuit size and the number of primary inputs. Based on this algorithm, the detection probabilities of stuck-at faults are estimated. Experimental results using ISCAS benchmark circuits show the effectiveness and the improvement of this technique over the simple algorithm as well as the weight averaging algorithm. The correlation coefficients of the results are extremely good and the algorithm is very fast.