VACSEM: Verifying Average Errors in Approximate Circuits Using Simulation-Enhanced Model Counting

Approximate computing is an effective computing paradigm to reduce area, delay, and power for error-tolerant applications. Average error is a widely-used metric for approximate circuits, measuring the average deviation between the outputs of exact and approximate circuits. This paper proposes VACSEM, a formal method to verify average errors in approximate circults using simulatlon-enhanced model counting. VACSEM leverages circuit structure information and logic simulation to speed up verification. Experimental results show that VACSEM is on average 35 x faster than the state-of-the-art method.