Groebner basis based formal verification of large arithmetic circuits using Gaussian elimination and cone-based polynomial extraction

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Verification of arithmetic circuits is essential as they form the main part of many practical designs such as signal processing and multimedia applications. In these applications, the size of the datapath could be very large so that contemporary verification methods would be almost incapable of verifying such circuits in reasonable time and memory usage. This paper addresses formal verification of large integer arithmetic circuits using symbolic computer algebra techniques. In order to efficiently verify gate level arithmetic circuits, we model the circuit and the specification with polynomial system and the verification problem is formulated as membership testing of the given specification polynomial in corresponding ideal of the circuit polynomials. The membership testing needs Groebner basis reduction. In order to overcome the intensive polynomial reduction needed in Groebner basis computation so that we can deal with verifying large arithmetic circuits, the fanout-free regions (cones) of the circuit are extracted and represented as corresponding polynomials automatically. For further improvement, we make use of Gaussian elimination concept to perform specification polynomial reduction w.r.t Groebner basis using a matrix representation of the problem. To evaluate the effectiveness of our verification technique, we have applied it to very large arithmetic circuits with different architectures. The experimental results show that the proposed verification technique is scalable enough so that large arithmetic circuits can efficiently be verified in reasonable run time and memory usage.