Optimal Reversible Logic Circuit Synthesis Based on a Hybrid DFS-BFS Technique

Logic synthesis with reversible circuits has received considerable interest in the light of advances recently made in quantum computation. In this paper, we propose an improved technique for synthesizing reversible circuits based on a combined depth-first search (DFS) and breadth-first search (BFS) algorithm. A method based on DFS alone may often take a long time to converge, whereas, a BFS based method requires a large amount of memory for designing a circuit of moderate complexity. To strike a balance between these two approaches, we propose a hybrid DFS-BFS based synthesis algorithm that reduces the computation time compared to the DFS method and requires less space compared to the BFS method, while optimizing the cost of the circuit. Synthesis results on several reversible benchmark circuits have been reported.