Research On Evolutionary Design And Optimization Method Of Reversible Logic Gates

As the size and density of integrated circuits continue to increase,the width of the wires inside the chip will reach the atomic level soon.The influence of the quantum effect and the energy consumption caused by irreversible logic operation is increasing correspondingly.Quantum reversible logic circuit is a kind of circuit which is based on reversible operation.It will not create any energy consumption because no information is lost during operations.Thus,it may break the bottleneck of development of integrated circuit from the origin.Meanwhile,it is a logical expression of quantum computing,and therefore has an extremely important research value and broad application prospects.Quantum reversible logic gates are the basic components of reversible logic circuits,but the existing types are few and the design is difficult.In this thesis,the structural characteristics of reversible logic gates and genetic algorithm are discussed in detail.After learned genetic algorithm theory and the design method of existing reversible logic gates,the design and optimization method of reversible quantum logic gates are studied in depth.The research results are as follow:(1)By analyzing and studying the characteristics of quantum gates which are contained by NCV gate library,the structural features of NCV gate library and cascaded array model of reversible logic gate are obtained.(2)Based on this model,an integer array coding scheme based on quantum gate structure is proposed in this thesis.The scheme can encode any reversible logic gate using the symbol set {0,1,2,3,4,5},which avoids the problem that the size of the encoding library expand exponentially with the increase of the input and simplifies the coding complexity of the algorithm.(3)In order to make the algorithm applicable to the evolutionary design of reversible logic gates,a new mutation operator is added into the calculation of fitness to handle the quantum entanglement inside the quantum gate dynamically.The operator reduces the individual generating time and improves the efficiency of the algorithm.(4)A new kind of reversible logic gate named ZC gate is proposed,and the NCV realization of this gate is designed by the algorithm.In addition,some commonly used reversible logic gates are optimized by the algorithm.Through analyzing the experimental results,the general isomorphism criterion of the reversible logic gate is obtained.Through exploring of the issues which are indispensable in the design of reversible logic gate,an automatic design and optimization methods of reversible logic gate is obtained.The research and results in this thesis will do help to the design and implementation of multi-bit quantum logic gates and the optimal design of large-scale reversible logic circuits.