摘要
针对现有多级逻辑近似优化算法在大型电路优化时无法较好兼顾优化效果与算法速度的问题,提出一种基于常量替换的多级逻辑电路面积优化算法。该算法通过在与非图(AIG)中引入节点输出距离、常量传输距离等参数,并结合提出的多扇出节点常量替换过程中错误率控制方法,在全局范围内提取合适替换的候选节点集和每个候选节点输出的常量替换值;同时,通过根据电路规模选取不同的错误率计算方法等策略,实现了错误率约束下的多级逻辑电路面积近似优化并使算法速度得到提高。所提算法用C语言和ABC内置命令编程实现,使用EPFL及MCNC电路进行测试。实验结果表明:所提算法与已提出的常量替换方法相比,面积优化效果提升48.77%;相较于近似关心集重代换的近似逻辑综合(ALSRAC)优化算法,所提算法在面积优化和运算时间上分别有1.28%和60.91%的提升。
According to the reported multi-level logic approximation optimization algorithm which can not balance the optimization effect and working speed well for largecircuits.It is proposed to use constant substitution in conjunction with and-inverter-graph(AIG)to optimize the logic at multiple levels for circuit areas.A set of candidate nodes to be replaced and a constant value for the node to be replaced are determined by employing the proposed error rate control technique of constant substitution of multiple fan-out nodes and a number of parameters known as node output distance,constant transmission distance,and so forth.Furthermore,according to the circuit size,different error rate calculation methods are selected to improve the speed of the algorithm.The proposed algorithm is programmed in C and implemented with the ABC tool and tested with EPFL and MCNC bench-marks.The experimental results show,compared with the report's similar methods,the proposed algorithm can save 48.77%area.When compared to approximate logic synthesis by resubstitution with approximate care(ALSRAC),this method achieves a 1.28%increase in area optimization and a 60.91%reduction in running time.
作者
赵维凯
王伦耀
岑旭梦
夏银水
储著飞
ZHAO Weikai;WANG Lunyao;CEN Xumeng;XIA Yinshui;CHU Zhufei(Faculty of Electrical Engineering and Computer Science,Ningbo University,Ningbo 315211,China;School of Information Engineering,College of Science&Technology Ningbo University,Ningbo 315300,China)
出处
《北京航空航天大学学报》
EI
CAS
CSCD
北大核心
2024年第9期2893-2901,共9页
Journal of Beijing University of Aeronautics and Astronautics
基金
国家自然科学基金(U1709218,61471211,61871242)。
关键词
多级电路
近似计算
误差约束
常量替换
逻辑优化
multi-level circuit
approximate computing
error constraint
constant substitution
logic optimization
