With the increasing application of machine learning (ML) algorithms in
embedded systems, there is a rising necessity to design low-cost computer
arithmetic for these resource-constrained systems. As a result, emerging models
of computation, such as approximate and stochastic computing, that leverage the
inherent error-resilience of such algorithms are being actively explored for
implementing ML inference on resource-constrained systems. Approximate
computing (AxC) aims to provide disproportionate gains in the power,
performance, and area (PPA) of an application by allowing some level of
reduction in its behavioral accuracy (BEHAV). Using approximate operators
(AxOs) for computer arithmetic forms one of the more prevalent methods of
implementing AxC. AxOs provide the additional scope for finer granularity of
optimization, compared to only precision scaling of computer arithmetic. To
this end, designing platform-specific and cost-efficient approximate operators
forms an important research goal. Recently, multiple works have reported using
AI/ML-based approaches for synthesizing novel FPGA-based AxOs. However, most of
such works limit usage of AI/ML to designing ML-based surrogate functions used
during iterative optimization processes. To this end, we propose a novel data
analysis-driven mathematical programming-based approach to synthesizing
approximate operators for FPGAs. Specifically, we formulate mixed integer
quadratically constrained programs based on the results of correlation analysis
of the characterization data and use the solutions to enable a more directed
search approach for evolutionary optimization algorithms. Compared to
traditional evolutionary algorithms-based optimization, we report up to 21%
improvement in the hypervolume, for joint optimization of PPA and BEHAV, in the
design of signed 8-bit multipliers.

使用数据分析驱动的数学规划方法，合成 FPGA 的近似运算器，实现在嵌入式系统中机器学习推理的联合优化，取得了高达 21% 的超体积改进。