Expectation-Oriented Framework for Automating Approximate Programming

We describe ExpAX, a framework for automating approximate programming based on programmer-specified error expectations. Three components constitute ExpAX: (1) a programming model based on a new kind of program specification, which we refer to as expectations. Our programming model enables programmers to implicitly relax the accuracy constraints without explicitly mark-ing operations approximate; (2) a novel approximation safety anal-ysis that automatically identifies a safe-to-approximate subset of the program operations; and (3) an optimization that automatically marks a subset of the safe-to-approximate operations as approxi-mate while considering the error expectation. Further, we formulate the process of automatically marking operations as approximate as an optimization problem and provide a genetic algorithm to solve it. We evaluate ExpAX using a diverse set of applications and show that it can provide significant energy savings while improving the quality-of-result degradation. 1