Efficient flow reversal tool
by
Serge Fantino
Université de Nice Sophia Antipolis (UNSA)

An important issue when applying reverse mode in automatic differentiation (AD) is to be able to perform the differential code evaluation in regressive order. We will first introduce some classical vocabulary often used in compiler theory, and give an abstract formulation of the problem. We will present different ways to address it, depending on the hypothesis we made over input code and specification we intended for output code. We will discuss the advantages and drawbacks of those solutions in legacy AD tools implementations. That leads us to define new hypothesis and specifications, and give a more accurate algorithm based on a syntactic driven control flow graph transformation. Then we will present the actual implementation of this algorithm that is part of a new AD tool developed from the ground at the UNSA, and discuss some technical issues as well as some results we got.

http://homepages.feis.herts.ac.uk/~comqun/AD2000/Ext_Abstracts/fantino.ps

Date received: February 21, 2000

Copyright © 2000 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # cads-86.