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Showing papers by "Andrea Walther published in 2001"


Book ChapterDOI
23 Jul 2001
TL;DR: A new approach to reversing program executions that runs the forward simulation and the reversal process at the same speed and illustrates the principle structure of time-minimal parallel reversal schedules and quotes the required resources.
Abstract: For computational purposes such as debugging, derivative computations using the reverse mode of automatic differentiation, or optimal control by Newton’s method, one may need to reverse the execution of a program The simplest option is to record a complete execution log and then to read it backwards As a result, massive amounts of storage are normally required This paper proposes a new approach to reversing program executions The presented technique runs the forward simulation and the reversal process at the same speed For that purpose, one only employs a fixed and usually small amount of memory pads called checkpoints to store intermediate states and a certain number of processors The execution log is generated piecewise by restarting the evaluation repeatedly and concurrently from suitably placed checkpoints The paper illustrates the principle structure of time-minimal parallel reversal schedules and quotes the required resources Furthermore, some specific aspects of adjoint calculations are discussed Initial results for the steering of a Formula 1 car are shown

3 citations