Work

Periodicity is Optimal for Offline and Online Multi-Stage Adjoint Computations

Year: 2015
Type: report
Abstract: We reexamine the work of Aupy et al. on optimal algorithms for multi-stageadjoint computations, where two levels of memories are available. Previousoptimal algorithm had a quadratic execution time. Here, with structuralarguments, namely periodicity, on the optimal solution, we provide an optimalalgorithm in constant time, with appropriate pre-processing. We also provide an asymptotically optimal algorithm for the online problem,when the adjoint graph size is not known before-hand. Again, this algorithmsrely on the proof that the optimal solution for multi-stage adjoint computationsis weakly periodic. We conjecture a closed-form formula for the period. Finally, we experimentallyaccess the convergence speed of the approximation ratio for the online problem,through simulations.
Source: HAL
Language: English
Open Access status: green
OpenAlex ID: W2625037576
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