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Section: New Results

AD tools infrastructure

Participants : Laurent Hascoët, Paul Hovland [Argonne National Lab. (Illinois, USA)] , Sri Hari Krishna Narayanan [Argonne National Lab. (Illinois, USA)] .

We have an ongoing partnership with Paul Hovland's team at Argonne National Lab, formalized by joint participation in the Inria-Illinois joint lab on petascale computing and with travels funded by the Partner University Fund (PUF) of the French embassy in the USA.

In this framework, we worked on the goal of blending our AD tool Tapenade with Argonne's tool OpenAD, buy developing bridges between their internal representations, through a common external representation of analyzed programs. This representation called XAIF is based on XML. We have developed running prototypes of these bridges in both directions, that run on a few examples and that need further development to allow each tool to take advantage of the other's analyses and models. This was supported by two visits of Krishna Narayanan to Inria and one of Laurent Hascoët to Argonne.

We also continued joint development of the Adjoinable-MPI library (AMPI) that provides efficient tangent and adjoint differentiation for MPI-parallel codes, independently of the AD tool used (now AdolC, dco, OpenAD, Tapenade).

We also extracted from Tapenade a standalone kernel (with documented API) for program parsing, analysis, and unparsing, which is not specific to AD and which could be used to develop other source-to-source code transformations. Paul Hovland's team and another Argonne team have shown interest for this library.