ArcNum: an Arcane-based numerical framework used in porous media flow simulation applications

This article presents ArcNum, a framework built on the Arcane platform, designed to easily and efficiently develop and maintain the numerical core in finite-volume and finite-element applications. This framework first enables the automatic generation of code needed to instantiate and handle complex physical models from a textual description, through its component called GUMP. ArcNum also offers software components to create, register and evaluate a set of physical laws, requiring only the specification of their inputs, outputs, and corresponding mathematical formulations. Finally, the framework includes a component named Contribution, which combines law evaluation with automatic differentiation to assemble linear systems efficiently. The framework ArcNum has been used to develop an open source Arcane-based porous media flow simulation proxy-app, named ShArc. Single and two-phase porous media flow simulations performed with ShArc are presented to complete the framework description. In order to illustrate the ability to use ArcNum for High Performance Computing, massively parallel simulations conducted with ShArc are finally presented.