JustRelax.jl

Need to solve a very large multi-physics problem on many GPUs in parallel? Just Relax!

JustRelax.jl is a collection of accelerated iterative pseudo-transient solvers using MPI and multiple CPU or GPU backends. It's part of the PTSolvers organisation and developed within the GPU4GEO project. Current publications, outreach and news can be found on the GPU4GEO website.

The package relies on other packages as building blocks and parallelisation tools:

• ParallelStencil.jl - device agnostic parallel kernels
• ImplicitGlobalGrid.jl - (GPU-aware) distributed parallelisation (MPI)
• GeoParams.jl - Material physics
• JustPIC.jl - Particle-in-cell advection

The package serves several purposes:

• It provides a collection of solvers to be used in prototyping new applications

• It provides some standardization so that application codes can

  • more easily handle local material properties through the use of GeoParams.jl
  • more easily switch between a pseudo-transient solver and another solvers (e.g. an explicit thermal solvers)

• It provides a natural repository for contributions of new solvers for use by the larger community

We provide several miniapps, each designed to solve a well-specified benchmark problem, in order to provide

• examples of usage in high-performance computing
• basis on which to build more full-featured application codes
• cases for reference and performance tests