v23.0

What is new?

• Lagrangian phase model (one-way coupling)
• Overset grids (neknek)
• Particle tracking
• Single source udf+oudf
• Device support BoomerAMG
• Improved runtime statistics
• 4th-kind Chebyshev smoothers
• Configureable time averaging
• Extrapolation initialGuess method
• Scaleable JIT compilation
• Real gas support for lowMach
• More examples
• Various bug fixes

Good to know

• [udf] Changes in include files do not trigger a rebuild automatically
• [udf] Plugins kernels will be loaded automatically (call in UDF_LoadKernels no longer required)

Breaking Changes

• [nrsconfig] Ensure env-vars CC, CXX and FC point to the correct MPI compiler wrappers (see README.md for an example)
• [udf] Plugin header files need to be included explicitly
• [udf] Rename bc->wrk => bc->usrwrk
• [udf] Update to new API of lowMach plugin (see lowMach example)
• Time step was added to nekRS::outfld(..., int step, ...)
• [par] Use pMGSchedule instead of pMultigridCoarsening (see help for more details)
• [par] Rename writeControl value runTime => simulationTime
• [par] Remove multigrid qualifier coarse
• [par] Remove SEMFEM solver specification from key preconditioner, use semfemSolver instead
• [par] Replace stressFormulation = true by equation = navierStokes+variableViscosity
• [par] Replace bcType fixedValue by codedFixedValue
• [par] Replace elasticity by pcg+block for mesh solver
• Use occa::memory mesh_t objects for vgeo, cubvgeo, ggeom, sgeom, LMM, invLMM (no longer mirrored on host)
• All boundaryIDs need to be assigned in boundaryTypeMap (use none for an internal boundary)

Known Bugs / Restrictions

• Code is not fully optimized on CPUs in general and Intel GPUs
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Thanks to our Contributors

@neil-lindquist, @kris-rowe, @pwang234, @nandu90, @yhaomin2007

We are grateful to all who added new features, filed issues or helped resolve them,
asked and answered questions, and were part of inspiring discussions.

v22.0

What is new?

• Multi-session (uncoupled) support
• Support unaligned symmetry boundary condition
• Support (unaligned) traction boundary condition
• Better performance on AMD MI-GPUs
• FLOP counters
• Various bug fixes

Good to know

• OpenCL support is now disabled by default

Breaking Changes

• [udf] Rename udfBuildKernel => oudfBuildKernel
• [par] Separate details of coarse grid discretization from coarse grid solver
  e.g., coarseSolver = SEMFEM+AmgX is replaced by
  coarseSolver = AmgX and coarseGridDiscretization = SEMFEM
• [par] Remove preconditioner=semg and preconditioner=semg_amg
• [udf] Rename plug-in name avg => tavg
• [udf] Rename udf.converged => udf.timeStepConverged
• [nrsconfig] Rename env-var AMGX_ENABLE => ENABLE_AMGX

Known Bugs / Restrictions

• Mesh solver does not support CHT and unaligned sym/shl BCs
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• 258

Thanks to our Contributors

@tcew, @kris-rowe, @aprilnovak

We are grateful to all who added new features, filed issues or helped resolve them,
asked and answered questions, and were part of inspiring discussions.

A special shout out to Tim Warburton at VT for tuning some critical kernels.