Dear all, We are pleased to announce the release of Nektar++ v5.4.0. As always, if you encounter any problems please feel free to contact us on the mailing list nektar-users@imperial.ac.uk. You can also report bugs and issues on our issue tracker (https://gitlab.nektar.info/nektar/nektar/-/issues). This release includes a range of new features and improvements over the 5.3.0 release: **Library** - Add unit tests for Polylib (!1533) - Add the absolution tolerance for the iterative linear system solver (!1549) - Redesign of Parareal driver (!1509) - Add PFASST driver (!1501) - Add local p-refinement functionality (!1508) - Tidy-up SDC schemes (!1550) - Add min/max and fmin/fmax function to the interpretor registry (!1552) - Fix a _m128d to _m128i conversion bug in sse2.hpp (!1551) - Register TimeIntegrationMethod to SessionReader (!1539) - Remove unecessary for loop in NekLinSysIterGMRES (!1554) - Generalize the use of size_t in TimeIntegration (!1555) - Fix convergence error in Fixed-point Jacobi algorithm (!1561) - Tidy-up NekLinSys (!1562) - Tidy-up TimeIntegration (!1505) - Fix Adams-Bashforth time integration scheme (!1558) - Remove unused Kernel directory (!1560) - Remove unused files in BasicUtils (!1564) - Fix convergence error in Fixed-point Jacobi algorithm (!1561) - Update parallel-in-time code base in fieldconvert (!1565) - Tidy-up Basis and Points classes (!1568) - Remove unused function GetKey in NekFactory (!1567) - Add new functionality and code improvements for the local p-refinement (!1571) - Fix v_Exscan compilation bug (!1566) - Tidy-up of comm class (!1572) - Tidy-up Nektar tolerances (!1570) - Tidy-up UnsteadySystem (!1579) - Fix StaticCond approach + GMRES when restarting (!1583) - Tidy-up NekManager (!1587) - Slightly reduce memory allocation in GMRES (!1586) - Tidy-up Advection class (!1580) - Tidy-up diffusion class and subclasses (!1581) - Tidy-up NekNonlinSys and fix some issues (!1563) - Avoid pre-allocating memory in GMRES (!1591) - Added a local space version of GMRES and ConjugateGradient (!1575) - Added a jacobi preconditioner building on diagonal impelemtation (!1575) - Add a priori convergence and null-input check to GMRES (!1590) - Tidy-up/removed unused Lapack function definition (!1573) - Some Tidy-up in MatrixFreeOps (!1599) - Accelerate interpolation for regular and straight-edge elements (!1283) - Fix an indexing error in MatrixFreeOps (!1602) - Update Session File for Parallel-in-Time (!1516) - Partially fix hdf5 partition for Parareal (!1611) - Update Collection for Parareal-in-Time (!1607) - New version of CreateCollection using basisKey (!1603) - Remove unused Domain.cpp and Domain.h file (!1609) - Remove useless ReadExpressions and SubstituteExpressions function in          sessionReader (!1608) - Corrected workspace size in triangle BwdTrans (!1610) - Reactivate Reactivate Movement_fixed_3D_stacked_cylinders_curved_hdf5_par     test except on ARM MacOS (!1536) - Rename communicator in LinearAlgebra (!1612) - Add IProductWRTDerivBase operator for 3DH1D problems (!1483) - Full support of mixed-order elements in DG (!1606) - Use default keyword for destructor in Driver (!1624) - Add additional test for SDC time-integration(!1621) - Fix to compiler flags for MSVC (!1604) - Correct bug in scotch initialisation for substructuring (!1634) **CompressibleFlowSolver** - Fix AUSM3 Riemann solver and add tests to the CI (!1537) - Set initial condition check points files to zero (0) (!1535) - Prevent file overwrite with restart for the Compressible flow solver (!1540) - Register Projection and GJPStabilisation in SessionReader (!1542) - Redesign of AUSM Riemann solver class (!1577) - Redesign of the compressible flow solver. Removal of RinglebFlow and          IsentropicVortex subclasses (!1584) - Redesign of PreconCfs class (!1578) - Fix virtual functions in ContField class (!1616) - Tidy-up Compressible flow solver print status (!1615) - Update of for parallel-in-time (!1589) - Fix some memory bugs for implicit compressible flow solver with LDGNS (!1617) **IncNavierStokesSolver** - Add an option to mask variables for the linear stability problem (!1280) **ShallowWaterSolver** - Fix NonlinearPeregrine solver due to a change of API (!1637) **FieldConvert** - Add option to use .csv files in pointdatatofld module (!1545) - Add a new module to output power spectral in a given area (!1271) - Add a new module to do field averaging (!1271) **IncNavierStokesSolver** - Register SolverType in SessionReader (!1541) - Prevent file overwrite with restart for the IsentropicVortex solver (!1543) - Fix GJP stabilisation for curved 3D elements (!1593) - Enable SVV and GJP stabilisation for unresolved scales in VCSImplicit (!1592) - Fix tolerance in KovaFlow_m10_VCSImplicit_SVV (!1619) **Miscellaneous** - Fix compilation against TetGen 1.6 (!1547) - Tidy-up Parareal initial condition output (!1534) - Remove double entry in documentation and slightly tidy-up code (!1530) - Fixed deadlock problem for the LowEnergyBlock preconditioner which appeared   for specific combinations of meshes and boundary conditions (!1553) - Add a check to avoid unnecessary copy in DoOdoProjecton function (!1582) - Update user guide and developer guide (!1598) - Some various tidy-up (!1585) - Added support for performance tests (!1614) - Integrated performance tests into the CI system and enabled a test (!1629) - Added additional performance tests and updated test documentation (!1631) - Fix VmathTimer compilation error (!1635) - Fix SIMD compilation error (!1636) - Update ShallowWaterSolver performance test (!1643) **NekMesh** - Changed CMake to set NEKTAR_USE_THREAD_SAFETY to ON when MeshGen is set to ON (!1546) - Fixed a bug where MeshElement/Tetrahedron did not assign edge IDs in the      constructor (!1596) **Documentation** - Fix missing Tikz external package requires for bookworm (!1638) **CI** - Add testing and packaging for Debian bookworm (!1638) Cheers, Chris -- Chris Cantwell Senior Lecturer in Aeronautics Department of Aeronautics Imperial College London South Kensington Campus London SW7 2AZ Tel: +44 (0)20 759 45050 Email: c.cantwell@imperial.ac.uk www.imperial.ac.uk/people/c.cantwell