CHANGES

# 20.07

  -- Nodal hypre solver now supports coarsening before hypre is called.

  -- A new ParmParse parameter, `amrex.the_arena_is_managed` is introduced to set the default memory
     type of `The_Arena`.

  -- MFIter is now OMP thread safe when it is compiled with GPU support.

  -- Overset support is added to cell-center and tensor linear solvers.

  -- Remove compile time flag, BACKTRACE, for simplicity.

  -- Updates on Blueprint and Ascent.

  -- HDF5 support in GNU Make and CMake.

  -- CMake support for DPC++.

  -- Add -DNDEBUG for non-debug build.

  -- Support for Windows.

  -- Support for ParallelContext in Particles.

  -- Non const iterator for neighbor list.

  -- Tool for comparing single-level plotfiles of all nodalities.

  -- GNU Make: Use -M instead the perl script to generate dependencies.

  -- Particle: Remove directly accessing the m_idata and m_rdata structs internally.

  -- Extend the makeSFC method to take an additional argument where the user can override the number
     of processes a BoxArray is distributed to.

  -- Turn tiling off by default for gpu.

# 20.06

  -- Set a non-default CMAKE_INSTALL_PREFIX only if AMReX is the
     top-level CMake project. Otherwise, the default of a downstream
     project using AMReX as subproject will be placed in a quite
     confusing, temporary directory.

  -- C order support for Array2D and Array3D.

  -- Disable unqualified abs function within amrex namespace.

  -- Updates for SENSEI 3.2.

  -- CMake: link to OpenMP::Fortran only when needed.

  -- DPC++ support.

  -- Add non-const data() to GpuArray.

  -- Fix HIP version of scan.

  -- Return immediately from GPU memcpy if size is zero.

  -- Documentation on EB linear solvers.

# 20.05

  -- AMReX's git history has been rewritten.  If you have problems due
     to this, follow the instruction here. https://xkcd.com/1597/  We
     also have a new CONTRIBUTING.md.

  -- EB linear solvers: You now need to specify the location of
     diffusion coefficient (face center or face centroid) and the
     location of the unknowns (cell center or cell centroid).

  -- Optimization of makeKnapSack and makeSFC.

  -- Unification of GPU and CPU versions of neighbor particle /
     neighbor list implementations.

  -- New HostDeviceParallelFor functions that can run on either host
     or device depending on the launch region flag.

  -- Add CUPTI trace for CUDA kernel timing.

  -- Implement ENABLE_FORTRAN (BL_NO_FORT) option in CMake.

  -- Fix CUDA build of tools.

  -- Fix invalid git version in CMake.

# 20.04

  -- BaseFab can no longer be used on device.  Many BaseFab functions
     now requires RunOn::Device or RunOn::Host template parameter when
     GPU support is enabled.

  -- FillPatch* funcitons are now templated to support FabArray in
     addition to MultiFab.

  -- Fix -pthread for nvcc by default in Make.unknown

  -- EB now has the option to build coarse level from GeometryShop
     when coarsening from fine level fails.  This could be used for
     hyperbolic system with EB resolved to the finest level

  -- CMake: add C++ 17 among valid options for AMREX_CXX_STANDARD

  -- Add option to set fixed number of iterations in the Fortran
     interface of linear solver

  -- Fabs in alias FabArray now carries EB information.

  -- Add AMREX_LOOP_3D and 4D macros.

  -- Make amrex::Random() return numbers in the same interval for both
     CPU and GPU: [0:1)

  -- More flux register functionality for flash

  -- Chunked partition in particle redistribution to use less memory.

# 20.03

  -- AmrCore can now be built without using ParmParse.

  -- Improve BL_NO_FORT support.

  -- Fix OMP bug in MFIter constructors taking BoxArray and
     DistributionMapping.

  -- Cray compiler has been re-enabled in CMake.

  -- For device only code, the users can now use #if AMREX_DIVICE_COMPILE.

  -- Fix an integer overflow issue in TileArray cache.

# 20.02

  -- RealVect updated for GPU.

  -- Support for restarting from HDF5 particle checkpoint file.

  -- Improvement of MacProjector and NodalProjector

# 20.01

  -- GPU host device version of swap.

  -- Fix an edge case of gpu block reduce where the block size is less
     than a warp.

  -- Always check MPI buffer size for overflow.

  -- CMake support for PETSc.

  -- Include C sources in the CUDA proprecessing.

  -- It's now safe to construct a zero components Fab.

  -- CXXSTD: option to set c++ standard in GNU make system

  -- Improve performance of the nodal linear solver on GPU.

# 19.12

  -- Fix potential deadlocks in amrex::Random.

  -- MultiFab::Swap that does shallow swap if it can, does deep swap
     otherwise.

  -- FabArray::arena function that returns the Arena used to build.

  -- Nodal projection sync residuals are implemented for RAP.

  -- GPU support for initializing Fabs to NaNs.

# 19.11

  -- AmrCore::regrid will now simply return instead of abort if the
     base level is already the maximal level.

  -- Add NodalProjector that wraps MLMG for convenience.

  -- Enforce in AmrCore that blocking factor must be a power of 2.

  -- Add support to write plotfile in HDF5 format.

  -- FabArray's Reduce functions can now take lambda working on Array4
     in addition of FAB.

  -- Add AMREX_REAL_MIN, AMREX_REAL_MAX and AMREX_REAL_LOWEST for
     convenience.

  -- GPU launch functions and macros are now safe with empty boxes.

  -- Remove FabView from BaseFab.

  -- Avoid race conditions in GPU reduction code called multiple
     times.

  -- MLMG tensor solver is fixed for AMR.

# 19.10

  -- Add inhomogeneous Neumann BC to MLMG for convenience.

  -- Fix a corner case of tensor solver.

  -- Various fixes for single precision and particle real.

  -- Add amrex::Long that has a size of 8.

  -- Add int8_t support in typecheck.

  -- C++ user literal _rt for amrex::Real and _prt for
     amrex::ParticleReal.

  -- EB MAC projector now requires the user to specify whether the
     face velocities are defined on face centers or centroids.

# 19.09

  -- First pass of Sr/EB on GPU.

  -- Optimization of particle redistribution.

  -- EB integral: add integral of x*y*z

  -- HostDevice::Atomic::Add that does atomic add for both device and
     host omp code.

  -- makeFineMask: optional arguments specifying coarse and fine flag
     values.

  -- Optimization of FabArray communication for GPU by merging small
     kernels.

# 19.08

  -- MacProjector has the option to set maximal coarsening level.

  -- OwnerMask and OverlapMask are now built on GPU.

  -- Random number generation on GPU no longer requires an call to
     initialize seeds.  They are done in amrex::Initialize and resize
     is not needed when launching with more threads than the size of
     seed array.

  -- Optimization of NeighborParticles.

# 19.07

  -- Geometry/CoordSys: Static class members have been removed.
     Functions such as `isPeriodic`, `isAnyPeriodic`, `isAllPeriodic`,
     `ProbLo`, `ProbHi`, `IsCartesian`, `IsRZ`, and `IsSPHERICAL` are
     now non-static.  The default Geometry can been obtained via
     `DefaultGeometry()` function.

  -- Funciton amrex::Loop and amrex:LoopConcurrent are added to help
     looping over cells in a Box.

  -- Nodal solver: A bug in nodal owner mask that could affect
     covergence was fixed.

  -- Fortran amrex_amrcore_module: add amrex_set_boxarray,
     amrex_set_distromap, and amrex_set_finest_level.

  -- Option to allocate MultiFab data in arenas different from
     The_Arena().

  -- Option to tag MultiFabs and query their memory usages.

  -- AsyncFab has been deleted.

# 19.06

  -- Geometry/CoordSys: New constructor and define function are added.
     We plan to remove static data from Geometry and its base CoordSys
     in the next release.  This means most of the static functions in
     Geometry class will become non-static.  These include
     `isPeriodic`, `isAnyPeriodic`, `isAllPeriodic`, `ProbLo`,
     `ProbHi`, `IsCartesian`, `IsRZ`, and `IsSPHERICAL`.  You can
     prepare codes now for the upcoming changes.  In almost all cases,
     all you have to do is replace `Geometry::function` with
     `DefaultGeometry().function`.

  -- Add tensor linear solvers for viscous flows with and without EB.

  -- Algoim: A modified version of Algoim is added.  This removes the
     dependence of 3d EB nodal MLMG solver on the official Algoim code
     and Blitz.

  -- EB: Fix the potential ownership issue is IndexSpace.

  -- Add a new FillPatchTwoLevels for EB.

# 19.05

  -- Interface of virtual function Interpolater::interp has changed.

  -- Add Fortran funcntions for shared memory reductions.

  -- EB nodal linear solver: The default bottom solver is now bicgcg.
     It starts with bicgstab and switches cg if bicgstab fails.

  -- EB nodal linear solver: Finished the implementation of matrix
     coarsening with RAP.

  -- Particle: Option for adding runtime struct of array components.

  -- Add a trilinear interpolation option for 3D.

  -- Add more support for non-uniform grow vectors to MultiFab and
     FabArray.

  -- AmrMesh: n_error_buf is now IntVect.  This allows for different
     number of error buffer cells in different directions.

  -- Using PETSc as bottom solver no longer requires Hypre.
 
# 19.04

  -- SUNDIALS 4 support.

  -- Option to disable device sync in MFIter.

  -- Functions for prefetch unified memory.

  -- GNU Make system: It is now an error if a function with return
     type does not return.

  -- GNU Make system: Pass C++ flags to nvcc when compiling C codes.

  -- Allocate 3/4 of gpu memory upfront in The_Arena.

  -- BaseFab now has Allocator template parameter.

  -- Random number generation on gpu.

# 19.03

  -- Deprecated Fortran framework F_BaseLib and linear solver F_MG
     have been removed.  A number of tools written in F_BaseLib have
     been migrated to Tools/Plotfile/.  Note that the Fortran wrappers
     to C++ (F_Interfaces) are still there.

  -- In addition to launch macros, there are now functions for
     lauching, amrex::launch, amrex::For and amrex::ParallelFor.
     These improves debuggability. 

  -- If compiled with BASEFAB_IS_PINNED, pinned memory will be used
     for BaseFab meta-data.  On systems with nvlink, this improves the
     performance a little bit.

  -- Performance improvement in particle redistribution.

  -- Particle NeighborList has been moved from tutorial to AMReX
     proper.

  -- Cell-centered MLMG linear solver have been ported to GPU.

# 19.02

  -- Array4 class that contains the important information in BaseFab
     class.  It can be captured by lambda and used on gpu.

  -- A number of new macros for launching for loops: AMREX_FOR_1D,
     AMREX_FOR_3D, AMREX_FOR_4D, AMREX_PARALLEL_FOR_1D,
     AMREX_PARALLEL_FOR_3D, and AMREX_PARALLEL_FOR_4D.

  -- Disable cuda aware MPI by default.  It can be enabled with
     parameter amrex.use_gpu_aware_mpi.

# 19.01

  -- Documentation and Tutorials on GPU

  -- EB implicit function using spline

  -- FabArray::fabPtr() function takes MFIter and returns a device
     pointer to BaseFab.

# 18.12

  -- More GPU supports

# 18.11

  -- GPU support in Base and Particle

  -- BaseFab is no longer polymorphic

  -- EB now supports ghost cells outside physical domain

# 18.10

  -- MacProjector class for MAC projection

  -- Support for Dirichlet EB in linear solver

  -- Option to use PETSc as bottom solver

  -- Multi-level linear solver with EB not crossing coarse/fine
     boundary. 

  -- Sundials 3 support

# 18.09

  -- Cell-centered linear solver with homogeneous Neumann embedded
     boundary. 

  -- Hypre as a bottom solver has a IJ matrix interface and supports
     homogeneous Neumann boundary condition on embedded boundary.

  -- Old embedded boundary codes have been removed.

# 18.08

  -- Faster geometry generation is available at Src/EB2.
     Tutorials/EB/CNS is now based on EB2.

  -- AMReX is now fully compliant with xSDK.

  -- Fortran interface for particles.  See Tutorials/Amr/Advection_F/
     for an example.

# 18.07

  -- Pre- and post-interpolation hooks in FillPatch.

  -- NDEBUG is no longer defined in xSDK mode.

# 18.06

  -- When amrex::Initialize is called, optional std::ostream arguments
     can be passed in and their defaults are std::cout and std::cerr.

  -- ParmParse inputs files can now contain Fortran namelist that can
     be accessed from Fortan (and Frotran only).  These Fortran inputs
     are stored in amrex_namelist character variable in
     amrex_parmparse_module, and can be read with standard Fortran
     I/O.
     
  -- There is a new non-blocking parallel copy function in
     MultiFab/FabArray called ParallelCopy_nowait.  It returns a
     CopierHandle object and can later be used to finish the
     communication with CopierHandle::finish().

# 18.05

  -- FillBoundary and ParallelCopy functions can now take IntVect
     arguments as the number of ghost cells.  That is the number of
     ghost cells could be different for different directions.

  -- MultiFab, iMultiFab and FabArray can have different number of
     ghost cells in different directions.

  -- Fortran module mempool_module has been renamed amrex_mempool_module.

  -- Many macros have been renamed.
     * USE_PARTICLES and PARTICLES have been renamed AMREX_PARTICLES
     * DIMENSION_AGNOSTIC has been renamed AMREX_DIMENSION_AGNOSTIC
     * USE_CVODE has been renamed AMREX_USE_CVODE
     * DEBUG has been renamed AMREX_DEBUG

 -- amrex::Array is now an alias to std::array in stead of amrex::Vector.

# 18.04

  -- New BoxList constructors making a given number of Boxes from a
     single Box.

  -- Optimization of particle redistribution

  -- MLMG nodal linear solver: add solvability fix

  -- Modification to amrex::Initialize and Finalize to make it
     suitable as a library in an application that does not use AMReX
     as a framework.

# 18.03

  -- STL support for EB

# 18.02

  -- Fortran interface: added new functions amrex_multifab_build_alias
     and amrex_imultifab_build_alias.

  -- Documentation in reST/Sphinx.  See Docs/Readme.sphinx for more
     details.

  -- Src/LinearSolvers/MLMG now supports nodal based data.

  -- Fortran module AMReX_fillpatch_module takes a user provided
     callback function for filling physical boundary conditions.  That
     function used to use 0-based index for component (i.e., the last
     index).  For consistence with 1-based index for component in
     other Fortran modules, this has been changed to 1-based index for
     component.

# 18.01

  -- New linear solver MLMG at Src/LinearSolvers/MLMG/.  Currently it
     supports cell-centered single level and multi-level composite
     solve.  Fortran interface is also available at
     Src/F_Interfaces/LinearSolvers/.  See Tutorials/LinearSolvers for
     tutorials.

# 17.12

  -- Ported more features (including dynamic scheduling and explicit
     tile size) of MFIter from C++ to Fortran.

  -- Added procedures to Fortran amrex_multifab_module to add,
     subtract, multiply, divide, saxpy and lincomb (linear
     combination).  Note that we call it saxpy, but it doesn't mean
     single precision.

  -- The `configure; make; make install` build approach enables linear
     solvers by default now.

  -- MultiFab and iMultiFab now support move assignment operator.
     This allows for swapping two MultiFabs without deep copying.  For
     instance, std::swap(mf1, mf2);

  -- Tutorials/Amr/Advection_AmrCore changes from using
     `Vector<unique_ptr<MultiFab>>` to `Vector<MultiFab>`.

# 17.11

  -- AMREX_ASSERT_WITH_MESSAGE and AMREX_ALWAYS_ASSERT_WITH_MESSAGE
     are new macros for assertion when it fails additional message
     will be printed.   For example:

         AMREX_ASSERT_WITH_MESSAGE(x > y, "reason why x > y must be true");

  -- amrex::Array is deprecated and replaced by amrex::Vector.
     Currently Array is an alias to Vector.  So this should not break
     any codes.  In the future, we will remove Array completely.
     Therefore it is recommended that application codes should start
     replacing Array with Vector.  There is a script,
     amrex/Tools/Migration/amrex_array_to_vector.sh, to help.  But use
     it with caution.   If it is completely gibberish to you, you
     probably shouldn't use the script. 

  -- functions for printing to a file in a parallel and thread-safe manner
     have been added. For example:

        amrex::AllPrintToFile("output") << "Hello from rank " << rank << 
                                           " and thread " << thread << "\n";

     will print out the requested information to separate files for each 
     rank and thread.

# 17.10

  -- Added a load balance approach to Amr/AmrLevel.  The runtime
     parameters for this is amr.loadbalance_with_workestimates and
     amr.loadbalance_level0_int.  The latter is for single level
     (i.e., amr.max_level=0) only.  For multi-level runs, load balance
     is done during regrid and thus the load balance interval is
     controlled by amr.regrid_int.  To use this approach, AmrLevel
     derivative must has a StateData for work estimates and its index
     is returned by virtual function int WorkEstType().

  -- MFIter now supports dynamic scheduling of OpenMP threads.  For
     example,
 
       for (MFIter mfi(mf, MFItInfo().SetDynamic(true).EnableTiling(tile_size);
            mfi.isValid(); ++mfi)
       { ... }

  -- Added EBFluxRegister to Src/EB for refluxing and
     re-redistribution in EB.

  -- amrex.signal_handling = 1 is a new runtime parameter that can be
     used to control whether AMReX should handle signals like SIGSEGV
     etc.