1# Changes/Release Notes 2 3On this page we provide a summary of the main API changes, new features and examples for each release of libCEED. 4 5(main)= 6 7## Current `main` branch 8 9### Interface changes 10 11- Add `bool` field type for `CeedQFunctionContext` and related interfaces to use `bool` fields. 12- `CEED_BASIS_COLLOCATED` removed; users should only use `CEED_BASIS_NONE`. 13- Remove unneeded pointer for `CeedElemRestrictionGetELayout`. 14 15### New features 16 17- Add `CeedOperatorCreateAtPoints` which evaluates the `CeedQFunction` at arbitrary locations in each element, for use in Particle in Cell, Material Point Method, and similar methods. 18- Add `CeedElemRestrictionGetLLayout` to provide L-vector layout for strided `CeedElemRestriction` created with `CEED_BACKEND_STRIDES`. 19 20### Examples 21 22- Add deal.II example with CEED BP suite. 23 24(v0-12)= 25 26## v0.12 (Oct 31, 2023) 27 28### Interface changes 29 30- Update `CeedOperatorContext*` functions to `CeedOperator*Context*` functions for consistency. 31For example, `CeedOperatorContextGetFieldLabel` was renamed to `CeedOperatorGetContextFieldLabel`. 32- Removed `CeedBasisSetNumQuadraturePoints` as redundant and bug-prone interface. 33 34### New features 35 36- Added {c:func}`CeedOperatorGetFieldByName` to access a specific `CeedOperatorField` by its name. 37- Update `/cpu/self/memcheck/*` backends to help verify `CeedVector` array access assumptions and `CeedQFunction` user output assumptions. 38- Update {c:func}`CeedOperatorLinearAssembleDiagonal` to provide default implementation that supports `CeedOperator` with multiple active bases. 39- Added Sycl backends `/gpu/sycl/ref`, `/gpu/sycl/shared`, and `/gpu/sycl/gen`. 40- Added {c:func}`CeedBasisApplyAtPoints` for evaluation of values and derivatives at arbitrary points inside elements. 41- Added support for non-tensor $H(\text{curl})$ finite element spaces with {c:func}`CeedBasisCreateHcurl`. 42- Added {c:func}`CeedElemRestrictionCreateCurlOriented`, similar to {c:func}`CeedElemRestrictionCreateOriented`, for element restrictions requiring more general element transformations such as those for high-order $H(\text{curl})$ spaces on tetrahedra (see [https://dl.acm.org/doi/pdf/10.1145/3524456](https://dl.acm.org/doi/pdf/10.1145/3524456)). 43- Added {c:func}`CeedOperatorLinearAssemblePointBlockDiagonalSymbolic` to create COO mapping for mapping out of {c:func}`CeedOperatorLinearAssemblePointBlockDiagonal`. 44- Added support for application codes which manage multiple {ref}`Ceed` objects, parallelized across OpenMP threads. 45 46### Examples 47 48- Add `DMSwarm` example demonstrating interpolation from background mesh to swarm points and projection from swarm points to background mesh. 49 50#### {ref}`example-petsc-bps` 51 52- Requires PETSc version 3.19 or later. 53 54#### {ref}`example-petsc-navier-stokes` 55 56- Updated restart and checkpointing interface. 57- Add data-driven subgrid-stress model. 58- Add differential filtering of solution. 59- Add turbulence statistics collection over spanwise-symmetric geometries. 60- Add Taylor-Green vortex initial condition. 61- Add Riemann-based outflow boundary conditions. 62- Added vortex shedding and flow past cylinder example, including calculations for lift, drag, and heat transfer. 63- Add Internal Damping Layer (IDL) for helping turbulent simulation stability. 64- Derive `CeedBasis` from `PetscFE`, and various other internal maintainability updates. 65 66(v0-11)= 67 68## v0.11 (Dec 24, 2022) 69 70### Interface changes 71 72- Added {c:func}`CeedOperatorSetName` for more readable {c:func}`CeedOperatorView` output. 73- Added {c:func}`CeedBasisCreateProjection` to facilitate interpolation between nodes for separate `CeedBases`. 74- Rename and move {c:func}`CeedCompositeOperatorGetNumSub` and {c:func}`CeedCompositeOperatorGetSubList` to public interface. 75- Renamed `CEED_BASIS_COLLOCATED` to `CEED_BASIS_NONE` for clarity. 76Some users previously misinterpreted a `CeedOperator` field using `CEED_BASIS_COLLOCATED` as meaning that the entire `CeedOperator` used a quadrature space that is collocated with the nodal space of the active bases. 77 78### New features 79 80- Update `/cpu/self/memcheck/*` backends to help verify `CeedQFunctionContext` data sizes provided by user. 81- Improved support for $H(\text{div})$ bases. 82- Added `CeedInt_FMT` to support potential future use of larger integer sizes. 83- Added `CEED_QFUNCTION_ATTR` for setting compiler attributes/pragmas to `CEED_QFUNCTION_HELPER` and `CEED_QFUNCTION`. 84- OCCA backend updated to latest OCCA release; DPC++ and OMP OCCA modes enabled. 85Due to a limitation of the OCCA parser, typedefs are required to use pointers to arrays in QFunctions with the OCCA backend. 86This issue will be fixed in a future OCCA release. 87 88### Bugfix 89 90- Fix bug in setting device id for GPU backends. 91- Fix storing of indices for `CeedElemRestriction` on the host with GPU backends. 92- Fix `CeedElemRestriction` sizing for {c:func}`CeedOperatorAssemblePointBlockDiagonal`. 93- Fix bugs in CPU implementation of {c:func}`CeedOperatorLinearAssemble` when there are different number of active input modes and active output modes. 94 95### Examples 96 97#### {ref}`example-petsc-navier-stokes` 98 99- Various performance enhancements, analytic matrix-free and assembled Jacobian, and PETSc solver configurations for GPUs. 100- Refactored to improve code reuse and modularity. 101- Support for primitive variables for more accurate boundary layers and all-speed flow. 102- Added $YZ\beta$ shock capturing scheme and Shock Tube example. 103- Added Channel example, with comparison to analytic solutions. 104- Added Flat Plate with boundary layer mesh and compressible Blasius inflow condition based on Chebyshev collocation solution of the Blasius equations. 105- Added strong and weak synthetic turbulence generation (STG) inflow boundary conditions. 106- Added "freestream" boundary conditions based on HLLC Riemann solver. 107- Automated stabilization coefficients for different basis degree. 108 109#### {ref}`example-petsc-bps` 110 111- Support for convergence studies. 112 113### Maintainability 114 115- Refactored `/gpu/cuda/shared` and `/gpu/cuda/gen` as well as `/gpu/hip/shared` and `/gpu/hip/gen` backend to improve maintainablity and reduce duplicated code. 116- Enabled support for `p > 8` for `/gpu/*/shared` backends. 117- Switch to `clang-format` over `astyle` for automatic formatting; Makefile command changed to `make format` from `make style`. 118- Improved test harness. 119 120(v0-10-1)= 121 122## v0.10.1 (Apr 11, 2022) 123 124### Interface changes 125 126- Added {c:func}`CeedQFunctionSetUserFlopsEstimate` and {c:func}`CeedOperatorGetFlopsEstimate` to facilitate estimating FLOPs in operator application. 127 128### New features 129 130- Switched MAGMA backends to use runtime compilation for tensor basis kernels (and element restriction kernels, in non-deterministic `/gpu/*/magma` backends). 131This reduces time to compile the library and increases the range of parameters for which the MAGMA tensor basis kernels will work. 132 133### Bugfix 134 135- Install JiT source files in install directory to fix GPU functionality for installed libCEED. 136 137(v0-10)= 138 139## v0.10 (Mar 21, 2022) 140 141### Interface changes 142 143- Update {c:func}`CeedQFunctionGetFields` and {c:func}`CeedOperatorGetFields` to include number of fields. 144- Promote to the public API: QFunction and Operator field objects, `CeedQFunctionField` and `CeedOperatorField`, and associated getters, {c:func}`CeedQFunctionGetFields`; {c:func}`CeedQFunctionFieldGetName`; {c:func}`CeedQFunctionFieldGetSize`; {c:func}`CeedQFunctionFieldGetEvalMode`; {c:func}`CeedOperatorGetFields`; {c:func}`CeedOperatorFieldGetElemRestriction`; {c:func}`CeedOperatorFieldGetBasis`; and {c:func}`CeedOperatorFieldGetVector`. 145- Clarify and document conditions where `CeedQFunction` and `CeedOperator` become immutable and no further fields or suboperators can be added. 146- Add {c:func}`CeedOperatorLinearAssembleQFunctionBuildOrUpdate` to reduce object creation overhead in assembly of CeedOperator preconditioning ingredients. 147- Promote {c:func}`CeedOperatorCheckReady`to the public API to facilitate interactive interfaces. 148- Warning added when compiling OCCA backend to alert users that this backend is experimental. 149- `ceed-backend.h`, `ceed-hash.h`, and `ceed-khash.h` removed. Users should use `ceed/backend.h`, `ceed/hash.h`, and `ceed/khash.h`. 150- Added {c:func}`CeedQFunctionGetKernelName`; refactored {c:func}`CeedQFunctionGetSourcePath` to exclude function kernel name. 151- Clarify documentation for {c:func}`CeedVectorTakeArray`; this function will error if {c:func}`CeedVectorSetArray` with `copy_mode == CEED_USE_POINTER` was not previously called for the corresponding `CeedMemType`. 152- Added {c:func}`CeedVectorGetArrayWrite` that allows access to uninitialized arrays; require initialized data for {c:func}`CeedVectorGetArray`. 153- Added {c:func}`CeedQFunctionContextRegisterDouble` and {c:func}`CeedQFunctionContextRegisterInt32` with {c:func}`CeedQFunctionContextSetDouble` and {c:func}`CeedQFunctionContextSetInt32` to facilitate easy updating of {c:struct}`CeedQFunctionContext` data by user defined field names. 154- Added {c:func}`CeedQFunctionContextGetFieldDescriptions` to retrieve user defined descriptions of fields that are registered with `CeedQFunctionContextRegister*`. 155- Renamed `CeedElemTopology` entries for clearer namespacing between libCEED enums. 156- Added type `CeedSize` equivalent to `ptrdiff_t` for array sizes in {c:func}`CeedVectorCreate`, {c:func}`CeedVectorGetLength`, `CeedElemRestrictionCreate*`, {c:func}`CeedElemRestrictionGetLVectorSize`, and {c:func}`CeedOperatorLinearAssembleSymbolic`. This is a breaking change. 157- Added {c:func}`CeedOperatorSetQFunctionUpdated` to facilitate QFunction data re-use between operators sharing the same quadrature space, such as in a multigrid hierarchy. 158- Added {c:func}`CeedOperatorGetActiveVectorLengths` to get shape of CeedOperator. 159 160### New features 161 162- `CeedScalar` can now be set as `float` or `double` at compile time. 163- Added JiT utilities in `ceed/jit-tools.h` to reduce duplicated code in GPU backends. 164- Added support for JiT of QFunctions with `#include "relative/path/local-file.h"` statements for additional local files. Note that files included with `""` are searched relative to the current file first, then by compiler paths (as with `<>` includes). To use this feature, one should adhere to relative paths only, not compiler flags like `-I`, which the JiT will not be aware of. 165- Remove need to guard library headers in QFunction source for code generation backends. 166- `CeedDebugEnv()` macro created to provide debugging outputs when Ceed context is not present. 167- Added {c:func}`CeedStringAllocCopy` to reduce repeated code for copying strings internally. 168- Added {c:func}`CeedPathConcatenate` to facilitate loading kernel source files with a path relative to the current file. 169- Added support for non-tensor $H(\text{div})$ elements, to include CPU backend implementations and {c:func}`CeedBasisCreateHdiv` convenience constructor. 170- Added {c:func}`CeedQFunctionSetContextWritable` and read-only access to `CeedQFunctionContext` data as an optional feature to improve GPU performance. By default, calling the `CeedQFunctionUser` during {c:func}`CeedQFunctionApply` is assumed to write into the `CeedQFunctionContext` data, consistent with the previous behavior. Note that if a user asserts that their `CeedQFunctionUser` does not write into the `CeedQFunctionContext` data, they are responsible for the validity of this assertion. 171- Added support for element matrix assembly in GPU backends. 172 173### Maintainability 174 175- Refactored preconditioner support internally to facilitate future development and improve GPU completeness/test coverage. 176- `Include-what-you-use` makefile target added as `make iwyu`. 177- Create backend constant `CEED_FIELD_MAX` to reduce magic numbers in codebase. 178- Put GPU JiTed kernel source code into separate files. 179- Dropped legacy version support in PETSc based examples to better utilize PETSc DMPlex and Mat updates to support libCEED; current minimum PETSc version for the examples is v3.17. 180 181(v0-9)= 182 183## v0.9 (Jul 6, 2021) 184 185### Interface changes 186 187- Minor modification in error handling macro to silence pedantic warnings when compiling with Clang, but no functional impact. 188 189### New features 190 191- Add {c:func}`CeedVectorAXPY` and {c:func}`CeedVectorPointwiseMult` as a convenience for stand-alone testing and internal use. 192- Add `CEED_QFUNCTION_HELPER` macro to properly annotate QFunction helper functions for code generation backends. 193- Add `CeedPragmaOptimizeOff` macro for code that is sensitive to floating point errors from fast math optimizations. 194- Rust support: split `libceed-sys` crate out of `libceed` and [publish both on crates.io](https://crates.io/crates/libceed). 195 196### Performance improvements 197 198### Examples 199 200- Solid mechanics mini-app updated to explore the performance impacts of various formulations in the initial and current configurations. 201- Fluid mechanics example adds GPU support and improves modularity. 202 203### Deprecated backends 204 205- The `/cpu/self/tmpl` and `/cpu/self/tmpl/sub` backends have been removed. These backends were intially added to test the backend inheritance mechanism, but this mechanism is now widely used and tested in multiple backends. 206 207(v0-8)= 208 209## v0.8 (Mar 31, 2021) 210 211### Interface changes 212 213- Error handling improved to include enumerated error codes for C interface return values. 214- Installed headers that will follow semantic versioning were moved to {code}`include/ceed` directory. These headers have been renamed from {code}`ceed-*.h` to {code}`ceed/*.h`. Placeholder headers with the old naming schema are currently provided, but these headers will be removed in the libCEED v0.9 release. 215 216### New features 217 218- Julia and Rust interfaces added, providing a nearly 1-1 correspondence with the C interface, plus some convenience features. 219- Static libraries can be built with `make STATIC=1` and the pkg-config file is installed accordingly. 220- Add {c:func}`CeedOperatorLinearAssembleSymbolic` and {c:func}`CeedOperatorLinearAssemble` to support full assembly of libCEED operators. 221 222### Performance improvements 223 224- New HIP MAGMA backends for hipMAGMA library users: `/gpu/hip/magma` and `/gpu/hip/magma/det`. 225- New HIP backends for improved tensor basis performance: `/gpu/hip/shared` and `/gpu/hip/gen`. 226 227### Examples 228 229- {ref}`example-petsc-elasticity` example updated with traction boundary conditions and improved Dirichlet boundary conditions. 230- {ref}`example-petsc-elasticity` example updated with Neo-Hookean hyperelasticity in current configuration as well as improved Neo-Hookean hyperelasticity exploring storage vs computation tradeoffs. 231- {ref}`example-petsc-navier-stokes` example updated with isentropic traveling vortex test case, an analytical solution to the Euler equations that is useful for testing boundary conditions, discretization stability, and order of accuracy. 232- {ref}`example-petsc-navier-stokes` example updated with support for performing convergence study and plotting order of convergence by polynomial degree. 233 234(v0-7)= 235 236## v0.7 (Sep 29, 2020) 237 238### Interface changes 239 240- Replace limited {code}`CeedInterlaceMode` with more flexible component stride {code}`compstride` in {code}`CeedElemRestriction` constructors. 241 As a result, the {code}`indices` parameter has been replaced with {code}`offsets` and the {code}`nnodes` parameter has been replaced with {code}`lsize`. 242 These changes improve support for mixed finite element methods. 243- Replace various uses of {code}`Ceed*Get*Status` with {code}`Ceed*Is*` in the backend API to match common nomenclature. 244- Replace {code}`CeedOperatorAssembleLinearDiagonal` with {c:func}`CeedOperatorLinearAssembleDiagonal` for clarity. 245- Linear Operators can be assembled as point-block diagonal matrices with {c:func}`CeedOperatorLinearAssemblePointBlockDiagonal`, provided in row-major form in a {code}`ncomp` by {code}`ncomp` block per node. 246- Diagonal assemble interface changed to accept a {ref}`CeedVector` instead of a pointer to a {ref}`CeedVector` to reduce memory movement when interfacing with calling code. 247- Added {c:func}`CeedOperatorLinearAssembleAddDiagonal` and {c:func}`CeedOperatorLinearAssembleAddPointBlockDiagonal` for improved future integration with codes such as MFEM that compose the action of {ref}`CeedOperator`s external to libCEED. 248- Added {c:func}`CeedVectorTakeAray` to sync and remove libCEED read/write access to an allocated array and pass ownership of the array to the caller. 249 This function is recommended over {c:func}`CeedVectorSyncArray` when the {code}`CeedVector` has an array owned by the caller that was set by {c:func}`CeedVectorSetArray`. 250- Added {code}`CeedQFunctionContext` object to manage user QFunction context data and reduce copies between device and host memory. 251- Added {c:func}`CeedOperatorMultigridLevelCreate`, {c:func}`CeedOperatorMultigridLevelCreateTensorH1`, and {c:func}`CeedOperatorMultigridLevelCreateH1` to facilitate creation of multigrid prolongation, restriction, and coarse grid operators using a common quadrature space. 252 253### New features 254 255- New HIP backend: `/gpu/hip/ref`. 256- CeedQFunction support for user `CUfunction`s in some backends 257 258### Performance improvements 259 260- OCCA backend rebuilt to facilitate future performance enhancements. 261- PETSc BPs suite improved to reduce noise due to multiple calls to {code}`mpiexec`. 262 263### Examples 264 265- {ref}`example-petsc-elasticity` example updated with strain energy computation and more flexible boundary conditions. 266 267### Deprecated backends 268 269- The `/gpu/cuda/reg` backend has been removed, with its core features moved into `/gpu/cuda/ref` and `/gpu/cuda/shared`. 270 271(v0-6)= 272 273## v0.6 (Mar 29, 2020) 274 275libCEED v0.6 contains numerous new features and examples, as well as expanded 276documentation in [this new website](https://libceed.org). 277 278### New features 279 280- New Python interface using [CFFI](https://cffi.readthedocs.io/) provides a nearly 281 1-1 correspondence with the C interface, plus some convenience features. For instance, 282 data stored in the {cpp:type}`CeedVector` structure are available without copy as 283 {py:class}`numpy.ndarray`. Short tutorials are provided in 284 [Binder](https://mybinder.org/v2/gh/CEED/libCEED/main?urlpath=lab/tree/examples/tutorials/). 285- Linear QFunctions can be assembled as block-diagonal matrices (per quadrature point, 286 {c:func}`CeedOperatorAssembleLinearQFunction`) or to evaluate the diagonal 287 ({c:func}`CeedOperatorAssembleLinearDiagonal`). These operations are useful for 288 preconditioning ingredients and are used in the libCEED's multigrid examples. 289- The inverse of separable operators can be obtained using 290 {c:func}`CeedOperatorCreateFDMElementInverse` and applied with 291 {c:func}`CeedOperatorApply`. This is a useful preconditioning ingredient, 292 especially for Laplacians and related operators. 293- New functions: {c:func}`CeedVectorNorm`, {c:func}`CeedOperatorApplyAdd`, 294 {c:func}`CeedQFunctionView`, {c:func}`CeedOperatorView`. 295- Make public accessors for various attributes to facilitate writing composable code. 296- New backend: `/cpu/self/memcheck/serial`. 297- QFunctions using variable-length array (VLA) pointer constructs can be used with CUDA 298 backends. (Single source is coming soon for OCCA backends.) 299- Fix some missing edge cases in CUDA backend. 300 301### Performance Improvements 302 303- MAGMA backend performance optimization and non-tensor bases. 304- No-copy optimization in {c:func}`CeedOperatorApply`. 305 306### Interface changes 307 308- Replace {code}`CeedElemRestrictionCreateIdentity` and 309 {code}`CeedElemRestrictionCreateBlocked` with more flexible 310 {c:func}`CeedElemRestrictionCreateStrided` and 311 {c:func}`CeedElemRestrictionCreateBlockedStrided`. 312- Add arguments to {c:func}`CeedQFunctionCreateIdentity`. 313- Replace ambiguous uses of {cpp:enum}`CeedTransposeMode` for L-vector identification 314 with {cpp:enum}`CeedInterlaceMode`. This is now an attribute of the 315 {cpp:type}`CeedElemRestriction` (see {c:func}`CeedElemRestrictionCreate`) and no 316 longer passed as `lmode` arguments to {c:func}`CeedOperatorSetField` and 317 {c:func}`CeedElemRestrictionApply`. 318 319### Examples 320 321libCEED-0.6 contains greatly expanded examples with {ref}`new documentation <Examples>`. 322Notable additions include: 323 324- Standalone {ref}`ex2-surface` ({file}`examples/ceed/ex2-surface`): compute the area of 325 a domain in 1, 2, and 3 dimensions by applying a Laplacian. 326 327- PETSc {ref}`example-petsc-area` ({file}`examples/petsc/area.c`): computes surface area 328 of domains (like the cube and sphere) by direct integration on a surface mesh; 329 demonstrates geometric dimension different from topological dimension. 330 331- PETSc {ref}`example-petsc-bps`: 332 333 - {file}`examples/petsc/bpsraw.c` (formerly `bps.c`): transparent CUDA support. 334 - {file}`examples/petsc/bps.c` (formerly `bpsdmplex.c`): performance improvements 335 and transparent CUDA support. 336 - {ref}`example-petsc-bps-sphere` ({file}`examples/petsc/bpssphere.c`): 337 generalizations of all CEED BPs to the surface of the sphere; demonstrates geometric 338 dimension different from topological dimension. 339 340- {ref}`example-petsc-multigrid` ({file}`examples/petsc/multigrid.c`): new p-multigrid 341 solver with algebraic multigrid coarse solve. 342 343- {ref}`example-petsc-navier-stokes` ({file}`examples/fluids/navierstokes.c`; formerly 344 `examples/navier-stokes`): unstructured grid support (using PETSc's `DMPlex`), 345 implicit time integration, SU/SUPG stabilization, free-slip boundary conditions, and 346 quasi-2D computational domain support. 347 348- {ref}`example-petsc-elasticity` ({file}`examples/solids/elasticity.c`): new solver for 349 linear elasticity, small-strain hyperelasticity, and globalized finite-strain 350 hyperelasticity using p-multigrid with algebraic multigrid coarse solve. 351 352(v0-5)= 353 354## v0.5 (Sep 18, 2019) 355 356For this release, several improvements were made. Two new CUDA backends were added to 357the family of backends, of which, the new `cuda-gen` backend achieves state-of-the-art 358performance using single-source {ref}`CeedQFunction`. From this release, users 359can define Q-Functions in a single source code independently of the targeted backend 360with the aid of a new macro `CEED QFUNCTION` to support JIT (Just-In-Time) and CPU 361compilation of the user provided {ref}`CeedQFunction` code. To allow a unified 362declaration, the {ref}`CeedQFunction` API has undergone a slight change: 363the `QFunctionField` parameter `ncomp` has been changed to `size`. This change 364requires setting the previous value of `ncomp` to `ncomp*dim` when adding a 365`QFunctionField` with eval mode `CEED EVAL GRAD`. 366 367Additionally, new CPU backends 368were included in this release, such as the `/cpu/self/opt/*` backends (which are 369written in pure C and use partial **E-vectors** to improve performance) and the 370`/cpu/self/ref/memcheck` backend (which relies upon the 371[Valgrind](http://valgrind.org/) Memcheck tool to help verify that user 372{ref}`CeedQFunction` have no undefined values). 373This release also included various performance improvements, bug fixes, new examples, 374and improved tests. Among these improvements, vectorized instructions for 375{ref}`CeedQFunction` code compiled for CPU were enhanced by using `CeedPragmaSIMD` 376instead of `CeedPragmaOMP`, implementation of a {ref}`CeedQFunction` gallery and 377identity Q-Functions were introduced, and the PETSc benchmark problems were expanded 378to include unstructured meshes handling were. For this expansion, the prior version of 379the PETSc BPs, which only included data associated with structured geometries, were 380renamed `bpsraw`, and the new version of the BPs, which can handle data associated 381with any unstructured geometry, were called `bps`. Additionally, other benchmark 382problems, namely BP2 and BP4 (the vector-valued versions of BP1 and BP3, respectively), 383and BP5 and BP6 (the collocated versions---for which the quadrature points are the same 384as the Gauss Lobatto nodes---of BP3 and BP4 respectively) were added to the PETSc 385examples. Furthermoew, another standalone libCEED example, called `ex2`, which 386computes the surface area of a given mesh was added to this release. 387 388Backends available in this release: 389 390| CEED resource (`-ceed`) | Backend | 391|--------------------------|-----------------------------------------------------| 392| `/cpu/self/ref/serial` | Serial reference implementation | 393| `/cpu/self/ref/blocked` | Blocked reference implementation | 394| `/cpu/self/ref/memcheck` | Memcheck backend, undefined value checks | 395| `/cpu/self/opt/serial` | Serial optimized C implementation | 396| `/cpu/self/opt/blocked` | Blocked optimized C implementation | 397| `/cpu/self/avx/serial` | Serial AVX implementation | 398| `/cpu/self/avx/blocked` | Blocked AVX implementation | 399| `/cpu/self/xsmm/serial` | Serial LIBXSMM implementation | 400| `/cpu/self/xsmm/blocked` | Blocked LIBXSMM implementation | 401| `/cpu/occa` | Serial OCCA kernels | 402| `/gpu/occa` | CUDA OCCA kernels | 403| `/omp/occa` | OpenMP OCCA kernels | 404| `/ocl/occa` | OpenCL OCCA kernels | 405| `/gpu/cuda/ref` | Reference pure CUDA kernels | 406| `/gpu/cuda/reg` | Pure CUDA kernels using one thread per element | 407| `/gpu/cuda/shared` | Optimized pure CUDA kernels using shared memory | 408| `/gpu/cuda/gen` | Optimized pure CUDA kernels using code generation | 409| `/gpu/magma` | CUDA MAGMA kernels | 410 411Examples available in this release: 412 413:::{list-table} 414:header-rows: 1 415:widths: auto 416* - User code 417 - Example 418* - `ceed` 419 - * ex1 (volume) 420 * ex2 (surface) 421* - `mfem` 422 - * BP1 (scalar mass operator) 423 * BP3 (scalar Laplace operator) 424* - `petsc` 425 - * BP1 (scalar mass operator) 426 * BP2 (vector mass operator) 427 * BP3 (scalar Laplace operator) 428 * BP4 (vector Laplace operator) 429 * BP5 (collocated scalar Laplace operator) 430 * BP6 (collocated vector Laplace operator) 431 * Navier-Stokes 432* - `nek5000` 433 - * BP1 (scalar mass operator) 434 * BP3 (scalar Laplace operator) 435::: 436 437(v0-4)= 438 439## v0.4 (Apr 1, 2019) 440 441libCEED v0.4 was made again publicly available in the second full CEED software 442distribution, release CEED 2.0. This release contained notable features, such as 443four new CPU backends, two new GPU backends, CPU backend optimizations, initial 444support for operator composition, performance benchmarking, and a Navier-Stokes demo. 445The new CPU backends in this release came in two families. The `/cpu/self/*/serial` 446backends process one element at a time and are intended for meshes with a smaller number 447of high order elements. The `/cpu/self/*/blocked` backends process blocked batches of 448eight interlaced elements and are intended for meshes with higher numbers of elements. 449The `/cpu/self/avx/*` backends rely upon AVX instructions to provide vectorized CPU 450performance. The `/cpu/self/xsmm/*` backends rely upon the 451[LIBXSMM](http://github.com/hfp/libxsmm) package to provide vectorized CPU 452performance. The `/gpu/cuda/*` backends provide GPU performance strictly using CUDA. 453The `/gpu/cuda/ref` backend is a reference CUDA backend, providing reasonable 454performance for most problem configurations. The `/gpu/cuda/reg` backend uses a simple 455parallelization approach, where each thread treats a finite element. Using just in time 456compilation, provided by nvrtc (NVidia Runtime Compiler), and runtime parameters, this 457backend unroll loops and map memory address to registers. The `/gpu/cuda/reg` backend 458achieve good peak performance for 1D, 2D, and low order 3D problems, but performance 459deteriorates very quickly when threads run out of registers. 460 461A new explicit time-stepping Navier-Stokes solver was added to the family of libCEED 462examples in the `examples/petsc` directory (see {ref}`example-petsc-navier-stokes`). 463This example solves the time-dependent Navier-Stokes equations of compressible gas 464dynamics in a static Eulerian three-dimensional frame, using structured high-order 465finite/spectral element spatial discretizations and explicit high-order time-stepping 466(available in PETSc). Moreover, the Navier-Stokes example was developed using PETSc, 467so that the pointwise physics (defined at quadrature points) is separated from the 468parallelization and meshing concerns. 469 470Backends available in this release: 471 472| CEED resource (`-ceed`) | Backend | 473|--------------------------|-----------------------------------------------------| 474| `/cpu/self/ref/serial` | Serial reference implementation | 475| `/cpu/self/ref/blocked` | Blocked reference implementation | 476| `/cpu/self/tmpl` | Backend template, defaults to `/cpu/self/blocked` | 477| `/cpu/self/avx/serial` | Serial AVX implementation | 478| `/cpu/self/avx/blocked` | Blocked AVX implementation | 479| `/cpu/self/xsmm/serial` | Serial LIBXSMM implementation | 480| `/cpu/self/xsmm/blocked` | Blocked LIBXSMM implementation | 481| `/cpu/occa` | Serial OCCA kernels | 482| `/gpu/occa` | CUDA OCCA kernels | 483| `/omp/occa` | OpenMP OCCA kernels | 484| `/ocl/occa` | OpenCL OCCA kernels | 485| `/gpu/cuda/ref` | Reference pure CUDA kernels | 486| `/gpu/cuda/reg` | Pure CUDA kernels using one thread per element | 487| `/gpu/magma` | CUDA MAGMA kernels | 488 489Examples available in this release: 490 491:::{list-table} 492:header-rows: 1 493:widths: auto 494* - User code 495 - Example 496* - `ceed` 497 - * ex1 (volume) 498* - `mfem` 499 - * BP1 (scalar mass operator) 500 * BP3 (scalar Laplace operator) 501* - `petsc` 502 - * BP1 (scalar mass operator) 503 * BP3 (scalar Laplace operator) 504 * Navier-Stokes 505* - `nek5000` 506 - * BP1 (scalar mass operator) 507 * BP3 (scalar Laplace operator) 508::: 509 510(v0-3)= 511 512## v0.3 (Sep 30, 2018) 513 514Notable features in this release include active/passive field interface, support for 515non-tensor bases, backend optimization, and improved Fortran interface. This release 516also focused on providing improved continuous integration, and many new tests with code 517coverage reports of about 90%. This release also provided a significant change to the 518public interface: a {ref}`CeedQFunction` can take any number of named input and output 519arguments while {ref}`CeedOperator` connects them to the actual data, which may be 520supplied explicitly to `CeedOperatorApply()` (active) or separately via 521`CeedOperatorSetField()` (passive). This interface change enables reusable libraries 522of CeedQFunctions and composition of block solvers constructed using 523{ref}`CeedOperator`. A concept of blocked restriction was added to this release and 524used in an optimized CPU backend. Although this is typically not visible to the user, 525it enables effective use of arbitrary-length SIMD while maintaining cache locality. 526This CPU backend also implements an algebraic factorization of tensor product gradients 527to perform fewer operations than standard application of interpolation and 528differentiation from nodes to quadrature points. This algebraic formulation 529automatically supports non-polynomial and non-interpolatory bases, thus is more general 530than the more common derivation in terms of Lagrange polynomials on the quadrature points. 531 532Backends available in this release: 533 534| CEED resource (`-ceed`) | Backend | 535|-------------------------|-----------------------------------------------------| 536| `/cpu/self/blocked` | Blocked reference implementation | 537| `/cpu/self/ref` | Serial reference implementation | 538| `/cpu/self/tmpl` | Backend template, defaults to `/cpu/self/blocked` | 539| `/cpu/occa` | Serial OCCA kernels | 540| `/gpu/occa` | CUDA OCCA kernels | 541| `/omp/occa` | OpenMP OCCA kernels | 542| `/ocl/occa` | OpenCL OCCA kernels | 543| `/gpu/magma` | CUDA MAGMA kernels | 544 545Examples available in this release: 546 547:::{list-table} 548:header-rows: 1 549:widths: auto 550* - User code 551 - Example 552* - `ceed` 553 - * ex1 (volume) 554* - `mfem` 555 - * BP1 (scalar mass operator) 556 * BP3 (scalar Laplace operator) 557* - `petsc` 558 - * BP1 (scalar mass operator) 559 * BP3 (scalar Laplace operator) 560* - `nek5000` 561 - * BP1 (scalar mass operator) 562 * BP3 (scalar Laplace operator) 563::: 564 565(v0-21)= 566 567## v0.21 (Sep 30, 2018) 568 569A MAGMA backend (which relies upon the 570[MAGMA](https://bitbucket.org/icl/magma) package) was integrated in libCEED for this 571release. This initial integration set up the framework of using MAGMA and provided the 572libCEED functionality through MAGMA kernels as one of libCEED’s computational backends. 573As any other backend, the MAGMA backend provides extended basic data structures for 574{ref}`CeedVector`, {ref}`CeedElemRestriction`, and {ref}`CeedOperator`, and implements 575the fundamental CEED building blocks to work with the new data structures. 576In general, the MAGMA-specific data structures keep the libCEED pointers to CPU data 577but also add corresponding device (e.g., GPU) pointers to the data. Coherency is handled 578internally, and thus seamlessly to the user, through the functions/methods that are 579provided to support them. 580 581Backends available in this release: 582 583| CEED resource (`-ceed`) | Backend | 584|-------------------------|---------------------------------| 585| `/cpu/self` | Serial reference implementation | 586| `/cpu/occa` | Serial OCCA kernels | 587| `/gpu/occa` | CUDA OCCA kernels | 588| `/omp/occa` | OpenMP OCCA kernels | 589| `/ocl/occa` | OpenCL OCCA kernels | 590| `/gpu/magma` | CUDA MAGMA kernels | 591 592Examples available in this release: 593 594:::{list-table} 595:header-rows: 1 596:widths: auto 597* - User code 598 - Example 599* - `ceed` 600 - * ex1 (volume) 601* - `mfem` 602 - * BP1 (scalar mass operator) 603 * BP3 (scalar Laplace operator) 604* - `petsc` 605 - * BP1 (scalar mass operator) 606* - `nek5000` 607 - * BP1 (scalar mass operator) 608::: 609 610(v0-2)= 611 612## v0.2 (Mar 30, 2018) 613 614libCEED was made publicly available the first full CEED software distribution, release 615CEED 1.0. The distribution was made available using the Spack package manager to provide 616a common, easy-to-use build environment, where the user can build the CEED distribution 617with all dependencies. This release included a new Fortran interface for the library. 618This release also contained major improvements in the OCCA backend (including a new 619`/ocl/occa` backend) and new examples. The standalone libCEED example was modified to 620compute the volume volume of a given mesh (in 1D, 2D, or 3D) and placed in an 621`examples/ceed` subfolder. A new `mfem` example to perform BP3 (with the application 622of the Laplace operator) was also added to this release. 623 624Backends available in this release: 625 626| CEED resource (`-ceed`) | Backend | 627|-------------------------|---------------------------------| 628| `/cpu/self` | Serial reference implementation | 629| `/cpu/occa` | Serial OCCA kernels | 630| `/gpu/occa` | CUDA OCCA kernels | 631| `/omp/occa` | OpenMP OCCA kernels | 632| `/ocl/occa` | OpenCL OCCA kernels | 633 634Examples available in this release: 635 636:::{list-table} 637:header-rows: 1 638:widths: auto 639* - User code 640 - Example 641* - `ceed` 642 - * ex1 (volume) 643* - `mfem` 644 - * BP1 (scalar mass operator) 645 * BP3 (scalar Laplace operator) 646* - `petsc` 647 - * BP1 (scalar mass operator) 648* - `nek5000` 649 - * BP1 (scalar mass operator) 650::: 651 652(v0-1)= 653 654## v0.1 (Jan 3, 2018) 655 656Initial low-level API of the CEED project. The low-level API provides a set of Finite 657Elements kernels and components for writing new low-level kernels. Examples include: 658vector and sparse linear algebra, element matrix assembly over a batch of elements, 659partial assembly and action for efficient high-order operators like mass, diffusion, 660advection, etc. The main goal of the low-level API is to establish the basis for the 661high-level API. Also, identifying such low-level kernels and providing a reference 662implementation for them serves as the basis for specialized backend implementations. 663This release contained several backends: `/cpu/self`, and backends which rely upon the 664[OCCA](http://github.com/libocca/occa) package, such as `/cpu/occa`, 665`/gpu/occa`, and `/omp/occa`. 666It also included several examples, in the `examples` folder: 667A standalone code that shows the usage of libCEED (with no external 668dependencies) to apply the Laplace operator, `ex1`; an `mfem` example to perform BP1 669(with the application of the mass operator); and a `petsc` example to perform BP1 670(with the application of the mass operator). 671 672Backends available in this release: 673 674| CEED resource (`-ceed`) | Backend | 675|-------------------------|---------------------------------| 676| `/cpu/self` | Serial reference implementation | 677| `/cpu/occa` | Serial OCCA kernels | 678| `/gpu/occa` | CUDA OCCA kernels | 679| `/omp/occa` | OpenMP OCCA kernels | 680 681Examples available in this release: 682 683| User code | Example | 684|-----------------------|-----------------------------------| 685| `ceed` | ex1 (scalar Laplace operator) | 686| `mfem` | BP1 (scalar mass operator) | 687| `petsc` | BP1 (scalar mass operator) | 688``` 689