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