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