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- Add `CeedVectorReturnCeed` and similar when parent `Ceed` context for a libCEED object is only needed once in a calling scope. 20 21### Examples 22 23- Add deal.II example with CEED BP suite. 24 25(v0-12)= 26 27## v0.12 (Oct 31, 2023) 28 29### Interface changes 30 31- Update `CeedOperatorContext*` functions to `CeedOperator*Context*` functions for consistency. 32For example, `CeedOperatorContextGetFieldLabel` was renamed to `CeedOperatorGetContextFieldLabel`. 33- Removed `CeedBasisSetNumQuadraturePoints` as redundant and bug-prone interface. 34 35### New features 36 37- Added {c:func}`CeedOperatorGetFieldByName` to access a specific `CeedOperatorField` by its name. 38- Update `/cpu/self/memcheck/*` backends to help verify `CeedVector` array access assumptions and `CeedQFunction` user output assumptions. 39- Update {c:func}`CeedOperatorLinearAssembleDiagonal` to provide default implementation that supports `CeedOperator` with multiple active bases. 40- Added Sycl backends `/gpu/sycl/ref`, `/gpu/sycl/shared`, and `/gpu/sycl/gen`. 41- Added {c:func}`CeedBasisApplyAtPoints` for evaluation of values and derivatives at arbitrary points inside elements. 42- Added support for non-tensor $H(\text{curl})$ finite element spaces with {c:func}`CeedBasisCreateHcurl`. 43- 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)). 44- Added {c:func}`CeedOperatorLinearAssemblePointBlockDiagonalSymbolic` to create COO mapping for mapping out of {c:func}`CeedOperatorLinearAssemblePointBlockDiagonal`. 45- Added support for application codes which manage multiple {ref}`Ceed` objects, parallelized across OpenMP threads. 46 47### Examples 48 49- Add `DMSwarm` example demonstrating interpolation from background mesh to swarm points and projection from swarm points to background mesh. 50 51#### {ref}`example-petsc-bps` 52 53- Requires PETSc version 3.19 or later. 54 55#### {ref}`example-petsc-navier-stokes` 56 57- Updated restart and checkpointing interface. 58- Add data-driven subgrid-stress model. 59- Add differential filtering of solution. 60- Add turbulence statistics collection over spanwise-symmetric geometries. 61- Add Taylor-Green vortex initial condition. 62- Add Riemann-based outflow boundary conditions. 63- Added vortex shedding and flow past cylinder example, including calculations for lift, drag, and heat transfer. 64- Add Internal Damping Layer (IDL) for helping turbulent simulation stability. 65- Derive `CeedBasis` from `PetscFE`, and various other internal maintainability updates. 66 67(v0-11)= 68 69## v0.11 (Dec 24, 2022) 70 71### Interface changes 72 73- Added {c:func}`CeedOperatorSetName` for more readable {c:func}`CeedOperatorView` output. 74- Added {c:func}`CeedBasisCreateProjection` to facilitate interpolation between nodes for separate `CeedBases`. 75- Rename and move {c:func}`CeedCompositeOperatorGetNumSub` and {c:func}`CeedCompositeOperatorGetSubList` to public interface. 76- Renamed `CEED_BASIS_COLLOCATED` to `CEED_BASIS_NONE` for clarity. 77Some 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. 78 79### New features 80 81- Update `/cpu/self/memcheck/*` backends to help verify `CeedQFunctionContext` data sizes provided by user. 82- Improved support for $H(\text{div})$ bases. 83- Added `CeedInt_FMT` to support potential future use of larger integer sizes. 84- Added `CEED_QFUNCTION_ATTR` for setting compiler attributes/pragmas to `CEED_QFUNCTION_HELPER` and `CEED_QFUNCTION`. 85- OCCA backend updated to latest OCCA release; DPC++ and OMP OCCA modes enabled. 86Due to a limitation of the OCCA parser, typedefs are required to use pointers to arrays in QFunctions with the OCCA backend. 87This issue will be fixed in a future OCCA release. 88 89### Bugfix 90 91- Fix bug in setting device id for GPU backends. 92- Fix storing of indices for `CeedElemRestriction` on the host with GPU backends. 93- Fix `CeedElemRestriction` sizing for {c:func}`CeedOperatorAssemblePointBlockDiagonal`. 94- Fix bugs in CPU implementation of {c:func}`CeedOperatorLinearAssemble` when there are different number of active input modes and active output modes. 95 96### Examples 97 98#### {ref}`example-petsc-navier-stokes` 99 100- Various performance enhancements, analytic matrix-free and assembled Jacobian, and PETSc solver configurations for GPUs. 101- Refactored to improve code reuse and modularity. 102- Support for primitive variables for more accurate boundary layers and all-speed flow. 103- Added $YZ\beta$ shock capturing scheme and Shock Tube example. 104- Added Channel example, with comparison to analytic solutions. 105- Added Flat Plate with boundary layer mesh and compressible Blasius inflow condition based on Chebyshev collocation solution of the Blasius equations. 106- Added strong and weak synthetic turbulence generation (STG) inflow boundary conditions. 107- Added "freestream" boundary conditions based on HLLC Riemann solver. 108- Automated stabilization coefficients for different basis degree. 109 110#### {ref}`example-petsc-bps` 111 112- Support for convergence studies. 113 114### Maintainability 115 116- 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. 117- Enabled support for `p > 8` for `/gpu/*/shared` backends. 118- Switch to `clang-format` over `astyle` for automatic formatting; Makefile command changed to `make format` from `make style`. 119- Improved test harness. 120 121(v0-10-1)= 122 123## v0.10.1 (Apr 11, 2022) 124 125### Interface changes 126 127- Added {c:func}`CeedQFunctionSetUserFlopsEstimate` and {c:func}`CeedOperatorGetFlopsEstimate` to facilitate estimating FLOPs in operator application. 128 129### New features 130 131- Switched MAGMA backends to use runtime compilation for tensor basis kernels (and element restriction kernels, in non-deterministic `/gpu/*/magma` backends). 132This reduces time to compile the library and increases the range of parameters for which the MAGMA tensor basis kernels will work. 133 134### Bugfix 135 136- Install JiT source files in install directory to fix GPU functionality for installed libCEED. 137 138(v0-10)= 139 140## v0.10 (Mar 21, 2022) 141 142### Interface changes 143 144- Update {c:func}`CeedQFunctionGetFields` and {c:func}`CeedOperatorGetFields` to include number of fields. 145- 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`. 146- Clarify and document conditions where `CeedQFunction` and `CeedOperator` become immutable and no further fields or suboperators can be added. 147- Add {c:func}`CeedOperatorLinearAssembleQFunctionBuildOrUpdate` to reduce object creation overhead in assembly of CeedOperator preconditioning ingredients. 148- Promote {c:func}`CeedOperatorCheckReady`to the public API to facilitate interactive interfaces. 149- Warning added when compiling OCCA backend to alert users that this backend is experimental. 150- `ceed-backend.h`, `ceed-hash.h`, and `ceed-khash.h` removed. Users should use `ceed/backend.h`, `ceed/hash.h`, and `ceed/khash.h`. 151- Added {c:func}`CeedQFunctionGetKernelName`; refactored {c:func}`CeedQFunctionGetSourcePath` to exclude function kernel name. 152- 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`. 153- Added {c:func}`CeedVectorGetArrayWrite` that allows access to uninitialized arrays; require initialized data for {c:func}`CeedVectorGetArray`. 154- 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. 155- Added {c:func}`CeedQFunctionContextGetFieldDescriptions` to retrieve user defined descriptions of fields that are registered with `CeedQFunctionContextRegister*`. 156- Renamed `CeedElemTopology` entries for clearer namespacing between libCEED enums. 157- 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. 158- Added {c:func}`CeedOperatorSetQFunctionUpdated` to facilitate QFunction data re-use between operators sharing the same quadrature space, such as in a multigrid hierarchy. 159- Added {c:func}`CeedOperatorGetActiveVectorLengths` to get shape of CeedOperator. 160 161### New features 162 163- `CeedScalar` can now be set as `float` or `double` at compile time. 164- Added JiT utilities in `ceed/jit-tools.h` to reduce duplicated code in GPU backends. 165- 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. 166- Remove need to guard library headers in QFunction source for code generation backends. 167- `CeedDebugEnv()` macro created to provide debugging outputs when Ceed context is not present. 168- Added {c:func}`CeedStringAllocCopy` to reduce repeated code for copying strings internally. 169- Added {c:func}`CeedPathConcatenate` to facilitate loading kernel source files with a path relative to the current file. 170- Added support for non-tensor $H(\text{div})$ elements, to include CPU backend implementations and {c:func}`CeedBasisCreateHdiv` convenience constructor. 171- 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. 172- Added support for element matrix assembly in GPU backends. 173 174### Maintainability 175 176- Refactored preconditioner support internally to facilitate future development and improve GPU completeness/test coverage. 177- `Include-what-you-use` makefile target added as `make iwyu`. 178- Create backend constant `CEED_FIELD_MAX` to reduce magic numbers in codebase. 179- Put GPU JiTed kernel source code into separate files. 180- 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. 181 182(v0-9)= 183 184## v0.9 (Jul 6, 2021) 185 186### Interface changes 187 188- Minor modification in error handling macro to silence pedantic warnings when compiling with Clang, but no functional impact. 189 190### New features 191 192- Add {c:func}`CeedVectorAXPY` and {c:func}`CeedVectorPointwiseMult` as a convenience for stand-alone testing and internal use. 193- Add `CEED_QFUNCTION_HELPER` macro to properly annotate QFunction helper functions for code generation backends. 194- Add `CeedPragmaOptimizeOff` macro for code that is sensitive to floating point errors from fast math optimizations. 195- Rust support: split `libceed-sys` crate out of `libceed` and [publish both on crates.io](https://crates.io/crates/libceed). 196 197### Performance improvements 198 199### Examples 200 201- Solid mechanics mini-app updated to explore the performance impacts of various formulations in the initial and current configurations. 202- Fluid mechanics example adds GPU support and improves modularity. 203 204### Deprecated backends 205 206- 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. 207 208(v0-8)= 209 210## v0.8 (Mar 31, 2021) 211 212### Interface changes 213 214- Error handling improved to include enumerated error codes for C interface return values. 215- 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. 216 217### New features 218 219- Julia and Rust interfaces added, providing a nearly 1-1 correspondence with the C interface, plus some convenience features. 220- Static libraries can be built with `make STATIC=1` and the pkg-config file is installed accordingly. 221- Add {c:func}`CeedOperatorLinearAssembleSymbolic` and {c:func}`CeedOperatorLinearAssemble` to support full assembly of libCEED operators. 222 223### Performance improvements 224 225- New HIP MAGMA backends for hipMAGMA library users: `/gpu/hip/magma` and `/gpu/hip/magma/det`. 226- New HIP backends for improved tensor basis performance: `/gpu/hip/shared` and `/gpu/hip/gen`. 227 228### Examples 229 230- {ref}`example-petsc-elasticity` example updated with traction boundary conditions and improved Dirichlet boundary conditions. 231- {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. 232- {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. 233- {ref}`example-petsc-navier-stokes` example updated with support for performing convergence study and plotting order of convergence by polynomial degree. 234 235(v0-7)= 236 237## v0.7 (Sep 29, 2020) 238 239### Interface changes 240 241- Replace limited {code}`CeedInterlaceMode` with more flexible component stride {code}`compstride` in {code}`CeedElemRestriction` constructors. 242 As a result, the {code}`indices` parameter has been replaced with {code}`offsets` and the {code}`nnodes` parameter has been replaced with {code}`lsize`. 243 These changes improve support for mixed finite element methods. 244- Replace various uses of {code}`Ceed*Get*Status` with {code}`Ceed*Is*` in the backend API to match common nomenclature. 245- Replace {code}`CeedOperatorAssembleLinearDiagonal` with {c:func}`CeedOperatorLinearAssembleDiagonal` for clarity. 246- 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. 247- 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. 248- 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. 249- 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. 250 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`. 251- Added {code}`CeedQFunctionContext` object to manage user QFunction context data and reduce copies between device and host memory. 252- 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. 253 254### New features 255 256- New HIP backend: `/gpu/hip/ref`. 257- CeedQFunction support for user `CUfunction`s in some backends 258 259### Performance improvements 260 261- OCCA backend rebuilt to facilitate future performance enhancements. 262- PETSc BPs suite improved to reduce noise due to multiple calls to {code}`mpiexec`. 263 264### Examples 265 266- {ref}`example-petsc-elasticity` example updated with strain energy computation and more flexible boundary conditions. 267 268### Deprecated backends 269 270- The `/gpu/cuda/reg` backend has been removed, with its core features moved into `/gpu/cuda/ref` and `/gpu/cuda/shared`. 271 272(v0-6)= 273 274## v0.6 (Mar 29, 2020) 275 276libCEED v0.6 contains numerous new features and examples, as well as expanded 277documentation in [this new website](https://libceed.org). 278 279### New features 280 281- New Python interface using [CFFI](https://cffi.readthedocs.io/) provides a nearly 282 1-1 correspondence with the C interface, plus some convenience features. For instance, 283 data stored in the {cpp:type}`CeedVector` structure are available without copy as 284 {py:class}`numpy.ndarray`. Short tutorials are provided in 285 [Binder](https://mybinder.org/v2/gh/CEED/libCEED/main?urlpath=lab/tree/examples/tutorials/). 286- Linear QFunctions can be assembled as block-diagonal matrices (per quadrature point, 287 {c:func}`CeedOperatorAssembleLinearQFunction`) or to evaluate the diagonal 288 ({c:func}`CeedOperatorAssembleLinearDiagonal`). These operations are useful for 289 preconditioning ingredients and are used in the libCEED's multigrid examples. 290- The inverse of separable operators can be obtained using 291 {c:func}`CeedOperatorCreateFDMElementInverse` and applied with 292 {c:func}`CeedOperatorApply`. This is a useful preconditioning ingredient, 293 especially for Laplacians and related operators. 294- New functions: {c:func}`CeedVectorNorm`, {c:func}`CeedOperatorApplyAdd`, 295 {c:func}`CeedQFunctionView`, {c:func}`CeedOperatorView`. 296- Make public accessors for various attributes to facilitate writing composable code. 297- New backend: `/cpu/self/memcheck/serial`. 298- QFunctions using variable-length array (VLA) pointer constructs can be used with CUDA 299 backends. (Single source is coming soon for OCCA backends.) 300- Fix some missing edge cases in CUDA backend. 301 302### Performance Improvements 303 304- MAGMA backend performance optimization and non-tensor bases. 305- No-copy optimization in {c:func}`CeedOperatorApply`. 306 307### Interface changes 308 309- Replace {code}`CeedElemRestrictionCreateIdentity` and 310 {code}`CeedElemRestrictionCreateBlocked` with more flexible 311 {c:func}`CeedElemRestrictionCreateStrided` and 312 {c:func}`CeedElemRestrictionCreateBlockedStrided`. 313- Add arguments to {c:func}`CeedQFunctionCreateIdentity`. 314- Replace ambiguous uses of {cpp:enum}`CeedTransposeMode` for L-vector identification 315 with {cpp:enum}`CeedInterlaceMode`. This is now an attribute of the 316 {cpp:type}`CeedElemRestriction` (see {c:func}`CeedElemRestrictionCreate`) and no 317 longer passed as `lmode` arguments to {c:func}`CeedOperatorSetField` and 318 {c:func}`CeedElemRestrictionApply`. 319 320### Examples 321 322libCEED-0.6 contains greatly expanded examples with {ref}`new documentation <Examples>`. 323Notable additions include: 324 325- Standalone {ref}`ex2-surface` ({file}`examples/ceed/ex2-surface`): compute the area of 326 a domain in 1, 2, and 3 dimensions by applying a Laplacian. 327 328- PETSc {ref}`example-petsc-area` ({file}`examples/petsc/area.c`): computes surface area 329 of domains (like the cube and sphere) by direct integration on a surface mesh; 330 demonstrates geometric dimension different from topological dimension. 331 332- PETSc {ref}`example-petsc-bps`: 333 334 - {file}`examples/petsc/bpsraw.c` (formerly `bps.c`): transparent CUDA support. 335 - {file}`examples/petsc/bps.c` (formerly `bpsdmplex.c`): performance improvements 336 and transparent CUDA support. 337 - {ref}`example-petsc-bps-sphere` ({file}`examples/petsc/bpssphere.c`): 338 generalizations of all CEED BPs to the surface of the sphere; demonstrates geometric 339 dimension different from topological dimension. 340 341- {ref}`example-petsc-multigrid` ({file}`examples/petsc/multigrid.c`): new p-multigrid 342 solver with algebraic multigrid coarse solve. 343 344- {ref}`example-petsc-navier-stokes` ({file}`examples/fluids/navierstokes.c`; formerly 345 `examples/navier-stokes`): unstructured grid support (using PETSc's `DMPlex`), 346 implicit time integration, SU/SUPG stabilization, free-slip boundary conditions, and 347 quasi-2D computational domain support. 348 349- {ref}`example-petsc-elasticity` ({file}`examples/solids/elasticity.c`): new solver for 350 linear elasticity, small-strain hyperelasticity, and globalized finite-strain 351 hyperelasticity using p-multigrid with algebraic multigrid coarse solve. 352 353(v0-5)= 354 355## v0.5 (Sep 18, 2019) 356 357For this release, several improvements were made. Two new CUDA backends were added to 358the family of backends, of which, the new `cuda-gen` backend achieves state-of-the-art 359performance using single-source {ref}`CeedQFunction`. From this release, users 360can define Q-Functions in a single source code independently of the targeted backend 361with the aid of a new macro `CEED QFUNCTION` to support JIT (Just-In-Time) and CPU 362compilation of the user provided {ref}`CeedQFunction` code. To allow a unified 363declaration, the {ref}`CeedQFunction` API has undergone a slight change: 364the `QFunctionField` parameter `ncomp` has been changed to `size`. This change 365requires setting the previous value of `ncomp` to `ncomp*dim` when adding a 366`QFunctionField` with eval mode `CEED EVAL GRAD`. 367 368Additionally, new CPU backends 369were included in this release, such as the `/cpu/self/opt/*` backends (which are 370written in pure C and use partial **E-vectors** to improve performance) and the 371`/cpu/self/ref/memcheck` backend (which relies upon the 372[Valgrind](http://valgrind.org/) Memcheck tool to help verify that user 373{ref}`CeedQFunction` have no undefined values). 374This release also included various performance improvements, bug fixes, new examples, 375and improved tests. Among these improvements, vectorized instructions for 376{ref}`CeedQFunction` code compiled for CPU were enhanced by using `CeedPragmaSIMD` 377instead of `CeedPragmaOMP`, implementation of a {ref}`CeedQFunction` gallery and 378identity Q-Functions were introduced, and the PETSc benchmark problems were expanded 379to include unstructured meshes handling were. For this expansion, the prior version of 380the PETSc BPs, which only included data associated with structured geometries, were 381renamed `bpsraw`, and the new version of the BPs, which can handle data associated 382with any unstructured geometry, were called `bps`. Additionally, other benchmark 383problems, namely BP2 and BP4 (the vector-valued versions of BP1 and BP3, respectively), 384and BP5 and BP6 (the collocated versions---for which the quadrature points are the same 385as the Gauss Lobatto nodes---of BP3 and BP4 respectively) were added to the PETSc 386examples. Furthermoew, another standalone libCEED example, called `ex2`, which 387computes the surface area of a given mesh was added to this release. 388 389Backends available in this release: 390 391| CEED resource (`-ceed`) | Backend | 392|--------------------------|-----------------------------------------------------| 393| `/cpu/self/ref/serial` | Serial reference implementation | 394| `/cpu/self/ref/blocked` | Blocked reference implementation | 395| `/cpu/self/ref/memcheck` | Memcheck backend, undefined value checks | 396| `/cpu/self/opt/serial` | Serial optimized C implementation | 397| `/cpu/self/opt/blocked` | Blocked optimized C implementation | 398| `/cpu/self/avx/serial` | Serial AVX implementation | 399| `/cpu/self/avx/blocked` | Blocked AVX implementation | 400| `/cpu/self/xsmm/serial` | Serial LIBXSMM implementation | 401| `/cpu/self/xsmm/blocked` | Blocked LIBXSMM implementation | 402| `/cpu/occa` | Serial OCCA kernels | 403| `/gpu/occa` | CUDA OCCA kernels | 404| `/omp/occa` | OpenMP OCCA kernels | 405| `/ocl/occa` | OpenCL OCCA kernels | 406| `/gpu/cuda/ref` | Reference pure CUDA kernels | 407| `/gpu/cuda/reg` | Pure CUDA kernels using one thread per element | 408| `/gpu/cuda/shared` | Optimized pure CUDA kernels using shared memory | 409| `/gpu/cuda/gen` | Optimized pure CUDA kernels using code generation | 410| `/gpu/magma` | CUDA MAGMA kernels | 411 412Examples available in this release: 413 414:::{list-table} 415:header-rows: 1 416:widths: auto 417* - User code 418 - Example 419* - `ceed` 420 - * ex1 (volume) 421 * ex2 (surface) 422* - `mfem` 423 - * BP1 (scalar mass operator) 424 * BP3 (scalar Laplace operator) 425* - `petsc` 426 - * BP1 (scalar mass operator) 427 * BP2 (vector mass operator) 428 * BP3 (scalar Laplace operator) 429 * BP4 (vector Laplace operator) 430 * BP5 (collocated scalar Laplace operator) 431 * BP6 (collocated vector Laplace operator) 432 * Navier-Stokes 433* - `nek5000` 434 - * BP1 (scalar mass operator) 435 * BP3 (scalar Laplace operator) 436::: 437 438(v0-4)= 439 440## v0.4 (Apr 1, 2019) 441 442libCEED v0.4 was made again publicly available in the second full CEED software 443distribution, release CEED 2.0. This release contained notable features, such as 444four new CPU backends, two new GPU backends, CPU backend optimizations, initial 445support for operator composition, performance benchmarking, and a Navier-Stokes demo. 446The new CPU backends in this release came in two families. The `/cpu/self/*/serial` 447backends process one element at a time and are intended for meshes with a smaller number 448of high order elements. The `/cpu/self/*/blocked` backends process blocked batches of 449eight interlaced elements and are intended for meshes with higher numbers of elements. 450The `/cpu/self/avx/*` backends rely upon AVX instructions to provide vectorized CPU 451performance. The `/cpu/self/xsmm/*` backends rely upon the 452[LIBXSMM](http://github.com/hfp/libxsmm) package to provide vectorized CPU 453performance. The `/gpu/cuda/*` backends provide GPU performance strictly using CUDA. 454The `/gpu/cuda/ref` backend is a reference CUDA backend, providing reasonable 455performance for most problem configurations. The `/gpu/cuda/reg` backend uses a simple 456parallelization approach, where each thread treats a finite element. Using just in time 457compilation, provided by nvrtc (NVidia Runtime Compiler), and runtime parameters, this 458backend unroll loops and map memory address to registers. The `/gpu/cuda/reg` backend 459achieve good peak performance for 1D, 2D, and low order 3D problems, but performance 460deteriorates very quickly when threads run out of registers. 461 462A new explicit time-stepping Navier-Stokes solver was added to the family of libCEED 463examples in the `examples/petsc` directory (see {ref}`example-petsc-navier-stokes`). 464This example solves the time-dependent Navier-Stokes equations of compressible gas 465dynamics in a static Eulerian three-dimensional frame, using structured high-order 466finite/spectral element spatial discretizations and explicit high-order time-stepping 467(available in PETSc). Moreover, the Navier-Stokes example was developed using PETSc, 468so that the pointwise physics (defined at quadrature points) is separated from the 469parallelization and meshing concerns. 470 471Backends available in this release: 472 473| CEED resource (`-ceed`) | Backend | 474|--------------------------|-----------------------------------------------------| 475| `/cpu/self/ref/serial` | Serial reference implementation | 476| `/cpu/self/ref/blocked` | Blocked reference implementation | 477| `/cpu/self/tmpl` | Backend template, defaults to `/cpu/self/blocked` | 478| `/cpu/self/avx/serial` | Serial AVX implementation | 479| `/cpu/self/avx/blocked` | Blocked AVX implementation | 480| `/cpu/self/xsmm/serial` | Serial LIBXSMM implementation | 481| `/cpu/self/xsmm/blocked` | Blocked LIBXSMM implementation | 482| `/cpu/occa` | Serial OCCA kernels | 483| `/gpu/occa` | CUDA OCCA kernels | 484| `/omp/occa` | OpenMP OCCA kernels | 485| `/ocl/occa` | OpenCL OCCA kernels | 486| `/gpu/cuda/ref` | Reference pure CUDA kernels | 487| `/gpu/cuda/reg` | Pure CUDA kernels using one thread per element | 488| `/gpu/magma` | CUDA MAGMA kernels | 489 490Examples available in this release: 491 492:::{list-table} 493:header-rows: 1 494:widths: auto 495* - User code 496 - Example 497* - `ceed` 498 - * ex1 (volume) 499* - `mfem` 500 - * BP1 (scalar mass operator) 501 * BP3 (scalar Laplace operator) 502* - `petsc` 503 - * BP1 (scalar mass operator) 504 * BP3 (scalar Laplace operator) 505 * Navier-Stokes 506* - `nek5000` 507 - * BP1 (scalar mass operator) 508 * BP3 (scalar Laplace operator) 509::: 510 511(v0-3)= 512 513## v0.3 (Sep 30, 2018) 514 515Notable features in this release include active/passive field interface, support for 516non-tensor bases, backend optimization, and improved Fortran interface. This release 517also focused on providing improved continuous integration, and many new tests with code 518coverage reports of about 90%. This release also provided a significant change to the 519public interface: a {ref}`CeedQFunction` can take any number of named input and output 520arguments while {ref}`CeedOperator` connects them to the actual data, which may be 521supplied explicitly to `CeedOperatorApply()` (active) or separately via 522`CeedOperatorSetField()` (passive). This interface change enables reusable libraries 523of CeedQFunctions and composition of block solvers constructed using 524{ref}`CeedOperator`. A concept of blocked restriction was added to this release and 525used in an optimized CPU backend. Although this is typically not visible to the user, 526it enables effective use of arbitrary-length SIMD while maintaining cache locality. 527This CPU backend also implements an algebraic factorization of tensor product gradients 528to perform fewer operations than standard application of interpolation and 529differentiation from nodes to quadrature points. This algebraic formulation 530automatically supports non-polynomial and non-interpolatory bases, thus is more general 531than the more common derivation in terms of Lagrange polynomials on the quadrature points. 532 533Backends available in this release: 534 535| CEED resource (`-ceed`) | Backend | 536|-------------------------|-----------------------------------------------------| 537| `/cpu/self/blocked` | Blocked reference implementation | 538| `/cpu/self/ref` | Serial reference implementation | 539| `/cpu/self/tmpl` | Backend template, defaults to `/cpu/self/blocked` | 540| `/cpu/occa` | Serial OCCA kernels | 541| `/gpu/occa` | CUDA OCCA kernels | 542| `/omp/occa` | OpenMP OCCA kernels | 543| `/ocl/occa` | OpenCL OCCA kernels | 544| `/gpu/magma` | CUDA MAGMA kernels | 545 546Examples available in this release: 547 548:::{list-table} 549:header-rows: 1 550:widths: auto 551* - User code 552 - Example 553* - `ceed` 554 - * ex1 (volume) 555* - `mfem` 556 - * BP1 (scalar mass operator) 557 * BP3 (scalar Laplace operator) 558* - `petsc` 559 - * BP1 (scalar mass operator) 560 * BP3 (scalar Laplace operator) 561* - `nek5000` 562 - * BP1 (scalar mass operator) 563 * BP3 (scalar Laplace operator) 564::: 565 566(v0-21)= 567 568## v0.21 (Sep 30, 2018) 569 570A MAGMA backend (which relies upon the 571[MAGMA](https://bitbucket.org/icl/magma) package) was integrated in libCEED for this 572release. This initial integration set up the framework of using MAGMA and provided the 573libCEED functionality through MAGMA kernels as one of libCEED’s computational backends. 574As any other backend, the MAGMA backend provides extended basic data structures for 575{ref}`CeedVector`, {ref}`CeedElemRestriction`, and {ref}`CeedOperator`, and implements 576the fundamental CEED building blocks to work with the new data structures. 577In general, the MAGMA-specific data structures keep the libCEED pointers to CPU data 578but also add corresponding device (e.g., GPU) pointers to the data. Coherency is handled 579internally, and thus seamlessly to the user, through the functions/methods that are 580provided to support them. 581 582Backends available in this release: 583 584| CEED resource (`-ceed`) | Backend | 585|-------------------------|---------------------------------| 586| `/cpu/self` | Serial reference implementation | 587| `/cpu/occa` | Serial OCCA kernels | 588| `/gpu/occa` | CUDA OCCA kernels | 589| `/omp/occa` | OpenMP OCCA kernels | 590| `/ocl/occa` | OpenCL OCCA kernels | 591| `/gpu/magma` | CUDA MAGMA kernels | 592 593Examples available in this release: 594 595:::{list-table} 596:header-rows: 1 597:widths: auto 598* - User code 599 - Example 600* - `ceed` 601 - * ex1 (volume) 602* - `mfem` 603 - * BP1 (scalar mass operator) 604 * BP3 (scalar Laplace operator) 605* - `petsc` 606 - * BP1 (scalar mass operator) 607* - `nek5000` 608 - * BP1 (scalar mass operator) 609::: 610 611(v0-2)= 612 613## v0.2 (Mar 30, 2018) 614 615libCEED was made publicly available the first full CEED software distribution, release 616CEED 1.0. The distribution was made available using the Spack package manager to provide 617a common, easy-to-use build environment, where the user can build the CEED distribution 618with all dependencies. This release included a new Fortran interface for the library. 619This release also contained major improvements in the OCCA backend (including a new 620`/ocl/occa` backend) and new examples. The standalone libCEED example was modified to 621compute the volume volume of a given mesh (in 1D, 2D, or 3D) and placed in an 622`examples/ceed` subfolder. A new `mfem` example to perform BP3 (with the application 623of the Laplace operator) was also added to this release. 624 625Backends available in this release: 626 627| CEED resource (`-ceed`) | Backend | 628|-------------------------|---------------------------------| 629| `/cpu/self` | Serial reference implementation | 630| `/cpu/occa` | Serial OCCA kernels | 631| `/gpu/occa` | CUDA OCCA kernels | 632| `/omp/occa` | OpenMP OCCA kernels | 633| `/ocl/occa` | OpenCL OCCA kernels | 634 635Examples available in this release: 636 637:::{list-table} 638:header-rows: 1 639:widths: auto 640* - User code 641 - Example 642* - `ceed` 643 - * ex1 (volume) 644* - `mfem` 645 - * BP1 (scalar mass operator) 646 * BP3 (scalar Laplace operator) 647* - `petsc` 648 - * BP1 (scalar mass operator) 649* - `nek5000` 650 - * BP1 (scalar mass operator) 651::: 652 653(v0-1)= 654 655## v0.1 (Jan 3, 2018) 656 657Initial low-level API of the CEED project. The low-level API provides a set of Finite 658Elements kernels and components for writing new low-level kernels. Examples include: 659vector and sparse linear algebra, element matrix assembly over a batch of elements, 660partial assembly and action for efficient high-order operators like mass, diffusion, 661advection, etc. The main goal of the low-level API is to establish the basis for the 662high-level API. Also, identifying such low-level kernels and providing a reference 663implementation for them serves as the basis for specialized backend implementations. 664This release contained several backends: `/cpu/self`, and backends which rely upon the 665[OCCA](http://github.com/libocca/occa) package, such as `/cpu/occa`, 666`/gpu/occa`, and `/omp/occa`. 667It also included several examples, in the `examples` folder: 668A standalone code that shows the usage of libCEED (with no external 669dependencies) to apply the Laplace operator, `ex1`; an `mfem` example to perform BP1 670(with the application of the mass operator); and a `petsc` example to perform BP1 671(with the application of the mass operator). 672 673Backends available in this release: 674 675| CEED resource (`-ceed`) | Backend | 676|-------------------------|---------------------------------| 677| `/cpu/self` | Serial reference implementation | 678| `/cpu/occa` | Serial OCCA kernels | 679| `/gpu/occa` | CUDA OCCA kernels | 680| `/omp/occa` | OpenMP OCCA kernels | 681 682Examples available in this release: 683 684| User code | Example | 685|-----------------------|-----------------------------------| 686| `ceed` | ex1 (scalar Laplace operator) | 687| `mfem` | BP1 (scalar mass operator) | 688| `petsc` | BP1 (scalar mass operator) | 689``` 690