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