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