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