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