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