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