xref: /petsc/doc/changes/321.md (revision b11d9968bc79904c690b122f9399be46447eb113) !

# Changes: 3.21

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```{rubric} General:
```

- Add single precision support for using HYPRE and MFEM
- Require Fortran 2003 compiler with GET_COMMAND_ARGUMENT() support for building PETSc with Fortran bindings

```{rubric} Configure/Build:
```

- Add `--download-blis-use-openmp=0` to force `download-blis` to not build with OpenMP when `with-openmp` is provided
- Add `PetscBLASSetNumThreads()` and `PetscBLASGetNumThreads()` for controlling how many threads the BLAS routines use
- Change `win_cl` and similar `win32fe` compiler wrappers to `win32fe_cl`
- Add build support for Intel oneAPI compilers `icx` and `ifx` on Microsoft Windows with compiler wrappers `win32fe_icx` and `win32fe_ifx` (only static library build with `ifx`)
- Add lib/petsc/bin/maint/runjobs.py list-of-jobs script to allow submitting a subset of the jobs to the CI

```{rubric} Sys:
```

- Add `PetscBench` an object class for managing benchmarks in PETSc
- Deprecate `PetscVoidFunction`, `PetscVoidStarFunction`, and `PetscErrorCodeFunction` typedefs in favor of
  `PetscVoidFn` and `PetscErrorCodeFn`
- Add `PetscOptionsBoundedReal()` and `PetscOptionsRangeReal()`
- Rename PETSc stream types to `PETSC_STREAM_DEFAULT`, `PETSC_STREAM_NONBLOCKING`, `PETSC_STREAM_DEFAULT_WITH_BARRIER` and `PETSC_STREAM_NONBLOCKING_WITH_BARRIER`. The root device context uses `PETSC_STREAM_DEFAULT` by default

```{rubric} Event Logging:
```

```{rubric} PetscViewer:
```

- Change `PetscViewerRestoreSubViewer()` to no longer need a call to `PetscViewerFlush()` after it
- Introduce `PetscOptionsRestoreViewer()` that must be called after `PetscOptionsGetViewer()` and `PetscOptionsGetViewers()`
  to ensure thread safety
- Add `PetscViewerASCIIWORLDSetFileUnit()`

```{rubric} PetscDraw:
```

```{rubric} AO:
```

```{rubric} IS:
```

- Add `ISLocalToGlobalMappingGetNodeInfo()` and `ISLocalToGlobalMappingRestoreNodeInfo()` to access neighboring information of local indices
- Add support to load an `ISLocalToGlobalMapping` via `ISLocalToGlobalMappingLoad()` from data previously stored using `ISLocalToGlobalMappingView()`
- Add `ISLocalToGlobalMappingGetBlockMultiLeavesSF()` to share local block data

```{rubric} VecScatter / PetscSF:
```

- Add MPI-4.0 persistent neighborhood collectives support. Use -sf_neighbor_persistent along with -sf_type neighbor to enable it
- Add `PetscSFCreateStridedSF()` to communicate strided blocks of data

```{rubric} PF:
```

```{rubric} Vec:
```

- Add `VecGhostGetGhostIS()` to get the ghost indices of a ghosted vector
- Add `-vec_mdot_use_gemv` to let `VecMDot()`, `VecMTDot()` use BLAS2 `gemv()` instead of custom unrolled kernel. Default is on
- Add `-vec_maxpy_use_gemv` to let `VecMAXPY()` use BLAS2 `gemv()` instead of custom unrolled kernel. Default is off
- `VecReplaceArray()` on the first Vec obtained from `VecDuplicateVecs()` with either of the two above \*\_use_gemv options won't work anymore. If needed, turn them off or use `VecDuplicateVec()` instead
- `VecScale()` is now a logically collective operation
- Add `VecISShift()` to shift a part of the vector
- `VecISSet()` does no longer accept NULL as index set
- `VecLoad()` automatically determines whether the file was written using 32-bit or 64-bit indices, and files can read with PETSc built either way

```{rubric} PetscSection:
```

- Add `PetscSectionGetBlockStarts()` and `PetscSectionSetBlockStarts()`
- Add argument to `PetscSectionCreateGlobalSection()` that can ignore the local section permutation
- Add `PetscSectionCreateComponentSubsection()`

```{rubric} PetscPartitioner:
```

- Add edge weights to `PetscPartitionerPartition()`

```{rubric} Mat:
```

- Reset `MATLMVM` history vectors if size is changed
- Add specific support for `MatMultHermitianTranspose()` and `MatMultHermitianTransposeAdd()` in `MATSHELL`, `MATDENSE`, `MATNEST`, and `MATSCALAPACK`
- Add function `MatProductGetAlgorithm()`
- `MATTRANSPOSEVIRTUAL`, `MATHERMITIANTRANSPOSEVIRTUAL`, `MATNORMAL`, `MATNORMALHERMITIAN`, and `MATCOMPOSITE` now derive from `MATSHELL`. This implies a new behavior for those `Mat`, as calling `MatAssemblyBegin()`/`MatAssemblyEnd()` destroys scalings and shifts for `MATSHELL`, but it was not previously the case for other `MatType`
- Add function `MatGetRowSumAbs()` to compute vector of L1 norms of rows ([B]AIJ only)
- Add partial support for `MatBackwardSolve()`/`MatForwardSolve()` with `MATSOLVERMKL_PARDISO` and `MATSOLVERMKL_CPARDISO`
- Deprecate `MATIS` options `-matis_xxx`. Use `-mat_is_xxx`
- Add support for repeated entries in the local part of the local to global map for `MATIS` via the routines `MatISSetAllowRepeated()` and `MatISGetAllowRepeated()`
- Add support to dump and load a matrix of `MATIS` type
- Add dense representations of symmetric Broyden matrices `MATLMVMDBFGS`, `MATLMVMDDFP`, and `MATLMVMDQN`
- Add `MATSELLHIP` and the corresponding HIP kernels for matrix-vector multiplication

```{rubric} MatCoarsen:
```

- Add `MatCoarsenSetMaximumIterations()` with corresponding option `-mat_coarsen_max_it <4>`. The number of iteration of the coarsening method. Used for the HEM coarsener
- Add `MatCoarsenSetThreshold()` with corresponding option `-mat_coarsen_threshold <-1>`. Threshold for filtering graph for HEM. Like GAMG < 0 means no filtering
- Change API for several PetscCD methods used internally in `PCGAMG` and `MatCoarsen` (eg, change `PetscCDSetChuckSize()` to `PetscCDSetChunckSize()`), remove `Mat` argument from\`\`PetscCDGetASMBlocks()\`\`

```{rubric} PC:
```

- Add `PCGAMGSetLowMemoryFilter()` with corresponding option `-pc_gamg_low_memory_threshold_filter`. Use the system `MatFilter` graph/matrix filter, without a temporary copy of the graph, otherwise use method that can be faster
- Add `PCGAMGASMSetHEM()` with corresponding option `-pc_gamg_asm_hem_aggs N`. Use ASM smoother constructed from N applications of heavy edge matching
- `PCMAT` use `MatSolve()` if implemented by the matrix type
- Add `PCLMVMSetUpdateVec()` for the automatic update of the LMVM preconditioner inside a SNES solve
- Add `PCGAMGSetInjectionIndex()` with corresponding option `-pc_gamg_injection_index i,j,k...`. Inject provided indices of fine grid operator as first coarse grid restriction (sort of p-multigrid for C1 elements)
- Add `PC_JACOBI_ROWL1` to `PCJacobiType` to use (scaled) l1 row norms for diagonal approximation with scaling of off-diagonal elements
- Add `PCJacobiSetRowl1Scale()` and `-pc_jacobi_rowl1_scale scale` to access new scale member of PC_Jacobi class, for new row l1 Jacobi
- Add `-mg_fine_...` prefix alias for fine grid options to override `-mg_levels_...` options, like `-mg_coarse_...`
- The generated sub-matrices in `PCFIELDSPLIT`, `PCASM`, and `PCBJACOBI` now retain any null space or near null space attached to them even if the non-zero structure of the outer matrix changes
- Add support for multiple subdomain per MPI process in `PCBDDC`
- Add `PCJacobiGetDiagonal()` to access the Jacobi inverted matrix diagonal and its square root variant

```{rubric} KSP:
```

```{rubric} SNES:
```

- Add support for Quasi-Newton models in `SNESNEWTONTR` via `SNESNewtonTRSetQNType`
- Add support for trust region norm customization in `SNESNEWTONTR` via `SNESNewtonTRSetNormType`
- Remove default of `KSPPREONLY` and `PCLU` for `SNESNASM` subdomain solves: for `SNESASPIN` use `-npc_sub_ksp_type preonly -npc_sub_pc_type lu`
- Add function typedefs `SNESInitialGuessFn`, `SNESFunctionFn`, `SNESObjectiveFn`, `SNESJacobianFn`, and `SNESNGSFn`
- Deprecate `DMDASNESFunction`, `DMDASNESJacobian`, `DMDASNESObjective`, `DMDASNESFunctionVec`, `DMDASNESJacobianVec`, and `DMDASNESObjectiveVec`
  in favor of `DMDASNESFunctionFn`, `DMDASNESJacobianFn`, `DMDASNESObjectiveFn`, `DMDASNESFunctionVecFn`, `DMDASNESJacobianVecFn`, and `DMDASNESObjectiveVecFn`

```{rubric} SNESLineSearch:
```

- Deprecate `SNESLineSearchShellSetUserFunc()` and `SNESLineSearchShellGetUserFunc()` in favor of `SNESLineSearchShellSetApply()` and `SNESLineSearchShellGetApply()`

```{rubric} TS:
```

- Add support for custom predictor callbacks in the second-order generalized-alpha method using `TSAlpha2SetPredictor()`
- Allow adaptivity to change time step size in first step of second-order generalized-alpha method
- Add `TSSetPostEventStep()` to control the first step after event
- Rename `TSSetPostEventIntervalStep()` to `TSSetPostEventSecondStep()`, controlling the second step after event
- Rename option `-ts_event_post_eventinterval_step` to `-ts_event_post_event_second_step`
- Change the (event) indicator functions type from `PetscScalar[]` to `PetscReal[]` in the user `indicator()` callback set by `TSSetEventHandler()`
- Add `TSGetStepRollBack()` to access the internal rollback flag
- Add boolean flag to `TSSetResize()` to control when to resize

```{rubric} TAO:
```

- Deprecate `TaoCancelMonitors()` (resp. `-tao_cancelmonitors`) in favor of `TaoMonitorCancel()` (resp. `-tao_monitor_cancel`)
- Deprecate `-tao_view_gradient`, `-tao_view_ls_residual`, `-tao_view_solution`, and `-tao_view_stepdirection` in favor of
  `-tao_monitor_gradient`, `-tao_monitor_ls_residual`, `-tao_monitor_solution`, and `-tao_monitor_step`
- Deprecate `-tao_draw_solution`, `-tao_draw_gradient`, and `-tao_draw_step` in favor of `-tao_monitor_solution_draw`, `-tao_monitor_gradient_draw`, and `-tao_monitor_step_draw`
- Deprecate `TaoSetMonitor()` in favor of `TaoMonitorSet()`
- Deprecate all of the provided `Tao` monitor routine names in favor of the standard PETSc naming conventions

```{rubric} DM/DA:
```

- Add MPI reduction inside `SNESComputeObjective_DMDA()`. No need to call reduction in local callback
- Deprecate `PetscSimplePointFunc` in favor of `PetscSimplePointFn`
- Move `DMPlexReorderDefaultFlag` to `DMReorderDefaultFlag`
- Add `DMCreateSectionPermutation()`, `DMReorderSectionGetType()`, and `DMReorderSectionSetType()`
- Add `DMReorderSectionGetDefault()` and `DMReorderSectionSetDefault()` to allow point permutations when sections are built automatically
- Change interface to `DMCreateSectionSubDM()` to add component specification
- Add `DMDAGetBoundaryType()`

```{rubric} DMSwarm:
```

- Add continuous `DM` argument to `DMSwarmProjectFields()`
- Add `DMSwarmGetFieldInfo()`
- Add `DMSwarmVectorGetField()`

```{rubric} DMPlex:
```

- Drop support for MED, i.e. remove `DMPlexCreateMedFromFile()` and `--with-med`
- Change protototype of `DMPlexSetSNESLocalFEM()`. Now it accepts a single context and a Boolean indicating to use the objective function callback
- Replace `DMProjectCoordinates()` with `DMSetCoordinateDisc()`
- Add argument to `DMPlexCreateCoordinateSpace()`
- Add `DMPlexCoordMap` and some default maps
- Add Boolean argument to `DMPlexPartitionLabelCreateSF()` to sort ranks
- Add `DMClearAuxiliaryVec()` to clear the auxiliary data
- Add ignoreLabelHalo, sanitizeSubmesh, and ownershipTransferSF arguments to `DMPlexFilter()`
- Change `DMPlexSetIsoperiodicFaceSF()`, `DMPlexGetIsoperiodicFaceSF()`, and `DMPlexSetIsoperiodicFaceTransform()` to accept multiple values for different periodic pairings

```{rubric} FE/FV:
```

- Add Jacobian type argument to `PetscFEIntegrateBdJacobian()`
- Add `PetscFVClone()`
- Add `PetscFVCreateDualSpace()`

```{rubric} DMNetwork:
```

```{rubric} DMStag:
```

- Add support for `DMLocalToLocalBegin()` and `DMLocalToLocalEnd()`
- Add `DMStagSetRefinementFactor()` and `DMStagGetRefinementFactor()` to set and get the refinement ratio
- Add support for arbitrary refinement ratio and degree of freedom in interpolation and restriction

```{rubric} DT:
```

- Add `PetscDSUpdateBoundaryLabels()`

```{rubric} Fortran:
```