Date: 2025-03-28T21:10:41+00:00

Actual source code: petscsectiontypes.h

      1: #pragma once

      3: /* SUBMANSEC = PetscSection */

      5: /*S
      6:   PetscSection - Mapping from integers in a designated range to contiguous sets of integers.

      8:   The range of a `PetscSection` is in the space of
      9:   contiguous sets of integers. These ranges are frequently interpreted as domains of other array-like objects,
     10:   especially other `PetscSection`, `Vec`s, and `IS`s. The domain is set with `PetscSectionSetChart()` and does not need to
     11:   start at 0. For each point in the domain of a `PetscSection`, the output set is represented through an offset and a
     12:   count, which are set using `PetscSectionSetOffset()` and `PetscSectionSetDof()` respectively. Lookup is typically using
     13:   accessors or routines like `VecGetValuesSection()`.

     15:   The `PetscSection` object and methods are intended to be used in the PETSc `Vec` and `Mat` implementations. The indices returned by the `PetscSection`
     16:   are appropriate for the kind of `Vec` it is associated with. For example, if the vector being indexed is a local vector, we call the section a
     17:   local section. If the section indexes a global vector, we call it a global section. For parallel vectors, like global vectors, we use negative
     18:   indices to indicate dofs owned by other processes.

     20:   Level: beginner

     22: .seealso: [PetscSection](ch_petscsection), `PetscSectionCreate()`, `PetscSectionDestroy()`, `PetscSectionSym`
     23: S*/
     24: typedef struct _p_PetscSection *PetscSection;

     26: /*S
     27:   PetscSectionSym - Symmetries of the data referenced by a `PetscSection`.

     29:   Often the order of data index by a `PetscSection` is meaningful, and describes additional structure, such as points on a
     30:   line, grid, or lattice.  If the data is accessed from a different "orientation", then the image of the data under
     31:   access then undergoes a symmetry transformation.  A `PetscSectionSym` specifies these symmetries.  The types of
     32:   symmetries that can be specified are of the form R * P, where R is a diagonal matrix of scalars, and P is a permutation.

     34:   Level: developer

     36: .seealso: [PetscSection](ch_petscsection), `PetscSection`, `PetscSectionSymCreate()`, `PetscSectionSymDestroy()`, `PetscSectionSetSym()`, `PetscSectionGetSym()`, `PetscSectionSetFieldSym()`,
     37:           `PetscSectionGetFieldSym()`, `PetscSectionGetSymPoints()`, `PetscSectionSymType`, `PetscSectionSymSetType()`, `PetscSectionSymGetType()`
     38: S*/
     39: typedef struct _p_PetscSectionSym *PetscSectionSym;

     41: /*J
     42:   PetscSectionSymType - String with the name of a `PetscSectionSym` type.

     44:   Level: developer

     46:   Note:
     47:   `PetscSectionSym` has no default implementation, but is used by `DM` in `PetscSectionSymCreateLabel()`.

     49: .seealso: [PetscSection](ch_petscsection), `PetscSectionSymSetType()`, `PetscSectionSymGetType()`, `PetscSectionSym`, `PetscSectionSymCreate()`, `PetscSectionSymRegister()`
     50: J*/
     51: typedef const char *PetscSectionSymType;