1 #ifndef PETSCSECTIONTYPES_H 2 #define PETSCSECTIONTYPES_H 3 4 /* SUBMANSEC = PetscSection */ 5 6 /*S 7 PetscSection - Mapping from integers in a designated range to contiguous sets of integers. 8 9 In contrast to `IS`, which maps from integers to single integers, the range of a `PetscSection` is in the space of 10 contiguous sets of integers. These ranges are frequently interpreted as domains of other array-like objects, 11 especially other `PetscSection`, `Vec`s, and `IS`s. The domain is set with `PetscSectionSetChart()` and does not need to 12 start at 0. For each point in the domain of a `PetscSection`, the output set is represented through an offset and a 13 count, which are set using `PetscSectionSetOffset()` and `PetscSectionSetDof()` respectively. Lookup is typically using 14 accessors or routines like `VecGetValuesSection()`. 15 16 The `PetscSection` object and methods are intended to be used in the PETSc `Vec` and `Mat` implementations. The indices returned by the `PetscSection` 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 local section. If the section indexes a global vector, we call it a global section. For parallel vectors, like global vectors, we use negative indices to indicate dofs owned by other processes. 17 18 Level: beginner 19 20 .seealso: [PetscSection](sec_petscsection), `PetscSectionCreate()`, `PetscSectionDestroy()`, `PetscSectionSym` 21 S*/ 22 typedef struct _p_PetscSection *PetscSection; 23 24 /*S 25 PetscSectionSym - Symmetries of the data referenced by a `PetscSection`. 26 27 Often the order of data index by a `PetscSection` is meaningful, and describes additional structure, such as points on a 28 line, grid, or lattice. If the data is accessed from a different "orientation", then the image of the data under 29 access then undergoes a symmetry transformation. A `PetscSectionSym` specifies these symmetries. The types of 30 symmetries that can be specified are of the form R * P, where R is a diagonal matrix of scalars, and P is a permutation. 31 32 Level: developer 33 34 .seealso: `PetscSection`, `PetscSectionSymCreate()`, `PetscSectionSymDestroy()`, `PetscSectionSetSym()`, `PetscSectionGetSym()`, `PetscSectionSetFieldSym()`, 35 `PetscSectionGetFieldSym()`, `PetscSectionGetSymPoints()`, `PetscSectionSymType`, `PetscSectionSymSetType()`, `PetscSectionSymGetType()` 36 S*/ 37 typedef struct _p_PetscSectionSym *PetscSectionSym; 38 39 /*J 40 PetscSectionSymType - String with the name of a `PetscSectionSym` type. 41 42 Level: developer 43 44 Note: 45 `PetscSectionSym` has no default implementation, but is used by `DM` in `PetscSectionSymCreateLabel()`. 46 47 .seealso: `PetscSectionSymSetType()`, `PetscSectionSymGetType()`, `PetscSectionSym`, `PetscSectionSymCreate()`, `PetscSectionSymRegister()` 48 J*/ 49 typedef const char *PetscSectionSymType; 50 51 #endif 52