1a4963045SJacob Faibussowitsch #pragma once 2ea844a1aSMatthew Knepley 3*ce78bad3SBarry Smith /* MANSEC = Vec */ 4ac09b921SBarry Smith /* SUBMANSEC = PetscSection */ 5ac09b921SBarry Smith 6ea844a1aSMatthew Knepley /*S 7ea844a1aSMatthew Knepley PetscSection - Mapping from integers in a designated range to contiguous sets of integers. 8ea844a1aSMatthew Knepley 920662ed9SBarry Smith The range of a `PetscSection` is in the space of 10ea844a1aSMatthew Knepley contiguous sets of integers. These ranges are frequently interpreted as domains of other array-like objects, 1187497f52SBarry Smith especially other `PetscSection`, `Vec`s, and `IS`s. The domain is set with `PetscSectionSetChart()` and does not need to 1287497f52SBarry Smith start at 0. For each point in the domain of a `PetscSection`, the output set is represented through an offset and a 1387497f52SBarry Smith count, which are set using `PetscSectionSetOffset()` and `PetscSectionSetDof()` respectively. Lookup is typically using 1487497f52SBarry Smith accessors or routines like `VecGetValuesSection()`. 15ea844a1aSMatthew Knepley 1620662ed9SBarry Smith The `PetscSection` object and methods are intended to be used in the PETSc `Vec` and `Mat` implementations. The indices returned by the `PetscSection` 1720662ed9SBarry Smith 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 1820662ed9SBarry Smith local section. If the section indexes a global vector, we call it a global section. For parallel vectors, like global vectors, we use negative 1920662ed9SBarry Smith indices to indicate dofs owned by other processes. 20db527f05SMatthew G. Knepley 21ea844a1aSMatthew Knepley Level: beginner 22ea844a1aSMatthew Knepley 23db527f05SMatthew G. Knepley .seealso: [PetscSection](sec_petscsection), `PetscSectionCreate()`, `PetscSectionDestroy()`, `PetscSectionSym` 24ea844a1aSMatthew Knepley S*/ 25ea844a1aSMatthew Knepley typedef struct _p_PetscSection *PetscSection; 26ea844a1aSMatthew Knepley 27ea844a1aSMatthew Knepley /*S 2887497f52SBarry Smith PetscSectionSym - Symmetries of the data referenced by a `PetscSection`. 29ea844a1aSMatthew Knepley 3087497f52SBarry Smith Often the order of data index by a `PetscSection` is meaningful, and describes additional structure, such as points on a 31ea844a1aSMatthew Knepley line, grid, or lattice. If the data is accessed from a different "orientation", then the image of the data under 3287497f52SBarry Smith access then undergoes a symmetry transformation. A `PetscSectionSym` specifies these symmetries. The types of 33ea844a1aSMatthew Knepley symmetries that can be specified are of the form R * P, where R is a diagonal matrix of scalars, and P is a permutation. 34ea844a1aSMatthew Knepley 35ea844a1aSMatthew Knepley Level: developer 36ea844a1aSMatthew Knepley 3720662ed9SBarry Smith .seealso: [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionSymCreate()`, `PetscSectionSymDestroy()`, `PetscSectionSetSym()`, `PetscSectionGetSym()`, `PetscSectionSetFieldSym()`, 38db781477SPatrick Sanan `PetscSectionGetFieldSym()`, `PetscSectionGetSymPoints()`, `PetscSectionSymType`, `PetscSectionSymSetType()`, `PetscSectionSymGetType()` 39ea844a1aSMatthew Knepley S*/ 40ea844a1aSMatthew Knepley typedef struct _p_PetscSectionSym *PetscSectionSym; 41ea844a1aSMatthew Knepley 42ea844a1aSMatthew Knepley /*J 4387497f52SBarry Smith PetscSectionSymType - String with the name of a `PetscSectionSym` type. 44ea844a1aSMatthew Knepley 45ea844a1aSMatthew Knepley Level: developer 46ea844a1aSMatthew Knepley 4787497f52SBarry Smith Note: 4887497f52SBarry Smith `PetscSectionSym` has no default implementation, but is used by `DM` in `PetscSectionSymCreateLabel()`. 49ea844a1aSMatthew Knepley 5020662ed9SBarry Smith .seealso: [PetscSection](sec_petscsection), `PetscSectionSymSetType()`, `PetscSectionSymGetType()`, `PetscSectionSym`, `PetscSectionSymCreate()`, `PetscSectionSymRegister()` 51ea844a1aSMatthew Knepley J*/ 52ea844a1aSMatthew Knepley typedef const char *PetscSectionSymType; 53