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<center><a href="https://gitlab.com/petsc/petsc/-/blob/966382dc56242773704ef5f5cee7aa2db3ebc577/include/petscsectiontypes.h">Actual source code: petscsectiontypes.h</a></center><br>
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<a name="line1"> 1: </a><font color="#A020F0">#pragma once</font>
<a name="line3"> 3: </a><font color="#B22222">/* MANSEC = <a href="../manualpages/Vec/Vec.html">Vec</a> */</font>
<a name="line4"> 4: </a><font color="#B22222">/* SUBMANSEC = <a href="../manualpages/PetscSection/PetscSection.html">PetscSection</a> */</font>
<a name="line6"> 6: </a><font color="#B22222">/*S</font>
<a name="line7"> 7: </a><font color="#B22222"> <a href="../manualpages/PetscSection/PetscSection.html">PetscSection</a> - Mapping from integers in a designated range to contiguous sets of integers.</font>
<a name="line9"> 9: </a><font color="#B22222"> The range of a `<a href="../manualpages/PetscSection/PetscSection.html">PetscSection</a>` is in the space of</font>
<a name="line10"> 10: </a><font color="#B22222"> contiguous sets of integers. These ranges are frequently interpreted as domains of other array-like objects,</font>
<a name="line11"> 11: </a><font color="#B22222"> especially other `<a href="../manualpages/PetscSection/PetscSection.html">PetscSection</a>`, `<a href="../manualpages/Vec/Vec.html">Vec</a>`s, and `<a href="../manualpages/IS/IS.html">IS</a>`s. The domain is set with `<a href="../manualpages/PetscSection/PetscSectionSetChart.html">PetscSectionSetChart</a>()` and does not need to</font>
<a name="line12"> 12: </a><font color="#B22222"> start at 0. For each point in the domain of a `<a href="../manualpages/PetscSection/PetscSection.html">PetscSection</a>`, the output set is represented through an offset and a</font>
<a name="line13"> 13: </a><font color="#B22222"> count, which are set using `<a href="../manualpages/PetscSection/PetscSectionSetOffset.html">PetscSectionSetOffset</a>()` and `<a href="../manualpages/PetscSection/PetscSectionSetDof.html">PetscSectionSetDof</a>()` respectively. Lookup is typically using</font>
<a name="line14"> 14: </a><font color="#B22222"> accessors or routines like `<a href="../manualpages/Vec/VecGetValuesSection.html">VecGetValuesSection</a>()`.</font>
<a name="line16"> 16: </a><font color="#B22222"> The `<a href="../manualpages/PetscSection/PetscSection.html">PetscSection</a>` object and methods are intended to be used in the PETSc `<a href="../manualpages/Vec/Vec.html">Vec</a>` and `<a href="../manualpages/Mat/Mat.html">Mat</a>` implementations. The indices returned by the `<a href="../manualpages/PetscSection/PetscSection.html">PetscSection</a>`</font>
<a name="line17"> 17: </a><font color="#B22222"> are appropriate for the kind of `<a href="../manualpages/Vec/Vec.html">Vec</a>` it is associated with. For example, if the vector being indexed is a local vector, we call the section a</font>
<a name="line18"> 18: </a><font color="#B22222"> local section. If the section indexes a global vector, we call it a global section. For parallel vectors, like global vectors, we use negative</font>
<a name="line19"> 19: </a><font color="#B22222"> indices to indicate dofs owned by other processes.</font>
<a name="line21"> 21: </a><font color="#B22222"> Level: beginner</font>
<a name="line23"> 23: </a><font color="#B22222">.seealso: [<a href="../manualpages/PetscSection/PetscSection.html">PetscSection</a>](ch_petscsection), `<a href="../manualpages/PetscSection/PetscSectionCreate.html">PetscSectionCreate</a>()`, `<a href="../manualpages/PetscSection/PetscSectionDestroy.html">PetscSectionDestroy</a>()`, `<a href="../manualpages/PetscSection/PetscSectionSym.html">PetscSectionSym</a>`</font>
<a name="line24"> 24: </a><font color="#B22222">S*/</font>
<a name="line25"> 25: </a><font color="#4169E1">typedef struct _p_PetscSection *<a href="../manualpages/PetscSection/PetscSection.html">PetscSection</a>;</font>
<a name="line27"> 27: </a><font color="#B22222">/*S</font>
<a name="line28"> 28: </a><font color="#B22222"> <a href="../manualpages/PetscSection/PetscSectionSym.html">PetscSectionSym</a> - Symmetries of the data referenced by a `<a href="../manualpages/PetscSection/PetscSection.html">PetscSection</a>`.</font>
<a name="line30"> 30: </a><font color="#B22222"> Often the order of data index by a `<a href="../manualpages/PetscSection/PetscSection.html">PetscSection</a>` is meaningful, and describes additional structure, such as points on a</font>
<a name="line31"> 31: </a><font color="#B22222"> line, grid, or lattice. If the data is accessed from a different "orientation", then the image of the data under</font>
<a name="line32"> 32: </a><font color="#B22222"> access then undergoes a symmetry transformation. A `<a href="../manualpages/PetscSection/PetscSectionSym.html">PetscSectionSym</a>` specifies these symmetries. The types of</font>
<a name="line33"> 33: </a><font color="#B22222"> symmetries that can be specified are of the form R * P, where R is a diagonal matrix of scalars, and P is a permutation.</font>
<a name="line35"> 35: </a><font color="#B22222"> Level: developer</font>
<a name="line37"> 37: </a><font color="#B22222">.seealso: [<a href="../manualpages/PetscSection/PetscSection.html">PetscSection</a>](ch_petscsection), `<a href="../manualpages/PetscSection/PetscSection.html">PetscSection</a>`, `<a href="../manualpages/PetscSection/PetscSectionSymCreate.html">PetscSectionSymCreate</a>()`, `<a href="../manualpages/PetscSection/PetscSectionSymDestroy.html">PetscSectionSymDestroy</a>()`, `<a href="../manualpages/PetscSection/PetscSectionSetSym.html">PetscSectionSetSym</a>()`, `<a href="../manualpages/PetscSection/PetscSectionGetSym.html">PetscSectionGetSym</a>()`, `<a href="../manualpages/PetscSection/PetscSectionSetFieldSym.html">PetscSectionSetFieldSym</a>()`,</font>
<a name="line38"> 38: </a><font color="#B22222"> `<a href="../manualpages/PetscSection/PetscSectionGetFieldSym.html">PetscSectionGetFieldSym</a>()`, `PetscSectionGetSymPoints()`, `<a href="../manualpages/PetscSection/PetscSectionSymType.html">PetscSectionSymType</a>`, `<a href="../manualpages/PetscSection/PetscSectionSymSetType.html">PetscSectionSymSetType</a>()`, `<a href="../manualpages/PetscSection/PetscSectionSymGetType.html">PetscSectionSymGetType</a>()`</font>
<a name="line39"> 39: </a><font color="#B22222">S*/</font>
<a name="line40"> 40: </a><font color="#4169E1">typedef struct _p_PetscSectionSym *<a href="../manualpages/PetscSection/PetscSectionSym.html">PetscSectionSym</a>;</font>
<a name="line42"> 42: </a><font color="#B22222">/*J</font>
<a name="line43"> 43: </a><font color="#B22222"> <a href="../manualpages/PetscSection/PetscSectionSymType.html">PetscSectionSymType</a> - String with the name of a `<a href="../manualpages/PetscSection/PetscSectionSym.html">PetscSectionSym</a>` type.</font>
<a name="line45"> 45: </a><font color="#B22222"> Level: developer</font>
<a name="line47"> 47: </a><font color="#B22222"> Note:</font>
<a name="line48"> 48: </a><font color="#B22222"> `<a href="../manualpages/PetscSection/PetscSectionSym.html">PetscSectionSym</a>` has no default implementation, but is used by `<a href="../manualpages/DM/DM.html">DM</a>` in `<a href="../manualpages/DMLabel/PetscSectionSymCreateLabel.html">PetscSectionSymCreateLabel</a>()`.</font>
<a name="line50"> 50: </a><font color="#B22222">.seealso: [<a href="../manualpages/PetscSection/PetscSection.html">PetscSection</a>](ch_petscsection), `<a href="../manualpages/PetscSection/PetscSectionSymSetType.html">PetscSectionSymSetType</a>()`, `<a href="../manualpages/PetscSection/PetscSectionSymGetType.html">PetscSectionSymGetType</a>()`, `<a href="../manualpages/PetscSection/PetscSectionSym.html">PetscSectionSym</a>`, `<a href="../manualpages/PetscSection/PetscSectionSymCreate.html">PetscSectionSymCreate</a>()`, `<a href="../manualpages/PetscSection/PetscSectionSymRegister.html">PetscSectionSymRegister</a>()`</font>
<a name="line51"> 51: </a><font color="#B22222">J*/</font>
<a name="line52"> 52: </a><font color="#4169E1">typedef const char *<a href="../manualpages/PetscSection/PetscSectionSymType.html">PetscSectionSymType</a>;</font>
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