IndexSet

class IndexSet : public godzilla::PetscObjectWrapper<IS>

IndexSets are objects used to do efficient indexing into other data structures such as Vector and Matrix

Public Functions

void assign(const IndexSet &src)

Replace the content of this index set with the content of another index set.

Parameters:

src – The index set to copy from

void create(MPI_Comm comm)

Creates an index set object.

Parameters:

comm – The MPI communicator

IndexSet complement(Int nmin, Int nmax) const

Generates the complement index set.

That is all indices that are NOT in the given set.

Parameters:

  • nmin – The first index desired in the local part of the complement

  • nmax – The largest index desired in the local part of the complement (note that all indices in this indexs set must be greater or equal to nmin and less than nmax)

void destroy()

Destroys an index set.

bool is_null() const

Test if the index set is “null”.

Returns:

true is the label is null, false otherwise

IndexSet duplicate() const

Creates a duplicate copy of an index set.

Returns:

The copy of the index set

bool equal(const IndexSet &other) const

Compares if this index set has the same set of indices as the other

Parameters:

other – The index set to compare with

Returns:

true if the index sets are equal, false otherwise

bool equal_unsorted(const IndexSet &other) const

Compares if this index set has the same set of indices as the other

Note

This routine does NOT sort the contents of the index sets before the comparison is made, i.e., the order of indices is important.

Parameters:

other – The index set to compare with

Returns:

true if the index sets are equal, false otherwise

IndexSetBorrowedIndices borrow_indices()

Borrow the indices from this index set.

String get_type() const

Gets the index set type name.

Returns:

The type name

void get_point_range(Int &start, Int &end, const Int *&points) const

Returns a description of the points in an IndexSet suitable for traversal.

Parameters:

  • start – The first index

  • end – One past the last index

  • points – The indices

void restore_point_range(Int start, Int end, const Int *points) const

Destroys the traversal description created with get_point_range

Parameters:

  • start – The first index

  • end – One past the last index

  • points – The indices

void get_point_subrange(Int start, Int end, const Int *points) const

Configures the IndexSet to be a subrange for the traversal information given.

Parameters:

  • start – The first index of the subrange

  • end – One past the last index for the subrange

  • points – The indices for the entire range, from get_point_range

std::tuple<Int, Int> get_min_max() const

Gets the minimum and maximum values.

Returns:

A tuple containing the minimum and maximum values

Int get_size() const

Returns the global length of an index set.

Returns:

The global size of the index set

Int get_local_size() const

Returns the local (processor) length of an index set.

Returns:

The local size of the index set

Int locate(Int key) const

Determine the location of an index within the local component of an index set.

Parameters:

key – The index to locate

Returns:

if >= 0, a location within the index set that is equal to the key, otherwise the key is not in the index set

bool identity() const

Determines whether index set is the identity mapping.

Returns:

true if the index set is the identity mapping, false otherwise

void set_identity()

Sets the index set to be the identity mapping.

bool permutation() const

Determines whether index set is a permutation.

Returns:

true if the index set is a permutation, false otherwise

void set_permutation()

Informs the index set that it is a permutation.

void set_type(String type)

Builds a index set, for a particular type.

Parameters:

type – The type of index set to build

bool empty() const

Checks if the IndexSet is empty (i.e., has no indices)

Returns:

true if the index set is empty, false otherwise

void shift(Int offset)

Shift all indices by given offset.

Parameters:

offset – The offset to shift the indices by

bool sorted() const

Checks the indices to determine whether they have been sorted.

Returns:

true is index set is sorted

void sort() const

Sort the indices of the index set.

void sort_remove_dups() const

Sort the indices of the index set, removing duplicates.

void view(PetscViewer viewer = PETSC_VIEWER_STDOUT_WORLD) const

View the index set.

Parameters:

viewer – The PETSc viewer

Public Static Functions

static IndexSet create_general(MPI_Comm comm, const std::vector<Int> &idx, CopyMode copy_mode = COPY_VALUES)

Creates a data structure for an index set containing a list of integers.

Parameters:

  • comm – The MPI communicator

  • idx – The length of the index set

  • copy_mode – The copy mode see, CopyMode for details

static IndexSet intersect(const IndexSet &is1, const IndexSet &is2)

Computes the intersection of two index sets, by sorting and comparing.

Parameters:

  • is1 – The first index set

  • is2 – The second index set

Returns:

The sorted intersection of is1 and is2

static void copy(const IndexSet &src, IndexSet &dest)

Copies an index set.

Parameters:

  • src – The index set to copy from

  • dest – The index set to copy to

static IndexSet concatenate(MPI_Comm comm, const std::vector<IndexSet> &is_list)

Forms a new IS by locally concatenating the indices from an IS list without reordering.

Parameters:

  • comm – The MPI communicator

  • is_list – The list of index sets to concatenate

Returns:

The concatenated index set

static IndexSet difference(const IndexSet &is1, const IndexSet &is2)

Computes the difference between two index sets.

Parameters:

  • is1 – The first index set, to have items removed from it

  • is2 – Index values to be removed

Returns:

The difference between is1 and is2

static IndexSet expand(const IndexSet &is1, const IndexSet &is2)

Computes the union of two index sets, by concatenating 2 lists and removing duplicates.

Parameters:

  • is1 – The first index set

  • is2 – The second index set

Returns:

The union of is1 and is2

static IndexSet sum(const IndexSet &is1, const IndexSet &is2)

Computes the sum (union) of two index sets.

Parameters:

  • is1 – The first index set

  • is2 – The second index set

Returns:

The sum of is1 and is2