petsc4py.PETSc.IS#

class petsc4py.PETSc.IS#

Bases: Object

A collection of indices.

IS objects are used to index into vectors and matrices and to set up vector scatters.

See also

IS

Enumerations

Type

Methods Summary

allGather()

Concatenate index sets stored across processors.

buildTwoSided([toindx])

Create an index set describing a global mapping.

complement(nmin, nmax)

Create a complement index set.

copy([result])

Copy the contents of the index set into another.

create([comm])

Create an IS.

createBlock(bsize, indices[, comm])

Create a blocked index set.

createGeneral(indices[, comm])

Create an IS with indices.

createStride(size[, first, step, comm])

Create an index set consisting of evenly spaced values.

destroy()

Destroy the index set.

difference(iset)

Return the difference between two index sets.

duplicate()

Create a copy of the index set.

embed(iset, drop)

Embed self into iset.

equal(iset)

Return whether the index sets have the same set of indices or not.

expand(iset)

Return the union of two (possibly unsorted) index sets.

getBlockIndices()

Return the indices of an index set with type IS.Type.BLOCK.

getBlockSize()

Return the number of elements in a block.

getIndices()

Return the indices of the index set.

getInfo()

Return stride information for an index set with type IS.Type.STRIDE.

getLocalSize()

Return the process-local length of the index set.

getSize()

Return the global length of an index set.

getSizes()

Return the local and global sizes of the index set.

getStride()

Return size and stride information.

getType()

Return the index set type associated with the IS.

invertPermutation([nlocal])

Invert the index set.

isIdentity()

Return whether the index set has been declared as an identity.

isPermutation()

Return whether an index set has been declared to be a permutation.

isSorted()

Return whether the indices have been sorted.

load(viewer)

Load a stored index set.

renumber([mult])

Renumber the non-negative entries of an index set, starting from 0.

setBlockIndices(bsize, indices)

Set the indices for an index set with type IS.Type.BLOCK.

setBlockSize(bs)

Set the block size of the index set.

setIdentity()

Mark the index set as being an identity.

setIndices(indices)

Set the indices of an index set.

setPermutation()

Mark the index set as being a permutation.

setStride(size[, first, step])

Set the stride information for an index set with type IS.Type.STRIDE.

setType(is_type)

Set the type of the index set.

sort()

Sort the indices of an index set.

sum(iset)

Return the union of two (sorted) index sets.

toGeneral()

Convert the index set type to IS.Type.GENERAL.

union(iset)

Return the union of two (possibly unsorted) index sets.

view([viewer])

Display the index set.

Attributes Summary

array

View of the index set as an array of integers.

block_size

The number of elements in a block.

identity

True if index set is an identity, False otherwise.

indices

The indices of the index set.

local_size

The local size of the index set.

permutation

True if index set is a permutation, False otherwise.

size

The global size of the index set.

sizes

The local and global sizes of the index set.

sorted

True if index set is sorted, False otherwise.

Methods Documentation

allGather()#

Concatenate index sets stored across processors.

Collective.

The returned index set will be the same on every processor.

See also

ISAllGather

Source code at petsc4py/PETSc/IS.pyx:306

Return type:

IS

buildTwoSided(toindx=None)#

Create an index set describing a global mapping.

Collective.

This function generates an index set that contains new numbers from remote or local on the index set.

Parameters:

toindx (IS | None) – Index set describing which indices to send, default is to send natural numbering.

Returns:

New index set containing the new numbers from remote or local.

Return type:

IS

See also

ISBuildTwoSided

Source code at petsc4py/PETSc/IS.pyx:335

complement(nmin, nmax)#

Create a complement index set.

Collective.

The complement set of indices is all indices that are not in the provided set (and within the provided bounds).

Parameters:
  • nmin (int) – Minimum index that can be found in the local part of the complement index set.

  • nmax (int) – One greater than the maximum index that can be found in the local part of the complement index set.

Return type:

IS

Notes

For a parallel index set, this will generate the local part of the complement on each process.

To generate the entire complement (on each process) of a parallel index set, first call IS.allGather and then call this method.

Source code at petsc4py/PETSc/IS.pyx:676

copy(result=None)#

Copy the contents of the index set into another.

Collective.

Parameters:

result (IS | None) – The target index set. If None then IS.duplicate is called first.

Returns:

The copied index set. If result is not None then this is returned here.

Return type:

IS

See also

IS.duplicate, ISCopy

Source code at petsc4py/PETSc/IS.pyx:255

create(comm=None)#

Create an IS.

Collective.

Parameters:

comm (Comm | None) – MPI communicator, defaults to Sys.getDefaultComm.

Return type:

Self

See also

ISCreate

Source code at petsc4py/PETSc/IS.pyx:87

createBlock(bsize, indices, comm=None)#

Create a blocked index set.

Collective.

Parameters:
Return type:

Self

See also

ISCreateBlock

Source code at petsc4py/PETSc/IS.pyx:171

createGeneral(indices, comm=None)#

Create an IS with indices.

Collective.

Parameters:
Return type:

Self

See also

ISCreateGeneral

Source code at petsc4py/PETSc/IS.pyx:141

createStride(size, first=0, step=0, comm=None)#

Create an index set consisting of evenly spaced values.

Collective.

Parameters:
  • size (int) – The length of the locally owned portion of the index set.

  • first (int) – The first element of the index set.

  • step (int) – The difference between adjacent indices.

  • comm (Comm | None) – MPI communicator, defaults to Sys.getDefaultComm.

Return type:

Self

See also

ISCreateStride

Source code at petsc4py/PETSc/IS.pyx:205

destroy()#

Destroy the index set.

Collective.

See also

ISDestroy

Source code at petsc4py/PETSc/IS.pyx:74

Return type:

Self

difference(iset)#

Return the difference between two index sets.

Collective.

Parameters:

iset (IS) – Index set to compute the difference with.

Returns:

Index set representing the difference between self and iset.

Return type:

IS

See also

ISDifference

Source code at petsc4py/PETSc/IS.pyx:652

duplicate()#

Create a copy of the index set.

Collective.

See also

IS.copy, ISDuplicate

Source code at petsc4py/PETSc/IS.pyx:241

Return type:

IS

embed(iset, drop)#

Embed self into iset.

Not collective.

The embedding is performed by finding the locations in iset that have the same indices as self.

Parameters:
  • iset (IS) – The index set to embed into.

  • drop (bool) – Flag indicating whether to drop indices from self that are not in iset.

Returns:

The embedded index set.

Return type:

IS

See also

ISEmbed

Source code at petsc4py/PETSc/IS.pyx:712

equal(iset)#

Return whether the index sets have the same set of indices or not.

Collective.

Parameters:

iset (IS) – The index set to compare indices with.

Return type:

bool

See also

ISEqual

Source code at petsc4py/PETSc/IS.pyx:552

expand(iset)#

Return the union of two (possibly unsorted) index sets.

Collective.

To compute the union, expand concatenates the two index sets and removes any duplicates.

Parameters:

iset (IS) – Index set to compute the union with.

Returns:

The new, combined, index set.

Return type:

IS

See also

ISExpand

Source code at petsc4py/PETSc/IS.pyx:590

getBlockIndices()#

Return the indices of an index set with type IS.Type.BLOCK.

Not collective.

Source code at petsc4py/PETSc/IS.pyx:835

Return type:

ArrayInt

getBlockSize()#

Return the number of elements in a block.

Not collective.

See also

ISGetBlockSize

Source code at petsc4py/PETSc/IS.pyx:439

Return type:

int

getIndices()#

Return the indices of the index set.

Not collective.

See also

ISGetIndices

Source code at petsc4py/PETSc/IS.pyx:791

Return type:

ArrayInt

getInfo()#

Return stride information for an index set with type IS.Type.STRIDE.

Not collective.

Returns:

  • first (int) – First element of the index set.

  • step (int) – Difference between adjacent indices.

Return type:

tuple[int, int]

Source code at petsc4py/PETSc/IS.pyx:905

getLocalSize()#

Return the process-local length of the index set.

Not collective.

See also

ISGetLocalSize

Source code at petsc4py/PETSc/IS.pyx:403

Return type:

int

getSize()#

Return the global length of an index set.

Not collective.

See also

ISGetSize

Source code at petsc4py/PETSc/IS.pyx:389

Return type:

int

getSizes()#

Return the local and global sizes of the index set.

Not collective.

Returns:

  • local_size (int) – The local size.

  • global_size (int) – The global size.

Return type:

tuple[int, int]

Source code at petsc4py/PETSc/IS.pyx:417

getStride()#

Return size and stride information.

Not collective.

Returns:

  • size (int) – Length of the locally owned portion of the index set.

  • first (int) – First element of the index set.

  • step (int) – Difference between adjacent indices.

Return type:

tuple[int, int, int]

Source code at petsc4py/PETSc/IS.pyx:881

getType()#

Return the index set type associated with the IS.

Not collective.

See also

ISGetType

Source code at petsc4py/PETSc/IS.pyx:127

Return type:

str

invertPermutation(nlocal=None)#

Invert the index set.

Collective.

For this to be correct the index set must be a permutation.

Parameters:

nlocal (int | None) – The number of indices on this processor in the resulting index set, defaults to PETSC_DECIDE.

Return type:

IS

Source code at petsc4py/PETSc/IS.pyx:365

isIdentity()#

Return whether the index set has been declared as an identity.

Collective.

See also

ISIdentity

Source code at petsc4py/PETSc/IS.pyx:538

Return type:

bool

isPermutation()#

Return whether an index set has been declared to be a permutation.

Logically collective.

See also

ISPermutation

Source code at petsc4py/PETSc/IS.pyx:511

Return type:

bool

isSorted()#

Return whether the indices have been sorted.

Collective.

See also

ISSorted

Source code at petsc4py/PETSc/IS.pyx:484

Return type:

bool

load(viewer)#

Load a stored index set.

Collective.

Parameters:

viewer (Viewer) – Binary file viewer, either Viewer.Type.BINARY or Viewer.Type.HDF5.

Return type:

Self

See also

ISLoad

Source code at petsc4py/PETSc/IS.pyx:283

renumber(mult=None)#

Renumber the non-negative entries of an index set, starting from 0.

Collective.

Parameters:

mult (IS | None) – The multiplicity of each entry in self, default implies a multiplicity of 1.

Returns:

  • int – One past the largest entry of the new index set.

  • IS – The renumbered index set.

Return type:

tuple[int, IS]

See also

ISRenumber

Source code at petsc4py/PETSc/IS.pyx:743

setBlockIndices(bsize, indices)#

Set the indices for an index set with type IS.Type.BLOCK.

Collective.

Parameters:
  • bsize (int) – Number of elements in each block.

  • indices (Sequence[int]) – List of integers.

Return type:

None

Source code at petsc4py/PETSc/IS.pyx:812

setBlockSize(bs)#

Set the block size of the index set.

Logically collective.

Parameters:

bs (int) – Block size.

Return type:

None

See also

ISSetBlockSize

Source code at petsc4py/PETSc/IS.pyx:453

setIdentity()#

Mark the index set as being an identity.

Logically collective.

See also

ISSetIdentity

Source code at petsc4py/PETSc/IS.pyx:525

Return type:

Self

setIndices(indices)#

Set the indices of an index set.

Logically collective.

The index set is assumed to be of type IS.Type.GENERAL.

Source code at petsc4py/PETSc/IS.pyx:774

Parameters:

indices (Sequence[int]) –

Return type:

None

setPermutation()#

Mark the index set as being a permutation.

Logically collective.

See also

ISSetPermutation

Source code at petsc4py/PETSc/IS.pyx:498

Return type:

Self

setStride(size, first=0, step=1)#

Set the stride information for an index set with type IS.Type.STRIDE.

Logically collective.

Parameters:
  • size (int) – Length of the locally owned portion of the index set.

  • first (int) – First element of the index set.

  • step (int) – Difference between adjacent indices.

Return type:

None

Source code at petsc4py/PETSc/IS.pyx:857

setType(is_type)#

Set the type of the index set.

Collective.

Parameters:

is_type (Type | str) – The index set type.

Return type:

None

See also

ISSetType

Source code at petsc4py/PETSc/IS.pyx:108

sort()#

Sort the indices of an index set.

Collective.

See also

ISSort

Source code at petsc4py/PETSc/IS.pyx:471

Return type:

Self

sum(iset)#

Return the union of two (sorted) index sets.

Collective.

Parameters:

iset (IS) – The index set to compute the union with.

Return type:

IS

See also

ISSum

Source code at petsc4py/PETSc/IS.pyx:571

toGeneral()#

Convert the index set type to IS.Type.GENERAL.

Collective.

See also

ISToGeneral, ISType

Source code at petsc4py/PETSc/IS.pyx:322

Return type:

Self

union(iset)#

Return the union of two (possibly unsorted) index sets.

Collective.

This function will call either ISSum or ISExpand depending on whether or not the input sets are already sorted.

Sequential only (as ISSum is sequential only).

Parameters:

iset (IS) – Index set to compute the union with.

Returns:

The new, combined, index set.

Return type:

IS

See also

IS.expand, IS.sum

Source code at petsc4py/PETSc/IS.pyx:617

view(viewer=None)#

Display the index set.

Collective.

Parameters:

viewer (Viewer | None) – Viewer used to display the IS.

Return type:

None

See also

ISView

Source code at petsc4py/PETSc/IS.pyx:55

Attributes Documentation

array#

View of the index set as an array of integers.

Not collective.

Source code at petsc4py/PETSc/IS.pyx:1034

block_size#

The number of elements in a block.

Not collective.

See also

IS.getBlockSize

Source code at petsc4py/PETSc/IS.pyx:1008

identity#

True if index set is an identity, False otherwise.

Collective.

See also

IS.isIdentity

Source code at petsc4py/PETSc/IS.pyx:941

indices#

The indices of the index set.

Not collective.

See also

IS.getIndices

Source code at petsc4py/PETSc/IS.pyx:1021

local_size#

The local size of the index set.

Not collective.

See also

IS.getLocalSize

Source code at petsc4py/PETSc/IS.pyx:995

permutation#

True if index set is a permutation, False otherwise.

Logically collective.

See also

IS.isPermutation

Source code at petsc4py/PETSc/IS.pyx:928

size#

The global size of the index set.

Not collective.

See also

IS.getSize

Source code at petsc4py/PETSc/IS.pyx:982

sizes#

The local and global sizes of the index set.

Not collective.

See also

IS.getSizes

Source code at petsc4py/PETSc/IS.pyx:969

sorted#

True if index set is sorted, False otherwise.

Collective.

See also

IS.isSorted

Source code at petsc4py/PETSc/IS.pyx:954