cc.redberry.core.indices

Class IndicesSymmetries

java.lang.Object

cc.redberry.core.indices.IndicesSymmetries

public final class IndicesSymmetries
extends java.lang.Object

Wrapper of PermutationGroup that holds symmetries of indices. This class aggregates symmetries added via methods add(...) and calculate permutation group generated by these symmetries on the invocation of methods getPermutationGroup(), getPositionsInOrbits() etc. After permutation group was calculated the modification of symmetries is forbidden: all methods add(...) will throw IllegalStateException.

Since:

1.0

Method Summary

Modifier and Type	Method and Description
void	add(boolean sign, int[] permutation) Adds specified symmetry written in one-line notation to this symmetries.
void	add(byte type, boolean sign, int... permutation) Adds specified symmetry written in one-line notation to symmetries of indices of specified type.
void	add(IndexType type, boolean sign, int... permutation) Adds specified symmetry written in one-line notation to symmetries of indices of specified type.
void	addAll(java.util.Collection<Permutation> symmetry) Adds specified symmetries to this.
void	addAntiSymmetry(IndexType type, int... permutation) Adds specified antisymmetry written in one-line notation to symmetries of indices of specified type.
void	addAntiSymmetry(int... permutation) Adds specified antisymmetry written in one-line notation to this symmetries.
void	addSymmetries(java.util.Collection<Permutation> symmetries) Adds specified symmetries to this.
void	addSymmetries(Permutation... symmetries) Adds specified symmetries to this.
void	addSymmetry(byte type, Permutation symmetry) Adds specified symmetry to symmetries of indices of specified type.
void	addSymmetry(IndexType type, int... permutation) Adds specified permutation written in one-line notation to symmetries of indices of specified type.
void	addSymmetry(int... permutation) Adds specified permutation written in one-line notation to this symmetries.
void	addSymmetry(Permutation symmetry) Adds specified symmetry to this.
boolean	availableForModification() Returns true if one can add new symmetries to this, or false, if this symmetries is already in use in some tensors; in latter case, the invocation of method add(...) will throw exception.
IndicesSymmetries	clone()
static IndicesSymmetries	create(StructureOfIndices structureOfIndices) Creates symmetries with empty generating set.
static IndicesSymmetries	create(StructureOfIndices structureOfIndices, java.util.List<Permutation> generators) Creates symmetries of indices with specified structure and with specified generating set.
static IndicesSymmetries	create(StructureOfIndices structureOfIndices, PermutationGroup group) Creates symmetries of indices with specified structure and with specified permutation group.
static IndicesSymmetries	getEmpty() For indices with zero length
java.util.List<Permutation>	getGenerators() Returns generating set (unmodifiable) of this symmetries.
PermutationGroup	getPermutationGroup() Returns a permutation group that represents symmetries of this indices.
short[]	getPositionsInOrbits() Returns positions of indices in the array of orbits of underlying permutation group.
StructureOfIndices	getStructureOfIndices() Returns underlying structure of indices.
boolean	isTrivial() Returns true if all generators are identity (and, consequently, the underlying permutation group is trivial) and false otherwise.
void	setAntiSymmetric() Makes this symmetries totally antisymmetric in all its indices (for each type).
void	setSymmetric() Makes this symmetries totally symmetric in all its indices (for each type).
java.lang.String	toString()

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Method Detail

create

public static IndicesSymmetries create(StructureOfIndices structureOfIndices)

Creates symmetries with empty generating set.

Parameters:

structureOfIndices - structure of indices for which this symmetries can be assigned

Returns:

symmetries with empty generating set for indices with specified structure

create

public static IndicesSymmetries create(StructureOfIndices structureOfIndices,
                                       PermutationGroup group)

Creates symmetries of indices with specified structure and with specified permutation group.

Parameters:

structureOfIndices - structure of indices for which this symmetries can be assigned

group - permutation group

Returns:

symmetries with specified permutation group for indices with specified structure

Throws:

java.lang.IllegalArgumentException - if group.degree() != structureOfIndices.size()

create

public static IndicesSymmetries create(StructureOfIndices structureOfIndices,
                                       java.util.List<Permutation> generators)

Creates symmetries of indices with specified structure and with specified generating set.

Parameters:

structureOfIndices - structure of indices for which this symmetries can be assigned

generators - generating set

Returns:

symmetries with specified generating set for indices with specified structure

Throws:

java.lang.IllegalArgumentException - if some generator in generators have degree different from size of structureOfIndices

getStructureOfIndices

public StructureOfIndices getStructureOfIndices()

Returns underlying structure of indices.

Returns:

structure of indices

getGenerators

public java.util.List<Permutation> getGenerators()

Returns generating set (unmodifiable) of this symmetries.

Returns:

generating set (unmodifiable) of this symmetries

getPermutationGroup

public PermutationGroup getPermutationGroup()

Returns a permutation group that represents symmetries of this indices. The invocation of this method makes this instance unmodifiable, i.e. invocation of method add(...) after invocation of this method will cause exception.

Returns:

permutation group that represents symmetries of this indices

getPositionsInOrbits

public short[] getPositionsInOrbits()

Returns positions of indices in the array of orbits of underlying permutation group. Specifically, this method returns PermutationGroup.getPositionsInOrbits() converted to short[]. This method returns same reference each time; so, if one will use the returned array, do not forget to clone it, The invocation of this method makes this instance unmodifiable, i.e. invocation of method add(...) after invocation of this method will cause exception.

Returns:

positions of indices in the array of orbits of underlying permutation group

See Also:

PermutationGroup.getPositionsInOrbits()

isTrivial

public final boolean isTrivial()

Returns true if all generators are identity (and, consequently, the underlying permutation group is trivial) and false otherwise.

Returns:

true if all generators are identity

availableForModification

public boolean availableForModification()

Returns true if one can add new symmetries to this, or false, if this symmetries is already in use in some tensors; in latter case, the invocation of method add(...) will throw exception.

Returns:

true if one can add new symmetries to this, or false, if this symmetries is already in use in some tensors; in latter case, the invocation of method add(...) will throw exception.

addSymmetry

public void addSymmetry(int... permutation)

Adds specified permutation written in one-line notation to this symmetries.

Parameters:

permutation - permutation written in one-line notation

Throws:

java.lang.IllegalStateException - if this instance of symmetries is already in use (permutation group calculated)

java.lang.IllegalArgumentException - if specified permutation is inconsistent with one-line notation

java.lang.IllegalArgumentException - if this structure of indices is inconsistent with specified permutation (permutation mixes indices of different types)

addAntiSymmetry

public void addAntiSymmetry(int... permutation)

Adds specified antisymmetry written in one-line notation to this symmetries.

Parameters:

permutation - permutation written in one-line notation

Throws:

java.lang.IllegalStateException - if this instance of symmetries is already in use (permutation group calculated)

java.lang.IllegalArgumentException - if specified permutation is inconsistent with one-line notation

java.lang.IllegalArgumentException - if order of specified permutation is odd

java.lang.IllegalArgumentException - if this structure of indices is inconsistent with specified permutation (permutation mixes indices of different types)

add

public void add(boolean sign,
                int[] permutation)

Adds specified symmetry written in one-line notation to this symmetries.

Parameters:

sign - true for antisymmetry, false for symmetry

permutation - permutation written in one-line notation

Throws:

java.lang.IllegalStateException - if this instance of symmetries is already in use (permutation group calculated)

java.lang.IllegalArgumentException - if specified permutation is inconsistent with one-line notation

java.lang.IllegalArgumentException - when inputting antisymmetry with odd order

java.lang.IllegalArgumentException - if this structure of indices is inconsistent with specified permutation (permutation mixes indices of different types)

addSymmetry

public void addSymmetry(IndexType type,
                        int... permutation)

Adds specified permutation written in one-line notation to symmetries of indices of specified type.

Parameters:

type - type of indices

permutation - permutation written in one-line notation

Throws:

java.lang.IllegalStateException - if this instance of symmetries is already in use (permutation group calculated)

java.lang.IllegalArgumentException - if specified permutation is inconsistent with one-line notation

java.lang.IllegalArgumentException - if length of specified permutation differs from the size of indices of specified type

addAntiSymmetry

public void addAntiSymmetry(IndexType type,
                            int... permutation)

Adds specified antisymmetry written in one-line notation to symmetries of indices of specified type.

Parameters:

type - type of indices

permutation - permutation written in one-line notation

Throws:

java.lang.IllegalStateException - if this instance of symmetries is already in use (permutation group calculated)

java.lang.IllegalArgumentException - if specified permutation is inconsistent with one-line notation

java.lang.IllegalArgumentException - if order of specified permutation is odd

java.lang.IllegalArgumentException - if length of specified permutation differs from the size of indices of specified type

add

public void add(IndexType type,
                boolean sign,
                int... permutation)

Adds specified symmetry written in one-line notation to symmetries of indices of specified type.

Parameters:

type - type of indices

sign - true for antisymmetry, false for symmetry

permutation - permutation written in one-line notation

Throws:

java.lang.IllegalStateException - if this instance of symmetries is already in use (permutation group calculated)

java.lang.IllegalArgumentException - if specified permutation is inconsistent with one-line notation

java.lang.IllegalArgumentException - when inputting antisymmetry with odd order

java.lang.IllegalArgumentException - if length of specified permutation differs from the size of indices of specified type

add

public void add(byte type,
                boolean sign,
                int... permutation)

Adds specified symmetry written in one-line notation to symmetries of indices of specified type.

Parameters:

type - type of indices

sign - true for antisymmetry, false for symmetry

permutation - permutation written in one-line notation

Throws:

java.lang.IllegalStateException - if this instance of symmetries is already in use (permutation group calculated)

java.lang.IllegalArgumentException - if specified permutation is inconsistent with one-line notation

java.lang.IllegalArgumentException - when inputting antisymmetry with odd order

java.lang.IllegalArgumentException - if length of specified permutation differs from the size of indices of specified type

addSymmetry

public void addSymmetry(byte type,
                        Permutation symmetry)

Adds specified symmetry to symmetries of indices of specified type.

Parameters:

type - type of indices

symmetry - symmetry

Throws:

java.lang.IllegalStateException - if this instance of symmetries is already in use (permutation group calculated)

java.lang.IllegalArgumentException - if this structure of indices is inconsistent with specified permutation (permutation mixes indices of different types)

addSymmetry

public void addSymmetry(Permutation symmetry)

Adds specified symmetry to this.

Parameters:

symmetry - symmetry

Throws:

java.lang.IllegalStateException - if this instance of symmetries is already in use (permutation group calculated)

java.lang.IllegalArgumentException - if this structure of indices is inconsistent with specified permutation (permutation mixes indices of different types)

addSymmetries

public void addSymmetries(Permutation... symmetries)

Adds specified symmetries to this.

Parameters:

symmetries - symmetries

Throws:

java.lang.IllegalStateException - if this instance of symmetries is already in use (permutation group calculated)

java.lang.IllegalArgumentException - if this structure of indices is inconsistent with specified permutation (permutation mixes indices of different types)

addSymmetries

public void addSymmetries(java.util.Collection<Permutation> symmetries)

Adds specified symmetries to this.

Parameters:

symmetries - symmetries

Throws:

java.lang.IllegalStateException - if this instance of symmetries is already in use (permutation group calculated)

java.lang.IllegalArgumentException - if this structure of indices is inconsistent with specified permutation (permutation mixes indices of different types)

addAll

public void addAll(java.util.Collection<Permutation> symmetry)

Adds specified symmetries to this.

Parameters:

symmetry - symmetry

Throws:

java.lang.IllegalStateException - if this instance of symmetries is already in use (permutation group calculated)

java.lang.IllegalArgumentException - if this structure of indices is inconsistent with specified permutation (permutation mixes indices of different types)

setSymmetric

public void setSymmetric()

Makes this symmetries totally symmetric in all its indices (for each type). The invocation of this method makes this instance unmodifiable, i.e. invocation of method add(...) after invocation of this method will cause exception.

Throws:

java.lang.IllegalStateException - if this instance of symmetries is already in use (permutation group calculated)

setAntiSymmetric

public void setAntiSymmetric()

Makes this symmetries totally antisymmetric in all its indices (for each type). The invocation of this method makes this instance unmodifiable, i.e. invocation of method add(...) after invocation of this method will cause exception.

Throws:

java.lang.IllegalStateException - if this instance of symmetries is already in use (permutation group calculated)

clone

public IndicesSymmetries clone()

Overrides:

clone in class java.lang.Object

getEmpty

public static IndicesSymmetries getEmpty()

For indices with zero length

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object