cc.redberry.core.indexmapping

Class IndexMappings

java.lang.Object

cc.redberry.core.indexmapping.IndexMappings

public final class IndexMappings
extends java.lang.Object

Central public facade of this package. Provides static methods for calculation of mappings between indices.

Since:

1.0

Method Summary

Modifier and Type	Method and Description
static boolean	anyMappingExists(Tensor a, Tensor b) Returns true if there is mapping from a on tensor b or vice versa.
static java.lang.Boolean	compare1(Tensor u, Tensor v) Returns true if tensor u mathematically (not programming) equals to tensor v, false if they they differ only in the sign and null otherwise.
static MappingsPort	createBijectiveProductPort(Tensor[] from, Tensor[] to) Creates output port of mappings of two products of tensors represented as arrays of multipliers, where each multiplier of from will be mapped on the multiplier of to at the same position.
static MappingsPort	createPort(Tensor from, Tensor to) Creates output port of mappings from tensor from onto tensor to.
static boolean	equals(Tensor u, Tensor v) Returns true if tensor u mathematically (not programming) equals to tensor v.
static java.util.Set<Mapping>	getAllMappings(Tensor from, Tensor to) Returns a set of all possible mappings of tensor from on tensor to.
static Mapping	getFirst(Tensor from, Tensor to) Returns the first mapping of tensor from on tensor to.
static boolean	isZeroDueToSymmetry(Tensor t) Returns true if specified tensor is zero in consequence of its symmetries: is both symmetric and asymmetric with respect to some permutation at the same time.
static boolean	mappingExists(Tensor from, Tensor to) Returns true if there is mapping of tensor from on tensor to.
static boolean	positiveMappingExists(Tensor from, Tensor to) Returns true if there is positive mapping of tensor from on tensor to.
static MappingsPort	simpleTensorsPort(SimpleTensor from, SimpleTensor to) Creates output port of mappings of two simple tensors and does not take into account the arguments of fields.
static boolean	testMapping(Mapping mapping, Tensor from, Tensor to) Tests whether specified mapping is a mapping from from tensor onto to tensor.

Methods inherited from class java.lang.Object

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

Method Detail

createPort

public static MappingsPort createPort(Tensor from,
                                      Tensor to)

Creates output port of mappings from tensor from onto tensor to.

Parameters:

from - from tensor

to - to tensor

Returns:

output port of mappings

simpleTensorsPort

public static MappingsPort simpleTensorsPort(SimpleTensor from,
                                             SimpleTensor to)

Creates output port of mappings of two simple tensors and does not take into account the arguments of fields.

Parameters:

from - from tensor

to - to tensor

Returns:

port of mappings of indices

createBijectiveProductPort

public static MappingsPort createBijectiveProductPort(Tensor[] from,
                                                      Tensor[] to)

Creates output port of mappings of two products of tensors represented as arrays of multipliers, where each multiplier of from will be mapped on the multiplier of to at the same position. Such ordering can be obtained via ProductsBijectionsPort. In contrast to createPortOfBuffers(cc.redberry.core.tensor.Tensor, cc.redberry.core.tensor.Tensor), this method will fully handles mappings of free indices on contracted ones (like e.g. _i^j -> _k^k).

Parameters:

from - from tensor

to - to tensor

Returns:

port of mappings of indices

getFirst

public static Mapping getFirst(Tensor from,
                               Tensor to)

Returns the first mapping of tensor from on tensor to.

Parameters:

from - from tensor

to - to tensor

Returns:

mapping of indices of tensor from on tensor to

testMapping

public static boolean testMapping(Mapping mapping,
                                  Tensor from,
                                  Tensor to)

Tests whether specified mapping is a mapping from from tensor onto to tensor.

Parameters:

mapping - mapping

from - tensor from

to - tensor to

Returns:

true if specified mapping is a mapping from from tensor onto to tensor and false in other case.

anyMappingExists

public static boolean anyMappingExists(Tensor a,
                                       Tensor b)

Returns true if there is mapping from a on tensor b or vice versa.

Parameters:

a - tensor

b - tensor

Returns:

true if there is mapping from a on tensor b or vice versa

mappingExists

public static boolean mappingExists(Tensor from,
                                    Tensor to)

Returns true if there is mapping of tensor from on tensor to.

Parameters:

from - from tensor

to - to tensor

Returns:

true if there is mapping of tensor from on tensor to

positiveMappingExists

public static boolean positiveMappingExists(Tensor from,
                                            Tensor to)

Returns true if there is positive mapping of tensor from on tensor to.

Parameters:

from - from tensor

to - to tensor

Returns:

true if there is positivemapping of tensor from on tensor to

equals

public static boolean equals(Tensor u,
                             Tensor v)

Returns true if tensor u mathematically (not programming) equals to tensor v.

Parameters:

u - tensor

v - tensor

Returns:

true if specified tensors are mathematically (not programming) equal

compare1

public static java.lang.Boolean compare1(Tensor u,
                                         Tensor v)

Returns true if tensor u mathematically (not programming) equals to tensor v, false if they they differ only in the sign and null otherwise.

Parameters:

u - tensor

v - tensor

Returns:

true true if tensor u mathematically (not programming) equals to tensor v, false if they they differ only in the sign and null otherwise

isZeroDueToSymmetry

public static boolean isZeroDueToSymmetry(Tensor t)

Returns true if specified tensor is zero in consequence of its symmetries: is both symmetric and asymmetric with respect to some permutation at the same time.

Parameters:

t - tensor

Returns:

true if specified tensor is zero in consequence of its symmetries

getAllMappings

public static java.util.Set<Mapping> getAllMappings(Tensor from,
                                                    Tensor to)

Returns a set of all possible mappings of tensor from on tensor to.

Parameters:

from - from tensor

to - to tensor

Returns:

a set of all possible mappings of tensor from on tensor to