cc.redberry.core.tensor

Class Product

java.lang.Object

cc.redberry.core.tensor.Tensor

cc.redberry.core.tensor.MultiTensor

cc.redberry.core.tensor.Product

All Implemented Interfaces:

java.lang.Comparable<Tensor>, java.lang.Iterable<Tensor>

public final class Product
extends MultiTensor

Representation of product of mathematical expressions.

The implementation keeps numerical factor, indexless multipliers, and multipliers with non empty free indices separately. If there is no numeric factor in product, it is equal to 1. Bot indexless and indexed data are sorted according to Tensor.compareTo(Tensor) method. Indexed data is additionally sorted according to a special comparator based on StructureOfContractions of this product.

Since:

1.0

Method Summary

Modifier and Type	Method and Description
Tensor	get(int i) Returns element at i-th position.
Tensor[]	getAllScalars() Returns all scalar factors in this product.
Tensor[]	getAllScalarsWithoutFactor() Returns all scalar factors in this product excluding the numerical factor.
TensorBuilder	getBuilder() Creates a builder for this tensor.
ProductContent	getContent() Returns the product content, i.e.
Tensor	getDataSubProduct() Returns the product of indexed (with non empty free indices) multipliers of this tensor.
Complex	getFactor() Returns numerical factor of this product.
TensorFactory	getFactory() Returns a factory for this tensor.
Tensor[]	getIndexless() Returns a copy of indexless data.
Tensor	getIndexlessSubProduct() Returns indexless data as a product of tensors.
Indices	getIndices() Returns indices of this tensor.
Tensor[]	getRange(int from, int to) Retrieves several sub-tensors from current tensor.
Tensor	getSubProductWithoutFactor() Returns this product but without numeric factor.
Tensor	getWithoutFactor(int i) Returns element at i-th position excluding numerical factor of this product from numbering.
Tensor	remove(int position) Removes tensor at the specified position and returns the result.
Tensor	set(int i, Tensor tensor) Returns new tensor instance with i-th sub-tensor replaced by provided tensor.
int	size() Returns the number of elements in this tensor.
int	sizeOfIndexlessPart() Returns the size of indexless part (including numerical factor).
int	sizeWithoutFactor() Returns the size of product without factor.
java.lang.String	toString(OutputFormat format) Returns a string representation of a tensor according to the specified OutputFormat.

Methods inherited from class cc.redberry.core.tensor.MultiTensor

remove, remove, select

Methods inherited from class cc.redberry.core.tensor.Tensor

compareTo, hashCode, iterator, toArray, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Method Detail

getIndices

public Indices getIndices()

Description copied from class: Tensor

Returns indices of this tensor.

Overrides:

getIndices in class MultiTensor

Returns:

indices of this tensor

get

public Tensor get(int i)

Description copied from class: Tensor

Returns element at i-th position.

Specified by:

get in class Tensor

Parameters:

i - position

Returns:

element at i-th position

getRange

public Tensor[] getRange(int from,
                         int to)

Description copied from class: Tensor

Retrieves several sub-tensors from current tensor. This function is faster than sequential invocations of Tensor.get(int) method.

Overrides:

getRange in class Tensor

Parameters:

from - index of first sub-tensor to be retrieved (inclusive)

to - next index after last sub-tensor to be retrieved (exclusive)

Returns:

array with retrieved tensors

size

public int size()

Description copied from class: Tensor

Returns the number of elements in this tensor.

Specified by:

size in class Tensor

Returns:

the number of elements in this tensor

sizeWithoutFactor

public int sizeWithoutFactor()

Returns the size of product without factor. I.e. if factor is one, then sizeWithoutFactor() == size(), otherwise sizeWithoutFactor() == size() - 1.

Returns:

size of product without factor

sizeOfIndexlessPart

public int sizeOfIndexlessPart()

Returns the size of indexless part (including numerical factor).

Returns:

size of indexless part (including numerical factor)

set

public Tensor set(int i,
                  Tensor tensor)

Description copied from class: Tensor

Returns new tensor instance with i-th sub-tensor replaced by provided tensor.

Overrides:

set in class Tensor

Parameters:

i - index of sub-tensor to be replaced

tensor - tensor to replace i-th sub-tensor

Returns:

new instance of tensor

remove

public Tensor remove(int position)

Description copied from class: MultiTensor

Removes tensor at the specified position and returns the result.

Specified by:

remove in class MultiTensor

Parameters:

position - position in tensor

Returns:

result of removing

getWithoutFactor

public Tensor getWithoutFactor(int i)

Returns element at i-th position excluding numerical factor of this product from numbering. So, if factor is one, then this method returns get(i), otherwise is returns get(i-1).

Parameters:

i - position

Returns:

element at i-th position excluding numerical factor of this product from numbering

getFactor

public Complex getFactor()

Returns numerical factor of this product.

Returns:

numerical factor of this product

getContent

public ProductContent getContent()

Returns the product content, i.e. the information about the corresponding graph.

Returns:

product content

getIndexless

public Tensor[] getIndexless()

Returns a copy of indexless data.

Returns:

a copy of indexless data

getBuilder

public TensorBuilder getBuilder()

Description copied from class: Tensor

Creates a builder for this tensor. See TensorBuilder for more information.

Specified by:

getBuilder in class Tensor

Returns:

builder for this tensor

getAllScalars

public Tensor[] getAllScalars()

Returns all scalar factors in this product. For example, if this is 2*a*f_mn*G^mn*f_a*T^ab, the result will be [2,a,f_mn*G^mn].

Returns:

all scalar factors in this product

getAllScalarsWithoutFactor

public Tensor[] getAllScalarsWithoutFactor()

Returns all scalar factors in this product excluding the numerical factor. For example, if this is 2*a*f_mn*G^mn*f_a*T^ab, the result will be [a,f_mn*G^mn].

Returns:

all scalar factors in this product excluding the numerical factor

getIndexlessSubProduct

public Tensor getIndexlessSubProduct()

Returns indexless data as a product of tensors.

Returns:

indexless data as a product of tensors

getSubProductWithoutFactor

public Tensor getSubProductWithoutFactor()

Returns this product but without numeric factor.

Returns:

this product but without numeric factor

getDataSubProduct

public Tensor getDataSubProduct()

Returns the product of indexed (with non empty free indices) multipliers of this tensor.

Returns:

product of indexed (with non empty free indices) multipliers of this tensor

getFactory

public TensorFactory getFactory()

Description copied from class: Tensor

Returns a factory for this tensor. See TensorFactory for more information.

Specified by:

getFactory in class Tensor

Returns:

builder for this tensor

toString

public java.lang.String toString(OutputFormat format)

Description copied from class: Tensor

Returns a string representation of a tensor according to the specified OutputFormat.

Specified by:

toString in class Tensor

Parameters:

format - output format

Returns:

a string representation of a tensor