Package org.flag4j.core

Class Shape

java.lang.Object

org.flag4j.core.Shape

All Implemented Interfaces:

Serializable

public class Shape
extends Object
implements Serializable

An object to store the shape of a tensor. Shapes are immutable.

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
private final int[]	dims	An array containing the size of each dimension of this shape.
private int[]	strides	An array containing the strides of all dimensions within this shape.
private BigInteger	totalEntries	Total entries of this shape.

Constructor Summary

Constructors

Constructor	Description
Shape(boolean computeStrides, int... dims)	Constructs a shape object from specified dimension measurements.
Shape(int... dims)	Constructs a shape object from specified dimension measurements.

Method Summary

Modifier and Type	Method	Description
int[]	createNewStrides()	Constructs strides for each dimension of this shape as if for a newly constructed tensor.
int	entriesIndex(int... indices)	Computes the index of the 1D data array for a dense tensor from tensor indices with this shape.
boolean	equals(Object b)	Checks if an object is equal to this shape.
int	get(int i)	Get the size of the shape object in the specified dimension.
int[]	getDims()	Gets the shape of a tensor as an array.
int[]	getIndices(int index)	Computes the nD tensor indices based on an index from the internal 1D data array.
void	getNextIndices(int[] currentIndices, int i)	Gets the next indices for a tensor with this shape.
int	getRank()	Gets the rank of a tensor with this shape.
int[]	getStrides()	Gets the shape of a tensor as an array.
int	hashCode()	Generates the hashcode for this shape object.
void	makeStridesIfNull()	If strides are null, create them.
Shape	swapAxes(int... axes)	Permutes the axes of this shape.
Shape	swapAxes(int axis1, int axis2)	Swaps two axes of this shape.
String	toString()	Converts this Shape object to a string format.
BigInteger	totalEntries()	Gets the total number of entries for a tensor with this shape.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Details

dims

private final int[] dims

An array containing the size of each dimension of this shape.

strides

private int[] strides

An array containing the strides of all dimensions within this shape.

totalEntries

private BigInteger totalEntries

Total entries of this shape. This is only computed on demand by totalEntries()

Constructor Details

Shape

public Shape(int... dims)

Constructs a shape object from specified dimension measurements.

Parameters:

dims - A list of the dimension measurements for this shape object. All entries must be non-negative.

Throws:

IllegalArgumentException - If any dimension is negative.

Shape

public Shape(boolean computeStrides,
 int... dims)

Constructs a shape object from specified dimension measurements.

Parameters:

computeStrides - Flag indicating if shape strides should be computed.

dims - A list of the dimension measurements for this shape object. All entries must be non-negative.

Throws:

IllegalArgumentException - If any dimension is negative.

Method Details

getRank

public int getRank()

Gets the rank of a tensor with this shape.

Returns:

The rank for a tensor with this shape.

getDims

public int[] getDims()

Gets the shape of a tensor as an array.

Returns:

Shape of a tensor as an integer array.

getStrides

public int[] getStrides()

Gets the shape of a tensor as an array.

Returns:

Shape of a tensor as an integer array.

get

public int get(int i)

Get the size of the shape object in the specified dimension.

Parameters:

i - Dimension to get the size of.

Returns:

The size of this shape object in the specified dimension.

createNewStrides

public int[] createNewStrides()

Constructs strides for each dimension of this shape as if for a newly constructed tensor. i.e. Strides will be a monotonically decreasing sequence with the last stride being 1.

Returns:

The strides for all dimensions of a newly constructed tensor with this shape.

makeStridesIfNull

public void makeStridesIfNull()

If strides are null, create them. Otherwise, do nothing.

entriesIndex

public int entriesIndex(int... indices)

Computes the index of the 1D data array for a dense tensor from tensor indices with this shape.

Parameters:

indices - Indices of tensor with this shape.

Returns:

The index of the element at the specified indices in the 1D data array of a dense tensor.

Throws:

IllegalArgumentException - If the number of indices does not match the rank of this shape.

IndexOutOfBoundsException - If any index does not fit within a tensor with this shape.

getIndices

public int[] getIndices(int index)

Computes the nD tensor indices based on an index from the internal 1D data array.

Parameters:

index - Index of internal 1D data array.

Returns:

The multidimensional indices corresponding to the 1D data array index. This will be an array of integers with size equal to the rank of this shape.

swapAxes

public Shape swapAxes(int axis1,
 int axis2)

Swaps two axes of this shape. New strides are constructed for this shape.

Parameters:

axis1 - First axis to swap.

axis2 - Second axis to swap.

Returns:

A copy of this shape with the specified axis swapped.

Throws:

ArrayIndexOutOfBoundsException - If either axis is not within [0, rank-1].

swapAxes

public Shape swapAxes(int... axes)

Permutes the axes of this shape.

Parameters:

axes - New axes permutation for the shape. This must be a permutation of {1, 2, 3, ... N} where N is the rank of this shape.

Returns:

Returns this shape.

Throws:

ArrayIndexOutOfBoundsException - If axes is not a permutation of {1, 2, 3, ... N}.

totalEntries

public BigInteger totalEntries()

Gets the total number of entries for a tensor with this shape.

Returns:

The total number of entries for a tensor with this shape.

equals

public boolean equals(Object b)

Checks if an object is equal to this shape.

Overrides:

equals in class Object

Parameters:

b - Object to compare with this shape.

Returns:

True if d is a Shape object and equal to this shape.

getNextIndices

public void getNextIndices(int[] currentIndices,
 int i)

Gets the next indices for a tensor with this shape.

Parameters:

currentIndices - Current indices. This array is modified.

i - Index of 1d data array.

hashCode

public int hashCode()

Generates the hashcode for this shape object. This is computed by passing the dims array of this shape object to Arrays.hashCode(int[]).

Overrides:

hashCode in class Object

Returns:

The hashcode for this array object.

toString

public String toString()

Converts this Shape object to a string format.

Overrides:

toString in class Object

Returns:

The string representation for this Shape object.