Package org.flag4j.linalg

Class TensorInvert

java.lang.Object

org.flag4j.linalg.TensorInvert

public final class TensorInvert
extends Object

This class provides methods for computing the 'inverse' of a tensor with respect to some tensor dot product operation.

Constructor Summary

Constructors

Modifier	Constructor	Description
private	TensorInvert()

Method Summary

Modifier and Type	Method	Description
private static Shape	getInvShape(Shape originalShape, int numIndices)	Computes the shape of the 'inverse' tensor given the original shape and the number of indices.
private static int	getProduct(int[] dims, int numIndices)	Computes the total number of entries in the last numIndices dimensions of a tensor with dimensions specified by dims.
static CTensor	inv(CTensor src, int numIndices)	Computes the 'inverse' of this tensor.
static Tensor	inv(Tensor src, int numIndices)	Computes the 'inverse' of this tensor.

Methods inherited from class java.lang.Object

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

Constructor Details

TensorInvert

private TensorInvert()

Method Details

inv

public static Tensor inv(Tensor src,
 int numIndices)

Computes the 'inverse' of this tensor. That is, computes the tensor X=this.tensorInv() such that src.tensorDot(X, numIndices) is the 'identity' tensor for the tensor dot product operation.

A tensor I is the identity for a tensor dot product if src.tensorDot(I, numIndices).equals(this).

Parameters:

src - Tensor to compute inverse of.

numIndices - The number of first numIndices which are involved in the inverse sum.

Returns:

The 'inverse' of this tensor as defined in the above sense.

Throws:

IllegalArgumentException - If numIndices is not positive.

inv

public static CTensor inv(CTensor src,
 int numIndices)

Computes the 'inverse' of this tensor. That is, computes the tensor X=this.tensorInv() such that src.tensorDot(X, numIndices) is the 'identity' tensor for the tensor dot product operation.

A tensor I is the identity for a tensor dot product if src.tensorDot(I, numIndices).equals(this).

Parameters:

src - Tensor to compute inverse of.

numIndices - The number of first numIndices which are involved in the inverse sum.

Returns:

The 'inverse' of this tensor as defined in the above sense.

Throws:

IllegalArgumentException - If numIndices is not positive.

getInvShape

private static Shape getInvShape(Shape originalShape,
 int numIndices)

Computes the shape of the 'inverse' tensor given the original shape and the number of indices.

Parameters:

originalShape - Shape of the original tensor.

numIndices - Number of indices that are involved in the inverse sum.

Returns:

The shape of the 'inverse' tensor.

getProduct

private static int getProduct(int[] dims,
 int numIndices)

Computes the total number of entries in the last numIndices dimensions of a tensor with dimensions specified by dims.

Parameters:

dims - Dimensions of the tensor.

numIndices - Number of last indices to compute product for.

Returns:

The total number of entries in the last numIndices dimensions of a tensor with dimensions specified by dims. That is, the product of the last numIndices entries of dims.