Class AbstractCooRingTensor<T extends AbstractCooRingTensor<T,U,V>,U extends AbstractDenseRingTensor<U,V>,V extends Ring<V>>

java.lang.Object

org.flag4j.arrays.backend.AbstractTensor<T,V[],V>

org.flag4j.arrays.backend.semiring_arrays.AbstractCooSemiringTensor<T,U,V>

org.flag4j.arrays.backend.ring_arrays.AbstractCooRingTensor<T,U,V>

Type Parameters:

T - Type of this sparse COO tensor.

U - Type of dense tensor equivalent to T. This type parameter is required because some ops (e.g. AbstractCooSemiringTensor.tensorDot(AbstractCooSemiringTensor, int[], int[]) ) between two sparse tensors results in a dense tensor.

V - Type of the Ring which the data of this tensor belong to.

All Implemented Interfaces:

Serializable, RingTensorMixin<T,T,V>, TensorOverRing<T,T,V[],V>, SemiringTensorMixin<T,T,V>, TensorOverSemiring<T,T,V[],V>

Direct Known Subclasses:

AbstractCooFieldTensor, CooRingTensor

public abstract class AbstractCooRingTensor<T extends AbstractCooRingTensor<T,U,V>,U extends AbstractDenseRingTensor<U,V>,V extends Ring<V>>
extends AbstractCooSemiringTensor<T,U,V>
implements RingTensorMixin<T,T,V>

Base class for all sparse Ring tensors stored in coordinate list (COO) format. The data of this COO tensor are elements of a Ring.

The non-zero data and non-zero indices of a COO tensor are mutable but the AbstractTensor.shape and total number of non-zero data is fixed.

Sparse tensors allow for the efficient storage of and ops on tensors that contain many zero values.

COO tensors are optimized for hyper-sparse tensors (i.e. tensors which contain almost all zeros relative to the size of the tensor).

A sparse COO tensor is stored as:

• The full shape of the tensor.
• The non-zero AbstractTensor.data of the tensor. All other data in the tensor are assumed to be zero. Zero value can also explicitly be stored in AbstractTensor.data.

• The AbstractCooSemiringTensor.indices of the non-zero value in the sparse tensor. Many ops assume indices to be sorted in a row-major format (i.e. last index increased fastest) but often this is not explicitly verified.

  The AbstractCooSemiringTensor.indices array has shape (nnz, rank) where AbstractCooSemiringTensor.nnz is the number of non-zero data in this sparse tensor and rank is the tensor rank of the tensor. This means indices[i] is the nD index of data[i].

See Also:

• Serialized Form

Field Summary

Fields inherited from class org.flag4j.arrays.backend.semiring_arrays.AbstractCooSemiringTensor

indices, nnz, sparsity, zeroElement

Fields inherited from class org.flag4j.arrays.backend.AbstractTensor

data, rank, shape

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AbstractCooRingTensor(Shape shape, V[] data, int[][] indices)	Creates a tensor with the specified data and shape.
protected	AbstractCooRingTensor(Shape shape, V[] data, int[][] indices, Object dummy)	Constructor useful for avoiding parameter validation while constructing COO tensors.

Method Summary

Modifier and Type	Method	Description
T	H(int... axes)	Computes the conjugate transpose of this tensor.
T	H(int axis1, int axis2)	Computes the conjugate transpose of a tensor by conjugating and exchanging axis1 and axis2.
T	sub(T b)	Computes the element-wise difference between two tensors of the same shape.

Methods inherited from class org.flag4j.arrays.backend.semiring_arrays.AbstractCooSemiringTensor

add, argmax, argmin, coalesce, coalesce, copy, dataLength, density, dropZeros, elemMult, flatten, flatten, get, getZeroElement, makeLikeDenseTensor, makeLikeTensor, makeLikeTensor, max, min, reshape, set, setZeroElement, sortIndices, sparsity, T, T, T, tensorDot, tensorTr, toDense

Methods inherited from class org.flag4j.arrays.backend.AbstractTensor

getData, getRank, getShape, makeLikeTensor, reshape, sameShape, totalEntries

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.flag4j.arrays.backend.ring_arrays.RingTensorMixin

add, addEq, argmax, argmaxAbs, argmin, argminAbs, conj, isOnes, isZeros, makeEmptyDataArray, max, maxAbs, min, minAbs, mult, multEq, norm, norm, prod, sub, subEq, sum

Methods inherited from interface org.flag4j.arrays.backend.ring_arrays.TensorOverRing

abs, H

Methods inherited from interface org.flag4j.arrays.backend.semiring_arrays.TensorOverSemiring

add, elemMult, getData, getRank, getShape, makeLikeTensor, tensorDot, tensorDot, tensorDot, tensorDot, tensorTr, tensorTr

Constructor Details

AbstractCooRingTensor

protected AbstractCooRingTensor(Shape shape,
 V[] data,
 int[][] indices)

Creates a tensor with the specified data and shape.

Parameters:

shape - Shape of this tensor.

data - Entries of this tensor. If this tensor is dense, this specifies all data within the tensor. If this tensor is sparse, this specifies only the non-zero data of the tensor.

AbstractCooRingTensor

protected AbstractCooRingTensor(Shape shape,
 V[] data,
 int[][] indices,
 Object dummy)

Constructor useful for avoiding parameter validation while constructing COO tensors.

Parameters:

shape - The shape of the tensor to construct.

data - The non-zero data of this tensor.

indices - The indices of the non-zero data.

dummy - Dummy object to distinguish this constructor from the safe variant. It is completely ignored in this constructor.

Method Details

sub

public T sub(T b)

Computes the element-wise difference between two tensors of the same shape.

Specified by:

sub in interface TensorOverRing<T extends AbstractCooRingTensor<T,U,V>,T extends AbstractCooRingTensor<T,U,V>,V extends Ring<V>[],V extends Ring<V>>

Parameters:

b - Second tensor in the element-wise difference.

Returns:

The difference of this tensor with b.

Throws:

TensorShapeException - If this tensor and b do not have the same shape.

H

public T H(int axis1,
 int axis2)

Computes the conjugate transpose of a tensor by conjugating and exchanging axis1 and axis2.

Specified by:

H in interface TensorOverRing<T extends AbstractCooRingTensor<T,U,V>,T extends AbstractCooRingTensor<T,U,V>,V extends Ring<V>[],V extends Ring<V>>

Parameters:

axis1 - First axis to exchange and conjugate.

axis2 - Second axis to exchange and conjugate.

Returns:

The conjugate transpose of this tensor according to the specified axes.

Throws:

IndexOutOfBoundsException - If either axis1 or axis2 are out of bounds for the rank of this tensor.

See Also:

• TensorOverRing.H()
• H(int...)

H

public T H(int... axes)

Computes the conjugate transpose of this tensor. That is, conjugates and permutes the axes of this tensor so that it matches the permutation specified by axes.

Specified by:

H in interface TensorOverRing<T extends AbstractCooRingTensor<T,U,V>,T extends AbstractCooRingTensor<T,U,V>,V extends Ring<V>[],V extends Ring<V>>

Parameters:

axes - Permutation of tensor axis. If the tensor has rank N, then this must be an array of length N which is a permutation of {0, 1, 2, ..., N-1}.

Returns:

The conjugate transpose of this tensor with its axes permuted by the axes array.

Throws:

IndexOutOfBoundsException - If any element of axes is out of bounds for the rank of this tensor.

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

See Also:

• H(int, int)
• TensorOverRing.H()