Package mklab.JGNN.core.matrix

Class AccessCol

java.lang.Object

mklab.JGNN.core.Tensor

mklab.JGNN.core.matrix.AccessCol

All Implemented Interfaces:

Iterable<Long>

public class AccessCol
extends Tensor

Accesses a column of a Matrix as if it were a dense Tensor. Prefer using Matrix.accessCol(long), which wraps usage of this class. Instances of this class share elements with the matrix which they access and do not allocate new memory.

Author:

Emmanouil Krasanakis

See Also:

• AccessRow

Field Summary

Fields inherited from class mklab.JGNN.core.Tensor

vectorization

Constructor Summary

Constructors

Constructor	Description
AccessCol(Matrix matrix, long col)	Instantiates a see-through access of a matrix column.

Method Summary

Modifier and Type	Method	Description
protected void	allocate(long size)
long	estimateNumNonZeroElements()	Provides an estimation for the non-zero number of elements stored in the tensor, where this number is equal to the size for dense tensors, but equal to the actual number of non-zero elements for sparse tensors.
double	get(long pos)	Retrieves the value of a tensor element at a given position.
void	persist()	If supported by the subclassed tensor, invalidates calls to Tensor.release() so that memory is de-allocated only when object references expire.
Tensor	put(long pos, double value)	Assign a value to a tensor element.
void	release()	If the subclassed tensor allows it, release all memory it takes up so that the garbage collector will eventually clean it up.
Iterator<Long>	traverseNonZeroElements()	Retrieves positions within the tensor that may hold non-zero elements.
Tensor	zeroCopy(long size)	Creates a tensor of the same class with a given size and all element set to zero.

Methods inherited from class mklab.JGNN.core.Tensor

abs, accessSubtensor, accessSubtensor, add, add, argmax, argmin, asColumn, asRow, assertFinite, assertMatching, assertSize, assign, cast, copy, density, describe, determineZeroCopy, dot, dot, expMinusOne, fromDouble, fromRange, fromRange, getDimensionName, getNonZeroElements, init, inverse, isMatching, iterator, log, max, min, multiply, multiply, negative, norm, normalized, putAdd, selfAbs, selfAdd, selfAdd, selfAdd, selfExpMinusOne, selfInverse, selfLog, selfMultiply, selfMultiply, selfNegative, selfSqrt, selfSubtract, setDimensionName, setDimensionName, setToNormalized, setToOnes, setToProbability, setToRandom, setToRandom, setToUniform, setToZero, size, sqrt, subtract, sum, toArray, toDouble, toProbability, toString, zeroCopy, zeroCopy

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Details

AccessCol

public AccessCol(Matrix matrix,
 long col)

Instantiates a see-through access of a matrix column.

Parameters:

matrix - The base matrix.

col - Which column to access.

Method Details

estimateNumNonZeroElements

public long estimateNumNonZeroElements()

Description copied from class: Tensor

Provides an estimation for the non-zero number of elements stored in the tensor, where this number is equal to the size for dense tensors, but equal to the actual number of non-zero elements for sparse tensors. Basically, this quantity is proportional to the allocated memory.

Overrides:

estimateNumNonZeroElements in class Tensor

Returns:

A long number equal to or less to the tensor size.

See Also:

• Tensor.density()

allocate

protected void allocate(long size)

Specified by:

allocate in class Tensor

put

public Tensor put(long pos,
 double value)

Description copied from class: Tensor

Assign a value to a tensor element. All tensor operations use this function to wrap element assignments.

Specified by:

put in class Tensor

Parameters:

pos - The position of the tensor element.

value - The value to assign.

Returns:

this Tensor instance.

See Also:

• Tensor.put(int, double)

get

public double get(long pos)

Description copied from class: Tensor

Retrieves the value of a tensor element at a given position. All tensor operations use this function to wrap element retrieval.

Specified by:

get in class Tensor

Parameters:

pos - The position of the tensor element

Returns:

The value of the tensor element

zeroCopy

public Tensor zeroCopy(long size)

Description copied from class: Tensor

Creates a tensor of the same class with a given size and all element set to zero.

Specified by:

zeroCopy in class Tensor

Parameters:

size - The size of the new tensor.

Returns:

A new tensor.

See Also:

• Tensor.zeroCopy(long)

traverseNonZeroElements

public Iterator<Long> traverseNonZeroElements()

Description copied from class: Tensor

Retrieves positions within the tensor that may hold non-zero elements. This guarantees that all non-zero elements positions are traversed but some of the returned positions could hold zero elements. For example, DenseTensor traverses all of its elements this way, whereas SparseTensor indeed traverses only non-zero elements.

Specified by:

traverseNonZeroElements in class Tensor

Returns:

An iterator that traverses positions within the tensor.

release

public void release()

Description copied from class: Tensor

If the subclassed tensor allows it, release all memory it takes up so that the garbage collector will eventually clean it up. This memory will be released anyway by Java once there are no more references to the object.

Specified by:

release in class Tensor

See Also:

• Tensor.persist()

persist

public void persist()

Description copied from class: Tensor

If supported by the subclassed tensor, invalidates calls to Tensor.release() so that memory is de-allocated only when object references expire.

Specified by:

persist in class Tensor

See Also:

• Tensor.release()