org.tensorflow.ndarray.index

Class Indices

java.lang.Object

org.tensorflow.ndarray.index.Indices

public final class Indices
extends Object

Helper class for instantiating Index objects.

Constructor Summary

Constructors

Constructor and Description
Indices()

Method Summary

Modifier and Type	Method and Description
static Index	all() An index that returns all elements of a dimension in the original order.
static Index	at(long coord) A coordinate that selects a specific element on a given dimension.
static Index	at(NdArray<? extends Number> coord) A coordinate that selects a specific element on a given dimension.
static Index	even() An index that returns only elements found at an even position in the original dimension.
static Index	flip() An index that returns only elements on a given dimension between two coordinates.
static Index	from(long start) An index that returns only elements on a given dimension starting at a specific coordinate.
static Index	hyperslab(long start, long stride, long count, long block) An index that returns elements according to an hyperslab defined by start, stride, count, block.
static Index	odd() An index that returns only elements found at an odd position in the original dimension.
static Index	range(long start, long end) An index that returns only elements on a given dimension between two coordinates.
static Index	seq(long... coords) An index that returns only specific elements on a given dimension.
static Index	seq(NdArray<? extends Number> coords) An index that returns only specific elements on a given dimension.
static Index	step(long stepLength) An index that skips a fixed amount of coordinates between each values returned.
static Index	to(long end) An index that returns only elements on a given dimension up to a specific coordinate.

Methods inherited from class java.lang.Object

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

Constructor Detail

Indices

public Indices()

Method Detail

at

public static Index at(long coord)

A coordinate that selects a specific element on a given dimension.

When this index is applied to a given dimension, the dimension is resolved as a single element and therefore is excluded from the computation of the rank.

For example, given a 3D matrix on the axis [x, y, z], if matrix.slice(all(), at(0), at(0), then the rank of the returned slice is 1 and its number of elements is x.numElements()

Parameters:

coord - coordinate of the element on the indexed axis

Returns:

index

at

public static Index at(NdArray<? extends Number> coord)

A coordinate that selects a specific element on a given dimension.

This is equivalent to call at(long) but where the value of the coordinate is provided by an N-dimensional array.

Parameters:

coord - scalar indicating the coordinate of the element on the indexed axis

Returns:

index

Throws:

IllegalRankException - if coord is not a scalar (rank 0)

all

public static Index all()

An index that returns all elements of a dimension in the original order.

Applying this index to a given dimension will return the original dimension directly.

For example, given a vector with n elements, all() returns x₀, x₁, ..., x_n-1

Returns:

index

seq

public static Index seq(long... coords)

An index that returns only specific elements on a given dimension.

For example, given a vector with n elements on the x axis, and n > 10, seq(8, 0, 3) returns x₈, x₀, x₃

Parameters:

coords - coordinates of the elements in the sequence

Returns:

index

seq

public static Index seq(NdArray<? extends Number> coords)

An index that returns only specific elements on a given dimension.

This is equivalent to seq(long...) but where the coordinates of the elements in the sequence are provided by an N-dimensional array.

Parameters:

coords - vector of coordinates of the elements in the sequence

Returns:

index

Throws:

IllegalRankException - if coords is not a vector (rank 1)

even

public static Index even()

An index that returns only elements found at an even position in the original dimension.

For example, given a vector with n elements on the x axis, and n is even, even() returns x₀, x₂, ..., x_n-2

Returns:

index

odd

public static Index odd()

An index that returns only elements found at an odd position in the original dimension.

For example, given a vector with n elements on the x axis, and n is even, odd() returns x₁, x₃, ..., x_n-1

Returns:

index

step

public static Index step(long stepLength)

An index that skips a fixed amount of coordinates between each values returned.

For example, given a vector with n elements on the x axis, step(k) returns x₀, x_k, x_k*2, ...

Parameters:

stepLength - the number of elements between each steps

Returns:

index

from

public static Index from(long start)

An index that returns only elements on a given dimension starting at a specific coordinate.

For example, given a vector with n elements on the x axis, and n > k, from(k) returns x_k, x_k+1, ..., x_n-1

Parameters:

start - coordinate of the first element of the sequence

Returns:

index

to

public static Index to(long end)

An index that returns only elements on a given dimension up to a specific coordinate.

For example, given a vector with n elements on the x axis, and n > k, to(k) returns x₀, x₁, ..., x_k

Parameters:

end - coordinate of the last element of the sequence (exclusive)

Returns:

index

range

public static Index range(long start,
                          long end)

An index that returns only elements on a given dimension between two coordinates.

For example, given a vector with n elements on the x axis, and n > k > j, range(j, k) returns x_j, x_j+1, ..., x_k

Parameters:

start - coordinate of the first element of the sequence

end - coordinate of the last element of the sequence (exclusive)

Returns:

index

flip

public static Index flip()

An index that returns only elements on a given dimension between two coordinates.

For example, given a vector with n elements on the x axis, and n > k > j, range(j, k) returns x_j, x_j+1, ..., x_k

Returns:

index

hyperslab

public static Index hyperslab(long start,
                              long stride,
                              long count,
                              long block)

An index that returns elements according to an hyperslab defined by start, stride, count, block. See Hyperslab.

Parameters:

start - Starting location for the hyperslab.

stride - The number of elements to separate each element or block to be selected.

count - The number of elements or blocks to select along the dimension.

block - The size of the block selected from the dimension.

Returns:

index