CompareAndBitpack

public final class CompareAndBitpack

Compare values of `input` to `threshold` and pack resulting bits into a `uint8`.

Each comparison returns a boolean `true` (if `input_value > threshold`) or and `false` otherwise.

This operation is useful for Locality-Sensitive-Hashing (LSH) and other algorithms that use hashing approximations of cosine and `L2` distances; codes can be generated from an input via:

codebook_size = 50
 codebook_bits = codebook_size * 32
 codebook = tf.get_variable('codebook', [x.shape[-1].value, codebook_bits],
                            dtype=x.dtype,
                            initializer=tf.orthogonal_initializer())
 codes = compare_and_threshold(tf.matmul(x, codebook), threshold=0.)
 codes = tf.bitcast(codes, tf.int32)  # go from uint8 to int32
 # now codes has shape x.shape[:-1] + [codebook_size]
 

NOTE: Currently, the innermost dimension of the tensor must be divisible by 8.

Given an `input` shaped `[s0, s1, ..., s_n]`, the output is a `uint8` tensor shaped `[s0, s1, ..., s_n / 8]`.

Constants

String

OP_NAME

The name of this op, as known by TensorFlow core engine

Public Methods

Output<TUint8>	asOutput() Returns the symbolic handle of the tensor.
static <T extends TType> CompareAndBitpack	create(Scope scope, Operand<T> input, Operand<T> threshold) Factory method to create a class wrapping a new CompareAndBitpack operation.
Output<TUint8>	output() The bitpacked comparisons.

Inherited Methods

From class org.tensorflow.op.RawOp

final boolean	equals(Object obj)
final int	hashCode()
Operation	op() Return this unit of computation as a single Operation.
final String	toString()

From class java.lang.Object

boolean	equals(Object arg0)
final Class<?>	getClass()
int	hashCode()
final void	notify()
final void	notifyAll()
String	toString()
final void	wait(long arg0, int arg1)
final void	wait(long arg0)
final void	wait()

From interface org.tensorflow.op.Op

abstract ExecutionEnvironment	env() Return the execution environment this op was created in.
abstract Operation	op() Return this unit of computation as a single Operation.

From interface org.tensorflow.Operand

abstract Output<TUint8>	asOutput() Returns the symbolic handle of the tensor.
abstract TUint8	asTensor() Returns the tensor at this operand.
abstract Shape	shape() Returns the (possibly partially known) shape of the tensor referred to by the Output of this operand.
abstract Class<TUint8>	type() Returns the tensor type of this operand

From interface org.tensorflow.ndarray.Shaped

abstract int	rank()
abstract Shape	shape()
abstract long	size() Computes and returns the total size of this container, in number of values.

Constants

public static final String OP_NAME

The name of this op, as known by TensorFlow core engine

Constant Value: "CompareAndBitpack"

Public Methods

public Output<TUint8> asOutput ()

Returns the symbolic handle of the tensor.

Inputs to TensorFlow operations are outputs of another TensorFlow operation. This method is used to obtain a symbolic handle that represents the computation of the input.

public static CompareAndBitpack create (Scope scope, Operand<T> input, Operand<T> threshold)

Factory method to create a class wrapping a new CompareAndBitpack operation.

Parameters

scope	current scope
input	Values to compare against `threshold` and bitpack.
threshold	Threshold to compare against.

Returns

• a new instance of CompareAndBitpack

public Output<TUint8> output ()

The bitpacked comparisons.