ai.djl.nn.recurrent

Class GRU

java.lang.Object

ai.djl.nn.AbstractBlock

ai.djl.nn.recurrent.RecurrentBlock

ai.djl.nn.recurrent.GRU

All Implemented Interfaces:

Block

public class GRU
extends RecurrentBlock

GRU is an abstract implementation of recurrent neural networks which applies GRU (Gated Recurrent Unit) recurrent layer to input.

Current implementation refers the [paper](http://arxiv.org/abs/1406.1078) - Gated Recurrent Unit. The definition of GRU here is slightly different from the paper but compatible with CUDNN.

The GRU operator is formulated as below:

$$ \begin{split}\begin{array}{ll} r_t = \mathrm{sigmoid}(W_{ir} x_t + b_{ir} + W_{hr} h_{(t-1)} + b_{hr}) \\ z_t = \mathrm{sigmoid}(W_{iz} x_t + b_{iz} + W_{hz} h_{(t-1)} + b_{hz}) \\ n_t = \tanh(W_{in} x_t + b_{in} + r_t * (W_{hn} h_{(t-1)}+ b_{hn})) \\ h_t = (1 - z_t) * n_t + z_t * h_{(t-1)} \\ \end{array}\end{split} $$

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	GRU.Builder The Builder to construct a GRU type of Block.

Nested classes/interfaces inherited from class ai.djl.nn.recurrent.RecurrentBlock

RecurrentBlock.BaseBuilder<T extends RecurrentBlock.BaseBuilder>

Field Summary

Fields inherited from class ai.djl.nn.recurrent.RecurrentBlock

batchFirst, bidirectional, dropRate, gates, hasBiases, numLayers, returnState, stateSize

Fields inherited from class ai.djl.nn.AbstractBlock

children, inputNames, inputShapes, parameters, version

Method Summary

Modifier and Type	Method and Description
static GRU.Builder	builder() Creates a builder to build a GRU.
protected NDList	forwardInternal(ParameterStore parameterStore, NDList inputs, boolean training, ai.djl.util.PairList<java.lang.String,java.lang.Object> params) A helper for Block.forward(ParameterStore, NDList, boolean, PairList) after initialization.

Methods inherited from class ai.djl.nn.recurrent.RecurrentBlock

beforeInitialize, getNumDirections, getOutputShapes, loadMetadata, prepare

Methods inherited from class ai.djl.nn.AbstractBlock

addChildBlock, addParameter, cast, clear, describeInput, forward, forward, forwardInternal, getChildren, getDirectParameters, getParameters, initialize, initializeChildBlocks, isInitialized, loadParameters, readInputShapes, saveInputShapes, saveMetadata, saveParameters, setInitializer, setInitializer, setInitializer, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface ai.djl.nn.Block

forward, validateLayout

Method Detail

forwardInternal

protected NDList forwardInternal(ParameterStore parameterStore,
                                 NDList inputs,
                                 boolean training,
                                 ai.djl.util.PairList<java.lang.String,java.lang.Object> params)

A helper for Block.forward(ParameterStore, NDList, boolean, PairList) after initialization.

Specified by:

forwardInternal in class AbstractBlock

Parameters:

parameterStore - the parameter store

inputs - the input NDList

training - true for a training forward pass

params - optional parameters

Returns:

the output of the forward pass

builder

public static GRU.Builder builder()

Creates a builder to build a GRU.

Returns:

a new builder