org.deeplearning4j.nn.layers.convolution

Class Deconvolution2DLayer

java.lang.Object

org.deeplearning4j.nn.layers.AbstractLayer<LayerConfT>

org.deeplearning4j.nn.layers.BaseLayer<ConvolutionLayer>

org.deeplearning4j.nn.layers.convolution.ConvolutionLayer

org.deeplearning4j.nn.layers.convolution.Deconvolution2DLayer

All Implemented Interfaces:

Serializable, Cloneable, Layer, Model

public class Deconvolution2DLayer
extends ConvolutionLayer

2D deconvolution layer implementation. Deconvolutions are also known as transpose convolutions or fractionally strided convolutions. In essence, deconvolutions swap forward and backward pass with regular 2D convolutions. See the paper by Matt Zeiler for details: http://www.matthewzeiler.com/wp-content/uploads/2017/07/cvpr2010.pdf For an intuitive guide to convolution arithmetic and shapes, see: https://arxiv.org/abs/1603.07285v1

Author:

Max Pumperla

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface org.deeplearning4j.nn.api.Layer

Layer.TrainingMode, Layer.Type

Field Summary

Fields inherited from class org.deeplearning4j.nn.layers.convolution.ConvolutionLayer

convolutionMode, dummyBias, dummyBiasGrad, helper, helperCountFail, i2d, log

Fields inherited from class org.deeplearning4j.nn.layers.BaseLayer

gradient, gradientsFlattened, gradientViews, optimizer, params, paramsFlattened, score, solver, weightNoiseParams

Fields inherited from class org.deeplearning4j.nn.layers.AbstractLayer

cacheMode, conf, dropoutApplied, dropoutMask, epochCount, index, input, iterationCount, iterationListeners, maskArray, maskState, preOutput

Constructor Summary

Constructors

Constructor and Description
Deconvolution2DLayer(NeuralNetConfiguration conf)
Deconvolution2DLayer(NeuralNetConfiguration conf, org.nd4j.linalg.api.ndarray.INDArray input)

Method Summary

Modifier and Type	Method and Description
org.nd4j.linalg.api.ndarray.INDArray	activate(boolean training) Trigger an activation with the last specified input
org.nd4j.linalg.primitives.Pair<Gradient,org.nd4j.linalg.api.ndarray.INDArray>	backpropGradient(org.nd4j.linalg.api.ndarray.INDArray epsilon) Calculate the gradient relative to the error in the next layer
org.nd4j.linalg.api.ndarray.INDArray	preOutput(boolean training)
protected org.nd4j.linalg.primitives.Pair<org.nd4j.linalg.api.ndarray.INDArray,org.nd4j.linalg.api.ndarray.INDArray>	preOutput(boolean training, boolean forBackprop) PreOutput method that also returns the im2col2d array (if being called for backprop), as this can be re-used instead of being calculated again.

Methods inherited from class org.deeplearning4j.nn.layers.convolution.ConvolutionLayer

calcL1, calcL2, fit, hasBias, isPretrainLayer, params, preOutput4d, setParams, transpose, type

Methods inherited from class org.deeplearning4j.nn.layers.BaseLayer

accumulateScore, activate, activate, clear, clearNoiseWeightParams, clone, computeGradientAndScore, fit, getGradientsViewArray, getOptimizer, getParam, getParamWithNoise, gradient, initParams, iterate, layerConf, numParams, paramTable, paramTable, preOutput, score, setBackpropGradientsViewArray, setParam, setParams, setParamsViewArray, setParamTable, setScoreWithZ, toString, update, update

Methods inherited from class org.deeplearning4j.nn.layers.AbstractLayer

activate, activate, activate, addListeners, applyConstraints, applyDropOutIfNecessary, applyMask, batchSize, conf, feedForwardMaskArray, getIndex, getInput, getInputMiniBatchSize, getListeners, getMaskArray, gradientAndScore, init, input, layerId, migrateInput, numParams, preOutput, preOutput, setCacheMode, setConf, setIndex, setInput, setInputMiniBatchSize, setListeners, setListeners, setMaskArray, validateInput

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.deeplearning4j.nn.api.Layer

getEpochCount, getIterationCount, setEpochCount, setIterationCount

Constructor Detail

Deconvolution2DLayer

public Deconvolution2DLayer(NeuralNetConfiguration conf)

Deconvolution2DLayer

public Deconvolution2DLayer(NeuralNetConfiguration conf,
                            org.nd4j.linalg.api.ndarray.INDArray input)

Method Detail

backpropGradient

public org.nd4j.linalg.primitives.Pair<Gradient,org.nd4j.linalg.api.ndarray.INDArray> backpropGradient(org.nd4j.linalg.api.ndarray.INDArray epsilon)

Description copied from interface: Layer

Calculate the gradient relative to the error in the next layer

Specified by:

backpropGradient in interface Layer

Overrides:

backpropGradient in class ConvolutionLayer

Parameters:

epsilon - w^(L+1)*delta^(L+1). Or, equiv: dC/da, i.e., (dC/dz)*(dz/da) = dC/da, where C is cost function a=sigma(z) is activation.

Returns:

Pair where Gradient is gradient for this layer, INDArray is epsilon needed by next layer, but before element-wise multiply by sigmaPrime(z). So for standard feed-forward layer, if this layer is L, then return.getSecond() == (w^(L)*(delta^(L))^T)^T

preOutput

public org.nd4j.linalg.api.ndarray.INDArray preOutput(boolean training)

Overrides:

preOutput in class ConvolutionLayer

preOutput

protected org.nd4j.linalg.primitives.Pair<org.nd4j.linalg.api.ndarray.INDArray,org.nd4j.linalg.api.ndarray.INDArray> preOutput(boolean training,
                                                                                                                               boolean forBackprop)

Description copied from class: ConvolutionLayer

PreOutput method that also returns the im2col2d array (if being called for backprop), as this can be re-used instead of being calculated again.

Overrides:

preOutput in class ConvolutionLayer

Parameters:

training - Train or test time (impacts dropout)

forBackprop - If true: return the im2col2d array for re-use during backprop. False: return null for second pair entry. Note that it may still be null in the case of CuDNN and the like.

Returns:

Pair of arrays: preOutput (activations) and optionally the im2col2d array

activate

public org.nd4j.linalg.api.ndarray.INDArray activate(boolean training)

Description copied from interface: Layer

Trigger an activation with the last specified input

Specified by:

activate in interface Layer

Overrides:

activate in class ConvolutionLayer

Parameters:

training - training or test mode

Returns:

the activation of the last specified input