@Override
public void init(
Map<String, INDArray> params,
NeuralNetConfiguration conf,
INDArray paramsView,
boolean initializeParams) {
if (((org.deeplearning4j.nn.conf.layers.ConvolutionLayer) conf.getLayer())
.getKernelSize()
.length
!= 2) throw new IllegalArgumentException("Filter size must be == 2");
org.deeplearning4j.nn.conf.layers.ConvolutionLayer layerConf =
(org.deeplearning4j.nn.conf.layers.ConvolutionLayer) conf.getLayer();
int[] kernel = layerConf.getKernelSize();
int nIn = layerConf.getNIn();
int nOut = layerConf.getNOut();
INDArray biasView = paramsView.get(NDArrayIndex.point(0), NDArrayIndex.interval(0, nOut));
INDArray weightView =
paramsView.get(NDArrayIndex.point(0), NDArrayIndex.interval(nOut, numParams(conf, true)));
params.put(BIAS_KEY, createBias(conf, biasView, initializeParams));
params.put(WEIGHT_KEY, createWeightMatrix(conf, weightView, initializeParams));
conf.addVariable(WEIGHT_KEY);
conf.addVariable(BIAS_KEY);
}
protected INDArray createWeightMatrix(
NeuralNetConfiguration conf, INDArray weightView, boolean initializeParams) {
/*
Create a 4d weight matrix of:
(number of kernels, num input channels, kernel height, kernel width)
Note c order is used specifically for the CNN weights, as opposed to f order elsewhere
Inputs to the convolution layer are:
(batch size, num input feature maps, image height, image width)
*/
org.deeplearning4j.nn.conf.layers.ConvolutionLayer layerConf =
(org.deeplearning4j.nn.conf.layers.ConvolutionLayer) conf.getLayer();
if (initializeParams) {
Distribution dist = Distributions.createDistribution(conf.getLayer().getDist());
int[] kernel = layerConf.getKernelSize();
return WeightInitUtil.initWeights(
new int[] {layerConf.getNOut(), layerConf.getNIn(), kernel[0], kernel[1]},
layerConf.getWeightInit(),
dist,
'c',
weightView);
} else {
int[] kernel = layerConf.getKernelSize();
return WeightInitUtil.reshapeWeights(
new int[] {layerConf.getNOut(), layerConf.getNIn(), kernel[0], kernel[1]},
weightView,
'c');
}
}
@Override
public void init(
Map<String, INDArray> params,
NeuralNetConfiguration conf,
INDArray paramsView,
boolean initializeParameters) {
if (!(conf.getLayer() instanceof org.deeplearning4j.nn.conf.layers.FeedForwardLayer))
throw new IllegalArgumentException(
"unsupported layer type: " + conf.getLayer().getClass().getName());
int length = numParams(conf, true);
if (paramsView.length() != length)
throw new IllegalStateException(
"Expected params view of length " + length + ", got length " + paramsView.length());
org.deeplearning4j.nn.conf.layers.FeedForwardLayer layerConf =
(org.deeplearning4j.nn.conf.layers.FeedForwardLayer) conf.getLayer();
int nIn = layerConf.getNIn();
int nOut = layerConf.getNOut();
int nWeightParams = nIn * nOut;
INDArray weightView =
paramsView.get(NDArrayIndex.point(0), NDArrayIndex.interval(0, nWeightParams));
INDArray biasView =
paramsView.get(
NDArrayIndex.point(0), NDArrayIndex.interval(nWeightParams, nWeightParams + nOut));
params.put(WEIGHT_KEY, createWeightMatrix(conf, weightView, initializeParameters));
params.put(BIAS_KEY, createBias(conf, biasView, initializeParameters));
conf.addVariable(WEIGHT_KEY);
conf.addVariable(BIAS_KEY);
}
@Override
public void init(Map<String, INDArray> params, NeuralNetConfiguration conf) {
if (conf.getKernelSize().length < 2)
throw new IllegalArgumentException("Filter size must be == 2");
params.put(BIAS_KEY, createBias(conf));
params.put(WEIGHT_KEY, createWeightMatrix(conf));
conf.addVariable(WEIGHT_KEY);
conf.addVariable(BIAS_KEY);
}
protected INDArray createWeightMatrix(NeuralNetConfiguration conf) {
/**
* Create a 4d weight matrix of: (number of kernels, num input channels, kernel height, kernel
* width) Inputs to the convolution layer are: (batch size, num input feature maps, image
* height, image width)
*/
Distribution dist = Distributions.createDistribution(conf.getDist());
return WeightInitUtil.initWeights(
Ints.concat(new int[] {conf.getNOut(), conf.getNIn()}, conf.getKernelSize()),
conf.getWeightInit(),
dist);
}
@Override
public void init(Map<String, INDArray> params, NeuralNetConfiguration conf) {
Distribution dist = Distributions.createDistribution(conf.getDist());
int nL = conf.getNOut(); // i.e., n neurons in this layer
int nLast = conf.getNIn(); // i.e., n neurons in previous layer
conf.addVariable(RECURRENT_WEIGHTS);
conf.addVariable(INPUT_WEIGHTS);
conf.addVariable(BIAS);
params.put(
RECURRENT_WEIGHTS, WeightInitUtil.initWeights(nL, 4 * nL + 3, conf.getWeightInit(), dist));
params.put(
INPUT_WEIGHTS, WeightInitUtil.initWeights(nLast, 4 * nL, conf.getWeightInit(), dist));
INDArray biases =
Nd4j.zeros(1, 4 * nL); // Order: input, forget, output, input modulation, i.e., IFOG
biases.put(
new NDArrayIndex[] {NDArrayIndex.interval(nL, 2 * nL), new NDArrayIndex(0)},
Nd4j.ones(1, nL).muli(5));
/*The above line initializes the forget gate biases to 5.
* See Sutskever PhD thesis, pg19:
* "it is important for [the forget gate activations] to be approximately 1 at the early stages of learning,
* which is accomplished by initializing [the forget gate biases] to a large value (such as 5). If it is
* not done, it will be harder to learn long range dependencies because the smaller values of the forget
* gates will create a vanishing gradients problem."
* http://www.cs.utoronto.ca/~ilya/pubs/ilya_sutskever_phd_thesis.pdf
*/
params.put(BIAS, biases);
params.get(RECURRENT_WEIGHTS).data().persist();
params.get(INPUT_WEIGHTS).data().persist();
params.get(BIAS).data().persist();
}
// 1 bias per feature map
protected INDArray createBias(
NeuralNetConfiguration conf, INDArray biasView, boolean initializeParams) {
// the bias is a 1D tensor -- one bias per output feature map
org.deeplearning4j.nn.conf.layers.ConvolutionLayer layerConf =
(org.deeplearning4j.nn.conf.layers.ConvolutionLayer) conf.getLayer();
if (initializeParams) biasView.assign(layerConf.getBiasInit());
return biasView;
}
@Override
public int numParams(NeuralNetConfiguration conf, boolean backprop) {
org.deeplearning4j.nn.conf.layers.FeedForwardLayer layerConf =
(org.deeplearning4j.nn.conf.layers.FeedForwardLayer) conf.getLayer();
int nIn = layerConf.getNIn();
int nOut = layerConf.getNOut();
return nIn * nOut + nOut; // weights + bias
}
protected INDArray createBias(
NeuralNetConfiguration conf, INDArray biasParamView, boolean initializeParameters) {
org.deeplearning4j.nn.conf.layers.FeedForwardLayer layerConf =
(org.deeplearning4j.nn.conf.layers.FeedForwardLayer) conf.getLayer();
if (initializeParameters) {
INDArray ret = Nd4j.valueArrayOf(layerConf.getNOut(), layerConf.getBiasInit());
biasParamView.assign(ret);
}
return biasParamView;
}
@Override
public int numParams(NeuralNetConfiguration conf, boolean backprop) {
org.deeplearning4j.nn.conf.layers.ConvolutionLayer layerConf =
(org.deeplearning4j.nn.conf.layers.ConvolutionLayer) conf.getLayer();
int[] kernel = layerConf.getKernelSize();
int nIn = layerConf.getNIn();
int nOut = layerConf.getNOut();
return nIn * nOut * kernel[0] * kernel[1] + nOut;
}
/**
* JSON model configuration passed in If you are entering a MultiLayerConfiguration JSON, your
* file name MUST contain '_multi'. Otherwise, it will be processed as a regular
* NeuralNetConfiguration
*
* <p>Takes in JSON file path Checks file path for indication of MultiLayer Reads JSON file to
* string Creates neural net configuration from string config
*/
@Override
public <E> E value(String value) throws Exception {
Boolean isMultiLayer = value.contains("_multi");
String json = FileUtils.readFileToString(new File(value));
if (isMultiLayer) {
return (E) MultiLayerConfiguration.fromJson(json);
} else {
return (E) NeuralNetConfiguration.fromJson(json);
}
}
private static void checkNinNoutForEachLayer(
int[] expNin, int[] expNout, MultiLayerConfiguration conf, MultiLayerNetwork network) {
// Check configuration
for (int i = 0; i < expNin.length; i++) {
NeuralNetConfiguration layerConf = conf.getConf(i);
assertTrue(layerConf.getNIn() == expNin[i]);
assertTrue(layerConf.getNOut() == expNout[i]);
}
// Check Layer
for (int i = 0; i < expNin.length; i++) {
Layer layer = network.getLayers()[i];
assertTrue(layer.conf().getNIn() == expNin[i]);
assertTrue(layer.conf().getNOut() == expNout[i]);
int[] weightShape = layer.getParam(DefaultParamInitializer.WEIGHT_KEY).shape();
assertTrue(weightShape[0] == expNin[i]);
assertTrue(weightShape[1] == expNout[i]);
}
}
/**
* Apply the regularization
*
* @param layer
* @param gradient
* @param param
*/
public void postApply(Layer layer, INDArray gradient, String param) {
NeuralNetConfiguration conf = layer.conf();
INDArray params = layer.getParam(param);
if (conf.isUseRegularization()
&& conf.getLayer().getL2() > 0
&& !(param.equals(DefaultParamInitializer.BIAS_KEY)))
gradient.addi(
params.mul(
conf.getLayer()
.getL2())); // dC/dw = dC0/dw + lambda/n * w where C0 is pre-l2 cost function
if (conf.isUseRegularization()
&& conf.getLayer().getL1() > 0
&& !(param.equals(DefaultParamInitializer.BIAS_KEY)))
gradient.addi(Transforms.sign(params).muli(conf.getLayer().getL1()));
if (conf.isMiniBatch()) gradient.divi(layer.getInputMiniBatchSize());
if (conf.isConstrainGradientToUnitNorm()) gradient.divi(gradient.norm2(Integer.MAX_VALUE));
}
public ModelAndGradient() {
NeuralNetConfiguration conf =
new NeuralNetConfiguration.Builder()
.lossFunction(LossFunctions.LossFunction.MCXENT)
.optimizationAlgo(OptimizationAlgorithm.ITERATION_GRADIENT_DESCENT)
.activationFunction("softmax")
.iterations(10)
.weightInit(WeightInit.XAVIER)
.learningRate(1e-1)
.nIn(4)
.nOut(3)
.layer(new org.deeplearning4j.nn.conf.layers.OutputLayer())
.build();
OutputLayer l =
LayerFactories.getFactory(conf.getLayer())
.create(conf, Arrays.<IterationListener>asList(new ScoreIterationListener(1)));
this.model = l;
l.setInput(Nd4j.ones(4));
l.setLabels(Nd4j.ones(3));
this.gradient = l.gradient();
}
@Test
public void testModelSerde() throws Exception {
ObjectMapper mapper = getMapper();
NeuralNetConfiguration conf =
new NeuralNetConfiguration.Builder()
.momentum(0.9f)
.optimizationAlgo(OptimizationAlgorithm.STOCHASTIC_GRADIENT_DESCENT)
.iterations(1000)
.constrainGradientToUnitNorm(true)
.learningRate(1e-1f)
.layer(
new org.deeplearning4j.nn.conf.layers.AutoEncoder.Builder()
.nIn(4)
.nOut(3)
.corruptionLevel(0.6)
.sparsity(0.5)
.lossFunction(LossFunctions.LossFunction.RECONSTRUCTION_CROSSENTROPY)
.build())
.build();
DataSet d2 = new IrisDataSetIterator(150, 150).next();
INDArray input = d2.getFeatureMatrix();
AutoEncoder da =
LayerFactories.getFactory(conf.getLayer())
.create(
conf,
Arrays.<IterationListener>asList(
new ScoreIterationListener(1), new HistogramIterationListener(1)),
0);
da.setInput(input);
ModelAndGradient g = new ModelAndGradient(da);
String json = mapper.writeValueAsString(g);
ModelAndGradient read = mapper.readValue(json, ModelAndGradient.class);
assertEquals(g, read);
}
protected INDArray createWeightMatrix(
NeuralNetConfiguration conf, INDArray weightParamView, boolean initializeParameters) {
org.deeplearning4j.nn.conf.layers.FeedForwardLayer layerConf =
(org.deeplearning4j.nn.conf.layers.FeedForwardLayer) conf.getLayer();
if (initializeParameters) {
Distribution dist = Distributions.createDistribution(layerConf.getDist());
INDArray ret =
WeightInitUtil.initWeights(
layerConf.getNIn(),
layerConf.getNOut(),
layerConf.getWeightInit(),
dist,
weightParamView);
return ret;
} else {
return WeightInitUtil.reshapeWeights(
new int[] {layerConf.getNIn(), layerConf.getNOut()}, weightParamView);
}
}
@Override
public Map<String, INDArray> getGradientsFromFlattened(
NeuralNetConfiguration conf, INDArray gradientView) {
org.deeplearning4j.nn.conf.layers.ConvolutionLayer layerConf =
(org.deeplearning4j.nn.conf.layers.ConvolutionLayer) conf.getLayer();
int[] kernel = layerConf.getKernelSize();
int nIn = layerConf.getNIn();
int nOut = layerConf.getNOut();
INDArray biasGradientView =
gradientView.get(NDArrayIndex.point(0), NDArrayIndex.interval(0, nOut));
INDArray weightGradientView =
gradientView
.get(NDArrayIndex.point(0), NDArrayIndex.interval(nOut, numParams(conf, true)))
.reshape('c', nOut, nIn, kernel[0], kernel[1]);
Map<String, INDArray> out = new LinkedHashMap<>();
out.put(BIAS_KEY, biasGradientView);
out.put(WEIGHT_KEY, weightGradientView);
return out;
}
@Override
public Map<String, INDArray> getGradientsFromFlattened(
NeuralNetConfiguration conf, INDArray gradientView) {
org.deeplearning4j.nn.conf.layers.FeedForwardLayer layerConf =
(org.deeplearning4j.nn.conf.layers.FeedForwardLayer) conf.getLayer();
int nIn = layerConf.getNIn();
int nOut = layerConf.getNOut();
int nWeightParams = nIn * nOut;
INDArray weightGradientView =
gradientView
.get(NDArrayIndex.point(0), NDArrayIndex.interval(0, nWeightParams))
.reshape('f', nIn, nOut);
INDArray biasView =
gradientView.get(
NDArrayIndex.point(0),
NDArrayIndex.interval(nWeightParams, nWeightParams + nOut)); // Already a row vector
Map<String, INDArray> out = new LinkedHashMap<>();
out.put(WEIGHT_KEY, weightGradientView);
out.put(BIAS_KEY, biasView);
return out;
}
/**
* Check backprop gradients for a MultiLayerNetwork.
*
* @param mln MultiLayerNetwork to test. This must be initialized.
* @param epsilon Usually on the order/ of 1e-4 or so.
* @param maxRelError Maximum relative error. Usually < 1e-5 or so, though maybe more for deep
* networks or those with nonlinear activation
* @param minAbsoluteError Minimum absolute error to cause a failure. Numerical gradients can be
* non-zero due to precision issues. For example, 0.0 vs. 1e-18: relative error is 1.0, but
* not really a failure
* @param print Whether to print full pass/failure details for each parameter gradient
* @param exitOnFirstError If true: return upon first failure. If false: continue checking even if
* one parameter gradient has failed. Typically use false for debugging, true for unit tests.
* @param input Input array to use for forward pass. May be mini-batch data.
* @param labels Labels/targets to use to calculate backprop gradient. May be mini-batch data.
* @return true if gradients are passed, false otherwise.
*/
public static boolean checkGradients(
MultiLayerNetwork mln,
double epsilon,
double maxRelError,
double minAbsoluteError,
boolean print,
boolean exitOnFirstError,
INDArray input,
INDArray labels) {
// Basic sanity checks on input:
if (epsilon <= 0.0 || epsilon > 0.1)
throw new IllegalArgumentException(
"Invalid epsilon: expect epsilon in range (0,0.1], usually 1e-4 or so");
if (maxRelError <= 0.0 || maxRelError > 0.25)
throw new IllegalArgumentException("Invalid maxRelativeError: " + maxRelError);
if (!(mln.getOutputLayer() instanceof BaseOutputLayer))
throw new IllegalArgumentException("Cannot check backprop gradients without OutputLayer");
// Check network configuration:
int layerCount = 0;
for (NeuralNetConfiguration n : mln.getLayerWiseConfigurations().getConfs()) {
org.deeplearning4j.nn.conf.Updater u = n.getLayer().getUpdater();
if (u == org.deeplearning4j.nn.conf.Updater.SGD) {
// Must have LR of 1.0
double lr = n.getLayer().getLearningRate();
if (lr != 1.0) {
throw new IllegalStateException(
"When using SGD updater, must also use lr=1.0 for layer "
+ layerCount
+ "; got "
+ u
+ " with lr="
+ lr);
}
} else if (u != org.deeplearning4j.nn.conf.Updater.NONE) {
throw new IllegalStateException(
"Must have Updater.NONE (or SGD + lr=1.0) for layer " + layerCount + "; got " + u);
}
}
mln.setInput(input);
mln.setLabels(labels);
mln.computeGradientAndScore();
Pair<Gradient, Double> gradAndScore = mln.gradientAndScore();
Updater updater = UpdaterCreator.getUpdater(mln);
updater.update(mln, gradAndScore.getFirst(), 0, mln.batchSize());
INDArray gradientToCheck =
gradAndScore
.getFirst()
.gradient()
.dup(); // need dup: gradients are a *view* of the full gradient array (which will
// change every time backprop is done)
INDArray originalParams =
mln.params().dup(); // need dup: params are a *view* of full parameters
int nParams = originalParams.length();
int totalNFailures = 0;
double maxError = 0.0;
for (int i = 0; i < nParams; i++) {
// (w+epsilon): Do forward pass and score
INDArray params = originalParams.dup();
params.putScalar(i, params.getDouble(i) + epsilon);
mln.setParameters(params);
mln.computeGradientAndScore();
double scorePlus = mln.score();
// (w-epsilon): Do forward pass and score
params.putScalar(i, params.getDouble(i) - 2 * epsilon); // +eps - 2*eps = -eps
mln.setParameters(params);
mln.computeGradientAndScore();
double scoreMinus = mln.score();
// Calculate numerical parameter gradient:
double scoreDelta = scorePlus - scoreMinus;
double numericalGradient = scoreDelta / (2 * epsilon);
if (Double.isNaN(numericalGradient))
throw new IllegalStateException(
"Numerical gradient was NaN for parameter " + i + " of " + nParams);
double backpropGradient = gradientToCheck.getDouble(i);
// http://cs231n.github.io/neural-networks-3/#gradcheck
// use mean centered
double relError =
Math.abs(backpropGradient - numericalGradient)
/ (Math.abs(numericalGradient) + Math.abs(backpropGradient));
if (backpropGradient == 0.0 && numericalGradient == 0.0)
relError = 0.0; // Edge case: i.e., RNNs with time series length of 1.0
if (relError > maxError) maxError = relError;
if (relError > maxRelError || Double.isNaN(relError)) {
double absError = Math.abs(backpropGradient - numericalGradient);
if (absError < minAbsoluteError) {
log.info(
"Param "
+ i
+ " passed: grad= "
+ backpropGradient
+ ", numericalGrad= "
+ numericalGradient
+ ", relError= "
+ relError
+ "; absolute error = "
+ absError
+ " < minAbsoluteError = "
+ minAbsoluteError);
} else {
if (print)
log.info(
"Param "
+ i
+ " FAILED: grad= "
+ backpropGradient
+ ", numericalGrad= "
+ numericalGradient
+ ", relError= "
+ relError
+ ", scorePlus="
+ scorePlus
+ ", scoreMinus= "
+ scoreMinus);
if (exitOnFirstError) return false;
totalNFailures++;
}
} else if (print) {
log.info(
"Param "
+ i
+ " passed: grad= "
+ backpropGradient
+ ", numericalGrad= "
+ numericalGradient
+ ", relError= "
+ relError);
}
}
if (print) {
int nPass = nParams - totalNFailures;
log.info(
"GradientCheckUtil.checkGradients(): "
+ nParams
+ " params checked, "
+ nPass
+ " passed, "
+ totalNFailures
+ " failed. Largest relative error = "
+ maxError);
}
return totalNFailures == 0;
}
// 1 bias per feature map
protected INDArray createBias(NeuralNetConfiguration conf) {
// the bias is a 1D tensor -- one bias per output feature map
return Nd4j.zeros(conf.getNOut());
}