# darch

0th

Percentile

##### Fit a deep neural network

Fit a deep neural network with optional pre-training and one of various fine-tuning algorithms.

##### Usage
darch(x, ...)# S3 method for default
darch(x, y, layers = 10, ..., autosave = F,
autosave.epochs = round(darch.numEpochs/20),
autosave.dir = "./darch.autosave", autosave.trim = F, bp.learnRate = 1,
bp.learnRateScale = 1, bootstrap = F, bootstrap.unique = T,
bootstrap.num = 0, cg.length = 2, cg.switchLayers = 1, darch = NULL,
darch.batchSize = 1, darch.dither = F, darch.dropout = 0,
darch.dropout.dropConnect = F, darch.dropout.momentMatching = 0,
darch.dropout.oneMaskPerEpoch = F, darch.elu.alpha = 1,
darch.errorFunction = if (darch.isClass) crossEntropyError else mseError,
darch.finalMomentum = 0.9, darch.fineTuneFunction = backpropagation,
darch.initialMomentum = 0.5, darch.isClass = T,
darch.maxout.poolSize = 2, darch.maxout.unitFunction = linearUnit,
darch.momentumRampLength = 1, darch.nesterovMomentum = T,
darch.numEpochs = 100, darch.returnBestModel = T,
darch.returnBestModel.validationErrorFactor = 1 - exp(-1),
darch.stopClassErr = -Inf, darch.stopErr = -Inf,
darch.stopValidClassErr = -Inf, darch.stopValidErr = -Inf,
darch.trainLayers = T, darch.unitFunction = sigmoidUnit,
darch.weightDecay = 0,
darch.weightUpdateFunction = weightDecayWeightUpdate, dataSet = NULL,
dataSetValid = NULL,
generateWeightsFunction = generateWeightsGlorotUniform, gputools = F,
gputools.deviceId = 0, logLevel = NULL, normalizeWeights = F,
normalizeWeightsBound = 15, paramsList = list(),
preProc.factorToNumeric = F, preProc.factorToNumeric.targets = F,
preProc.fullRank = T, preProc.fullRank.targets = F,
preProc.orderedToFactor.targets = T, preProc.params = F,
preProc.targets = F, rbm.allData = F, rbm.batchSize = 1,
rbm.consecutive = T, rbm.errorFunction = mseError,
rbm.finalMomentum = 0.9, rbm.initialMomentum = 0.5, rbm.lastLayer = 0,
rbm.learnRate = 1, rbm.learnRateScale = 1, rbm.momentumRampLength = 1,
rbm.numCD = 1, rbm.numEpochs = 0, rbm.unitFunction = sigmoidUnitRbm,
rbm.updateFunction = rbmUpdate, rbm.weightDecay = 2e-04, retainData = F,
rprop.decFact = 0.5, rprop.incFact = 1.2, rprop.initDelta = 1/80,
rprop.maxDelta = 50, rprop.method = "iRprop+", rprop.minDelta = 1e-06,
seed = NULL, shuffleTrainData = T, weights.max = 0.1,
weights.mean = 0, weights.min = -0.1, weights.sd = 0.01,
xValid = NULL, yValid = NULL)# S3 method for formula
darch(x, data, layers, ..., xValid = NULL, dataSet = NULL,
dataSetValid = NULL, logLevel = NULL, paramsList = list(),
darch = NULL)# S3 method for DataSet
darch(x, ...)
##### Arguments
x

Input data matrix or data.frame (darch.default) or formula (darch.formula) or '>DataSet (darch.DataSet).

...

y

Target data matrix or data.frame, if x is an input data matrix or data.frame.

layers

Vector containing one integer for the number of neurons of each layer. Defaults to c(a, 10, b), where a is the number of columns in the training data and b the number of columns in the targets. If this has length 1, it is used as the number of neurons in the hidden layer, not as the number of layers!

autosave

Logical indicating whether to activate automatically saving the '>DArch instance to a file during fine-tuning.

autosave.epochs

After how many epochs should auto-saving happen, by default after every 5 1, the network will only be saved once when thee fine-tuning is done.

autosave.dir

Directory for the autosave files, the file names will be e.g. autosave_010.net for the DArch instance after 10 epochs

autosave.trim

Whether to trim the network before saving it. This will remove the dataset and the layer weights, resulting in a network that is no longer usable for predictions or training. Useful when only statistics and settings need to be stored.

bp.learnRate

Learning rates for backpropagation, length is either one or the same as the number of weight matrices when using different learning rates for each layer.

bp.learnRateScale

The learn rate is multiplied by this value after each epoch.

bootstrap

Logical indicating whether to use bootstrapping to create a training and validation data set from the given training data.

bootstrap.unique

Logical indicating whether to take only unique samples for the training (TRUE, default) or take all drawn samples (FALSE), which will results in a bigger training set with duplicates. Note: This is ignored if bootstrap.num is greater than 0.

bootstrap.num

If this is greater than 0, bootstrapping will draw this number of training samples without replacement.

cg.length

Numbers of line search

cg.switchLayers

Indicates when to train the full network instead of only the upper two layers

darch

Existing '>DArch instance for which training is to be resumed. Note: When enabling pre-training, previous training results we be lost, see explanation for parameter rbm.numEpochs.

darch.batchSize

Batch size, i.e. the number of training samples that are presented to the network before weight updates are performed, for fine-tuning.

darch.dither

Whether to apply dither to numeric columns in the training input data.

darch.dropout

Dropout rates. If this is a vector it will be treated as the dropout rates for each individual layer. If one element is missing, the input dropout will be set to 0. When enabling darch.dropout.dropConnect, this vector needs an additional element (one element per weight matrix between two layers as opposed to one element per layer excluding the last layer).

darch.dropout.dropConnect

Whether to use DropConnect instead of dropout for the hidden layers. Will use darch.dropout as the dropout rates.

darch.dropout.momentMatching

How many iterations to perform during moment matching for dropout inference, 0 to disable moment matching.

Whether to generate a new mask for each batch (FALSE, default) or for each epoch (TRUE).

darch.elu.alpha

Alpha parameter for the exponential linear unit function. See exponentialLinearUnit.

darch.errorFunction

Error function during fine-tuning. Possible error functions include mseError,rmseError, and crossEntropyError.

darch.finalMomentum

Final momentum during fine-tuning.

darch.fineTuneFunction

Fine-tuning function. Possible values include backpropagation (default), rpropagation, minimizeClassifier and minimizeAutoencoder (unsupervised).

darch.initialMomentum

Initial momentum during fine-tuning.

darch.isClass

Whether output should be treated as class labels during fine-tuning and classification rates should be printed.

darch.maxout.poolSize

Pool size for maxout units, when using the maxout acitvation function. See maxoutUnit.

darch.maxout.unitFunction

Inner unit function used by maxout. See darch.unitFunction for possible unit functions.

darch.momentumRampLength

After how many epochs, relative to the overall number of epochs trained, should the momentum reach darch.finalMomentum? A value of 1 indicates that the darch.finalMomentum should be reached in the final epoch, a value of 0.5 indicates that darch.finalMomentum should be reached after half of the training is complete. Note that this will lead to bumps in the momentum ramp if training is resumed with the same parameters for darch.initialMomentum and darch.finalMomentum. Set darch.momentumRampLength to 0 to avoid this problem when resuming training.

darch.nesterovMomentum

Whether to use Nesterov Accelerated Momentum. (NAG) for gradient descent based fine-tuning algorithms.

darch.numEpochs

Number of epochs of fine-tuning.

darch.returnBestModel

Logical indicating whether to return the best model at the end of training, instead of the last.

darch.returnBestModel.validationErrorFactor

When evaluating models with validation data, how high should the validation error be valued, compared to the training error? This is a value between 0 and 1. By default, this value is 1 - exp(-1). The training error factor and the validation error factor will always add to 1, so if you pass 1 here, the training error will be ignored, and if you pass 0 here, the validation error will be ignored.

darch.stopClassErr

When the classification error is lower than or equal to this value, training is stopped (0..100).

darch.stopErr

When the value of the error function is lower than or equal to this value, training is stopped.

darch.stopValidClassErr

When the classification error on the validation data is lower than or equal to this value, training is stopped (0..100).

darch.stopValidErr

When the value of the error function on the validation data is lower than or equal to this value, training is stopped.

darch.trainLayers

Either TRUE to train all layers or a mask containing TRUE for all layers which should be trained and FALSE for all layers that should not be trained (no entry for the input layer).

darch.unitFunction

Layer function or vector of layer functions of length number of layers - 1. Note that the first entry signifies the layer function between layers 1 and 2, i.e. the output of layer 2. Layer 1 does not have a layer function, since the input values are used directly. Possible unit functions include linearUnit, sigmoidUnit, tanhUnit, rectifiedLinearUnit, softplusUnit, softmaxUnit, and maxoutUnit.

darch.weightDecay

Weight decay factor, defaults to 0. All weights will be multiplied by (1 - darch.weightDecay) prior to each weight update.

darch.weightUpdateFunction

Weight update function or vector of weight update functions, very similar to darch.unitFunction. Possible weight update functions include weightDecayWeightUpdate and maxoutWeightUpdate Note that maxoutWeightUpdate must be used on the layer after the maxout activation function!

dataSet

'>DataSet instance, passed from darch.DataSet(), may be specified manually.

dataSetValid

'>DataSet instance containing validation data.

generateWeightsFunction

Weight generation function or vector of layer generation functions of length number of layers - 1. Possible weight generation functions include generateWeightsUniform (default), generateWeightsNormal, generateWeightsGlorotNormal, generateWeightsGlorotUniform, generateWeightsHeNormal, and generateWeightsHeUniform.

gputools

Logical indicating whether to use gputools for matrix multiplication, if available.

gputools.deviceId

Integer specifying the device to use for GPU matrix multiplication. See chooseGpu.

logLevel

futile.logger log level. Uses the currently set log level by default, which is futile.logger::flog.info if it was not changed. Other available levels include, from least to most verbose: FATAL, ERROR, WARN, DEBUG, and TRACE.

normalizeWeights

Logical indicating whether to normalize weights (L2 norm = normalizeWeightsBound).

normalizeWeightsBound

Upper bound on the L2 norm of incoming weight vectors. Used only if normalizeWeights is TRUE.

paramsList

List of parameters, can include and does overwrite specified parameters listed above. Primary for convenience or for use in scripts.

preProc.factorToNumeric

Whether all factors should be converted to numeric.

preProc.factorToNumeric.targets

Whether all factors should be converted to numeric in the target data.

preProc.fullRank

Whether to use full rank encoding. See preProcess for details.

preProc.fullRank.targets

Whether to use full rank encoding for target data. See preProcess for details.

preProc.orderedToFactor.targets

Whether ordered factors in the target data should be converted to unordered factors. Note: Ordered factors are converted to numeric by dummyVars and no longer usable for classification tasks.

preProc.params

List of parameters to pass to the preProcess function for the input data or FALSE to disable input data pre-processing.

preProc.targets

Whether target data is to be centered and scaled. Unlike preProc.params, this is just a logical turning pre-processing for target data on or off, since this pre-processing has to be reverted when predicting new data. Most useful for regression tasks. Note: This will skew the raw network error.

rbm.allData

Logical indicating whether to use training and validation data for pre-training. Note: This also applies when using bootstrapping.

rbm.batchSize

Pre-training batch size.

rbm.consecutive

Logical indicating whether to train the RBMs one at a time for rbm.numEpochs epochs (TRUE, default) or alternatingly training each RBM for one epoch at a time (FALSE).

rbm.errorFunction

Error function during pre-training. This is only used to estimate the RBM error and does not affect the training itself. Possible error functions include mseError and rmseError.

rbm.finalMomentum

Final momentum during pre-training.

rbm.initialMomentum

Initial momentum during pre-training.

rbm.lastLayer

Numeric indicating at which layer to stop the pre-training. Possible values include 0, meaning that all layers are trained; positive integers, meaning to stop training after the RBM where rbm.lastLayer forms the visible layer; negative integers, meaning to stop the training at rbm.lastLayer RBMs from the top RBM.

rbm.learnRate

Learning rate during pre-training.

rbm.learnRateScale

The learn rates will be multiplied with this value after each epoch.

rbm.momentumRampLength

After how many epochs, relative to rbm.numEpochs, should the momentum reach rbm.finalMomentum? A value of 1 indicates that the rbm.finalMomentum should be reached in the final epoch, a value of 0.5 indicates that rbm.finalMomentum should be reached after half of the training is complete.

rbm.numCD

Number of full steps for which contrastive divergence is performed. Increasing this will slow training down considerably.

rbm.numEpochs

Number of pre-training epochs. Note: When passing a value other than 0 here and also passing an existing '>DArch instance via the darch parameter, the weights of the network will be completely reset! Pre-training is essentially a form of advanced weight initialization and it makes no sense to perform pre-training on a previously trained network.

rbm.unitFunction

Unit function during pre-training. Possible functions include sigmoidUnitRbm (default), tanhUnitRbm, and linearUnitRbm.

rbm.updateFunction

Update function during pre-training. Currently, darch only provides rbmUpdate.

rbm.weightDecay

Pre-training weight decay. Weights will be multiplied by (1 - rbm.weightDecay) prior to each weight update.

retainData

Logical indicating whether to store the training data in the '>DArch instance after training or when saving it to disk.

rprop.decFact

Decreasing factor for the training. Default is 0.6.

rprop.incFact

Increasing factor for the training Default is 1.2.

rprop.initDelta

Initialisation value for the update. Default is 0.0125.

rprop.maxDelta

Upper bound for step size. Default is 50

rprop.method

The method for the training. Default is "iRprop+"

rprop.minDelta

Lower bound for step size. Default is 0.000001

seed

Allows the specification of a seed which will be set via set.seed. Used in the context of darchBench.

shuffleTrainData

Logical indicating whether to shuffle training data before each epoch.

weights.max

max parameter to the runif function.

weights.mean

mean parameter to the rnorm function.

weights.min

min parameter to the runif function.

weights.sd

sd parameter to the rnorm function.

xValid

Validation input data matrix or data.frame.

yValid

Validation target data matrix or data.frame, if x is a data matrix or data.frame.

data

data.frame containing the dataset, if x is a formula.

##### Details

The darch package implements Deep Architecture Networks and restricted Boltzmann machines.

The creation of this package is motivated by the papers from G. Hinton et. al. from 2006 (see references for details) and from the MATLAB source code developed in this context. This package provides the possibility to generate deep architecture networks (darch) like the deep belief networks from Hinton et. al.. The deep architectures can then be trained with the contrastive divergence method. After this pre-training it can be fine tuned with several learning methods like backpropagation, resilient backpropagation and conjugate gradients as well as more recent techniques like dropout and maxout.

See https://github.com/maddin79/darch for further information, documentation, and releases.

 Package: darch Type: Package Version: 0.10.0 Date: 2015-11-12 License: GPL-2 or later LazyLoad: yes

##### Value

Fitted '>DArch instance

##### References

Hinton, G. E., S. Osindero, Y. W. Teh, A fast learning algorithm for deep belief nets, Neural Computation 18(7), S. 1527-1554, DOI: 10.1162/neco.2006.18.7.1527 2006.

Hinton, G. E., R. R. Salakhutdinov, Reducing the dimensionality of data with neural networks, Science 313(5786), S. 504-507, DOI: 10.1126/science.1127647, 2006.

Hinton, Geoffrey E. et al. (2012). "Improving neural networks by preventing coadaptation of feature detectors". In: Clinical Orthopaedics and Related Research abs/1207.0580. URL : http://arxiv.org/abs/1207.0580.

Goodfellow, Ian J. et al. (2013). "Maxout Networks". In: Proceedings of the 30th International Conference on Machine Learning, ICML 2013, Atlanta, GA, USA, 16-21 June 2013, pp. 1319-1327. URL: http://jmlr.org/proceedings/papers/v28/goodfellow13.html.

Drees, Martin (2013). "Implementierung und Analyse von tiefen Architekturen in R". German. Master's thesis. Fachhochschule Dortmund.

Rueckert, Johannes (2015). "Extending the Darch library for deep architectures". Project thesis. Fachhochschule Dortmund. URL: http://static.saviola.de/publications/rueckert_2015.pdf.

Other darch interface functions: darchBench, darchTest, plot.DArch, predict.DArch, print.DArch

##### Aliases
• darch
• darch.DataSet
• darch.default
• darch.formula
##### Examples
# NOT RUN {
data(iris)
model <- darch(Species ~ ., iris)
print(model)
predictions <- predict(model, newdata = iris, type = "class")
cat(paste("Incorrect classifications:", sum(predictions != iris[,5])))

trainData <- matrix(c(0,0,0,1,1,0,1,1), ncol = 2, byrow = TRUE)
trainTargets <- matrix(c(0,1,1,0), nrow = 4)
model2 <- darch(trainData, trainTargets, layers = c(2, 10, 1),
darch.numEpochs = 500, darch.stopClassErr = 0, retainData = T)
e <- darchTest(model2)
cat(paste0("Incorrect classifications on all examples: ", e[3], " (",
e[2], "%)\n"))

plot(model2)
# }
# NOT RUN {
#
# More examples can be found at