CODEWITHSUNDEEP
rmachine-learningr-caretactivation-functionmlp
Rajeev
Rajeev

Reputation: 37

Activation function used for mlpML in Caret

I am using the Caret package in R, trying to implement multi-layer perceptron for classifying satellite images. I am using method=mlpML, and I would like to know which activation function is being used.

Here is my code:

controlparameters<-trainControl(method = "repeatedcv",
                               number=5,
                               repeats = 5,
                               savePredictions=TRUE,
                                classProbs = TRUE)
mlp_grid<-expand.grid(layer1=13,
                      layer2=0,
                      layer3=0)
model< train(as.factor(Species)~.,
                   data = smotedata,
                   method='mlpML',
                   preProc =  c('center', 'scale'),
                   trcontrol=controlparameters,
                   tuneGrid=mlp_grid,
                   importance=T)

I used a single layer since it performed the best than using multi-layers.

Upvotes: 0

Views: 524

Answers (1)

desertnaut
desertnaut

Reputation: 60370

Looking at the caret source code for mlpML, it turns out that it uses the mlp function of the RSNNS package.

According to the RSNNS mlp documentation, its default arguments are:

mlp(x, ...)

## Default S3 method:
mlp(x, y, size = c(5), maxit = 100,
  initFunc = "Randomize_Weights", initFuncParams = c(-0.3, 0.3),
  learnFunc = "Std_Backpropagation", learnFuncParams = c(0.2, 0),
  updateFunc = "Topological_Order", updateFuncParams = c(0),
  hiddenActFunc = "Act_Logistic", shufflePatterns = TRUE,
  linOut = FALSE, outputActFunc = if (linOut) "Act_Identity" else
  "Act_Logistic", inputsTest = NULL, targetsTest = NULL,
  pruneFunc = NULL, pruneFuncParams = NULL, ...)

from which it is apparent that hiddenActFunc = "Act_Logistic", i.e the activation function for the hidden layers, is the logistic one.

Upvotes: 0

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