You are required to provide specifications for all the activation functions, the number of which is equal to the number of hidden layers plus 1. Thus in your case actfns=c(2,2) would suffice.
BKMooney wrote: > > Hi, > > I am trying to build a VERY basic neural network as a practice before > hopefully increasing my scope. To do so, I have been using package > "neural" > and the MLP related functions (mlp and mlptrain) within that package. > > So far, I have created a basic network, but I have been unable to change > the > default activation function. If someone has a suggestion, please advise. > > The goal of the network is to properly classify a number as positive or > negative. Simple 1-layer network with a single neuron in each layer. > > Rcode: > trainInput <- matrix(rnorm(10)) > trainAnswers <- ifelse(trainInput <0, -1, 1) > > trainNeurons <- 1 > > trainingData <- mlptrain(inp=trainInput, neurons=trainNeurons, > out=trainAnswers, it=1000) > > ## To call this network, we can see how it works on a set of known > positive > and negative values > > testInput <- matrix(-2:2) > mlp(testInput, trainingData$weight, trainingData$dist, > trainingData$neurons, > trainingData$actfns) > > Will vary - but output on my computer was: > [,1] > [1,] 0.001043291 > [2,] 0.001045842 > [3,] 0.072451270 > [4,] 0.950744548 > [5,] 0.950931168 > > So it's instead classifying the negatives as 0 and positives as 1 (getting > close to, anyhow - increasing the number of iterations, ie it=5000, makes > that more clear) > This results in a neural net with activation function 1/(1+exp(-x)) - > which > will never result in the -1 value that the answers contain. > > The documentation for package neural specifies the parameter "actfns", > which > should be a list containing the numeric code for the activation functions > of > each layer - however, anytime I try to put in a value for "actfns" (such > as > actfns=2 for hyperbolic tangent), I get the error: > > "Different activation function and active layer number" > > If anyone can shed light on what I'm doing wrong here with the activation > functions or how to change the activation functions, I'd really appreciate > it. > > Thanks! > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > > -- View this message in context: http://www.nabble.com/Activation-Functions-in-Package-Neural-tp24629050p25140965.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
