On 24 July 2013 19:25, ONKELINX, Thierry <thierry.onkel...@inbo.be> wrote: > Try rescaling your data prior to splitting it up into a training and test > set. Otherwise you end up with two different ways of scaling.
Thanks, good point. I have adjusted the code, however with no visible improvement. Also, I want to be able to revert the scaling operation to compare data to predicted values. I tried this: meas.tc <- testing[, "MEAS_TC"] * attr(testing, 'scaled:scale') + attr(testing, 'scaled:center') predicted.tc <- tc.xyf.prediction$prediction * attr(testing, 'scaled:scale') + attr(testing, 'scaled:center') but I get warnings, and values that are very wrong: Warning messages: 1: In testing[, "MEAS_TC"] * attr(testing, "scaled:scale") : longer object length is not a multiple of shorter object length 2: In testing[, "MEAS_TC"] * attr(testing, "scaled:scale") + attr(testing, : longer object length is not a multiple of shorter object length Adjusted code: (now also in a gist: https://gist.github.com/ottadini/6069736) # ===== # library(kohonen) somdata <- read.csv("somdata.csv") # Create SCALED test and training sets from data: inTrain <- sample(nrow(somdata), nrow(somdata)*(2/3)) training <- scale(somdata[inTrain, ]) testing <- scale(somdata[-inTrain, ], center = attr(training, "scaled:center"), scale = attr(training, "scaled:scale")) # Supervised kohonen map, where the dependent variable is MEAS_TC. # Attempting to follow the examples in Wehrens and Buydens, 2007, 21(5), J Stat Soft. # somdata[1] is the MEAS_TC variable somX <- training[, -1] somY <- training[, 1] tc.xyf <- xyf(data=somX, Y=somY, xweight=0.5, grid=somgrid(6, 6, "hexagonal"), contin=TRUE) # Prediction with test set: tc.xyf.prediction <- predict(tc.xyf, newdata=testing[, -1]) # Basic plot: x <- seq(nrow(testing)) plot(x, testing[, "MEAS_TC"], type="l", col="black", ylim=c(-2, 2)) par(new=TRUE) plot(x, tc.xyf.prediction$prediction, type="l", col="red", ylim=c(-2, 2)) # Still terrible. Do I have something wrong in scaling? # ===== # ______________________________________________ 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.
