Hi, Please don't forget to copy R-help on your reply - other people are likely to have more insight.
My understanding is that you want to replicate the shaded polygons produced by plot.svm on your own plot. That's why I suggested you first try add=TRUE, and if that doesn't work, then look at the code for plot.svm so you can see how the predicted values are calculated on a grid to be plotted. R is open source - you can extract the section from that function that does what you want, and make your own code to add it to another plot. I have no idea what "the tutorial" is; I suggested two things you could try based on the help and my understanding of R. Sarah On Thu, Dec 20, 2018 at 9:07 AM Luigi Marongiu <marongiu.lu...@gmail.com> wrote: > > Dear Sarah, > I have looked at the tutorial but I did not find what I was looking > for. Essentially, I would like to extract the data that make the > hyperplane (it should be a matrix of X,Y value, for a bidimensional > plane, I guess) so I can plot a line in another plot. I tried with > model$SV but it is not the right one. > Luigi > > On Thu, Dec 20, 2018 at 2:59 PM Sarah Goslee <sarah.gos...@gmail.com> wrote: > > > > Hi, > > > > According to the help for svm, which you probably should have started > > with, SV contains the support vectors, and index contains the position > > of the support vectors in the data matrix. > > > > As for plotting, plot.svm lets you pass additional options to plot so > > that you can customize the plot to your tastes. I'm not sure if > > add=TRUE is a useful option there, but you should try it. If that > > doesn't meet your needs, R is open source - you can easily look at the > > code for plot.svm and see what you need (basically the predicted > > values on agrid, if I'm understanding your goal correctly). > > > > Sarah > > > > On Thu, Dec 20, 2018 at 5:16 AM Luigi Marongiu <marongiu.lu...@gmail.com> > > wrote: > > > > > > Dear all, > > > I am using the package e1071 for modeling SVM. I obtain a model from > > > the data and I can plot the results; the plot shows the support > > > vectors (as 'X's) and the shaded areas as it should be. > > > However, I don't like the plot generated from the model and I would > > > like instead to have more control upon the plotting; in particular, I > > > would like to draw the hyperplane on plots I have already made from > > > the data available. > > > Is there a way to extract the values that are used to draw the hyperplane? > > > That is: plot(model) -- where model is obtained from svm() -- draws an > > > area in blue and one in red based on some values provided by model; > > > can I get these values so I can plot a line in a pre-existing plot? > > > Also, it is possible to extract the positions of the support vectors? > > > The names of the model generated by svm() are: > > > > names(mod) > > > [1] "call" "type" "kernel" "cost" > > > [5] "degree" "gamma" "coef0" "nu" > > > [9] "epsilon" "sparse" "scaled" "x.scale" > > > [13] "y.scale" "nclasses" "levels" "tot.nSV" > > > [17] "nSV" "labels" "SV" "index" > > > [21] "rho" "compprob" "probA" "probB" > > > [25] "sigma" "coefs" "na.action" "fitted" > > > [29] "decision.values" "terms" > > > > > > Which one should I look at? > > > Thank you > > > -- > > > Best regards, > > > Luigi > > > -- Sarah Goslee (she/her) http://www.numberwright.com ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.
