Hi, this is a question about the R package kernlab. I use kernlab as a library in a C++ program. The host application defines a graph kernel (defined by me), generates a gram matrix and trains kernlab directly on this gram matrix, like this: regm<-ksvm(K,y,kernel="matrix"), where K is the n x n gram kernelMatrix of my kernel, and y is the R-vector of quantitative target values. So, to make sure you got it: I don't want kernlab to compute the kernel values by itself. Rather, this is a task for the host application. Learning (see above) works well, but how do I predict a new instance? I couldn't find any information in this respect in the manual. The only examples for prediction were concerned with data from the input space, which i don't have, since my input space consists of graphs. I tried the following: predict(regm,x,type="response") where x is the 1xn R-matrix containing kernel values between the instance to be predicted and my training points. This won't work: Error in as.matrix(Z) : object "Z" not found. I'm using the current CRAN version of kernlab. Any help by kernlab users who had a similar task to do would be appreciated. Best regards, Andreas Maunz -- http://www.maunz.de Yoda of Borg are we: Futile is resistance. Assimilate you, we will.