inst/models/files/biasedsvm.R

In benmack/oneClass: One-class classification in the absence of test data

modelInfo <- 
  list(label="biased svm", 
       library="kernlab",
       loop=NULL,
       type="Classification",
       parameters=
         data.frame(parameter = c("sigma", "cNeg", "cMultiplier"), 
                    class = rep("numeric", 3),
                    label = c("Sigma", "Cost (U)", "Multiplier Cost (P)")),
       grid = function(x, y, len = NULL, seedGrid=NULL, ...) {
         grid <- expand.grid(sigma=c(.1, 1, 10, 100),  
                             cNeg=2^seq(-10, 15, 3),
                             cMultiplier=2^seq(2, 15, 2) ) 
       },
       fit = function(x, y, wts, param, lev, last, weights, 
                      classProbs, ...) {
         cPos <- param$cNeg*param$cMultiplier
         ksvm(x = as.matrix(x), y = y,
              kernel = rbfdot,
              kpar = list(sigma = param$sigma),
              C = 1,
              class.weights=c("un" = param$cNeg, "pos" = cPos),
              prob.model = FALSE, #=class.probs
              ...)
       }, 
       predict = function(modelFit, newdata, preProc = NULL, 
                          submodels = NULL) {
           predicted <- predict(modelFit, newdata) 
         return(predicted)
       },
       ### prob
       prob=function(modelFit, newdata, preProc = NULL, submodels = NULL) {
           predicted <- predict(modelFit, newdata) 
           probs <- predict(modelFit, newdata, type = "decision")
           probs <- cbind(probs, probs)
           colnames(probs) <- c("un", "pos")
         return(probs)
       },
       ### predictors
       predictors=NULL,
       ### tags
       tags=NULL,
       ### levels
       levels=function(x) c("un", "pos"),
       ### sort
       sort=function(x) x[order(x$sigma, x$cNeg, -x$cMultiplier), ],
       ### varImp
       varimp=NULL)  
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