title: slice option in plot function of package e1071
body: <p>I'm using the e1071 package in R. Just wondering what the slice option of the plot function does in the code below. I have read the manual for the package but did not understand what it said.</p>
  
  <pre><code>iris.svm &lt;- svm(Species ~ ., data = iris, probability = TRUE)
  plot(iris.svm, data = iris, Petal.Width ~ Petal.Length, slice = list(Sepal.Width = 3, Sepal.Length = 6))
  </code></pre>
  
  <p>Thanks.</p>