title: Error when tuning a support vector regression model in R
body: <p>I am exploring support vector machine regression with this tutorial <a href="http://www.svm-tutorial.com/2014/10/support-vector-regression-r/" rel="nofollow noreferrer">http://www.svm-tutorial.com/2014/10/support-vector-regression-r/</a>. I encounter  <code>Error in do.call(method, c(list(train.x, data = data, subset = train.ind[[sample]]), : 'what' must be a function or character string</code> when tuning the model using grid search but I am not sure what that means. Here are the codes I used: 
  <code>svm_m &lt;- svm(FuelRate~ Heading+Distance+Elevatio+YieldDry+HarvestM, data = fr_tr)</code>
  <code>tuneResult &lt;- tune(svm_m, FuelRate ~ Heading+Distance+Elevatio+YieldDry+HarvestM, data = fr_tr, ranges = list(epsilon = seq(0,1,0.1), cost=2^(2:9)))</code>. Can anyone teach me about the solution?    </p>