title: The gamma and cost parameter of SVM
body: <p>everybody, here is a weird phenomenon when I was using libSVM to make some predictions. </p>
  
  <p>When I set no parameters of SVM, I will get a 99.9% performance on the testing set. While, if I set parameters '-c 10 -g 5', I will get about 33% precision on the testing set. </p>
  
  <p>By the way, the SVM toolkit I am using is LibSVM.</p>
  
  <p>I wonder if there is something wrong with data set. And I could not figure out which result is more convincing. </p>