Added a missing check for division by zero.

--HG--
extra : convert_revision : svn%3Afdd8eb12-d10e-0410-9acb-85c331704f74/trunk%403306

dlib/svm/krls.h

@@ -93,6 +93,9 @@ namespace dlib
         {
             const scalar_type kx = kern(x,x);
             if (alpha.size() == 0)
+            {
+                // just ignore this sample if it is the zero vector (or really close to being zero)
+                if (std::abs(kx) > std::numeric_limits<scalar_type>::epsilon())
                 {
                     // set initial state since this is the first training example we have seen
 
@@ -106,6 +109,7 @@ namespace dlib
                     P.set_size(1,1);
                     P(0,0) = 1;
                 }
+            }
             else
             {
                 // fill in k