Added a requires clause to the set_tolerance() member function and

renamed clear() to clear_dictionary().

--HG--
extra : convert_revision : svn%3Afdd8eb12-d10e-0410-9acb-85c331704f74/trunk%402249

dlib/svm/krls.h

@@ -36,11 +36,18 @@ namespace dlib
             kernel(kernel_), 
             tolerance(tolerance_)
         {
-            clear();
+            clear_dictionary();
         }
 
         void set_tolerance (scalar_type tolerance_)
         {
+            // make sure requires clause is not broken
+            DLIB_ASSERT(tolerance_ >= 0,
+                "\tvoid krls::set_tolerance"
+                << "\n\tinvalid tolerance value"
+                << "\n\ttolerance: " << tolerance_
+                << "\n\tthis: " << this
+                );
             tolerance = tolerance_;
         }
 
@@ -49,7 +56,7 @@ namespace dlib
             return tolerance;
         }
 
-        void clear ()
+        void clear_dictionary ()
         {
             dictionary.clear();
             alpha.clear();

dlib/svm/krls_abstract.h

@@ -56,6 +56,8 @@ namespace dlib
             scalar_type tolerance_
         );
         /*!
+            requires
+                - tolerance_ >= 0
             ensures
                 - #get_tolerance() == tolerance_
         !*/
@@ -73,15 +75,12 @@ namespace dlib
                   less accurate decision function but also in less support vectors.
         !*/
 
-        void clear (
+        void clear_dictionary (
         );
         /*!
             ensures
-                - clears out all learned data and puts this object back to its
-                  initial state.
+                - clears out all learned data 
                   (e.g. #get_decision_function().support_vectors.size() == 0)
-                - #get_tolerance() == get_tolerance()
-                  (i.e. doesn't change the value of the tolerance)
         !*/
 
         scalar_type operator() (