diff --git a/dlib/svm/kcentroid.h b/dlib/svm/kcentroid.h
index c569beef6..70dcafcd4 100644
--- a/dlib/svm/kcentroid.h
+++ b/dlib/svm/kcentroid.h
@@ -56,6 +56,12 @@ namespace dlib
             return my_max_dictionary_size;
         }
 
+        const kernel_type& get_kernel (
+        ) const
+        {
+            return kernel;
+        }
+
         void clear_dictionary ()
         {
             dictionary.clear();
diff --git a/dlib/svm/kcentroid_abstract.h b/dlib/svm/kcentroid_abstract.h
index 5df70cc19..517c651c1 100644
--- a/dlib/svm/kcentroid_abstract.h
+++ b/dlib/svm/kcentroid_abstract.h
@@ -58,11 +58,17 @@ namespace dlib
             ensures
                 - this object is properly initialized
                 - #tolerance() == tolerance_
-                - #get_decision_function().kernel_function == kernel_
-                  (i.e. this object will use the given kernel function)
+                - #get_kernel() == kernel_
                 - #max_dictionary_size() == max_dictionary_size_
         !*/
 
+        const kernel_type& get_kernel (
+        ) const;
+        /*!
+            ensures
+                - returns a const reference to the kernel used by this object
+        !*/
+
         unsigned long max_dictionary_size(
         ) const;
         /*!
diff --git a/dlib/svm/kkmeans.h b/dlib/svm/kkmeans.h
index c0678ab45..325c8115b 100644
--- a/dlib/svm/kkmeans.h
+++ b/dlib/svm/kkmeans.h
@@ -39,6 +39,12 @@ namespace dlib
         {
         }
 
+        const kernel_type& get_kernel (
+        ) const
+        {
+            return kc.get_kernel();
+        }
+
         void set_kcentroid (
             const kcentroid<kernel_type>& kc_
         )
@@ -92,7 +98,7 @@ namespace dlib
 
             // make sure requires clause is not broken
             DLIB_ASSERT(samples.nc() == 1 && initial_centers.nc() == 1 &&
-                         initial_centers.nr() == number_of_centers(),
+                         initial_centers.nr() == static_cast<long>(number_of_centers()),
                 "\tvoid kkmeans::train()"
                 << "\n\tInvalid arguments to this function"
                 << "\n\tthis: " << this
diff --git a/dlib/svm/kkmeans_abstract.h b/dlib/svm/kkmeans_abstract.h
index 0383db6a2..a8adde00b 100644
--- a/dlib/svm/kkmeans_abstract.h
+++ b/dlib/svm/kkmeans_abstract.h
@@ -71,6 +71,13 @@ namespace dlib
                   by the k-means clustering algorithm.
         !*/
 
+        const kernel_type& get_kernel (
+        ) const;
+        /*!
+            ensures
+                - returns a const reference to the kernel used by this object
+        !*/
+
         void set_number_of_centers (
             unsigned long num
         );
diff --git a/dlib/svm/krls.h b/dlib/svm/krls.h
index e6274248b..4f158505e 100644
--- a/dlib/svm/krls.h
+++ b/dlib/svm/krls.h
@@ -51,6 +51,12 @@ namespace dlib
             return my_max_dictionary_size;
         }
 
+        const kernel_type& get_kernel (
+        ) const
+        {
+            return kernel;
+        }
+
         void clear_dictionary ()
         {
             dictionary.clear();
diff --git a/dlib/svm/krls_abstract.h b/dlib/svm/krls_abstract.h
index ca5df27cc..ae0c95e6a 100644
--- a/dlib/svm/krls_abstract.h
+++ b/dlib/svm/krls_abstract.h
@@ -58,6 +58,7 @@ namespace dlib
                 - #tolerance() == tolerance_
                 - #get_decision_function().kernel_function == kernel_
                   (i.e. this object will use the given kernel function)
+                - #get_kernel() == kernel_
                 - #max_dictionary_size() == max_dictionary_size_
         !*/
 
@@ -74,6 +75,13 @@ namespace dlib
                   less accurate decision function but also in less support vectors.
         !*/
 
+        const kernel_type& get_kernel (
+        ) const;
+        /*!
+            ensures
+                - returns a const reference to the kernel used by this object
+        !*/
+
         unsigned long max_dictionary_size(
         ) const;
         /*!