Added an overload of pick_initial_centers() that uses the linear kernel when no

other kernel is specified by the user.

dlib/svm/kkmeans.h

@@ -7,7 +7,7 @@
 #include "../matrix/matrix_abstract.h"
 #include "../algs.h"
 #include "../serialize.h"
-#include "kernel_abstract.h"
+#include "kernel.h"
 #include "../array.h"
 #include "kcentroid.h"
 #include "kkmeans_abstract.h"
@@ -361,6 +361,24 @@ namespace dlib
         
     }
 
+// ----------------------------------------------------------------------------------------
+
+    template <
+        typename vector_type1, 
+        typename vector_type2
+        >
+    void pick_initial_centers(
+        long num_centers, 
+        vector_type1& centers, 
+        const vector_type2& samples, 
+        double percentile = 0.01
+    )
+    {
+        typedef typename vector_type1::value_type sample_type;
+        linear_kernel<sample_type> kern;
+        pick_initial_centers(num_centers, centers, samples, kern, percentile);
+    }
+
 // ----------------------------------------------------------------------------------------
 
     template <

dlib/svm/kkmeans_abstract.h

@@ -237,6 +237,32 @@ namespace dlib
             - #centers == a vector containing the candidate centers found
     !*/
 
+// ----------------------------------------------------------------------------------------
+
+    template <
+        typename vector_type1, 
+        typename vector_type2
+        >
+    void pick_initial_centers(
+        long num_centers, 
+        vector_type1& centers, 
+        const vector_type2& samples, 
+        double percentile = 0.01
+    );
+    /*!
+        requires
+            - num_centers > 1
+            - 0 <= percentile < 1
+            - samples.size() > 1
+            - vector_type1 == something with an interface compatible with std::vector
+            - vector_type2 == something with an interface compatible with std::vector
+            - Both centers and samples must be able to contain dlib::matrix based row or
+              column vectors.
+        ensures
+            - performs: pick_initial_centers(num_centers, centers, samples, linear_kernel<sample_type>(), percentile)
+              (i.e. this function is simply an overload that uses the linear kernel.
+    !*/
+
 // ----------------------------------------------------------------------------------------
 
     template <