Added another constructor for sample pair objects. This one doesn't require

a distance argument.

dlib/manifold_regularization/ordered_sample_pair.h

@@ -23,6 +23,16 @@ namespace dlib
             _distance = std::numeric_limits<double>::infinity();
         }
 
+        ordered_sample_pair (
+            const unsigned long idx1,
+            const unsigned long idx2
+        )
+        {
+            _distance = std::numeric_limits<double>::infinity();
+            _index1 = idx1;
+            _index2 = idx2;
+        }
+
         ordered_sample_pair (
             const unsigned long idx1,
             const unsigned long idx2,

dlib/manifold_regularization/ordered_sample_pair_abstract.h

@@ -33,6 +33,17 @@ namespace dlib
                 - #distance() == std::numeric_limits<double>::infinity()
         !*/
 
+        ordered_sample_pair (
+            const unsigned long idx1,
+            const unsigned long idx2
+        );
+        /*!
+            ensures
+                - #index1() == idx1
+                - #index2() == idx2
+                - #distance() == std::numeric_limits<double>::infinity()
+        !*/
+
         ordered_sample_pair (
             const unsigned long idx1,
             const unsigned long idx2,

dlib/manifold_regularization/sample_pair.h

@@ -23,6 +23,24 @@ namespace dlib
             _distance = std::numeric_limits<double>::infinity();
         }
 
+        sample_pair (
+            const unsigned long idx1,
+            const unsigned long idx2
+        )
+        {
+            _distance = std::numeric_limits<double>::infinity();
+            if (idx1 < idx2)
+            {
+                _index1 = idx1;
+                _index2 = idx2;
+            }
+            else
+            {
+                _index1 = idx2;
+                _index2 = idx1;
+            }
+        }
+
         sample_pair (
             const unsigned long idx1,
             const unsigned long idx2,

dlib/manifold_regularization/sample_pair_abstract.h

@@ -37,6 +37,17 @@ namespace dlib
                 - #distance() == std::numeric_limits<double>::infinity()
         !*/
 
+        sample_pair (
+            const unsigned long idx1,
+            const unsigned long idx2
+        );
+        /*!
+            ensures
+                - #index1() == min(idx1,idx2)
+                - #index2() == max(idx1,idx2)
+                - #distance() == std::numeric_limits<double>::infinity()
+        !*/
+
         sample_pair (
             const unsigned long idx1,
             const unsigned long idx2,