Added get_double_in_range() to dlib::rand.

dlib/rand/rand_kernel_1.h

@@ -137,6 +137,15 @@ namespace dlib
                 return (a<<32)|b;
             }
 
+            double get_double_in_range (
+                double begin,
+                double end
+            )
+            {
+                DLIB_ASSERT(begin <= end);
+                return begin + get_random_double()*(end-begin);
+            }
+
             double get_random_double (
             )
             {

dlib/rand/rand_kernel_abstract.h

@@ -135,6 +135,20 @@ namespace dlib
                     - returns a random double number N where:  0.0 <= N < 1.0.
             !*/
 
+            double get_double_in_range (
+                double begin,
+                double end
+            );
+            /*!
+                requires
+                    - begin <= end
+                ensures
+                    - if (begin < end) then
+                        - returns a random double number N where:  begin <= N < end.
+                    - else
+                        - returns begin
+            !*/
+
             double get_random_gaussian (
             );
             /*!