From 4f367471aed2ac8947a6f9df19be3a0294a7d4bb Mon Sep 17 00:00:00 2001
From: Davis King <davis@dlib.net>
Date: Fri, 1 Apr 2016 11:38:16 -0400
Subject: [PATCH] Added a member function to get the line intercept from
 running_gradient.

---
 dlib/statistics/running_gradient.h          | 12 ++++++++++++
 dlib/statistics/running_gradient_abstract.h | 13 +++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/dlib/statistics/running_gradient.h b/dlib/statistics/running_gradient.h
index 368ce6b2b..1d40ac313 100644
--- a/dlib/statistics/running_gradient.h
+++ b/dlib/statistics/running_gradient.h
@@ -72,6 +72,18 @@ namespace dlib
             return w(0);
         }
 
+        double intercept (
+        ) const
+        {
+            // make sure requires clause is not broken
+            DLIB_ASSERT(current_n() > 0,
+                "\t double running_gradient::intercept()"
+                << "\n\t You must add more values into this object before calling this function."
+                << "\n\t this: " << this
+                );
+
+            return w(1);
+        }
         double standard_error ( 
         ) const
         {
diff --git a/dlib/statistics/running_gradient_abstract.h b/dlib/statistics/running_gradient_abstract.h
index b38060502..e5f007fb1 100644
--- a/dlib/statistics/running_gradient_abstract.h
+++ b/dlib/statistics/running_gradient_abstract.h
@@ -65,6 +65,19 @@ namespace dlib
                   of this line.
         !*/
 
+        double intercept (
+        ) const;
+        /*!
+            requires
+                - current_n() > 0
+            ensures
+                - This class fits a line to the time series data given to add().  This
+                  function returns the intercept of that line while gradient() returns the
+                  slope of that line.  This means that, for example, the next point that
+                  add() will see, as predicted by this best fit line, is the value
+                  intercept() + current_n()*gradient().
+        !*/
+
         double standard_error ( 
         ) const;
         /*!