From: Michael Orlitzky <michael@orlitzky.com>
Date: Mon, 25 Mar 2013 18:51:59 +0000 (-0400)
Subject: Simplify (subjectively) the steepest descent loop.
X-Git-Url: https://gitweb.michael.orlitzky.com/?a=commitdiff_plain;h=e8d03f4007b828784c68b1d4ff2ba8d644641cef;p=octave.git

Simplify (subjectively) the steepest descent loop.
---

diff --git a/optimization/steepest_descent.m b/optimization/steepest_descent.m
index 0a6475e..c0e88dd 100644
--- a/optimization/steepest_descent.m
+++ b/optimization/steepest_descent.m
@@ -58,14 +58,15 @@ function [x, k] = steepest_descent(g,  ...
 
     dk = -gk;
     alpha_k = step_size(xk);
-    xk = xk + (alpha_k * dk);
-    gk = g(xk);
+    x_next = xk + (alpha_k * dk);
 
     % We potentially just performed one more iteration than necessary
     % in order to simplify the loop. Note that due to the structure of
     % our loop, we will have k > max_iterations when we fail to
     % converge.
     k = k + 1;
+    xk = x_next;
+    gk = g(x_next);
   end
 
   x = xk;