From d559ce3d837cc1afff0a5f902c8cef28914ee63a Mon Sep 17 00:00:00 2001
From: Ryan Curtin <ryan@ratml.org>
Date: Mon, 23 Jun 2014 21:38:42 +0000
Subject: [PATCH] Fix for convergence, because sometimes the residue may
 increase (especially with ALS update rules).

---
 src/mlpack/methods/amf/amf_impl.hpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/mlpack/methods/amf/amf_impl.hpp b/src/mlpack/methods/amf/amf_impl.hpp
index 2bd0ee9753..9ee69a4b99 100644
--- a/src/mlpack/methods/amf/amf_impl.hpp
+++ b/src/mlpack/methods/amf/amf_impl.hpp
@@ -63,7 +63,7 @@ double AMF<InitializationRule, UpdateRule>::Apply(
 
   update.Initialize(V, r);
 
-  while (((oldResidue - residue) / oldResidue >= tolerance || iteration < 4) && iteration != maxIterations)
+  while ((std::abs(oldResidue - residue) / oldResidue >= tolerance || iteration < 4) && iteration != maxIterations)
   {
     // Update step.
     // Update the value of W and H based on the Update Rules provided