From d236358ec6e3ab49175d3e90237ccac730fcb00c Mon Sep 17 00:00:00 2001
From: Ray Speth <speth@mit.edu>
Date: Thu, 6 Dec 2012 17:31:31 +0000
Subject: [PATCH] [1D] Fixed oscillations in grid refinement when pruning is
 enabled

Points which are needed to satisfy the 'ratio' requirement are not removed when
pruning. Previously, it was possible for the solver to get stuck in a loop where
the same points were added and removed after successive grid refinements.
---
 src/oneD/refine.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/oneD/refine.cpp b/src/oneD/refine.cpp
index a521baf1d..44755f263 100644
--- a/src/oneD/refine.cpp
+++ b/src/oneD/refine.cpp
@@ -169,6 +169,12 @@ int Refiner::analyze(size_t n, const doublereal* z,
             m_loc[j-1] = 1;
             m_c["point "+int2str(j-1)] = 1;
         }
+        if (j > 1 && z[j+1]-z[j] > m_ratio * dz[j-2]) {
+            m_keep[j] = 1;
+        }
+        if (j < n-2 && z[j+1]-z[j] > m_ratio * dz[j+1]) {
+            m_keep[j] = 1;
+        }
         //if (m_loc.size() + n > m_npmax) goto done;
     }