[Boost-commit] svn:boost r80639 - trunk/boost/graph

Subject: [Boost-commit] svn:boost r80639 - trunk/boost/graph
From: jewillco_at_[hidden]
Date: 2012-09-22 15:32:32

Author: jewillco
Date: 2012-09-22 15:32:32 EDT (Sat, 22 Sep 2012)
New Revision: 80639
URL: http://svn.boost.org/trac/boost/changeset/80639

Log:
Fixed relax logic to not write predecessor map unless distance was actually changed in memory (although this case will never be hit unless registers have extra precision compared to memory); fixes #7226
Text files modified: 
   trunk/boost/graph/relax.hpp |    23 ++++++++++++++++-------                 
   1 files changed, 16 insertions(+), 7 deletions(-)

Modified: trunk/boost/graph/relax.hpp
==============================================================================
--- trunk/boost/graph/relax.hpp	(original)
+++ trunk/boost/graph/relax.hpp	2012-09-22 15:32:32 EDT (Sat, 22 Sep 2012)
@@ -53,17 +53,26 @@
       const D d_v = get(d, v);
       const W& w_e = get(w, e);
       
-      // The redundant gets in the return statements are to ensure that extra
-      // floating-point precision in x87 registers does not lead to relax()
-      // returning true when the distance did not actually change.
+      // The seemingly redundant comparisons after the distance puts are to
+      // ensure that extra floating-point precision in x87 registers does not
+      // lead to relax() returning true when the distance did not actually
+      // change.
       if ( compare(combine(d_u, w_e), d_v) ) {
         put(d, v, combine(d_u, w_e));
-        put(p, v, u);
-        return compare(get(d, v), d_v);
+        if (compare(get(d, v), d_v)) {
+          put(p, v, u);
+          return true;
+        } else {
+          return false;
+        }
       } else if (is_undirected && compare(combine(d_v, w_e), d_u)) {
         put(d, u, combine(d_v, w_e));
-        put(p, u, v);
-        return compare(get(d, u), d_u);
+        if (compare(get(d, u), d_u)) {
+          put(p, u, v);
+          return true;
+        } else {
+          return false;
+        }
       } else
         return false;
     }