From 78b87b88573b07189d328617c7c870dbfcff2b6d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C3=A5rd=20Skaflestad?= <Bard.Skaflestad@sintef.no>
Date: Tue, 27 May 2014 18:42:58 +0200
Subject: [PATCH] variableState: Don't form objects when references suffice

There's no need to form new objects, especially for the 'xvar', when
there are existing objects to which read-only references can be
bound.
---
 opm/autodiff/FullyImplicitBlackoilSolver_impl.hpp | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/opm/autodiff/FullyImplicitBlackoilSolver_impl.hpp b/opm/autodiff/FullyImplicitBlackoilSolver_impl.hpp
index 12cb372ef..52bd1ec2c 100644
--- a/opm/autodiff/FullyImplicitBlackoilSolver_impl.hpp
+++ b/opm/autodiff/FullyImplicitBlackoilSolver_impl.hpp
@@ -530,10 +530,10 @@ namespace {
 
             if (active_[ Gas]) {
                 // Define Sg Rs and Rv in terms of xvar.
-                ADB rsSat = fluidRsSat(state.pressure, cells_);
-                ADB rvSat = fluidRvSat(state.pressure, cells_);
-                ADB xvar = vars[ nextvar++ ];
-                ADB sg = isSg*xvar + isRv* so;
+                const ADB& rsSat = fluidRsSat(state.pressure, cells_);
+                const ADB& rvSat = fluidRvSat(state.pressure, cells_);
+                const ADB& xvar = vars[ nextvar++ ];
+                const ADB& sg = isSg*xvar + isRv* so;
                 state.saturation[ pu.phase_pos[ Gas ] ] = sg;
                 so = so - sg;