From 8a879147400d2a1930872da0195732fb83133e9d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C3=A5rd=20Skaflestad?= <Bard.Skaflestad@sintef.no>
Date: Wed, 2 Sep 2020 11:45:33 +0200
Subject: [PATCH] Don't Repeatedly Calculate Same Guiderate Value

Doing so works reduces the impact of the damping factor.
---
 .../eclipse/EclipseState/Schedule/Group/GuideRate.cpp | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/opm/parser/eclipse/EclipseState/Schedule/Group/GuideRate.cpp b/src/opm/parser/eclipse/EclipseState/Schedule/Group/GuideRate.cpp
index 8955cc2ef..da2bb081f 100644
--- a/src/opm/parser/eclipse/EclipseState/Schedule/Group/GuideRate.cpp
+++ b/src/opm/parser/eclipse/EclipseState/Schedule/Group/GuideRate.cpp
@@ -252,14 +252,19 @@ void GuideRate::assign_grvalue(const std::string&    wgname,
                                const GuideRateModel& model,
                                GuideRateValue&&      value)
 {
-    using std::swap;
-
     auto& v = this->values[wgname];
     if (v == nullptr) {
         v = std::make_unique<GRValState>();
     }
 
-    swap(v->prev, v->curr);
+    if (value.sim_time > v->curr.sim_time) {
+        // We've advanced in time since we previously calculated/stored this
+        // guiderate value.  Push current value into the past and prepare to
+        // capture new value.
+        using std::swap;
+
+        swap(v->prev, v->curr);
+    }
 
     v->curr = std::move(value);