From 60534d66b6cc4f0e6b66b3f83300f2befe94ef1f Mon Sep 17 00:00:00 2001
From: Tor Harald Sandve <tosa@norceresearch.no>
Date: Wed, 24 Feb 2021 12:56:38 +0100
Subject: [PATCH 1/3] FOR TESTING. Enable Diffusion by default

---
 ebos/eclproblem.hh | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/ebos/eclproblem.hh b/ebos/eclproblem.hh
index eba3a2d3e..df798b3b7 100644
--- a/ebos/eclproblem.hh
+++ b/ebos/eclproblem.hh
@@ -323,6 +323,12 @@ struct EnableGravity<TypeTag, TTag::EclBaseProblem> {
     static constexpr bool value = true;
 };
 
+// Enable diffusion
+template<class TypeTag>
+struct EnableDiffusion<TypeTag, TTag::EclBaseProblem> {
+    static constexpr bool value = true;
+};
+
 // only write the solutions for the report steps to disk
 template<class TypeTag>
 struct EnableWriteAllSolutions<TypeTag, TTag::EclBaseProblem> {

From 48ad67601090d9042dc35c4cc89a1a5fcea90816 Mon Sep 17 00:00:00 2001
From: Tor Harald Sandve <tosa@norceresearch.no>
Date: Thu, 25 Feb 2021 11:14:12 +0100
Subject: [PATCH 2/3] only update diffusivity when DIFFUSIVE is in the deck

---
 ebos/ecltransmissibility.hh | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/ebos/ecltransmissibility.hh b/ebos/ecltransmissibility.hh
index 9d2bcaf3b..8e2f5b69c 100644
--- a/ebos/ecltransmissibility.hh
+++ b/ebos/ecltransmissibility.hh
@@ -127,7 +127,7 @@ public:
 
         // get the ntg values, the ntg values are modified for the cells merged with minpv
         const std::vector<double>& ntg = eclState.fieldProps().get_double("NTG");
-
+        const bool updateDiffusivity = eclState.getSimulationConfig().isDiffusive() && enableDiffusion;
         unsigned numElements = elemMapper.size();
 
         extractPermeability_();
@@ -183,7 +183,7 @@ public:
         }
 
         // if diffusion is enabled, let's do the same for the "diffusivity"
-        if (enableDiffusion) {
+        if (updateDiffusivity) {
             diffusivity_->clear();
             diffusivity_->reserve(numElements*3*1.05);
             extractPorosity_();
@@ -396,7 +396,7 @@ public:
                 trans_[isId_(elemIdx, outsideElemIdx)] = trans;
 
                 // update the "thermal half transmissibility" for the intersection
-                if (enableDiffusion) {
+                if (updateDiffusivity) {
 
                     Scalar halfDiffusivity1;
                     Scalar halfDiffusivity2;

From ffe51aa346b111e851e6d03a5a5f93c26b839446 Mon Sep 17 00:00:00 2001
From: Tor Harald Sandve <tosa@norceresearch.no>
Date: Thu, 25 Feb 2021 15:22:01 +0100
Subject: [PATCH 3/3] return 0 diffusivity if diffusion in disabled

---
 ebos/ecltransmissibility.hh | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/ebos/ecltransmissibility.hh b/ebos/ecltransmissibility.hh
index 8e2f5b69c..8ef288cb6 100644
--- a/ebos/ecltransmissibility.hh
+++ b/ebos/ecltransmissibility.hh
@@ -498,7 +498,13 @@ public:
      * \brief Return the diffusivity for the intersection between two elements.
      */
     Scalar diffusivity(unsigned elemIdx1, unsigned elemIdx2) const
-    { return diffusivity_->at(isId_(elemIdx1, elemIdx2)); }
+    {
+        if(diffusivity_->empty())
+            return 0.0;
+
+        return diffusivity_->at(isId_(elemIdx1, elemIdx2));
+
+    }
 
 private: