From 299aa77e185cc0dfa219c9fd791cfea6e9c281e6 Mon Sep 17 00:00:00 2001
From: osae <osae@iris.no>
Date: Thu, 27 Aug 2015 19:22:59 +0200
Subject: [PATCH 1/3] Cell center depth also from zcorn average.

There is a sligth difference between the cell depth taken from the
centroid (opm) and a straightforward average of corner coordinates
(ecl). For the initialisation of Norne this causes some differences
when deciding cell center positions relative contact depths.
---
 opm/core/grid/GridHelpers.cpp | 11 +++++++++++
 opm/core/grid/GridHelpers.hpp |  7 +++++++
 2 files changed, 18 insertions(+)

diff --git a/opm/core/grid/GridHelpers.cpp b/opm/core/grid/GridHelpers.cpp
index 85006cc3..03528a18 100644
--- a/opm/core/grid/GridHelpers.cpp
+++ b/opm/core/grid/GridHelpers.cpp
@@ -57,6 +57,17 @@ const double* beginCellCentroids(const UnstructuredGrid& grid)
     return grid.cell_centroids;
 }
 
+double cellCenterDepth(const UnstructuredGrid& grid, int cell_index) 
+{
+    double zz = 0.0;
+    for (int i=grid.cell_facepos[cell_index+1]-2; i<grid.cell_facepos[cell_index+1]; ++i) {
+        for (int j=grid.face_nodepos[grid.cell_faces[i]]; j<grid.face_nodepos[grid.cell_faces[i]+1]; ++j) {
+            zz += (grid.node_coordinates+dimensions(grid)*(grid.face_nodes[j]))[2];
+        }
+    }
+    return zz/8.0;
+}
+
 double cellCentroidCoordinate(const UnstructuredGrid& grid, int cell_index,
                                  int coordinate)
 {
diff --git a/opm/core/grid/GridHelpers.hpp b/opm/core/grid/GridHelpers.hpp
index cd9ad084..fc7bfcee 100644
--- a/opm/core/grid/GridHelpers.hpp
+++ b/opm/core/grid/GridHelpers.hpp
@@ -137,6 +137,13 @@ struct CellCentroidTraits<UnstructuredGrid>
 CellCentroidTraits<UnstructuredGrid>::IteratorType
 beginCellCentroids(const UnstructuredGrid& grid);
 
+
+/// \brief Get vertical position of cell center ("zcorn" average.)
+/// \brief grid The grid.
+/// \brief cell_index The index of the specific cell.
+double cellCenterDepth(const UnstructuredGrid& grid, int cell_index);
+
+
 /// \brief Get a coordinate of a specific cell centroid.
 /// \brief grid The grid.
 /// \brief cell_index The index of the specific cell.

From 565fa4278eb11a675e80961a3f3e6dca583c8e6e Mon Sep 17 00:00:00 2001
From: osae <osae@iris.no>
Date: Thu, 10 Sep 2015 18:23:00 +0200
Subject: [PATCH 2/3] Add some comments and limit to 3 dimensions.

---
 opm/core/grid/GridHelpers.cpp | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/opm/core/grid/GridHelpers.cpp b/opm/core/grid/GridHelpers.cpp
index 03528a18..afbaf9b4 100644
--- a/opm/core/grid/GridHelpers.cpp
+++ b/opm/core/grid/GridHelpers.cpp
@@ -59,13 +59,22 @@ const double* beginCellCentroids(const UnstructuredGrid& grid)
 
 double cellCenterDepth(const UnstructuredGrid& grid, int cell_index) 
 {
+    // This method is an alternative to the method cellCentroidCoordinate(...) below.
+    // The cell center depth is computed as a raw average of cell corner depths.
+    // For cornerpoint grids, this is likely to give slightly different depths that seem
+    // to agree with eclipse.
+    assert(grid.dimensions == 3);
+    const int nd = 3; // Assuming 3-dimensional grid ...
+    const int nv = 8; // Assuming 2*4 vertices ...
     double zz = 0.0;
+    // Traverse the bottom and top cell-face
     for (int i=grid.cell_facepos[cell_index+1]-2; i<grid.cell_facepos[cell_index+1]; ++i) {
+        // Traverse the vertices associated with each face
         for (int j=grid.face_nodepos[grid.cell_faces[i]]; j<grid.face_nodepos[grid.cell_faces[i]+1]; ++j) {
-            zz += (grid.node_coordinates+dimensions(grid)*(grid.face_nodes[j]))[2];
+            zz += (grid.node_coordinates+nd*(grid.face_nodes[j]))[nd-1];
         }
     }
-    return zz/8.0;
+    return zz/nv;
 }
 
 double cellCentroidCoordinate(const UnstructuredGrid& grid, int cell_index,

From 1fdc4c39dce43a86bab11a4766151e046c7d62ea Mon Sep 17 00:00:00 2001
From: osae <osae@iris.no>
Date: Fri, 11 Sep 2015 11:47:27 +0200
Subject: [PATCH 3/3] Assure 4 vertices for each face of the grid.

---
 opm/core/grid/GridHelpers.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/opm/core/grid/GridHelpers.cpp b/opm/core/grid/GridHelpers.cpp
index afbaf9b4..e8d268a2 100644
--- a/opm/core/grid/GridHelpers.cpp
+++ b/opm/core/grid/GridHelpers.cpp
@@ -70,6 +70,7 @@ double cellCenterDepth(const UnstructuredGrid& grid, int cell_index)
     // Traverse the bottom and top cell-face
     for (int i=grid.cell_facepos[cell_index+1]-2; i<grid.cell_facepos[cell_index+1]; ++i) {
         // Traverse the vertices associated with each face
+        assert(grid.face_nodepos[grid.cell_faces[i]+1] - grid.face_nodepos[grid.cell_faces[i]] == nv/2);
         for (int j=grid.face_nodepos[grid.cell_faces[i]]; j<grid.face_nodepos[grid.cell_faces[i]+1]; ++j) {
             zz += (grid.node_coordinates+nd*(grid.face_nodes[j]))[nd-1];
         }