UgGridHelpers::createEclipseGrid( )

- A new function createEclipsegrid has been added to the UgGridHelpers
  namespace.

- The UnstructuredGrid C structure has been augmented with a new member:
  double * zcorn which can be used to hold a copy of the zcorn
  value *after* minpv induced modifications.

opm/core/grid.h

@@ -242,6 +242,16 @@ struct UnstructuredGrid
        cornerpoint grids.
     */
     int    *cell_facetag;
+
+
+    /*
+       This vector is retained to be able to construct an
+       EclipseGrid representation of the Grid. If the grid
+       processor actually modifies the elements of the zcorn
+       vector from the input the modified version is stored here;
+       otherwise we just use the default.
+    */
+    double * zcorn;
 };
 
 /**
@@ -290,6 +300,15 @@ allocate_grid(size_t ndims     ,
               size_t nnodes    );
 
 
+/**
+   Will allocate storage internally in the grid object to hold a copy
+   of the zcorn data supplied in the second argument.
+*/
+void
+attach_zcorn_copy(struct UnstructuredGrid* G ,
+                  const double * zcorn);
+
+
 /**
  * Import a grid from a character representation stored in file.
  *

opm/core/grid/GridHelpers.cpp

@@ -149,5 +149,29 @@ FaceCellTraits<UnstructuredGrid>::Type faceCells(const UnstructuredGrid& grid)
 {
     return FaceCellsProxy(grid);
 }
+
+
+Opm::EclipseGrid createEclipseGrid(const UnstructuredGrid& grid, const Opm::EclipseGrid& inputGrid ) {
+    const int * dims = UgGridHelpers::cartDims( grid );
+
+    if ((inputGrid.getNX( ) == static_cast<size_t>(dims[0])) &&
+        (inputGrid.getNY( ) == static_cast<size_t>(dims[1])) &&
+        (inputGrid.getNZ( ) == static_cast<size_t>(dims[2]))) {
+        std::vector<int> updatedACTNUM;
+        const int* global_cell = UgGridHelpers::globalCell( grid );
+
+        if (global_cell) {
+            updatedACTNUM.assign( inputGrid.getCartesianSize( ) , 0 );
+            for (int c = 0; c < numCells( grid ); c++) {
+                updatedACTNUM[global_cell[c]] = 1;
+            }
+        }
+
+        return Opm::EclipseGrid( inputGrid, grid.zcorn, updatedACTNUM );
+    } else {
+        throw std::invalid_argument("Size mismatch - dimensions of inputGrid argument and current UnstructuredGrid instance disagree");
+    }
+}
+
 }
 }

opm/core/grid/GridHelpers.hpp

@@ -22,6 +22,7 @@
 #define OPM_CORE_GRIDHELPERS_HEADER_INCLUDED
 
 #include <opm/core/grid.h>
+#include <opm/parser/eclipse/EclipseState/Grid/EclipseGrid.hpp>
 
 #include <opm/common/utility/platform_dependent/disable_warnings.h>
 #include <boost/range/iterator_range.hpp>
@@ -184,6 +185,31 @@ struct CellVolumeIteratorTraits<UnstructuredGrid>
     typedef const double* IteratorType;
 };
 
+    /**
+       Will create an EclipseGrid representation (i.e. based on
+       ZCORN and COORD) of the current UnstructuredGrid
+       instance. When creating the UnstructuredGrid the detailed
+       cornerpoint information is discarded, and it is difficult
+       to go backwards to recreated ZCORN and COORD.
+
+       The current implementation is based on retaining a copy of the
+       zcorn keyword after the Minpvprocessor has modified it.
+
+       We then create a new EclipseGrid instance based on the original
+       input grid, but we "replace" the ZCORN and ACTNUM keywords with
+       the updated versions.
+
+       If the tolerance in the call to create_grid_cornerpoint( ) is
+       finite the grid processing code might collapse cells, the z
+       coordinate transformations from this process will *not* be
+       correctly represented in the EclipseGrid created by this
+       method.
+    */
+
+/// \brief Construct an EclipseGrid instance based on the inputGrid, with modifications to
+/// zcorn and actnum from the dune UnstructuredGrid.
+Opm::EclipseGrid createEclipseGrid(const UnstructuredGrid& grid, const Opm::EclipseGrid& inputGrid );
+
 /// \brief Get an iterator over the cell volumes of a grid positioned at the first cell.
 const double* beginCellVolumes(const UnstructuredGrid& grid);
 

opm/core/grid/GridManager.cpp

@@ -19,6 +19,7 @@
 
 #include "config.h"
 
+#include <opm/core/grid/GridHelpers.hpp>
 #include <opm/core/grid/GridManager.hpp>
 #include <opm/core/grid.h>
 #include <opm/core/grid/cart_grid.h>
@@ -132,6 +133,7 @@ namespace Opm
                                           const std::vector<double>& poreVolumes)
     {
         struct grdecl g;
+        int cells_modified = 0;
         std::vector<int> actnum;
         std::vector<double> coord;
         std::vector<double> zcorn;
@@ -157,7 +159,7 @@ namespace Opm
             // Currently the pinchProcessor is not used and only opmfil is supported
             //bool opmfil = inputGrid.getMinpvMode() == MinpvMode::OpmFIL;
             bool opmfil = true;
-            mp.process(poreVolumes, minpv_value, actnum, opmfil, zcorn.data());
+            cells_modified = mp.process(poreVolumes, minpv_value, actnum, opmfil, zcorn.data());
         }
 
         const double z_tolerance = inputGrid.isPinchActive() ? inputGrid.getPinchThresholdThickness() : 0.0;
@@ -165,11 +167,13 @@ namespace Opm
         if (!ug_) {
             OPM_THROW(std::runtime_error, "Failed to construct grid.");
         }
+
+        if (cells_modified > 0) {
+            attach_zcorn_copy( ug_ , zcorn.data() );
+        }
     }
 
 
-
-
     void GridManager::createGrdecl(Opm::DeckConstPtr deck, struct grdecl &grdecl)
     {
         // Extract data from deck.

opm/core/grid/MinpvProcessor.hpp

@@ -48,11 +48,11 @@ namespace Opm
         /// will have the zcorn numbers changed so they are zero-thickness. Any
         /// cell below will be changed to include the deleted volume if mergeMinPCCells is true
         /// els the volume will be lost
-        void process(const std::vector<double>& pv,
+        int process(const std::vector<double>& pv,
-                     const double minpv,
+                    const double minpv,
-                     const std::vector<int>& actnum,
+                    const std::vector<int>& actnum,
-                     const bool mergeMinPVCells,
+                    const bool mergeMinPVCells,
-                     double* zcorn) const;
+                    double* zcorn) const;
     private:
         std::array<int,8> cornerIndices(const int i, const int j, const int k) const;
         std::array<double, 8> getCellZcorn(const int i, const int j, const int k, const double* z) const;
@@ -68,7 +68,7 @@ namespace Opm
 
 
 
-    inline void MinpvProcessor::process(const std::vector<double>& pv,
+    inline int MinpvProcessor::process(const std::vector<double>& pv,
                                         const double minpv,
                                         const std::vector<int>& actnum,
                                         const bool mergeMinPVCells,
@@ -85,6 +85,8 @@ namespace Opm
         //    is true, the higher four zcorn associated with the cell below
         //    is moved to these values (so it gains the deleted volume).
 
+        int cells_modified = 0;
+
         // Check for sane input sizes.
         const size_t log_size = dims_[0] * dims_[1] * dims_[2];
         if (pv.size() != log_size) {
@@ -107,6 +109,7 @@ namespace Opm
                         }
                         setCellZcorn(ii, jj, kk, cz, zcorn);
 
+
                         // optionally add removed volume to the cell below.
                         if (mergeMinPVCells) {
                             // Check if there is a cell below.
@@ -119,10 +122,12 @@ namespace Opm
                                 setCellZcorn(ii, jj, kk + 1, cz_below, zcorn);
                             }
                         }
+                        ++cells_modified;
                     }
                 }
             }
         }
+        return cells_modified;
     }
 
 

opm/core/grid/grid.c

@@ -48,6 +48,8 @@ destroy_grid(struct UnstructuredGrid *g)
 
         free(g->global_cell);
         free(g->cell_facetag);
+
+        free(g->zcorn);
     }
 
     free(g);
@@ -69,6 +71,18 @@ create_grid_empty(void)
 }
 
 
+void
+attach_zcorn_copy(struct UnstructuredGrid* G , const double * zcorn)
+{
+    size_t zcorn_elements = G->cartdims[0] * G->cartdims[1] * G->cartdims[2] * 8;
+    double * new_zcorn = realloc(G->zcorn , zcorn_elements * sizeof * G->zcorn );
+    if (new_zcorn) {
+        G->zcorn = new_zcorn;
+        memcpy(G->zcorn , zcorn , zcorn_elements * sizeof * G->zcorn );
+    }
+}
+
+
 struct UnstructuredGrid *
 allocate_grid(size_t ndims     ,
               size_t ncells    ,
@@ -83,6 +97,9 @@ allocate_grid(size_t ndims     ,
     G = create_grid_empty();
 
     if (G != NULL) {
+        /* zcorn cache - only for output. */
+        G->zcorn = NULL;
+
         /* Grid fields ---------------------------------------- */
         G->dimensions       = ndims;
         G->number_of_cells  = ncells;

tests/test_ug.cpp

@@ -21,6 +21,7 @@
 #include <opm/core/grid.h>
 #include <opm/core/grid/cornerpoint_grid.h>  /* compute_geometry */
 #include <opm/core/grid/GridManager.hpp>  /* compute_geometry */
+#include <opm/core/grid/GridHelpers.hpp>
 #include <opm/core/grid/cpgpreprocess/preprocess.h>
 #include <opm/parser/eclipse/Deck/Deck.hpp>
 #include <opm/parser/eclipse/Deck/DeckItem.hpp>
@@ -172,5 +173,5 @@ BOOST_AUTO_TEST_CASE(TOPS_Fully_Specified) {
 
     BOOST_CHECK(grid_equal(cgrid1, cgrid2));
 
-    Opm::EclipseGrid grid = gridM1.createEclipseGrid( *es1.getInputGrid( ) );
+    Opm::EclipseGrid grid = Opm::UgGridHelpers::createEclipseGrid( *cgrid1 , *es1.getInputGrid( ) );
 }