Move the if-serial run into CpGridVanguard::addLgrs(), warn if parallel

opm/models/utils/simulator.hh

@@ -139,17 +139,15 @@ public:
             OPM_END_PARALLEL_TRY_CATCH("Could not distribute the vanguard data: ", comm);
         }
 
-        // Only relevant for CpGrid
+        // Only relevant for CpGrid and serial runs.
         if (verbose_) {
             std::cout << "Adding LGRs, if any, in serial run\n" << std::flush;
         }
 
         {
-            if ( comm.size() == 1 ) { // serial run
-                OPM_BEGIN_PARALLEL_TRY_CATCH();
-                vanguard_->addLgrs();
-                OPM_END_PARALLEL_TRY_CATCH("Adding LGRs to the simulation vanguard in serial run failed: ", comm);
-            }
+            OPM_BEGIN_PARALLEL_TRY_CATCH();
+            vanguard_->addLgrs();
+            OPM_END_PARALLEL_TRY_CATCH("Adding LGRs to the simulation vanguard in serial run failed: ", comm);
         }
 
         if (verbose_) {

opm/simulators/flow/CpGridVanguard.hpp

@@ -255,7 +255,7 @@ public:
         // Check if input file contains Lgrs.
         //
         // If there are lgrs, create the grid with them, and update the leaf grid view.
-        if (const auto& lgrs = this->eclState().getLgrs(); lgrs.size() > 0) {
+        if (const auto& lgrs = this->eclState().getLgrs(); (lgrs.size() > 0) && (this->grid_->comm().size() == 1)) {
             OpmLog::info("\nAdding LGRs to the grid and updating its leaf grid view");
             this->addLgrsUpdateLeafView(lgrs, lgrs.size(), *this->grid_);
 
@@ -263,6 +263,9 @@ public:
             this->updateCellDepths_();
             this->updateCellThickness_();
         }
+        else {
+            Opm::OpmLog::warning("Adding LGRs in parallel run is not supported yet.\n");
+        }
     }
 
     unsigned int gridEquilIdxToGridIdx(unsigned int elemIndex) const {