add nullfvbaseelementcontext

opm/models/discretization/common/nullfvbaseelementcontext.hh

@@ -0,0 +1,312 @@
+// -*- mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+// vi: set et ts=4 sw=4 sts=4:
+/*
+
+  Copyright 2026 Equinor ASA
+
+  This file is part of the Open Porous Media project (OPM).
+
+  OPM is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 2 of the License, or
+  (at your option) any later version.
+
+  OPM is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with OPM.  If not, see <http://www.gnu.org/licenses/>.
+
+  Consult the COPYING file in the top-level source directory of this
+  module for the precise wording of the license and the list of
+  copyright holders.
+*/
+/*!
+ * \file
+ *
+ * \brief GPU-compatible stub of FvBaseElementContext.
+ *
+ * All methods are annotated with OPM_HOST_DEVICE and return dummy/default
+ * values. This class is intended as a placeholder so that GPU kernels that
+ * receive an element context can compile; it does not implement any real
+ * behaviour.
+ *
+ * The heavy Dune/grid infrastructure present in FvBaseElementContext is
+ * intentionally absent here because those types are not usable inside a
+ * CUDA/HIP kernel.
+ */
+#ifndef OPM_FV_BASE_ELEMENT_CONTEXT_GPU_HH
+#define OPM_FV_BASE_ELEMENT_CONTEXT_GPU_HH
+
+#include <opm/common/utility/gpuDecorators.hpp>
+#include <opm/models/discretization/common/fvbaseproperties.hh>
+#include <opm/models/discretization/common/linearizationtype.hh>
+
+#include <cstddef>
+
+namespace Opm
+{
+
+/*!
+ * \ingroup FiniteVolumeDiscretizations
+ *
+ * \brief GPU-compatible stub mirroring the public interface of FvBaseElementContext.
+ *
+ * Uses the same TypeTag-based template parameter as FvBaseElementContext; all
+ * concrete types are extracted via GetPropType at compile time.
+ *
+ * \tparam TypeTag  The type tag from which Scalar, PrimaryVariables, etc. are derived.
+ */
+template <class TypeTag>
+class NullFvBaseElementContext
+{
+public:
+    using Scalar = GetPropType<TypeTag, Properties::Scalar>;
+    using PrimaryVariables = GetPropType<TypeTag, Properties::PrimaryVariables>;
+    using IntensiveQuantities = GetPropType<TypeTag, Properties::IntensiveQuantities>;
+    using ExtensiveQuantities = GetPropType<TypeTag, Properties::ExtensiveQuantities>;
+    using Problem = GetPropType<TypeTag, Properties::Problem>;
+    using Model = GetPropType<TypeTag, Properties::Model>;
+    using GradientCalculator = GetPropType<TypeTag, Properties::GradientCalculator>;
+
+    // -----------------------------------------------------------------------
+    // Construction / assignment
+    // -----------------------------------------------------------------------
+
+    OPM_HOST_DEVICE NullFvBaseElementContext() = default;
+    OPM_HOST_DEVICE ~NullFvBaseElementContext() = default;
+    OPM_HOST_DEVICE NullFvBaseElementContext(const NullFvBaseElementContext&) = default;
+    OPM_HOST_DEVICE NullFvBaseElementContext(NullFvBaseElementContext&&) noexcept = default;
+    OPM_HOST_DEVICE NullFvBaseElementContext& operator=(const NullFvBaseElementContext&) = default;
+    OPM_HOST_DEVICE NullFvBaseElementContext& operator=(NullFvBaseElementContext&&) noexcept
+        = default;
+
+    // -----------------------------------------------------------------------
+    // Stencil / element update stubs
+    // -----------------------------------------------------------------------
+
+    OPM_HOST_DEVICE void updateAll()
+    {
+    }
+    OPM_HOST_DEVICE void updateStencil()
+    {
+    }
+    OPM_HOST_DEVICE void updatePrimaryStencil()
+    {
+    }
+    OPM_HOST_DEVICE void updateStencilTopology()
+    {
+    }
+    OPM_HOST_DEVICE void updateAllIntensiveQuantities()
+    {
+    }
+    OPM_HOST_DEVICE void updateIntensiveQuantities(unsigned /*timeIdx*/)
+    {
+    }
+    OPM_HOST_DEVICE void updatePrimaryIntensiveQuantities(unsigned /*timeIdx*/)
+    {
+    }
+    OPM_HOST_DEVICE void updateIntensiveQuantities(const PrimaryVariables& /*priVars*/,
+                                                   unsigned /*dofIdx*/,
+                                                   unsigned /*timeIdx*/)
+    {
+    }
+    OPM_HOST_DEVICE void updateAllExtensiveQuantities()
+    {
+    }
+    OPM_HOST_DEVICE void updateExtensiveQuantities(unsigned /*timeIdx*/)
+    {
+    }
+
+    // -----------------------------------------------------------------------
+    // Focus DOF
+    // -----------------------------------------------------------------------
+
+    OPM_HOST_DEVICE void setFocusDofIndex(unsigned dofIdx)
+    {
+        focusDofIdx_ = static_cast<int>(dofIdx);
+    }
+    OPM_HOST_DEVICE unsigned focusDofIndex() const
+    {
+        return focusDofIdx_;
+    }
+
+    // -----------------------------------------------------------------------
+    // Linearization type
+    // -----------------------------------------------------------------------
+
+    OPM_HOST_DEVICE LinearizationType linearizationType() const
+    {
+        return LinearizationType {};
+    }
+
+    // -----------------------------------------------------------------------
+    // Problem / model accessors — return references to dummy stored objects
+    // -----------------------------------------------------------------------
+
+    OPM_HOST_DEVICE const Problem& problem() const
+    {
+        return problem_;
+    }
+    OPM_HOST_DEVICE const Model& model() const
+    {
+        return model_;
+    }
+
+    // -----------------------------------------------------------------------
+    // DOF / face counts
+    // -----------------------------------------------------------------------
+
+    OPM_HOST_DEVICE std::size_t numDof(unsigned /*timeIdx*/) const
+    {
+        return 0;
+    }
+    OPM_HOST_DEVICE std::size_t numPrimaryDof(unsigned /*timeIdx*/) const
+    {
+        return 0;
+    }
+    OPM_HOST_DEVICE std::size_t numInteriorFaces(unsigned /*timeIdx*/) const
+    {
+        return 0;
+    }
+    OPM_HOST_DEVICE std::size_t numBoundaryFaces(unsigned /*timeIdx*/) const
+    {
+        return 0;
+    }
+
+    // -----------------------------------------------------------------------
+    // Global space index / volume
+    // -----------------------------------------------------------------------
+
+    OPM_HOST_DEVICE unsigned globalSpaceIndex(unsigned /*dofIdx*/, unsigned /*timeIdx*/) const
+    {
+        return 0;
+    }
+
+    OPM_HOST_DEVICE Scalar dofVolume(unsigned /*dofIdx*/, unsigned /*timeIdx*/) const
+    {
+        return Scalar {0};
+    }
+
+    OPM_HOST_DEVICE Scalar dofTotalVolume(unsigned /*dofIdx*/, unsigned /*timeIdx*/) const
+    {
+        return Scalar {0};
+    }
+
+    // -----------------------------------------------------------------------
+    // Boundary
+    // -----------------------------------------------------------------------
+
+    OPM_HOST_DEVICE bool onBoundary() const
+    {
+        return false;
+    }
+
+    // -----------------------------------------------------------------------
+    // Intensive quantities
+    // -----------------------------------------------------------------------
+
+    OPM_HOST_DEVICE const IntensiveQuantities& intensiveQuantities(unsigned /*dofIdx*/,
+                                                                   unsigned /*timeIdx*/) const
+    {
+        return intensiveQuantitiesStashed_;
+    }
+
+    OPM_HOST_DEVICE IntensiveQuantities& intensiveQuantities(unsigned /*dofIdx*/,
+                                                             unsigned /*timeIdx*/)
+    {
+        return intensiveQuantitiesStashed_;
+    }
+
+    OPM_HOST_DEVICE const IntensiveQuantities* thermodynamicHint(unsigned /*dofIdx*/,
+                                                                 unsigned /*timeIdx*/) const
+    {
+        return nullptr;
+    }
+
+    // -----------------------------------------------------------------------
+    // Primary variables
+    // -----------------------------------------------------------------------
+
+    OPM_HOST_DEVICE const PrimaryVariables& primaryVars(unsigned /*dofIdx*/,
+                                                        unsigned /*timeIdx*/) const
+    {
+        return priVarsStashed_;
+    }
+
+    // -----------------------------------------------------------------------
+    // Stash / restore
+    // -----------------------------------------------------------------------
+
+    OPM_HOST_DEVICE bool haveStashedIntensiveQuantities() const
+    {
+        return stashedDofIdx_ != -1;
+    }
+
+    OPM_HOST_DEVICE int stashedDofIdx() const
+    {
+        return stashedDofIdx_;
+    }
+
+    OPM_HOST_DEVICE void stashIntensiveQuantities(unsigned dofIdx)
+    {
+        stashedDofIdx_ = static_cast<int>(dofIdx);
+    }
+
+    OPM_HOST_DEVICE void restoreIntensiveQuantities(unsigned /*dofIdx*/)
+    {
+        stashedDofIdx_ = -1;
+    }
+
+    // -----------------------------------------------------------------------
+    // Gradient calculator
+    // -----------------------------------------------------------------------
+
+    OPM_HOST_DEVICE const GradientCalculator& gradientCalculator() const
+    {
+        return gradientCalculator_;
+    }
+
+    // -----------------------------------------------------------------------
+    // Extensive quantities
+    // -----------------------------------------------------------------------
+
+    OPM_HOST_DEVICE const ExtensiveQuantities& extensiveQuantities(unsigned /*fluxIdx*/,
+                                                                   unsigned /*timeIdx*/) const
+    {
+        return extensiveQuantitiesStashed_;
+    }
+
+    // -----------------------------------------------------------------------
+    // Storage cache flag
+    // -----------------------------------------------------------------------
+
+    OPM_HOST_DEVICE bool enableStorageCache() const
+    {
+        return enableStorageCache_;
+    }
+    OPM_HOST_DEVICE void setEnableStorageCache(bool yesno)
+    {
+        enableStorageCache_ = yesno;
+    }
+
+private:
+    // Dummy stored objects returned by reference accessors.
+    // On device these are default-constructed and carry no meaningful data.
+    Problem problem_ {};
+    Model model_ {};
+    GradientCalculator gradientCalculator_ {};
+    IntensiveQuantities intensiveQuantitiesStashed_ {};
+    ExtensiveQuantities extensiveQuantitiesStashed_ {};
+    PrimaryVariables priVarsStashed_ {};
+
+    int stashedDofIdx_ {-1};
+    int focusDofIdx_ {-1};
+    bool enableStorageCache_ {false};
+};
+
+} // namespace Opm
+
+#endif // OPM_FV_BASE_ELEMENT_CONTEXT_GPU_HH