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// -*- mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
// vi: set et ts=4 sw=4 sts=4:
/*
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
* \copydoc PffGridVector
*/
#ifndef EWOMS_PFF_GRID_VECTOR_HH
#define EWOMS_PFF_GRID_VECTOR_HH
#include <opm/models/utils/prefetch.hh>
#include <dune/grid/common/mcmgmapper.hh>
#include <dune/common/version.hh>
#include <vector>
namespace Opm {
/*!
* \brief A random-access container which stores data attached to a grid's degrees of
* freedom in a prefetch friendly manner.
*
* This container often reduces the number of cache faults considerably, thus improving
* performance. On the flipside data cannot be written to on an individual basis and it
* requires significantly more memory than a plain array. PffVector stands for "PreFetch
* Friendly Grid Vector".
*/
template <class GridView, class Stencil, class Data, class DofMapper>
class PffGridVector
{
using Element = typename GridView::template Codim<0>::Entity;
using ElementMapper = Dune::MultipleCodimMultipleGeomTypeMapper<GridView>;
public:
PffGridVector(const GridView& gridView, const DofMapper& dofMapper)
: gridView_(gridView)
, elementMapper_(gridView_, Dune::mcmgElementLayout())
, dofMapper_(dofMapper)
{ }
template <class DistFn>
void update(const DistFn& distFn)
{
unsigned numElements = gridView_.size(/*codim=*/0);
unsigned numLocalDofs = computeNumLocalDofs_();
elemData_.resize(numElements);
data_.resize(numLocalDofs);
// update the pointers for the element data: for this, we need to loop over the
// whole grid and update a stencil for each element
Data *curElemDataPtr = &data_[0];
Stencil stencil(gridView_, dofMapper_);
for (const auto& elem : elements(gridView_)) {
// set the DOF data pointer for the current element
unsigned elemIdx = elementMapper_.index(elem);
elemData_[elemIdx] = curElemDataPtr;
stencil.update(elem);
unsigned numDof = stencil.numDof();
for (unsigned localDofIdx = 0; localDofIdx < numDof; ++ localDofIdx)
distFn(curElemDataPtr[localDofIdx], stencil, localDofIdx);
// update the element data pointer to make it point to the beginning of the
// data for DOFs of the next element
curElemDataPtr += numDof;
}
}
void prefetch(const Element& elem) const
{
unsigned elemIdx = elementMapper_.index(elem);
// we use 0 as the temporal locality, because it is reasonable to assume that an
// entry will only be accessed once.
::Opm::prefetch</*temporalLocality=*/0>(elemData_[elemIdx]);
}
const Data& get(const Element& elem, unsigned localDofIdx) const
{
unsigned elemIdx = elementMapper_.index(elem);
return elemData_[elemIdx][localDofIdx];
}
private:
unsigned computeNumLocalDofs_() const
{
unsigned result = 0;
// loop over the whole grid and sum up the number of local DOFs of all Stencils
Stencil stencil(gridView_, dofMapper_);
for (const auto& elem : elements(gridView_)) {
stencil.update(elem);
result += stencil.numDof();
}
return result;
}
GridView gridView_;
ElementMapper elementMapper_;
const DofMapper& dofMapper_;
std::vector<Data> data_;
std::vector<Data*> elemData_;
};
} // namespace Opm
#endif
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