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multigrid.templates.h
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multigrid.templates.h
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// ---------------------------------------------------------------------
//
// Copyright (C) 1999 - 2020 by the deal.II authors
//
// This file is part of the deal.II library.
//
// The deal.II library is free software; you can use it, redistribute
// it, and/or modify it under the terms of the GNU Lesser General
// Public License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
// The full text of the license can be found in the file LICENSE.md at
// the top level directory of deal.II.
//
// ---------------------------------------------------------------------
#ifndef dealii_multigrid_templates_h
#define dealii_multigrid_templates_h
#include <deal.II/base/config.h>
#include <deal.II/base/logstream.h>
#include <deal.II/multigrid/multigrid.h>
#include <iostream>
DEAL_II_NAMESPACE_OPEN
template <typename VectorType>
void
Multigrid<VectorType>::reinit(const unsigned int min_level,
const unsigned int max_level)
{
Assert(min_level >= matrix->get_minlevel(),
ExcLowerRangeType<unsigned int>(min_level, matrix->get_minlevel()));
Assert(max_level <= matrix->get_maxlevel(),
ExcLowerRangeType<unsigned int>(matrix->get_maxlevel(), max_level));
Assert(min_level <= max_level,
ExcLowerRangeType<unsigned int>(max_level, min_level));
minlevel = min_level;
maxlevel = max_level;
// solution, t and defect2 are resized in cycle()
defect.resize(minlevel, maxlevel);
}
template <typename VectorType>
void
Multigrid<VectorType>::set_maxlevel(const unsigned int l)
{
reinit(minlevel, l);
}
template <typename VectorType>
void
Multigrid<VectorType>::set_minlevel(const unsigned int l, const bool relative)
{
const unsigned int new_minlevel = (relative) ? (maxlevel - l) : l;
reinit(new_minlevel, maxlevel);
}
template <typename VectorType>
void
Multigrid<VectorType>::set_cycle(typename Multigrid<VectorType>::Cycle c)
{
cycle_type = c;
}
template <typename VectorType>
void
Multigrid<VectorType>::set_edge_matrices(const MGMatrixBase<VectorType> &down,
const MGMatrixBase<VectorType> &up)
{
edge_out = &down;
edge_in = &up;
}
template <typename VectorType>
void
Multigrid<VectorType>::set_edge_flux_matrices(
const MGMatrixBase<VectorType> &down,
const MGMatrixBase<VectorType> &up)
{
edge_down = &down;
edge_up = &up;
}
template <typename VectorType>
void
Multigrid<VectorType>::level_v_step(const unsigned int level)
{
if (level == minlevel)
{
this->signals.coarse_solve(true, level);
(*coarse)(level, solution[level], defect[level]);
this->signals.coarse_solve(false, level);
return;
}
// smoothing of the residual
this->signals.pre_smoother_step(true, level);
pre_smooth->apply(level, solution[level], defect[level]);
this->signals.pre_smoother_step(false, level);
// compute residual on level, which includes the (CG) edge matrix
matrix->vmult(level, t[level], solution[level]);
if (edge_out != nullptr)
{
edge_out->vmult_add(level, t[level], solution[level]);
}
t[level].sadd(-1.0, 1.0, defect[level]);
// Get the defect on the next coarser level as part of the (DG) edge matrix
// and then the main part by the restriction of the transfer
if (edge_down != nullptr)
{
edge_down->vmult(level, t[level - 1], solution[level]);
defect[level - 1] -= t[level - 1];
}
this->signals.restriction(true, level);
transfer->restrict_and_add(level, defect[level - 1], t[level]);
this->signals.restriction(false, level);
// do recursion
level_v_step(level - 1);
// do coarse grid correction
this->signals.prolongation(true, level);
transfer->prolongate_and_add(level, solution[level], solution[level - 1]);
this->signals.prolongation(false, level);
// get in contribution from edge matrices to the defect
if (edge_in != nullptr)
{
edge_in->Tvmult(level, t[level], solution[level]);
defect[level] -= t[level];
}
if (edge_up != nullptr)
{
edge_up->Tvmult(level, t[level], solution[level - 1]);
defect[level] -= t[level];
}
// post-smoothing
this->signals.post_smoother_step(true, level);
post_smooth->smooth(level, solution[level], defect[level]);
this->signals.post_smoother_step(false, level);
}
template <typename VectorType>
void
Multigrid<VectorType>::level_step(const unsigned int level, Cycle cycle)
{
// Combine the defect from the initial copy_to_mg with the one that has come
// from the finer level by the transfer
defect2[level] += defect[level];
defect[level] = typename VectorType::value_type(0.);
if (level == minlevel)
{
this->signals.coarse_solve(true, level);
(*coarse)(level, solution[level], defect2[level]);
this->signals.coarse_solve(false, level);
return;
}
// smoothing of the residual
this->signals.pre_smoother_step(true, level);
pre_smooth->apply(level, solution[level], defect2[level]);
this->signals.pre_smoother_step(false, level);
// compute residual on level, which includes the (CG) edge matrix
matrix->vmult(level, t[level], solution[level]);
if (edge_out != nullptr)
edge_out->vmult_add(level, t[level], solution[level]);
t[level].sadd(-1.0, 1.0, defect2[level]);
// Get the defect on the next coarser level as part of the (DG) edge matrix
// and then the main part by the restriction of the transfer
if (edge_down != nullptr)
edge_down->vmult(level, defect2[level - 1], solution[level]);
else
defect2[level - 1] = typename VectorType::value_type(0.);
this->signals.restriction(true, level);
transfer->restrict_and_add(level, defect2[level - 1], t[level]);
this->signals.restriction(false, level);
// Every cycle starts with a recursion of its type.
level_step(level - 1, cycle);
// For W and F-cycle, repeat the process on the next coarser level except
// for the coarse solver which we invoke just once
if (level > minlevel + 1)
{
// while the W-cycle repeats itself, ...
if (cycle == w_cycle)
level_step(level - 1, cycle);
// ... the F-cycle does a V-cycle after an F-cycle, ...
else if (cycle == f_cycle)
level_step(level - 1, v_cycle);
// ... and the V-cycle does nothing.
}
// do coarse grid correction
this->signals.prolongation(true, level);
transfer->prolongate(level, t[level], solution[level - 1]);
this->signals.prolongation(false, level);
solution[level] += t[level];
// get in contribution from edge matrices to the defect
if (edge_in != nullptr)
{
edge_in->Tvmult(level, t[level], solution[level]);
defect2[level] -= t[level];
}
if (edge_up != nullptr)
{
edge_up->Tvmult(level, t[level], solution[level - 1]);
defect2[level] -= t[level];
}
// post-smoothing
this->signals.post_smoother_step(true, level);
post_smooth->smooth(level, solution[level], defect2[level]);
this->signals.post_smoother_step(false, level);
}
template <typename VectorType>
void
Multigrid<VectorType>::cycle()
{
// The defect vector has been initialized by copy_to_mg. Now adjust the
// other vectors. First out a check if we have the right number of levels.
if (solution.min_level() != minlevel || solution.max_level() != maxlevel)
{
solution.resize(minlevel, maxlevel);
t.resize(minlevel, maxlevel);
}
if (cycle_type != v_cycle &&
(defect2.min_level() != minlevel || defect2.max_level() != maxlevel))
defect2.resize(minlevel, maxlevel);
// And now we go and reinit the vectors on the levels.
for (unsigned int level = minlevel; level <= maxlevel; ++level)
{
// the vectors for level>minlevel will be overwritten by the apply()
// method of the smoother -> do not force them to be zeroed out here
solution[level].reinit(defect[level], level > minlevel);
t[level].reinit(defect[level], level > minlevel);
if (cycle_type != v_cycle)
defect2[level].reinit(defect[level]);
}
if (cycle_type == v_cycle)
level_v_step(maxlevel);
else
level_step(maxlevel, cycle_type);
}
template <typename VectorType>
void
Multigrid<VectorType>::vcycle()
{
// The defect vector has been initialized by copy_to_mg. Now adjust the
// other vectors. First out a check if we have the right number of levels.
if (solution.min_level() != minlevel || solution.max_level() != maxlevel)
{
solution.resize(minlevel, maxlevel);
t.resize(minlevel, maxlevel);
}
// And now we go and reinit the vectors on the levels.
for (unsigned int level = minlevel; level <= maxlevel; ++level)
{
solution[level].reinit(defect[level], level > minlevel);
t[level].reinit(defect[level], level > minlevel);
}
level_v_step(maxlevel);
}
template <typename VectorType>
boost::signals2::connection
Multigrid<VectorType>::connect_coarse_solve(
const std::function<void(const bool, const unsigned int)> &slot)
{
return this->signals.coarse_solve.connect(slot);
}
template <typename VectorType>
boost::signals2::connection
Multigrid<VectorType>::connect_restriction(
const std::function<void(const bool, const unsigned int)> &slot)
{
return this->signals.restriction.connect(slot);
}
template <typename VectorType>
boost::signals2::connection
Multigrid<VectorType>::connect_prolongation(
const std::function<void(const bool, const unsigned int)> &slot)
{
return this->signals.prolongation.connect(slot);
}
template <typename VectorType>
boost::signals2::connection
Multigrid<VectorType>::connect_pre_smoother_step(
const std::function<void(const bool, const unsigned int)> &slot)
{
return this->signals.pre_smoother_step.connect(slot);
}
template <typename VectorType>
boost::signals2::connection
Multigrid<VectorType>::connect_post_smoother_step(
const std::function<void(const bool, const unsigned int)> &slot)
{
return this->signals.post_smoother_step.connect(slot);
}
DEAL_II_NAMESPACE_CLOSE
#endif