Dear Wolfgang,
thank you for your swift reply! I am using Version 9.4.0, compiled from
source just last week - I checked the github as well but it seems like
there is no newer version available.
I've tried to make a minimal working example and will attach it. The code
now doesn't do anything expect for defining the class Delta_of_x that
inherits from Function, and its value() function, and then tries to
project said function into an FE vector of nodal values that I want to save
to disk. The current profile Delta(x) is in real, so I tried to change all
datatypes to double but it didn't seem to help with the linking error (and
I would want complex values for my actual problem, eventually). I'm
starting to suspect that I'm doing something wrong with the project
function, but I don't understand what if so. Either way, please find the
.cc and a makefile attached. I started from one of the examples at some
point so there is probably some unnecessary includes and similar things
left that I forgot to remove, I hope the problem is still understandable.
Thank you for your help, best
Kev
On Thursday, October 27, 2022 at 12:01:28 AM UTC+2 Wolfgang Bangerth wrote:
> On 10/26/22 12:57, Kev Se wrote:
> >
> > I've recently swapped from another FEM package to deal.ii and love it so
> > far. I recently managed so far to get a correct solution out for my
> > complex-valued, nonlinear PDE. So that's good! What I am a bit confused
> > about is the following: How do I use the VectorTools::project() type of
> > function for a general, complex-valued function?
> >
>
> Kev: It looks like the function you're trying to call is implemented but
> not instantiated for complex arguments. This wouldn't be the first
> function for which this is the case. Can you come up with as small a
> testcase that illustrates the problem? The program doesn't have to do
> anything useful other than showing that you can't link.
>
> Separately, though: Have you made sure that you are working with the
> latest version of deal.II? This may (or may not) be a bug that is
> already fixed.
>
> Best
> W.
>
> --
> ------------------------------------------------------------------------
> Wolfgang Bangerth email: [email protected]
> www: http://www.math.colostate.edu/~bangerth/
>
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# Set the name of the project and target:
SET(TARGET "mwe")
# Declare all source files the target consists of. Here, this is only
# the one step-X.cc file, but as you expand your project you may wish
# to add other source files as well. If your project becomes much larger,
# you may want to either replace the following statement by something like
# FILE(GLOB_RECURSE TARGET_SRC "source/*.cc")
# FILE(GLOB_RECURSE TARGET_INC "include/*.h")
# SET(TARGET_SRC ${TARGET_SRC} ${TARGET_INC})
# or switch altogether to the large project CMakeLists.txt file discussed
# in the "CMake in user projects" page accessible from the "User info"
# page of the documentation.
SET(TARGET_SRC
${TARGET}.cc
)
# Usually, you will not need to modify anything beyond this point...
CMAKE_MINIMUM_REQUIRED(VERSION 3.3.0)
FIND_PACKAGE(deal.II 9.4.0 QUIET
HINTS ${deal.II_DIR} ${DEAL_II_DIR} ../ ../../ $ENV{DEAL_II_DIR}
)
IF(NOT ${deal.II_FOUND})
MESSAGE(FATAL_ERROR "\n"
"*** Could not locate a (sufficiently recent) version of deal.II. ***\n\n"
"You may want to either pass a flag -DDEAL_II_DIR=/path/to/deal.II to
cmake\n"
"or set an environment variable \"DEAL_II_DIR\" that contains this path."
)
ENDIF()
DEAL_II_INITIALIZE_CACHED_VARIABLES()
PROJECT(${TARGET})
DEAL_II_INVOKE_AUTOPILOT()
#include <deal.II/base/quadrature_lib.h>
#include <deal.II/base/function.h>
#include <deal.II/lac/vector.h>
#include <deal.II/lac/dynamic_sparsity_pattern.h>
#include <deal.II/lac/sparse_matrix.h>
#include <deal.II/lac/solver_gmres.h>
#include <deal.II/lac/precondition.h>
#include <deal.II/grid/tria.h>
#include <deal.II/grid/grid_generator.h>
#include <deal.II/grid/grid_out.h>
#include <deal.II/grid/grid_refinement.h>
#include <deal.II/lac/sparse_direct.h>
#include <deal.II/fe/mapping_q1.h>
#include <deal.II/dofs/dof_handler.h>
#include <deal.II/dofs/dof_tools.h>
#include <deal.II/numerics/vector_tools.h>
#include <deal.II/numerics/matrix_tools.h>
#include <deal.II/numerics/data_out.h>
#include <deal.II/fe/fe_values.h>
#include <deal.II/fe/fe_dgq.h>
#include <deal.II/fe/fe_interface_values.h>
#include <deal.II/numerics/derivative_approximation.h>
#include <deal.II/meshworker/mesh_loop.h>
#include <iostream>
#include <fstream>
typedef std::complex<double> dcomp;
const dcomp J = {0, 1};
const int degree=1;
namespace mwe
{
using namespace dealii;
template <int dim>
class Delta_of_x : public Function<dim, dcomp>
{
public:
virtual dcomp value(const Point<dim> &p,
const unsigned int component = 0) const override;
};
template <int dim>
dcomp Delta_of_x<dim>::value(const Point<dim> &p,
const unsigned int component) const
{
dcomp returner = 0.0;
if (component == 0){
returner= tanh( (2.0*M_PI*p[0] - 7.5)/2.0 );
}
return returner;
}
template <int dim>
class AdvectionProblem
{
public:
AdvectionProblem();
void run();
private:
void setup_system(const bool initial_step);
void output_results(const unsigned int cycle) const;
Triangulation<dim> triangulation;
const MappingQ1<dim> mapping;
const FE_DGQ<dim> fe;
DoFHandler<dim> dof_handler;
const QGauss<dim> quadrature;
const QGauss<dim - 1> quadrature_face;
SparsityPattern sparsity_pattern;
Vector<dcomp> Delta_profile;
};
template <int dim>
AdvectionProblem<dim>::AdvectionProblem()
: mapping()
, fe(degree)
, dof_handler(triangulation)
, quadrature(fe.tensor_degree() + 2)
, quadrature_face(fe.tensor_degree() + 2)
{}
template <int dim>
void AdvectionProblem<dim>::setup_system(const bool initial_step)
{
if (initial_step){
dof_handler.distribute_dofs(fe);
Delta_profile.reinit(dof_handler.n_dofs());
}
DynamicSparsityPattern dsp(dof_handler.n_dofs());
DoFTools::make_flux_sparsity_pattern(dof_handler, dsp);
sparsity_pattern.copy_from(dsp);
}
template <int dim>
void AdvectionProblem<dim>::output_results(const unsigned int cycle) const
{
const std::string filename = "solution-" + std::to_string(cycle) + ".vtk";
std::cout << " Writing solution to <" << filename << '>' << std::endl;
std::ofstream output(filename);
Delta_of_x<dim> DeltaX;
AffineConstraints<dcomp> constraints;
constraints.close();
/************************************* PROBLEMATIC LINE BELOW ****************************/
VectorTools::project(dof_handler, constraints, QGauss<dim>(degree + 2), DeltaX, Delta_profile);
/************************************* PROBLEMATIC LINE ABOVE ****************************/
DataOut<dim> data_out;
data_out.build_patches(mapping);
data_out.attach_dof_handler(dof_handler);
data_out.add_data_vector(Delta_profile, "Delta", DataOut<dim>::type_dof_data);
data_out.write_vtk(output);
}
template <int dim>
void AdvectionProblem<dim>::run()
{
GridGenerator::hyper_cube(triangulation, 0.0, 50/(2.0*M_PI));
triangulation.refine_global(3);
setup_system(true);
output_results(0);
}
} // namespace mwe
int main()
{
try
{
mwe::AdvectionProblem<1> dgmethod;
dgmethod.run();
}
catch (std::exception &exc)
{
std::cerr << std::endl
<< std::endl
<< "----------------------------------------------------"
<< std::endl;
std::cerr << "Exception on processing: " << std::endl
<< exc.what() << std::endl
<< "Aborting!" << std::endl
<< "----------------------------------------------------"
<< std::endl;
return 1;
}
catch (...)
{
std::cerr << std::endl
<< std::endl
<< "----------------------------------------------------"
<< std::endl;
std::cerr << "Unknown exception!" << std::endl
<< "Aborting!" << std::endl
<< "----------------------------------------------------"
<< std::endl;
return 1;
}
return 0;
}
