Hello,
I am not sure if this post fits the ffc-dev list, but I would be
grateful if you send me some suggestions.
I want to use dolfin/ffc for solving image processing problems. I start
from Nonlinear Poisson demo. After linearization of the governing weak
equation, the input form file is as follows:
element = FiniteElement("Lagrange", "triangle", 1)
v = TestFunction(element)
U = TrialFunction(element)
U0= Function(element)
f = Function(element)
a = -v*(U0-f)*dot(grad(U0),grad(U))*dx
L = v*(0.01+dot(grad(U0),grad(U0)))*(U0-f)*dx +
0.01*dot(grad(v),grad(U0))*dx
The "f" represents the input image (at moment only a simple analytic
function is used). The form file compiles well, but when I try to make
the main program, there are some errors on NonlinearPoissonBilinearForm
matching.
The complete log of make:
[rfarahi@alteran cpp]$ make
`pkg-config --variable=compiler dolfin` `pkg-config --cflags dolfin` -c
main.cpp
main.cpp: In function `int main(int, char**)':
main.cpp:89: error: no matching function for call to
`NonlinearPoissonBilinearForm::NonlinearPoissonBilinearForm(dolfin::Function&)'
NonlinearPoisson.h:4672: note: candidates are:
NonlinearPoissonBilinearForm::NonlinearPoissonBilinearForm(const
NonlinearPoissonBilinearForm&)
NonlinearPoisson.h:4675: note:
NonlinearPoissonBilinearForm::NonlinearPoissonBilinearForm(dolfin::Function&,
dolfin::Function&)
mpic++: No such file or directory
make: *** [main.o] Error 1
If I change the script and delete the "f" term from the bilinear form,
the error doesn't show up:
element = FiniteElement("Lagrange", "triangle", 1)
v = TestFunction(element)
U = TrialFunction(element)
U0= Function(element)
f = Function(element)
a = -v*(U0)*dot(grad(U0),grad(U))*dx
L = v*(0.01+dot(grad(U0),grad(U0)))*(U0-f)*dx +
0.01*dot(grad(v),grad(U0))*dx
The input cpp file:
// Copyright (C) 2006-2007 Garth N. Wells.
// Licensed under the GNU LGPL Version 2.1.
//
// Modified by Anders Logg, 2005
//
// First added: 2005
// Last changed: 2007-08-20
//
#include <dolfin.h>
#include "NonlinearPoisson.h"
using namespace dolfin;
// Right-hand side
class Source : public Function
{
public:
Source(Mesh& mesh) : Function(mesh) {}
real eval(const real* x) const
{
return x[0];
}
};
// Dirichlet boundary condition
class DirichletBoundaryCondition : public Function, public TimeDependent
{
public:
DirichletBoundaryCondition(Mesh& mesh, real& t) : Function(mesh),
TimeDependent(t) {}
real eval(const real* x) const
{
return 1.0;
}
};
// Sub domain for Dirichlet boundary condition
class DirichletBoundary : public SubDomain
{
bool inside(const real* x, bool on_boundary) const
{
return std::abs(x[0] - 1.0) < DOLFIN_EPS && on_boundary;
}
};
int main(int argc, char* argv[])
{
dolfin_init(argc, argv);
// Set up problem
UnitSquare mesh(16, 16);
// Pseudo time
real t = 0.0;
// Create source function
Source f(mesh);
// Dirichlet boundary conditions
DirichletBoundary dirichlet_boundary;
DirichletBoundaryCondition g(mesh, t);
DirichletBC bc(g, mesh, dirichlet_boundary);
// Solution function
Function u;
// Create forms and nonlinear PDE
NonlinearPoissonBilinearForm a(u);
NonlinearPoissonLinearForm L(u, f);
NonlinearPDE pde(a, L, mesh, bc);
// Solve nonlinear problem in a series of steps
real dt = 1.0; real T = 3.0;
// pde.dolfin_set("Newton relative tolerance", 1e-6);
// pde.dolfin_set("Newton convergence criterion", "incremental");
// Solve
pde.solve(u, t, T, dt);
// Plot solution
plot(u);
// Save function to file
File file("nonlinear_poisson.pvd");
file << u;
return 0;
}
Any suggestion?
Bests,
Reza
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