//----------------------------------------------------------------------------
fei::SharedPtr<fei::LinearSystem>
fei::LinearSystem::Factory::createLinearSystem(fei::SharedPtr<fei::MatrixGraph>& matrixGraph)
{
fei::SharedPtr<fei::LinearSystem>
linsys(new snl_fei::LinearSystem_General(matrixGraph));
return(linsys);
}
int main(int argc, char* argv[])
{
// load the mesh file
Mesh mesh;
mesh.load("domain.mesh");
// a-priori mesh refinements
mesh.refine_all_elements();
mesh.refine_towards_boundary(5, 4, false);
mesh.refine_towards_boundary(1, 4);
mesh.refine_towards_boundary(3, 4);
// initialize the shapeset and the cache
H1ShapesetBeuchler shapeset;
PrecalcShapeset pss(&shapeset);
// spaces for velocities and pressure
H1Space xvel(&mesh, &shapeset);
H1Space yvel(&mesh, &shapeset);
H1Space press(&mesh, &shapeset);
// initialize boundary conditions
xvel.set_bc_types(xvel_bc_type);
xvel.set_bc_values(xvel_bc_value);
yvel.set_bc_types(yvel_bc_type);
press.set_bc_types(press_bc_type);
// set velocity and pressure polynomial degrees
xvel.set_uniform_order(P_INIT_VEL);
yvel.set_uniform_order(P_INIT_VEL);
press.set_uniform_order(P_INIT_PRESSURE);
// assign degrees of freedom
int ndofs = 0;
ndofs += xvel.assign_dofs(ndofs);
ndofs += yvel.assign_dofs(ndofs);
ndofs += press.assign_dofs(ndofs);
// velocities from the previous time step and for the Newton's iteration
Solution xprev, yprev, xiter, yiter, piter;
xprev.set_zero(&mesh);
yprev.set_zero(&mesh);
xiter.set_zero(&mesh);
yiter.set_zero(&mesh);
piter.set_zero(&mesh);
// set up weak formulation
WeakForm wf(3);
if (NEWTON_ON) {
wf.add_biform(0, 0, callback(bilinear_form_sym_0_0_1_1), SYM);
wf.add_biform(0, 0, callback(newton_bilinear_form_unsym_0_0), UNSYM, ANY, 2, &xprev, &yprev);
wf.add_biform(0, 1, callback(newton_bilinear_form_unsym_0_1), UNSYM, ANY, 2, &xprev, &yprev);
wf.add_biform(0, 2, callback(bilinear_form_unsym_0_2), ANTISYM);
wf.add_biform(1, 0, callback(newton_bilinear_form_unsym_1_0), UNSYM, ANY, 2, &xprev, &yprev);
wf.add_biform(1, 1, callback(bilinear_form_sym_0_0_1_1), SYM);
wf.add_biform(1, 1, callback(newton_bilinear_form_unsym_1_1), UNSYM, ANY, 2, &xprev, &yprev);
wf.add_biform(1, 2, callback(bilinear_form_unsym_1_2), ANTISYM);
wf.add_liform(0, callback(newton_F_0), ANY, 5, &xprev, &yprev, &xiter, &yiter, &piter);
wf.add_liform(1, callback(newton_F_1), ANY, 5, &xprev, &yprev, &xiter, &yiter, &piter);
wf.add_liform(2, callback(newton_F_2), ANY, 2, &xiter, &yiter);
}
else {
wf.add_biform(0, 0, callback(bilinear_form_sym_0_0_1_1), SYM);
wf.add_biform(0, 0, callback(simple_bilinear_form_unsym_0_0_1_1), UNSYM, ANY, 2, &xprev, &yprev);
wf.add_biform(1, 1, callback(bilinear_form_sym_0_0_1_1), SYM);
wf.add_biform(1, 1, callback(simple_bilinear_form_unsym_0_0_1_1), UNSYM, ANY, 2, &xprev, &yprev);
wf.add_biform(0, 2, callback(bilinear_form_unsym_0_2), ANTISYM);
wf.add_biform(1, 2, callback(bilinear_form_unsym_1_2), ANTISYM);
wf.add_liform(0, callback(simple_linear_form), ANY, 1, &xprev);
wf.add_liform(1, callback(simple_linear_form), ANY, 1, &yprev);
}
// visualization
VectorView vview("velocity [m/s]", 0, 0, 1500, 470);
ScalarView pview("pressure [Pa]", 0, 530, 1500, 470);
vview.set_min_max_range(0, 1.6);
vview.fix_scale_width(80);
//pview.set_min_max_range(-0.9, 1.0);
pview.fix_scale_width(80);
pview.show_mesh(true);
// matrix solver
UmfpackSolver umfpack;
// linear system
LinSystem linsys(&wf, &umfpack);
// nonlinear system
NonlinSystem nonsys(&wf, &umfpack);
if (NEWTON_ON) {
// set up the nonlinear system
nonsys.set_spaces(3, &xvel, &yvel, &press);
nonsys.set_pss(1, &pss);
}
else {
// set up the linear system
linsys.set_spaces(3, &xvel, &yvel, &press);
linsys.set_pss(1, &pss);
}
// main loop
char title[100];
int num_time_steps = FINAL_TIME / TAU;
for (int i = 1; i <= num_time_steps; i++)
{
TIME += TAU;
info("\n---- Time step %d, time = %g -----------------------------------", i, TIME);
// this is needed to update the time-dependent boundary conditions
ndofs = 0;
ndofs += xvel.assign_dofs(ndofs);
ndofs += yvel.assign_dofs(ndofs);
ndofs += press.assign_dofs(ndofs);
if (NEWTON_ON) {
Solution xsln, ysln, psln;
int it = 1;
double res_l2_norm;
do
{
info("\n---- Time step %d, Newton iter %d ---------------------------------\n", i, it++);
// assemble and solve
nonsys.assemble();
nonsys.solve(3, &xsln, &ysln, &psln);
res_l2_norm = nonsys.get_residuum_l2_norm();
info("Residuum L2 norm: %g\n", res_l2_norm);
// want to see Newtons iterations
//sprintf(title, "Time level %d, Newton iteration %d", i, it-1);
//vview.set_title(title);
//vview.show(&xsln, &ysln, EPS_LOW);
//pview.show(&psln);
//pview.wait_for_keypress();
xiter = xsln;
yiter = ysln;
piter = psln;
}
while (res_l2_norm > NEWTON_TOL);
// visualization at the end of the time step
sprintf(title, "Velocity, time %g", TIME);
vview.set_title(title);
vview.show(&xprev, &yprev, EPS_LOW);
sprintf(title, "Pressure, time %g", TIME);
pview.set_title(title);
pview.show(&piter);
// copying result of the Newton's iteration into xprev, yprev
xprev.copy(&xiter);
yprev.copy(&yiter);
}
else {
// assemble and solve
Solution xsln, ysln, psln;
linsys.assemble();
linsys.solve(3, &xsln, &ysln, &psln);
// visualization
sprintf(title, "Velocity, time %g", TIME);
vview.set_title(title);
vview.show(&xsln, &ysln, EPS_LOW);
sprintf(title, "Pressure, time %g", TIME);
pview.set_title(title);
pview.show(&psln);
//pview.wait_for_keypress();
xprev = xsln;
yprev = ysln;
}
// uncomment one of the following lines to generate a series of video frames
//vview.save_numbered_screenshot("velocity%03d.bmp", i, true);
//pview.save_numbered_screenshot("pressure%03d.bmp", i, true);
// the frames can then be converted to a video file with the command
// mencoder "mf://velocity*.bmp" -mf fps=20 -o velocity.avi -ovc lavc -lavcopts vcodec=mpeg4
}
// wait for keyboard or mouse input
View::wait("Waiting for keyboard or mouse input.");
return 0;
}
