bool RungeKutta::rk_time_step(double current_time, double time_step, Hermes::vector<Solution*> slns_time_prev,
Hermes::vector<Solution*> slns_time_new, bool jacobian_changed,
bool verbose, double newton_tol, int newton_max_iter,double newton_damping_coeff,
double newton_max_allowed_residual_norm)
{
return rk_time_step(current_time, time_step, slns_time_prev, slns_time_new,
Hermes::vector<Solution*>(), jacobian_changed, verbose, newton_tol, newton_max_iter,
newton_damping_coeff, newton_max_allowed_residual_norm);
}
// This is the same as the rk_time_step() function above but it does not have the err_vec vector.
bool rk_time_step(double current_time, double time_step, ButcherTable* const bt,
scalar* coeff_vec, DiscreteProblem* dp, MatrixSolverType matrix_solver,
bool verbose, bool is_linear, double newton_tol, int newton_max_iter,
double newton_damping_coeff, double newton_max_allowed_residual_norm)
{
return rk_time_step(current_time, time_step, bt,
coeff_vec, NULL, dp, matrix_solver,
verbose, is_linear, newton_tol, newton_max_iter,
newton_damping_coeff, newton_max_allowed_residual_norm);
}
bool RungeKutta::rk_time_step(double current_time, double time_step, Solution* sln_time_prev, Solution* sln_time_new,
Solution* error_fn, bool jacobian_changed, bool verbose, double newton_tol, int newton_max_iter,
double newton_damping_coeff, double newton_max_allowed_residual_norm)
{
Hermes::vector<Solution*> slns_time_prev = Hermes::vector<Solution*>();
slns_time_prev.push_back(sln_time_prev);
Hermes::vector<Solution*> slns_time_new = Hermes::vector<Solution*>();
slns_time_new.push_back(sln_time_new);
Hermes::vector<Solution*> error_fns = Hermes::vector<Solution*>();
error_fns.push_back(error_fn);
return rk_time_step(current_time, time_step, slns_time_prev, slns_time_new,
error_fns, jacobian_changed, verbose, newton_tol, newton_max_iter,
newton_damping_coeff, newton_max_allowed_residual_norm);
}
int main(int argc, char* argv[])
{
// Choose a Butcher's table or define your own.
ButcherTable bt(butcher_table_type);
if (bt.is_explicit()) info("Using a %d-stage explicit R-K method.", bt.get_size());
if (bt.is_diagonally_implicit()) info("Using a %d-stage diagonally implicit R-K method.", bt.get_size());
if (bt.is_fully_implicit()) info("Using a %d-stage fully implicit R-K method.", bt.get_size());
// Load the mesh.
Mesh mesh;
H2DReader mloader;
mloader.load("cathedral.mesh", &mesh);
// Perform initial mesh refinements.
for(int i = 0; i < INIT_REF_NUM; i++) mesh.refine_all_elements();
mesh.refine_towards_boundary(BDY_AIR, INIT_REF_NUM_BDY);
mesh.refine_towards_boundary(BDY_GROUND, INIT_REF_NUM_BDY);
// Enter boundary markers.
BCTypes bc_types;
bc_types.add_bc_dirichlet(Hermes::vector<std::string>(BDY_GROUND));
bc_types.add_bc_newton(BDY_AIR);
// Enter Dirichlet boundary values.
BCValues bc_values;
bc_values.add_const(BDY_GROUND, TEMP_INIT);
// Initialize an H1 space with default shapeset.
H1Space space(&mesh, &bc_types, &bc_values, P_INIT);
int ndof = Space::get_num_dofs(&space);
info("ndof = %d.", ndof);
// Previous time level solution (initialized by the external temperature).
Solution u_prev_time(&mesh, TEMP_INIT);
// Initialize weak formulation.
WeakForm wf;
wf.add_matrix_form(callback(stac_jacobian_vol));
wf.add_vector_form(callback(stac_residual_vol));
wf.add_matrix_form_surf(callback(stac_jacobian_surf), BDY_AIR);
wf.add_vector_form_surf(callback(stac_residual_surf), BDY_AIR);
// Project the initial condition on the FE space to obtain initial solution coefficient vector.
info("Projecting initial condition to translate initial condition into a vector.");
scalar* coeff_vec = new scalar[ndof];
OGProjection::project_global(&space, &u_prev_time, coeff_vec, matrix_solver);
// Initialize the FE problem.
bool is_linear = false;
DiscreteProblem dp(&wf, &space, is_linear);
// Initialize views.
ScalarView Tview("Temperature", new WinGeom(0, 0, 450, 600));
Tview.set_min_max_range(0,20);
Tview.fix_scale_width(30);
// Time stepping loop:
double current_time = 0.0; int ts = 1;
do
{
// Perform one Runge-Kutta time step according to the selected Butcher's table.
info("Runge-Kutta time step (t = %g, tau = %g, stages: %d).",
current_time, time_step, bt.get_size());
bool verbose = true;
bool is_linear = true;
if (!rk_time_step(current_time, time_step, &bt, coeff_vec, &dp, matrix_solver,
verbose, is_linear)) {
error("Runge-Kutta time step failed, try to decrease time step size.");
}
// Convert coeff_vec into a new time level solution.
Solution::vector_to_solution(coeff_vec, &space, &u_prev_time);
// Update time.
current_time += time_step;
// Show the new time level solution.
char title[100];
sprintf(title, "Time %3.2f, exterior temperature %3.5f", current_time, temp_ext(current_time));
Tview.set_title(title);
Tview.show(&u_prev_time);
// Increase counter of time steps.
ts++;
}
while (current_time < T_FINAL);
// Cleanup.
delete [] coeff_vec;
// Wait for the view to be closed.
View::wait();
return 0;
}
int main(int argc, char* argv[])
{
// Choose a Butcher's table or define your own.
ButcherTable bt(butcher_table_type);
// Load the mesh.
Mesh mesh;
H2DReader mloader;
mloader.load("cathedral.mesh", &mesh);
// Perform initial mesh refinements.
for(int i = 0; i < INIT_REF_NUM; i++) mesh.refine_all_elements();
mesh.refine_towards_boundary(BDY_AIR, INIT_REF_NUM_BDY);
mesh.refine_towards_boundary(BDY_GROUND, INIT_REF_NUM_BDY);
// Enter boundary markers.
BCTypes bc_types;
bc_types.add_bc_dirichlet(Hermes::vector<std::string>(BDY_GROUND));
bc_types.add_bc_newton(BDY_AIR);
// Enter Dirichlet boundary values.
BCValues bc_values;
bc_values.add_const(BDY_GROUND, TEMP_INIT);
// Initialize an H1 space with default shapeset.
H1Space space(&mesh, &bc_types, &bc_values, P_INIT);
int ndof = Space::get_num_dofs(&space);
info("ndof = %d.", ndof);
// Previous time level solution (initialized by the external temperature).
Solution u_prev_time(&mesh, TEMP_INIT);
// Initialize weak formulation.
WeakForm wf;
wf.add_matrix_form(callback(stac_jacobian));
wf.add_vector_form(callback(stac_residual));
wf.add_matrix_form_surf(callback(bilinear_form_surf), BDY_AIR);
wf.add_vector_form_surf(callback(linear_form_surf), BDY_AIR);
// Project the initial condition on the FE space to obtain initial solution coefficient vector.
info("Projecting initial condition to translate initial condition into a vector.");
scalar* coeff_vec = new scalar[ndof];
OGProjection::project_global(&space, &u_prev_time, coeff_vec, matrix_solver);
// Initialize the FE problem.
bool is_linear = false;
DiscreteProblem dp(&wf, &space, is_linear);
// Time stepping loop:
double current_time = 0.0; int ts = 1;
do
{
// Perform one Runge-Kutta time step according to the selected Butcher's table.
info("Runge-Kutta time step (t = %g, tau = %g, stages: %d).",
current_time, time_step, bt.get_size());
bool verbose = true;
if (!rk_time_step(current_time, time_step, &bt, coeff_vec, &dp, matrix_solver,
verbose, NEWTON_TOL, NEWTON_MAX_ITER)) {
error("Runge-Kutta time step failed, try to decrease time step size.");
}
// Convert coeff_vec into a new time level solution.
Solution::vector_to_solution(coeff_vec, &space, &u_prev_time);
// Update time.
current_time += time_step;
// Increase counter of time steps.
ts++;
}
while (current_time < time_step*5);
double sum = 0;
for (int i = 0; i < ndof; i++)
sum += coeff_vec[i];
printf("sum = %g\n", sum);
int success = 1;
if (fabs(sum - 3617.55) > 1e-1) success = 0;
// Cleanup.
delete [] coeff_vec;
if (success == 1) {
printf("Success!\n");
return ERR_SUCCESS;
}
else {
printf("Failure!\n");
return ERR_FAILURE;
}
}
int main(int argc, char* argv[])
{
// Choose a Butcher's table or define your own.
ButcherTable bt(butcher_table_type);
if (bt.is_explicit()) info("Using a %d-stage explicit R-K method.", bt.get_size());
if (bt.is_diagonally_implicit()) info("Using a %d-stage diagonally implicit R-K method.", bt.get_size());
if (bt.is_fully_implicit()) info("Using a %d-stage fully implicit R-K method.", bt.get_size());
// Load the mesh.
Mesh mesh;
H2DReader mloader;
mloader.load("cathedral.mesh", &mesh);
// Perform initial mesh refinements.
for(int i = 0; i < INIT_REF_NUM; i++) mesh.refine_all_elements();
mesh.refine_towards_boundary(BDY_AIR, INIT_REF_NUM_BDY);
mesh.refine_towards_boundary(BDY_GROUND, INIT_REF_NUM_BDY);
// Enter boundary markers.
BCTypes bc_types;
bc_types.add_bc_dirichlet(Hermes::vector<std::string>(BDY_GROUND));
bc_types.add_bc_newton(BDY_AIR);
// Enter Dirichlet boundary values.
BCValues bc_values;
bc_values.add_const(BDY_GROUND, TEMP_INIT);
// Initialize an H1 space with default shapeset.
H1Space space(&mesh, &bc_types, &bc_values, P_INIT);
int ndof = Space::get_num_dofs(&space);
info("ndof = %d.", ndof);
// Previous and next time level solutions.
Solution* sln_time_prev = new Solution(&mesh, TEMP_INIT);
Solution* sln_time_new = new Solution(&mesh);
// Initialize weak formulation.
WeakForm wf;
wf.add_matrix_form(callback(stac_jacobian_vol));
wf.add_vector_form(callback(stac_residual_vol), HERMES_ANY, sln_time_prev);
wf.add_matrix_form_surf(callback(stac_jacobian_surf), BDY_AIR, sln_time_prev);
wf.add_vector_form_surf(callback(stac_residual_surf), BDY_AIR, sln_time_prev);
// Initialize the FE problem.
bool is_linear = false;
DiscreteProblem dp(&wf, &space, is_linear);
// Time stepping loop:
double current_time = time_step; int ts = 1;
do
{
// Perform one Runge-Kutta time step according to the selected Butcher's table.
info("Runge-Kutta time step (t = %g s, tau = %g s, stages: %d).",
current_time, time_step, bt.get_size());
bool verbose = true;
bool is_linear = true;
if (!rk_time_step(current_time, time_step, &bt, sln_time_prev, sln_time_new, &dp, matrix_solver,
verbose, is_linear)) {
error("Runge-Kutta time step failed, try to decrease time step size.");
}
// Convert coeff_vec into a new time level solution.
//Solution::vector_to_solution(coeff_vec, &space, &u_prev_time);
// Increase current time and time step counter.
current_time += time_step;
ts++;
}
while (current_time < T_FINAL);
info("Coordinate (-2.0, 2.0) value = %lf", sln_time_new->get_pt_value(-2.0, 2.0));
info("Coordinate (-1.0, 2.0) value = %lf", sln_time_new->get_pt_value(-1.0, 2.0));
info("Coordinate ( 0.0, 2.0) value = %lf", sln_time_new->get_pt_value(0.0, 2.0));
info("Coordinate ( 1.0, 2.0) value = %lf", sln_time_new->get_pt_value(1.0, 2.0));
info("Coordinate ( 2.0, 2.0) value = %lf", sln_time_new->get_pt_value(2.0, 2.0));
bool success = true;
if (fabs(sln_time_new->get_pt_value(-2.0, 2.0) - 9.999982) > 1E-6) success = false;
if (fabs(sln_time_new->get_pt_value(-1.0, 2.0) - 10.000002) > 1E-6) success = false;
if (fabs(sln_time_new->get_pt_value( 0.0, 2.0) - 9.999995) > 1E-6) success = false;
if (fabs(sln_time_new->get_pt_value( 1.0, 2.0) - 10.000002) > 1E-6) success = false;
if (fabs(sln_time_new->get_pt_value( 2.0, 2.0) - 9.999982) > 1E-6) success = false;
if (success) {
printf("Success!\n");
return ERR_SUCCESS;
}
else {
printf("Failure!\n");
return ERR_FAILURE;
}
}
int main(int argc, char* argv[])
{
// Choose a Butcher's table or define your own.
ButcherTable bt(butcher_table_type);
if (bt.is_explicit()) info("Using a %d-stage explicit R-K method.", bt.get_size());
if (bt.is_diagonally_implicit()) info("Using a %d-stage diagonally implicit R-K method.", bt.get_size());
if (bt.is_fully_implicit()) info("Using a %d-stage fully implicit R-K method.", bt.get_size());
// Load the mesh.
Mesh mesh;
H2DReader mloader;
mloader.load("wall.mesh", &mesh);
// Perform initial mesh refinements.
for(int i = 0; i < INIT_REF_NUM; i++) mesh.refine_all_elements();
mesh.refine_towards_boundary(BDY_BOTTOM, INIT_REF_NUM_BDY);
// Enter boundary markers.
BCTypes bc_types;
bc_types.add_bc_neumann(Hermes::vector<int>(BDY_RIGHT, BDY_LEFT));
bc_types.add_bc_newton(Hermes::vector<int>(BDY_BOTTOM, BDY_TOP));
// Initialize an H1 space with default shapeset.
H1Space space(&mesh, &bc_types, NULL, P_INIT);
int ndof = Space::get_num_dofs(&space);
info("ndof = %d.", ndof);
// Previous and next time level solutions.
Solution* sln_time_prev = new Solution(&mesh, TEMP_INIT);
Solution* sln_time_new = new Solution(&mesh);
Solution* time_error_fn = new Solution(&mesh, 0.0);
// Initialize weak formulation.
WeakForm wf;
wf.add_matrix_form(stac_jacobian_vol, stac_jacobian_vol_ord, HERMES_NONSYM, HERMES_ANY, sln_time_prev);
wf.add_vector_form(stac_residual_vol, stac_residual_vol_ord, HERMES_ANY, sln_time_prev);
wf.add_matrix_form_surf(stac_jacobian_bottom, stac_jacobian_bottom_ord, BDY_BOTTOM, sln_time_prev);
wf.add_vector_form_surf(stac_residual_bottom, stac_residual_bottom_ord, BDY_BOTTOM, sln_time_prev);
wf.add_matrix_form_surf(stac_jacobian_top, stac_jacobian_top_ord, BDY_TOP, sln_time_prev);
wf.add_vector_form_surf(stac_residual_top, stac_residual_top_ord, BDY_TOP, sln_time_prev);
// Initialize the FE problem.
bool is_linear = true;
DiscreteProblem dp(&wf, &space, is_linear);
// Initialize views.
ScalarView Tview("Temperature", new WinGeom(0, 0, 1500, 400));
Tview.fix_scale_width(40);
ScalarView eview("Temporal error", new WinGeom(0, 450, 1500, 400));
eview.fix_scale_width(40);
// Graph for time step history.
SimpleGraph time_step_graph;
info("Time step history will be saved to file time_step_history.dat.");
// Time stepping loop:
double current_time = 0; int ts = 1;
do
{
// Perform one Runge-Kutta time step according to the selected Butcher's table.
info("Runge-Kutta time step (t = %g s, tau = %g s, stages: %d).",
current_time, time_step, bt.get_size());
bool verbose = true;
bool is_linear = true;
if (!rk_time_step(current_time, time_step, &bt, sln_time_prev, sln_time_new, time_error_fn, &dp, matrix_solver,
verbose, is_linear)) {
error("Runge-Kutta time step failed, try to decrease time step size.");
}
// Plot error function.
char title[100];
sprintf(title, "Temporal error, t = %g", current_time);
eview.set_title(title);
AbsFilter abs_tef(time_error_fn);
eview.show(&abs_tef, HERMES_EPS_VERYHIGH);
// Calculate relative time stepping error and decide whether the
// time step can be accepted. If not, then the time step size is
// reduced and the entire time step repeated. If yes, then another
// check is run, and if the relative error is very low, time step
// is increased.
double rel_err_time = calc_norm(time_error_fn, HERMES_H1_NORM) / calc_norm(sln_time_new, HERMES_H1_NORM) * 100;
info("rel_err_time = %g%%", rel_err_time);
if (rel_err_time > TIME_TOL_UPPER) {
info("rel_err_time above upper limit %g%% -> decreasing time step from %g to %g and restarting time step.",
TIME_TOL_UPPER, time_step, time_step * TIME_STEP_DEC_RATIO);
time_step *= TIME_STEP_DEC_RATIO;
continue;
}
if (rel_err_time < TIME_TOL_LOWER) {
info("rel_err_time = below lower limit %g%% -> increasing time step from %g to %g",
TIME_TOL_UPPER, time_step, time_step * TIME_STEP_INC_RATIO);
time_step *= TIME_STEP_INC_RATIO;
}
// Add entry to the timestep graph.
time_step_graph.add_values(current_time, time_step);
time_step_graph.save("time_step_history.dat");
// Update time.
current_time += time_step;
// Show the new time level solution.
sprintf(title, "Time %3.2f s", current_time);
Tview.set_title(title);
Tview.show(sln_time_new);
// Copy solution for the new time step.
sln_time_prev->copy(sln_time_new);
// Increase counter of time steps.
ts++;
}
while (current_time < T_FINAL);
// Cleanup.
delete sln_time_prev;
delete sln_time_new;
delete time_error_fn;
// Wait for the view to be closed.
View::wait();
return 0;
}
