/**
In order to do so, first a reasonable dt for stability is calculated and F,G,RHS are evaluated.
Afterwards, the Poisson pressure equation is solved and the velocitys are updated.
\param[in] printInfo boolean if additional informations on the fields and rediduum of p are printed
\param[in] verbose boolean if debbuging information should be printed (standard: false)
*/
void Compute::TimeStep(bool printInfo, bool verbose=false)
{
// TODO: test
// compute dt
if (verbose) std::cout << "Computing the timestep width..." << std::flush; // only for debugging issues
real_t dt = compute_dt();
if (verbose) std::cout << "Done.\n" << std::flush; // only for debugging issues
// compute F, G
MomentumEqu(dt);
update_boundary_values(); //update boundary values
// compute rhs
RHS(dt);
// solve Poisson equation
real_t residual(_epslimit + 1.0);
index_t iteration(0);
//while (iteration <= _param->IterMax() && residual > _epslimit){
while (true){
// one solver cycle is done here
residual = _solver->Cycle(_p, _rhs);
iteration++;
if (iteration > _param->IterMax()){
//if (printInfo) {
std::cout << "Warning: Solver did not converge! Residual: " << residual << "\n";
//}
break;
} else if (residual < _epslimit){
//if (printInfo) {
std::cout << "Solver converged after " << iteration << " timesteps. Residual: " << residual << "\n";
//}
break;
}
}
// compute new velocitys u, v
NewVelocities(dt);
update_boundary_values();
//update total time
_t += dt;
// print information
if (printInfo){
std::cout << "============================================================\n";
// total simulated time
std::cout << "Total simulated time: t = " << _t << "\n";
// timestep
std::cout << "Last timestep: dt = " << dt << "\n";
// magnitudes of the fields
std::cout << "max(F) = " << _F->AbsMax() << ", max(G) = " << _G->AbsMax() << ", max(rhs) = " << _rhs->AbsMax() << "\n";
std::cout << "max(u) = " << _u->AbsMax() << ", max(v) = " << _v->AbsMax() << ", max(p) = " << _p->AbsMax() << "\n";
//std::cout << "Average value of rhs: " << _rhs->average_value() << "\n";
std::cout << "============================================================\n";
}
}
int
main (int argc, char* argv[])
{
BoxLib::Initialize(argc,argv);
// What time is it now? We'll use this to compute total run time.
Real strt_time = ParallelDescriptor::second();
std::cout << std::setprecision(15);
// ParmParse is way of reading inputs from the inputs file
ParmParse pp;
int verbose = 0;
pp.query("verbose", verbose);
// We need to get n_cell from the inputs file - this is the number of cells on each side of
// a square (or cubic) domain.
int n_cell;
pp.get("n_cell",n_cell);
int max_grid_size;
pp.get("max_grid_size",max_grid_size);
// Default plot_int to 1, allow us to set it to something else in the inputs file
// If plot_int < 0 then no plot files will be written
int plot_int = 1;
pp.query("plot_int",plot_int);
// Default nsteps to 0, allow us to set it to something else in the inputs file
int nsteps = 0;
pp.query("nsteps",nsteps);
pp.query("do_tiling", do_tiling);
// Define a single box covering the domain
IntVect dom_lo(0,0,0);
IntVect dom_hi(n_cell-1,n_cell-1,n_cell-1);
Box domain(dom_lo,dom_hi);
// Initialize the boxarray "bs" from the single box "bx"
BoxArray bs(domain);
// Break up boxarray "bs" into chunks no larger than "max_grid_size" along a direction
bs.maxSize(max_grid_size);
// This defines the physical size of the box. Right now the box is [-1,1] in each direction.
RealBox real_box;
for (int n = 0; n < BL_SPACEDIM; n++) {
real_box.setLo(n,-1.0);
real_box.setHi(n, 1.0);
}
// This says we are using Cartesian coordinates
int coord = 0;
// This sets the boundary conditions to be doubly or triply periodic
int is_per[BL_SPACEDIM];
for (int i = 0; i < BL_SPACEDIM; i++) is_per[i] = 1;
// This defines a Geometry object which is useful for writing the plotfiles
Geometry geom(domain,&real_box,coord,is_per);
// This defines the mesh spacing
Real dx[BL_SPACEDIM];
for ( int n=0; n<BL_SPACEDIM; n++ )
dx[n] = ( geom.ProbHi(n) - geom.ProbLo(n) )/domain.length(n);
// Nghost = number of ghost cells for each array
int Nghost = 1;
// Ncomp = number of components for each array
int Ncomp = 1;
pp.query("ncomp", Ncomp);
// Allocate space for the old_phi and new_phi -- we define old_phi and new_phi as
PArray < MultiFab > phis(2, PArrayManage);
phis.set(0, new MultiFab(bs, Ncomp, Nghost));
phis.set(1, new MultiFab(bs, Ncomp, Nghost));
MultiFab* old_phi = &phis[0];
MultiFab* new_phi = &phis[1];
// Initialize both to zero (just because)
old_phi->setVal(0.0);
new_phi->setVal(0.0);
// Initialize phi by calling a Fortran routine.
// MFIter = MultiFab Iterator
#ifdef _OPENMP
#pragma omp parallel
#endif
for ( MFIter mfi(*new_phi,true); mfi.isValid(); ++mfi )
{
const Box& bx = mfi.tilebox();
init_phi(bx.loVect(),bx.hiVect(),
BL_TO_FORTRAN((*new_phi)[mfi]),Ncomp,
dx,geom.ProbLo(),geom.ProbHi());
}
// Call the compute_dt routine to return a time step which we will pass to advance
Real dt = compute_dt(dx[0]);
// Write a plotfile of the initial data if plot_int > 0 (plot_int was defined in the inputs file)
if (plot_int > 0) {
int n = 0;
const std::string& pltfile = BoxLib::Concatenate("plt",n,5);
writePlotFile(pltfile, *new_phi, geom);
}
Real adv_start_time = ParallelDescriptor::second();
for (int n = 1; n <= nsteps; n++)
{
// Swap the pointers so we don't have to allocate and de-allocate data
std::swap(old_phi, new_phi);
// new_phi = old_phi + dt * (something)
advance(old_phi, new_phi, dx, dt, geom);
// Tell the I/O Processor to write out which step we're doing
if (verbose && ParallelDescriptor::IOProcessor())
std::cout << "Advanced step " << n << std::endl;
// Write a plotfile of the current data (plot_int was defined in the inputs file)
if (plot_int > 0 && n%plot_int == 0) {
const std::string& pltfile = BoxLib::Concatenate("plt",n,5);
writePlotFile(pltfile, *new_phi, geom);
}
}
// Call the timer again and compute the maximum difference between the start time and stop time
// over all processors
Real advance_time = ParallelDescriptor::second() - adv_start_time;
Real stop_time = ParallelDescriptor::second() - strt_time;
const int IOProc = ParallelDescriptor::IOProcessorNumber();
ParallelDescriptor::ReduceRealMax(stop_time,IOProc);
ParallelDescriptor::ReduceRealMax(advance_time,IOProc);
ParallelDescriptor::ReduceRealMax(kernel_time,IOProc);
ParallelDescriptor::ReduceRealMax(FB_time,IOProc);
// Tell the I/O Processor to write out the "run time"
if (ParallelDescriptor::IOProcessor()) {
std::cout << "Kernel time = " << kernel_time << std::endl;
std::cout << "FB time = " << FB_time << std::endl;
std::cout << "Advance time = " << advance_time << std::endl;
std::cout << "Total run time = " << stop_time << std::endl;
}
// Say goodbye to MPI, etc...
BoxLib::Finalize();
}
int
main (int argc, char* argv[])
{
BoxLib::Initialize(argc,argv);
// What time is it now? We'll use this to compute total run time.
Real strt_time = ParallelDescriptor::second();
std::cout << std::setprecision(15);
// ParmParse is way of reading inputs from the inputs file
ParmParse pp;
// We need to get n_cell from the inputs file - this is the number of cells on each side of
// a square (or cubic) domain.
int n_cell;
pp.get("n_cell",n_cell);
// Default nsteps to 0, allow us to set it to something else in the inputs file
int max_grid_size;
pp.get("max_grid_size",max_grid_size);
// Default plot_int to 1, allow us to set it to something else in the inputs file
// If plot_int < 0 then no plot files will be written
int plot_int = 1;
pp.query("plot_int",plot_int);
// Default nsteps to 0, allow us to set it to something else in the inputs file
int nsteps = 0;
pp.query("nsteps",nsteps);
// Define a single box covering the domain
#if (BL_SPACEDIM == 2)
IntVect dom_lo(0,0);
IntVect dom_hi(n_cell-1,n_cell-1);
#else
IntVect dom_lo(0,0,0);
IntVect dom_hi(n_cell-1,n_cell-1,n_cell-1);
#endif
Box domain(dom_lo,dom_hi);
// Initialize the boxarray "bs" from the single box "bx"
BoxArray bs(domain);
// Break up boxarray "bs" into chunks no larger than "max_grid_size" along a direction
bs.maxSize(max_grid_size);
// This defines the physical size of the box. Right now the box is [-1,1] in each direction.
RealBox real_box;
for (int n = 0; n < BL_SPACEDIM; n++)
{
real_box.setLo(n,-1.0);
real_box.setHi(n, 1.0);
}
// This says we are using Cartesian coordinates
int coord = 0;
// This sets the boundary conditions to be doubly or triply periodic
int is_per[BL_SPACEDIM];
for (int i = 0; i < BL_SPACEDIM; i++) is_per[i] = 1;
// This defines a Geometry object which is useful for writing the plotfiles
Geometry geom(domain,&real_box,coord,is_per);
// This defines the mesh spacing
Real dx[BL_SPACEDIM];
for ( int n=0; n<BL_SPACEDIM; n++ )
dx[n] = ( geom.ProbHi(n) - geom.ProbLo(n) )/domain.length(n);
// Nghost = number of ghost cells for each array
int Nghost = 1;
// Ncomp = number of components for each array
int Ncomp = 1;
// Make sure we can fill the ghost cells from the adjacent grid
if (Nghost > max_grid_size)
std::cout << "NGHOST < MAX_GRID_SIZE -- grids are too small! " << std::endl;
// Allocate space for the old_phi and new_phi -- we define old_phi and new_phi as
// pointers to the MultiFabs
MultiFab* old_phi = new MultiFab(bs, Ncomp, Nghost);
MultiFab* new_phi = new MultiFab(bs, Ncomp, Nghost);
// Initialize both to zero (just because)
old_phi->setVal(0.0);
new_phi->setVal(0.0);
// Initialize the old_phi by calling a Fortran routine.
// MFIter = MultiFab Iterator
for ( MFIter mfi(*new_phi); mfi.isValid(); ++mfi )
{
const Box& bx = mfi.validbox();
FORT_INIT_PHI((*new_phi)[mfi].dataPtr(),
bx.loVect(),bx.hiVect(), &Nghost,
dx,geom.ProbLo(),geom.ProbHi());
}
// Call the compute_dt routine to return a time step which we will pass to advance
Real dt = compute_dt(dx[0]);
// Write a plotfile of the initial data if plot_int > 0 (plot_int was defined in the inputs file)
if (plot_int > 0)
{
int n = 0;
const std::string& pltfile = BoxLib::Concatenate("plt",n,5);
writePlotFile(pltfile, *new_phi, geom);
}
// build the flux multifabs
MultiFab* flux = new MultiFab[BL_SPACEDIM];
for (int dir = 0; dir < BL_SPACEDIM; dir++)
{
BoxArray edge_grids(bs);
// flux(dir) has one component, zero ghost cells, and is nodal in direction dir
edge_grids.surroundingNodes(dir);
flux[dir].define(edge_grids,1,0,Fab_allocate);
}
for (int n = 1; n <= nsteps; n++)
{
// Swap the pointers so we don't have to allocate and de-allocate data
std::swap(old_phi, new_phi);
// new_phi = old_phi + dt * (something)
advance(old_phi, new_phi, flux, dx, dt, geom);
// Tell the I/O Processor to write out which step we're doing
if (ParallelDescriptor::IOProcessor())
std::cout << "Advanced step " << n << std::endl;
// Write a plotfile of the current data (plot_int was defined in the inputs file)
if (plot_int > 0 && n%plot_int == 0)
{
const std::string& pltfile = BoxLib::Concatenate("plt",n,5);
writePlotFile(pltfile, *new_phi, geom);
}
}
// Call the timer again and compute the maximum difference between the start time and stop time
// over all processors
Real stop_time = ParallelDescriptor::second() - strt_time;
const int IOProc = ParallelDescriptor::IOProcessorNumber();
ParallelDescriptor::ReduceRealMax(stop_time,IOProc);
// Tell the I/O Processor to write out the "run time"
if (ParallelDescriptor::IOProcessor())
std::cout << "Run time = " << stop_time << std::endl;
// Say goodbye to MPI, etc...
BoxLib::Finalize();
}
