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/* Copyright 2020
*
* This file is part of WarpX.
*
* License: BSD-3-Clause-LBNL
*/
#include "WarpX.H"
#ifndef WARPX_DIM_RZ
# include "FieldSolver/FiniteDifferenceSolver/FiniteDifferenceAlgorithms/CartesianCKCAlgorithm.H"
# include "FieldSolver/FiniteDifferenceSolver/FiniteDifferenceAlgorithms/CartesianNodalAlgorithm.H"
# include "FieldSolver/FiniteDifferenceSolver/FiniteDifferenceAlgorithms/CartesianYeeAlgorithm.H"
#else
# include "FieldSolver/FiniteDifferenceSolver/FiniteDifferenceAlgorithms/CylindricalYeeAlgorithm.H"
#endif
#include "Utils/TextMsg.H"
#include "Utils/WarpXAlgorithmSelection.H"
#include "Utils/WarpXConst.H"
#include <AMReX.H>
#include <AMReX_Geometry.H>
#include <AMReX_IntVect.H>
#include <AMReX_Print.H>
#include <AMReX_REAL.H>
#include <AMReX_Vector.H>
#include <algorithm>
#include <memory>
/**
* Determine the timestep of the simulation. */
void
WarpX::ComputeDt ()
{
// Handle cases where the timestep is not limited by the speed of light
if (electromagnetic_solver_id == ElectromagneticSolverAlgo::None) {
WARPX_ALWAYS_ASSERT_WITH_MESSAGE(m_const_dt.has_value(), "warpx.const_dt must be specified with the electrostatic solver.");
for (int lev=0; lev<=max_level; lev++) {
dt[lev] = m_const_dt.value();
}
return;
}
// Determine the appropriate timestep as limited by the speed of light
const amrex::Real* dx = geom[max_level].CellSize();
amrex::Real deltat = 0.;
if (m_const_dt.has_value()) {
deltat = m_const_dt.value();
} else if (electromagnetic_solver_id == ElectromagneticSolverAlgo::PSATD) {
// Computation of dt for spectral algorithm
// (determined by the minimum cell size in all directions)
#if defined(WARPX_DIM_1D_Z)
deltat = cfl * dx[0] / PhysConst::c;
#elif defined(WARPX_DIM_XZ) || defined(WARPX_DIM_RZ)
deltat = cfl * std::min(dx[0], dx[1]) / PhysConst::c;
#else
deltat = cfl * std::min(dx[0], std::min(dx[1], dx[2])) / PhysConst::c;
#endif
} else {
// Computation of dt for FDTD algorithm
#ifdef WARPX_DIM_RZ
// - In RZ geometry
if (electromagnetic_solver_id == ElectromagneticSolverAlgo::Yee) {
deltat = cfl * CylindricalYeeAlgorithm::ComputeMaxDt(dx, n_rz_azimuthal_modes);
#else
// - In Cartesian geometry
if (grid_type == GridType::Collocated) {
deltat = cfl * CartesianNodalAlgorithm::ComputeMaxDt(dx);
} else if (electromagnetic_solver_id == ElectromagneticSolverAlgo::Yee
|| electromagnetic_solver_id == ElectromagneticSolverAlgo::ECT) {
deltat = cfl * CartesianYeeAlgorithm::ComputeMaxDt(dx);
} else if (electromagnetic_solver_id == ElectromagneticSolverAlgo::CKC) {
deltat = cfl * CartesianCKCAlgorithm::ComputeMaxDt(dx);
#endif
} else {
amrex::Abort(Utils::TextMsg::Err("ComputeDt: Unknown algorithm"));
}
}
dt.resize(0);
dt.resize(max_level+1,deltat);
if (do_subcycling) {
for (int lev = max_level-1; lev >= 0; --lev) {
dt[lev] = dt[lev+1] * refRatio(lev)[0];
}
}
}
void
WarpX::PrintDtDxDyDz ()
{
for (int lev=0; lev <= max_level; lev++) {
const amrex::Real* dx_lev = geom[lev].CellSize();
amrex::Print() << "Level " << lev << ": dt = " << dt[lev]
#if defined(WARPX_DIM_1D_Z)
<< " ; dz = " << dx_lev[0] << '\n';
#elif defined(WARPX_DIM_XZ) || defined(WARPX_DIM_RZ)
<< " ; dx = " << dx_lev[0]
<< " ; dz = " << dx_lev[1] << '\n';
#elif defined(WARPX_DIM_3D)
<< " ; dx = " << dx_lev[0]
<< " ; dy = " << dx_lev[1]
<< " ; dz = " << dx_lev[2] << '\n';
#endif
}
}
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