public override void Initialise(Dictionary <string, object> input_dict)
{
Console.WriteLine("Initialising Experiment");
// simulation domain inputs
Get_From_Dictionary <double>(input_dict, "dx", ref dx_dens); dx_pot = dx_dens;
Get_From_Dictionary <double>(input_dict, "dy", ref dy_dens); dy_pot = dy_dens;
Get_From_Dictionary <double>(input_dict, "dz", ref dz_dens); dz_pot = dz_dens;
Get_From_Dictionary(input_dict, "nx", ref nx_dens); nx_pot = nx_dens;
Get_From_Dictionary(input_dict, "ny", ref ny_dens); ny_pot = ny_dens;
Get_From_Dictionary(input_dict, "nz", ref nz_dens); nz_pot = nz_dens;
// physics parameters are done by the base method (the base will also try to get specific parameters detailed in the input files)
base.Initialise(input_dict);
// and initialise the data classes for density, its derivatives and the chemical potential
Initialise_DataClasses(input_dict);
// initialise the density solver
dens_solv = Get_Density_Solver(input_dict);
// initialise potential solver
if (using_flexPDE)
{
pois_solv = new ThreeD_PoissonSolver(this, using_flexPDE, input_dict);
}
else if (using_dealii)
{
pois_solv = new ThreeD_dealII_Solver(this, using_dealii, input_dict);
}
else
{
throw new NotImplementedException("Error - Must use either FlexPDE or deal.II for 2D potential solver!");
}
device_dimensions.Add("interface_depth", Layers[1].Zmax);
pois_solv.Initiate_Poisson_Solver(device_dimensions, boundary_conditions);
Console.WriteLine("Experimental parameters initialised");
}
protected override bool Run_Iteration_Routine(IDensity_Solve dens_solv, IPoisson_Solve pois_solv, double tol, int max_iterations)
{
// calculate initial potential with the given charge distribution
Console.WriteLine("Calculating initial potential grid");
pois_solv.Initiate_Poisson_Solver(device_dimensions, boundary_conditions);
if (chem_pot == null)
chem_pot = Physics_Base.q_e * pois_solv.Get_Potential(carrier_charge_density.Spin_Summed_Data + dopent_charge_density.Spin_Summed_Data);
Console.WriteLine("Initial grid complete");
// dens_solv.Set_DFT_Potential(carrier_charge_density);
// dens_solv.Get_ChargeDensity(layers, ref carrier_charge_density, ref dopent_charge_density, chem_pot);
// dens_solv.Set_DFT_Potential(carrier_charge_density);
dens_solv.Reset_DFT_Potential();
dens_solv.Update_DFT_Potential(carrier_charge_density);
int count = 0;
t = 1.0;
bool converged = false;
while (!converged)
{
Band_Data dens_old = carrier_charge_density.Spin_Summed_Data + dopent_charge_density.Spin_Summed_Data;
// Get charge rho(phi)
dens_solv.Get_ChargeDensity(layers, ref carrier_charge_density, ref dopent_charge_density, chem_pot);
// Generate charge-dependent part of the Jacobian, g'(phi) = -d(eps * d( )) - rho'(phi)
SpinResolved_Data rho_prime = dens_solv.Get_ChargeDensity_Deriv(layers, carrier_charge_density_deriv, dopent_charge_density_deriv, chem_pot);
// Solve stepping equation to find raw Newton iteration step, g'(phi) x = - g(phi)
// Calculate Laplacian operating on the given band energy, d(eps * d(phi))
gphi = -1.0 * chem_pot.Laplacian / Physics_Base.q_e - carrier_charge_density.Spin_Summed_Data - dopent_charge_density.Spin_Summed_Data;
gphi[0] = 0.0; gphi[gphi.Length - 1] = 0.0;
x = pois_solv.Calculate_Newton_Step(rho_prime, gphi);
// Calculate optimal damping parameter, t
t = t_damp * Calculate_optimal_t(t / t_damp, (chem_pot / Physics_Base.q_e), x, carrier_charge_density, dopent_charge_density, pois_solv, dens_solv, t_min);
// Check convergence
Band_Data dens_spin_summed = carrier_charge_density.Spin_Summed_Data + dopent_charge_density.Spin_Summed_Data;
Band_Data dens_diff = dens_spin_summed - dens_old;
double dens_abs_max = Math.Max(Math.Abs(dens_spin_summed.Max()), Math.Abs(dens_spin_summed.Min()));
for (int i = 0; i < dens_diff.Length; i++)
// only calculate density difference for densities more than 1% of the maximum value
if (Math.Abs(dens_spin_summed[i]) > 0.01 * dens_abs_max)
dens_diff[i] = Math.Abs(dens_diff[i] / dens_spin_summed[i]);
else
dens_diff[i] = 0.0;
// Update the DFT potential
dens_solv.Update_DFT_Potential(carrier_charge_density);
double[] diff = new double[Nz_Pot];
for (int j = 0; j < nz_pot; j++)
diff[j] = Math.Abs(gphi.vec[j]);
double convergence = diff.Sum();
if (Physics_Base.q_e * x.InfinityNorm() < tol)
converged = true;
// update band energy phi_new = phi_old + t * x
Console.WriteLine(Generate_Output_String(count, x, dens_diff));
chem_pot = chem_pot + t * Physics_Base.q_e * x;
count++;
base.Checkpoint();
// reset the potential if the added potential t * x is too small
if (converged || count > max_iterations)
{
Console.WriteLine("Maximum potential change at end of iteration was " + (t * Physics_Base.q_e * x.InfinityNorm()).ToString() + "meV");
break;
}
}
Console.WriteLine("Iteration complete");
return converged;
}
protected override bool Run_Iteration_Routine(IDensity_Solve dens_solv, IPoisson_Solve pois_solv, double tol, int max_iterations)
{
// calculate initial potential with the given charge distribution
Console.WriteLine("Calculating initial potential grid");
pois_solv.Initiate_Poisson_Solver(device_dimensions, boundary_conditions);
if (chem_pot == null)
{
chem_pot = Physics_Base.q_e * pois_solv.Get_Potential(carrier_charge_density.Spin_Summed_Data + dopent_charge_density.Spin_Summed_Data);
}
Console.WriteLine("Initial grid complete");
// dens_solv.Set_DFT_Potential(carrier_charge_density);
// dens_solv.Get_ChargeDensity(layers, ref carrier_charge_density, ref dopent_charge_density, chem_pot);
// dens_solv.Set_DFT_Potential(carrier_charge_density);
dens_solv.Reset_DFT_Potential();
dens_solv.Update_DFT_Potential(carrier_charge_density);
int count = 0;
t = 1.0;
bool converged = false;
while (!converged)
{
Band_Data dens_old = carrier_charge_density.Spin_Summed_Data + dopent_charge_density.Spin_Summed_Data;
// Get charge rho(phi)
dens_solv.Get_ChargeDensity(layers, ref carrier_charge_density, ref dopent_charge_density, chem_pot);
// Generate charge-dependent part of the Jacobian, g'(phi) = -d(eps * d( )) - rho'(phi)
SpinResolved_Data rho_prime = dens_solv.Get_ChargeDensity_Deriv(layers, carrier_charge_density_deriv, dopent_charge_density_deriv, chem_pot);
// Solve stepping equation to find raw Newton iteration step, g'(phi) x = - g(phi)
// Calculate Laplacian operating on the given band energy, d(eps * d(phi))
gphi = -1.0 * chem_pot.Laplacian / Physics_Base.q_e - carrier_charge_density.Spin_Summed_Data - dopent_charge_density.Spin_Summed_Data;
gphi[0] = 0.0; gphi[gphi.Length - 1] = 0.0;
x = pois_solv.Calculate_Newton_Step(rho_prime, gphi);
// Calculate optimal damping parameter, t
t = t_damp * Calculate_optimal_t(t / t_damp, (chem_pot / Physics_Base.q_e), x, carrier_charge_density, dopent_charge_density, pois_solv, dens_solv, t_min);
// Check convergence
Band_Data dens_spin_summed = carrier_charge_density.Spin_Summed_Data + dopent_charge_density.Spin_Summed_Data;
Band_Data dens_diff = dens_spin_summed - dens_old;
double dens_abs_max = Math.Max(Math.Abs(dens_spin_summed.Max()), Math.Abs(dens_spin_summed.Min()));
for (int i = 0; i < dens_diff.Length; i++)
{
// only calculate density difference for densities more than 1% of the maximum value
if (Math.Abs(dens_spin_summed[i]) > 0.01 * dens_abs_max)
{
dens_diff[i] = Math.Abs(dens_diff[i] / dens_spin_summed[i]);
}
else
{
dens_diff[i] = 0.0;
}
}
// Update the DFT potential
dens_solv.Update_DFT_Potential(carrier_charge_density);
double[] diff = new double[Nz_Pot];
for (int j = 0; j < nz_pot; j++)
{
diff[j] = Math.Abs(gphi.vec[j]);
}
double convergence = diff.Sum();
if (Physics_Base.q_e * x.InfinityNorm() < tol)
{
converged = true;
}
// update band energy phi_new = phi_old + t * x
Console.WriteLine(Generate_Output_String(count, x, dens_diff));
chem_pot = chem_pot + t * Physics_Base.q_e * x;
count++;
base.Checkpoint();
// reset the potential if the added potential t * x is too small
if (converged || count > max_iterations)
{
Console.WriteLine("Maximum potential change at end of iteration was " + (t * Physics_Base.q_e * x.InfinityNorm()).ToString() + "meV");
break;
}
}
Console.WriteLine("Iteration complete");
return(converged);
}
