Base class for Langevin equation integrator. More...

#include <langevin_base.hpp>

Inheritance diagram for BaseLangevin:

Public Member Functions
	BaseLangevin ()=default
	Default constructor.
bool	construct_grid (const Parameters parameters)
	Construct Langevin density field grid of appropriate n-D dimension.
bool	construct_1D_grid (const Parameters parameters)
	Build 1d Langevin density field grid & topology.
bool	construct_2D_grid (const Parameters parameters)
	Build 2d Langevin density field grid & mixed topology.
bool	initialize_grid (const Parameters parameters, rng_t &rng)
	Initial condition for density field: uniformly random.
void	prepare (const Coefficients &coefficients)
	Set initial condition of Langevin density field grid.
bool	check_boundary_conditions (const Parameters parameters)
	Check we have 2N boundary conditions for an N-dimensional grid.
void	apply_boundary_conditions (const Parameters parameters, int i_epoch)
	Set density field values only the grid edges per bc specs.
void	integrate_rungekutta (rng_t &rng)
	Runge-Kutta + stochastic integration + grid update.
void	integrate_euler (rng_t &rng)
	Explicit Euler + stochastic integration + grid update.
double	get_density_grid_value (const int) const
	Return the Langevin density field grid value at a given "node".
double	get_mean_density () const
	Expose mean density.
double	get_poisson_mean () const
	Compute Poisson RNG mean.
virtual void	set_nonlinear_coefficients (const Coefficients &coefficients)
	Method to set nonlinear coefficients for deterministic integration step: to be defined by application.
virtual double	nonlinear_rhs (const int i_cell, const grid_t &field) const
	Method to set nonlinear RHS of Langevin equation for deterministic integration step: to be defined by application.

Protected Attributes
int	n_cells
	Total number of cells in n-D grid.
grid_t	density_grid
	Density field grid.
grid_wiring_t	grid_wiring
	Neighorhood topology for all grid cells.
double	dt
	Time step, i.e, epoch-to-epoch Δt.
double	dx
	Grid spacing, i.e., spacing Δx between cell centers in all directions.
double	mean_density
	Grid-average of density field.
poisson_dist_t	poisson_sampler
	Function generating Poisson variates.
gamma_dist_t	gamma_sampler
	Function generating gamma variates.
gaussian_dist_t	gaussian_sampler
	Function generating normal variates.
double	linear_coefficient
	Dornic method coefficient.
double	noise_coefficient
	Dornic method coefficient.
double	lambda
	Dornic method stochastic-step variable.
double	lambda_on_explcdt
	Dornic method stochastic-step variable.
grid_t	k1_grid
	Runge-Kutta variable grid #1.
grid_t	k2_grid
	Runge-Kutta variable grid #2.
grid_t	k3_grid
	Runge-Kutta variable grid #3.
grid_t	aux_grid1
	Temporary density grid used to perform an integration step.
grid_t	aux_grid2
	Temporary density grid used to perform an integration step.

Detailed Description

Base class for Langevin equation integrator.

Definition at line 15 of file langevin_base.hpp.

Member Function Documentation

◆ apply_boundary_conditions()

void BaseLangevin::apply_boundary_conditions	(	const Parameters	parameters,
		int	i_epoch )

Set density field values only the grid edges per bc specs.

Apply boundary conditions along each edge in turn.

Definition at line 26 of file langevin_bc.cpp.

◆ check_boundary_conditions()

bool BaseLangevin::check_boundary_conditions ( const Parameters parameters )

Check we have 2N boundary conditions for an N-dimensional grid.

Check that 2x bcs are specified for each grid dimension, one for each edge.

Definition at line 10 of file langevin_bc.cpp.

◆ construct_1D_grid()

bool BaseLangevin::construct_1D_grid ( const Parameters parameters )

Build 1d Langevin density field grid & topology.

Construct 1D density field ρ(x,t) grid and corresponding cell-cell topologies.

Definition at line 10 of file langevin_construct_grid1d.cpp.

◆ construct_2D_grid()

bool BaseLangevin::construct_2D_grid ( const Parameters p )

Build 2d Langevin density field grid & mixed topology.

Construct a connected 2D grid to be used for solving the evolution of a density field ρ(x,t).

Implements mixed grid edge topology: i.e., x and y grid edges can separately be specified as "bounded" or "periodic". The "bounded" edge topology simply means those exterior grid cells are only connected to their neighboring grid-interior cells. The "periodic" edge topology means the grid cells along one edge are also connected to those on the opposite edge. If both x and y edges are periodic, the grid topology is toroidal. If only one edge is periodic, the grid topology is cylindrical. If both are bounded, the grid topology is a bounded plane.

Parameters

BaseLangevin integrator Parameters bundle.

Definition at line 26 of file langevin_construct_grid2d.cpp.

◆ construct_grid()

bool BaseLangevin::construct_grid ( const Parameters parameters )

Construct Langevin density field grid of appropriate n-D dimension.

Definition at line 9 of file langevin_construct_grid.cpp.

◆ get_density_grid_value()

double BaseLangevin::get_density_grid_value ( const int i ) const

Return the Langevin density field grid value at a given "node".

Definition at line 10 of file langevin_utilities.cpp.

◆ get_mean_density()

double BaseLangevin::get_mean_density ( ) const

Expose mean density.

Return the grid-averaged Langevin field mean value.

Definition at line 16 of file langevin_utilities.cpp.

◆ get_poisson_mean()

double BaseLangevin::get_poisson_mean ( ) const

Compute Poisson RNG mean.

Compute the mean field density times "lamba_product", which should be equal to the Poisson distribution mean

Definition at line 23 of file langevin_utilities.cpp.

◆ initialize_grid()

bool BaseLangevin::initialize_grid	(	const Parameters	parameters,
		rng_t &	rng )

Initial condition for density field: uniformly random.

Definition at line 9 of file langevin_ic.cpp.

◆ integrate_euler()

void BaseLangevin::integrate_euler ( rng_t & rng )

Explicit Euler + stochastic integration + grid update.

Perform explicit-Euler then stochastic integration steps, then update grid.

Definition at line 10 of file langevin_integrate_euler.cpp.

◆ integrate_rungekutta()

void BaseLangevin::integrate_rungekutta ( rng_t & rng )

Runge-Kutta + stochastic integration + grid update.

Runge-Kutta integration of the nonlinear and diffusion terms in the Langevin equation. Update of cells is done in the same loop as last Runge-Kutta step for efficiency.

Definition at line 13 of file langevin_integrate_rungekutta.cpp.

◆ nonlinear_rhs()

virtual double BaseLangevin::nonlinear_rhs	(	const int	i_cell,
		const grid_t &	field ) const

inlinevirtual

Method to set nonlinear RHS of Langevin equation for deterministic integration step: to be defined by application.

Reimplemented in DPLangevin.

Definition at line 89 of file langevin_base.hpp.

◆ prepare()

void BaseLangevin::prepare ( const Coefficients & coefficients )

Set initial condition of Langevin density field grid.

Set the Langevin equation coefficients and "lambda" coefficients.

Definition at line 11 of file langevin_prepare.cpp.

◆ set_nonlinear_coefficients()

virtual void BaseLangevin::set_nonlinear_coefficients ( const Coefficients & coefficients )

inlinevirtual

Method to set nonlinear coefficients for deterministic integration step: to be defined by application.

Reimplemented in DPLangevin.

Definition at line 87 of file langevin_base.hpp.

Member Data Documentation

◆ aux_grid1

grid_t BaseLangevin::aux_grid1

protected

Temporary density grid used to perform an integration step.

Definition at line 55 of file langevin_base.hpp.

◆ aux_grid2

grid_t BaseLangevin::aux_grid2

protected

Temporary density grid used to perform an integration step.

Definition at line 57 of file langevin_base.hpp.

◆ density_grid

grid_t BaseLangevin::density_grid

protected

Density field grid.

Definition at line 21 of file langevin_base.hpp.

◆ dt

double BaseLangevin::dt

protected

Time step, i.e, epoch-to-epoch Δt.

Definition at line 26 of file langevin_base.hpp.

◆ dx

double BaseLangevin::dx

protected

Grid spacing, i.e., spacing Δx between cell centers in all directions.

Definition at line 28 of file langevin_base.hpp.

◆ gamma_sampler

gamma_dist_t BaseLangevin::gamma_sampler

protected

Function generating gamma variates.

Definition at line 35 of file langevin_base.hpp.

◆ gaussian_sampler

gaussian_dist_t BaseLangevin::gaussian_sampler

protected

Function generating normal variates.

Definition at line 37 of file langevin_base.hpp.

◆ grid_wiring

grid_wiring_t BaseLangevin::grid_wiring

protected

Neighorhood topology for all grid cells.

Definition at line 23 of file langevin_base.hpp.

◆ k1_grid

grid_t BaseLangevin::k1_grid

protected

Runge-Kutta variable grid #1.

Definition at line 49 of file langevin_base.hpp.

◆ k2_grid

grid_t BaseLangevin::k2_grid

protected

Runge-Kutta variable grid #2.

Definition at line 51 of file langevin_base.hpp.

◆ k3_grid

grid_t BaseLangevin::k3_grid

protected

Runge-Kutta variable grid #3.

Definition at line 53 of file langevin_base.hpp.

◆ lambda

double BaseLangevin::lambda

protected

Dornic method stochastic-step variable.

Definition at line 44 of file langevin_base.hpp.

◆ lambda_on_explcdt

double BaseLangevin::lambda_on_explcdt

protected

Dornic method stochastic-step variable.

Definition at line 46 of file langevin_base.hpp.

◆ linear_coefficient

double BaseLangevin::linear_coefficient

protected

Dornic method coefficient.

Definition at line 40 of file langevin_base.hpp.

◆ mean_density

double BaseLangevin::mean_density

protected

Grid-average of density field.

Definition at line 30 of file langevin_base.hpp.

◆ n_cells

int BaseLangevin::n_cells

protected

Total number of cells in n-D grid.

Definition at line 19 of file langevin_base.hpp.

◆ noise_coefficient

double BaseLangevin::noise_coefficient

protected

Dornic method coefficient.

Definition at line 42 of file langevin_base.hpp.

◆ poisson_sampler

poisson_dist_t BaseLangevin::poisson_sampler

protected

Function generating Poisson variates.

Definition at line 33 of file langevin_base.hpp.

The documentation for this class was generated from the following files:

Public Member Functions

Protected Attributes

Detailed Description

Member Function Documentation

◆ apply_boundary_conditions()

◆ check_boundary_conditions()

◆ construct_1D_grid()

◆ construct_2D_grid()

◆ construct_grid()

◆ get_density_grid_value()

◆ get_mean_density()

◆ get_poisson_mean()

◆ initialize_grid()

◆ integrate_euler()

◆ integrate_rungekutta()

◆ nonlinear_rhs()

◆ prepare()

◆ set_nonlinear_coefficients()

Member Data Documentation

◆ aux_grid1

◆ aux_grid2

◆ density_grid

◆ dt

◆ dx

◆ gamma_sampler

◆ gaussian_sampler

◆ grid_wiring

◆ k1_grid

◆ k2_grid

◆ k3_grid

◆ lambda

◆ lambda_on_explcdt

◆ linear_coefficient

◆ mean_density

◆ n_cells

◆ noise_coefficient

◆ poisson_sampler