tidy3d.AutoGrid

class AutoGrid

Bases: AbstractAutoGrid

Specification for non-uniform grid along a given dimension.

Parameters:

• max_scale (float = 1.4) – Sets the maximum ratio between any two consecutive grid steps.

• mesher (GradedMesher = GradedMesher()) – The type of mesher to use to generate the grid automatically.

• dl_min (Optional[NonNegativeFloat] = None) – [units = um]. Lower bound of the grid size along this dimension regardless of structures present in the simulation, including override structures with enforced=True. It is a soft bound, meaning that the actual minimal grid size might be slightly smaller. If None or 0, a heuristic lower bound value will be applied.

• min_steps_per_wvl (float = 10.0) – Minimal number of steps per wavelength in each medium.

• min_steps_per_sim_size (float = 10.0) – Minimal number of steps per longest edge length of simulation domain bounding box. This is useful when the simulation domain size is subwavelength.

Example

>>> grid_1d = AutoGrid(min_steps_per_wvl=16, max_scale=1.4)

See also

UniformGrid

Uniform 1D grid.

GridSpec

Collective grid specification for all three dimensions.

Notebooks:

• Using automatic nonuniform meshing

Lectures:

• Time step size and CFL condition in FDTD

• Numerical dispersion in FDTD

Attributes

min_steps_per_wvl
min_steps_per_sim_size
max_scale
mesher
dl_min

Methods

estimated_min_dl(wavelength, structure_list, ...)

Estimated minimal grid size along the axis.

min_steps_per_wvl

min_steps_per_sim_size

estimated_min_dl(wavelength, structure_list, sim_size)

Estimated minimal grid size along the axis. The actual minimal grid size from mesher might be smaller.

Parameters:

• wavelength (float) – Wavelength to use for the step size and for dispersive media epsilon.

• structure_list (list[Structure]) – List of structures present in the simulation.

• sim_size (tuple[float, 3]) – Simulation domain size.

Returns:

Estimated minimal grid size from grid specification.

Return type:

float