tidy3d.EMEPeriodicitySweep

class EMEPeriodicitySweep

Bases: EMESweepSpec

Spec for sweeping number of repetitions of EME subgrids.

Parameters:

num_reps (list[dict[str, PositiveInt]]) – Number of periodic repetitions of named subgrids in this EME grid. At each sweep index, contains a dict mapping the name of a subgrid to the number of repetitions of that subgrid at that sweep index.

Notes

Useful for simulating long periodic structures like Bragg gratings, as it allows the EME solver to reuse the modes and cell interface scattering matrices.

Compared to setting num_reps directly in the eme_grid_spec, this sweep spec allows varying the number of repetitions, effectively simulating multiple structures in a single EME simulation.

For bent EME cells, this reuse remains valid only if the local mode problem is unchanged in each repeated copy. Bent anisotropic cells are therefore rejected when the reused mode would see a different tensor orientation in another copy, and bent custom media are only supported when no global-frame remapping of custom data is required.

Example

>>> n_list = [1, 50, 100]
>>> sweep_spec = EMEPeriodicitySweep(num_reps=[{"unit_cell": n} for n in n_list])

Attributes

num_sweep	Number of sweep indices.
num_reps

num_reps

property num_sweep

Number of sweep indices.