# How do I run a sweep with EME?

| Date       | Category    |
|------------|-------------|
| 2025-05-27 18:52:21 | EME |


For **length sweeps**, it is convenient to use a [`tidy3d.EMELengthSweep`](https://docs.flexcompute.com/projects/tidy3d/en/v2.7.1/api/_autosummary/tidy3d.EMELengthSweep.html) object, which can be passed to the `sweep_spec` parameter of the [`tidy3d.EMESimulation`](https://docs.flexcompute.com/projects/tidy3d/en/latest/api/_autosummary/tidy3d.EMESimulation.html) object. This process is demonstrated in [this tutorial](https://www.flexcompute.com/tidy3d/examples/notebooks/EMESolver/).

For **frequency sweeps**, it is sufficient to provide a list of frequencies to the `freqs` parameter of the [`tidy3d.EMESimulation`](https://docs.flexcompute.com/projects/tidy3d/en/latest/api/_autosummary/tidy3d.EMESimulation.html) object.

It is also possible to perform a sweep over the number of periods in a periodic structure using the `tidy3d.EMEPeriodicitySweep` object, as demonstrated in [this example](https://docs.flexcompute.com/projects/tidy3d/en/latest/notebooks/PCMBraggGratingFilter.html).