tighter tolerance used for mode solvers

Author: dmarek-flex

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 - By default, batch downloads will skip files that already exist locally. To force re-downloading and replace existing files, pass the `replace_existing=True` argument to `Batch.load()`, `Batch.download()`, or `BatchData.load()`.
 - The `BatchData.load_sim_data()` function now overwrites any previously downloaded simulation files (instead of skipping them).
+- Tighter `TOL_EIGS` used for mode solver, since `scipy` sometimes failed to find modes.
 
 ### Fixed
 - Giving opposite boundaries different names no longer causes a symmetry validator failure.

tidy3d/components/mode/solver.py

@@ -17,7 +17,7 @@
 # Consider vec to be complex if norm(vec.imag)/norm(vec) > TOL_COMPLEX
 TOL_COMPLEX = 1e-10
 # Tolerance for eigs
-TOL_EIGS = fp_eps
+TOL_EIGS = fp_eps / 10
 # Tolerance for deciding on the matrix to be diagonal or tensorial
 TOL_TENSORIAL = 1e-6
 # shift target neff by this value, both rel and abs, whichever results in larger shift