Fix to simultaneous bend and angle mode solve

CHANGELOG.md

@@ -5,7 +5,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
-## [2.7.0] - 2024-06-13
+## [2.7.0] - 2024-06-17
 
 ### Added
 - EME solver through `EMESimulation` class.
@@ -57,6 +57,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Default variant for silicon dioxide in material library switched from `Horiba` to `Palik_Lossless`.
 - Sources and monitors which are exactly at the simulation domain boundaries will now error. They can still be placed very close to the boundaries, but need to be on the inside of the region.
 - Relaxed `dt` stability criterion for 1D and 2D simulations.
+- Switched order of angle and bend transformations in mode solver when both are present.
 
 ### Fixed
 - Bug in PolySlab intersection if slab bounds are `inf` on one side.

tidy3d/plugins/mode/solver.py

@@ -139,11 +139,11 @@ def compute_modes(
         jac_e = np.real(np.copy(identity_tensor))
         jac_h = np.real(np.copy(identity_tensor))
 
-        if bend_radius is not None:
-            new_coords, jac_e, jac_h = radial_transform(new_coords, bend_radius, bend_axis)
-
         if np.abs(angle_theta) > 0:
-            new_coords, jac_e_tmp, jac_h_tmp = angled_transform(new_coords, angle_theta, angle_phi)
+            new_coords, jac_e, jac_h = angled_transform(new_coords, angle_theta, angle_phi)
+
+        if bend_radius is not None:
+            new_coords, jac_e_tmp, jac_h_tmp = radial_transform(new_coords, bend_radius, bend_axis)
             jac_e = np.einsum("ij...,jp...->ip...", jac_e_tmp, jac_e)
             jac_h = np.einsum("ij...,jp...->ip...", jac_h_tmp, jac_h)
 

tidy3d/plugins/mode/transforms.py

@@ -16,9 +16,9 @@ def radial_transform(coords, radius, bend_axis):
     offsetting the plane such that its center is a distance of ``radius`` away from the center of
     curvature, we have, e.g. for ``bend_axis=='y'``:
 
-        u = (x**2 + z**2)
+        u = sqrt(x**2 + z**2)
         v = y
-        w = R acos(x / u)
+        w = R asin(z / u)
 
     These are all evaluated at z = 0 below.
 
@@ -39,9 +39,6 @@ def radial_transform(coords, radius, bend_axis):
         Jacobian of the transformation at the E-field positions, shape ``(3, 3, Nx * Ny)``.
     jac_h: np.ndarrray
         Jacobian of the transformation at the H-field positions, shape ``(3, 3, Nx * Ny)``.
-    k_to_kp: np.ndarray
-        A matrix of shape (3, 3) that transforms the k-vector from the original coordinates to the
-        transformed ones.
     """
 
     Nx, Ny = coords[0].size - 1, coords[1].size - 1
@@ -101,7 +98,7 @@ def angled_transform(coords, angle_theta, angle_phi):
     Nx, Ny = coords[0].size - 1, coords[1].size - 1
 
     # The new coordinates are exactly the same at z = 0
-    new_coords = (np.copy(c) for c in coords)
+    new_coords = [np.copy(c) for c in coords]
 
     # The only nontrivial derivatives are dudz, dvdz and they are constant everywhere
     jac = np.zeros((3, 3, Nx * Ny))