fmm_matrices.transverse_permittivity_fft

fmm_matrices.transverse_permittivity_fft

Computes the eps matrix from [2012 Liu] equation 15 using fft scheme.

Args:

• permittivity: The permittivity array, with shape (..., nx, ny).
• expansion: The field expansion to be used.

Returns:

• None: The transverse permittivity matrix.