acoustotreams.expand

acoustotreams.expand(basis, modetype=None, *, k0=None, material=AcousticMaterial(1.3, 343.0, 0.0), where=True)[source]

Expansion matrix.

Expand the modes from one basis set in the modes from another basis set. For spherical and cylindrical waves, the modetype can also be changed, for example, from singular to regular. Only those expansions are available that result in a discrete set of modes. For example, plane waves can be expanded in spherical waves, but the inverse transformation generally requires a continuous spectrum of plane waves, so that the transformation becomes an integral over this spectrum.

Parameters:

  • basis (ScalarBasisSet or tuple) – Basis set. If it is a tuple of two basis sets, the output and input modes are taken accordingly; otherwise, both sets of modes are the same.

  • modetype (str, optional) – Mode type, used for ScalarSphericalWaveBasis and ScalarCylindricalWaveBasis.

  • k0 (float, optional) – Angular wavenumber in the air.

  • material (AcousticMaterial or tuple, optional) – Material parameters. Defaults to the air.

  • where (array_like of bool, optional) – Only evaluate specified parts of the expansion matrix. The given array must have a shape that matches the output shape.