acoustotreams.scw.translate_periodic

acoustotreams.scw.translate_periodic(k, kpar, a, rs, out, in_=None, rsin=None, eta=0)

Translation coefficients for cylindrical waves on a lattice.

Return the translation coefficents for the given modes on a lattice. The computations employ the fast converging Ewald summation from treams.lattice.

Parameters:

• k (float or complex) – Angular wavenumber in the medium.

• kpar ((D,)-array of float) – Parallel component of the wave vector. Has units of k. Defines the dimension with 1 <= D <= 2.

• a ((D,D)-array of float) – Lattice vectors in each row of the array. Have units of 1/k.

• rs ((M, 3)-array of float) – Shift vectors with respect to one lattice point. Have units of 1/k.

• out (2- or 3-tuple of arrays) – Output modes. If len(out) == 2, out[0] may be float and out[1] must be integer. If len(out) == 3, out[1] may be float, while out[0] and out[2] must be integer.

• in (2- or 3-tuple of arrays) – Input modes. If None is given, they are equal to the output modes. If len(in_) == 2, in_[0] may be float and in_[1] must be integer. If len(in_) == 3, in_[1] may be float, while in_[0] and in_[2] must be integer.

• rsin (float) – Shift vectors of the input modes. If None is given, they are equal to rs. Have units of 1/k.

• eta (float or complex, optional) – Splitting parameter for the Ewald summation of lattice sums. If zero, an estimation for the optimal value is done. Defaults to zero.

Returns:

array_like of complex