Line data    Source code

       1            0 : // Distributed under the MIT License.
       2              : // See LICENSE.txt for details.
       3              : 
       4              : #pragma once
       5              : 
       6              : #include <cstddef>
       7              : 
       8              : #include "DataStructures/ModalVector.hpp"
       9              : #include "DataStructures/Tensor/Tensor.hpp"
      10              : #include "Utilities/TMPL.hpp"
      11              : 
      12              : namespace ylm {
      13              : /// @{
      14              : /*!
      15              :  * \brief Converts real spherical harmonic coefficients of degree l into a
      16              :  * symmetric trace-free tensor of rank l.
      17              :  *
      18              :  * \details Spherical harmonics of degree l are equivalent to symmetric
      19              :  * trace-free tensors of rank l. This equivalence and the transformation is
      20              :  * given e.g. in \cite Thorne1980, Eqs. (2.10) - (2.14). The conversion
      21              :  * coefficients are hard-coded to numerical precision and implemented up to
      22              :  * order l=2.
      23              :  *
      24              :  * The spherical harmonic coefficients are expected to be sorted with ascending
      25              :  * m, i.e. (-m, -m+1, ... , m)
      26              :  */
      27            1 : Scalar<double> ylm_to_stf_0(const ModalVector& l0_coefs);
      28              : 
      29              : template <typename Frame>
      30            1 : tnsr::i<double, 3, Frame> ylm_to_stf_1(const ModalVector& l1_coefs);
      31              : 
      32              : template <typename Frame>
      33            1 : tnsr::ii<double, 3, Frame> ylm_to_stf_2(const ModalVector& l2_coefs);
      34              : /// @}
      35              : }  // namespace ylm