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/DataVector.hpp"
       9             : #include "Utilities/Gsl.hpp"
      10             : 
      11             : namespace ylm {
      12             : /// @{
      13             : /*!
      14             :  * \ingroup SpectralGroup
      15             :  *
      16             :  * \brief Evaluates a real spherical harmonic of order l at the requested
      17             :  * angles \f$\theta\f$ and \f$\phi\f$.
      18             :  *
      19             :  * The real spherical harmonics are defined as:
      20             :  * \begin{equation}
      21             :  * Y_{lm}(\theta, \phi) =
      22             :  * \begin{cases}
      23             :  * \sqrt{2} (-1)^m \mathcal{I}[Y_l^{|m|}] & \text{if } m < 0 \\
      24             :  *  Y_l^{0} & \text{if } m = 0 \\
      25             :  * \sqrt{2} (-1)^m \mathcal{R}[Y_l^{m}] & \text{if } m > 0
      26             :  * \end{cases}
      27             :  * \end{equation}
      28             :  *
      29             :  * where \f$Y_l^m\f$ are the complex spherical harmonics and \f$\mathcal{R}\f$
      30             :  * denotes the real part and \f$\mathcal{I}\f$ denotes the imaginary part.
      31             :  *
      32             :  * \note This implementation uses the boost implementation of spherical
      33             :  * harmonics. The calculation is not vectorized and may be slow.
      34             :  * Stability has not been tested for large l.
      35             :  */
      36           1 : void real_spherical_harmonic(gsl::not_null<DataVector*> spherical_harmonic,
      37             :                              const DataVector& theta, const DataVector& phi,
      38             :                              size_t l, int m);
      39             : 
      40           1 : DataVector real_spherical_harmonic(const DataVector& theta,
      41             :                                    const DataVector& phi, size_t l, int m);
      42             : /// @}
      43             : }  // namespace ylm