Line data    Source code

       1            0 : // Distributed under the MIT License.
       2              : // See LICENSE.txt for details.
       3              : 
       4              : #pragma once
       5              : 
       6              : namespace CurvedScalarWave::Worldtube {
       7              : 
       8              : namespace detail {
       9              : 
      10              : void check_alpha(double alpha);
      11              : 
      12              : void check_delta(double delta);
      13              : }  // namespace detail
      14              : 
      15              : /*!
      16              :  * \brief A smoothly broken power law that falls off to a constant value
      17              :  * for larger radii.
      18              :  *
      19              :  * \details The function is given by Eq. (3) of \cite Wittek:2024pis
      20              :  *
      21              :  * \begin{equation}
      22              :  * f(r) = R_\infty \left(\frac{r}{r_b}\right)^{\alpha} \left( 1 +
      23              :  * \left(\frac{r}{r_b}\right)^{1 / \Delta}\right)^{-\alpha\Delta}.
      24              :  * \end{equation}
      25              :  *
      26              :  * For radii $r \ll r_b$, the function obeys the power law $f(r) \propto
      27              :  * r^{\alpha}$. For radii $r \gg r_b$, the function asymptotes to $R_\infty$.
      28              :  * The parameter $\Delta$ determines the width of the transition region with a
      29              :  * larger value of $\Delta$ leading to a more gradual transition.
      30              :  *
      31              :  * This function is used to control the worldtube radius for more eccentric
      32              :  * orbits so the radius does not grow too large during the apoapsis passage
      33              :  * as this does not lead to performance gains and can cause problems with the
      34              :  * domain.
      35              :  */
      36            1 : double smooth_broken_power_law(double orbit_radius, double alpha,
      37              :                                double radius_at_inf, double rb, double delta);
      38              : /*!
      39              :  * \brief Returns the analytical derivative of `smooth_broken_power_law`.
      40              :  */
      41            1 : double smooth_broken_power_law_derivative(double orbit_radius, double alpha,
      42              :                                           double radius_at_inf, double rb,
      43              :                                           double delta);
      44              : }  // namespace CurvedScalarWave::Worldtube