Line data    Source code

       1           0 : // Distributed under the MIT License.
       2             : // See LICENSE.txt for details.
       3             : 
       4             : #pragma once
       5             : 
       6             : #include <utility>
       7             : 
       8             : namespace ScalarTensor {
       9             : /// @{
      10             : /*!
      11             :  * \brief Function to smoothly turn on the coupling terms.
      12             :  *
      13             :  * \details Implements Eq. B4 of \cite Okounkova:2019zjf :
      14             :  * \begin{align}
      15             :  *    t_*  &\equiv (t - t_\mathrm{s})/t_\mathrm{ramp} \,, \\
      16             :  *    F(t) &= t_*^5  (126 + t_* (-420 + t_* (540 + t_* (-315 + 70 t_*))))~,
      17             :  * \end{align}
      18             :  * where $ t_\mathrm{s} $ and $ t_\mathrm{ramp} $ are parameters that
      19             :  * control the start time and duration of the turn-on period.
      20             :  * Note that $F(t)$ is `smoothstep<4>`.
      21             :  */
      22           1 : double nonic_ramp_function(double time, double start_time, double ramp_time);
      23             : 
      24           1 : double nonic_ramp_function(double time,
      25             :                              std::pair<double, double> start_and_ramp_times);
      26             : /// @}
      27             : }  // namespace ScalarTensor