mrkiss_config.f90

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! -*- Mode:F90; Coding:us-ascii-unix; fill-column:129 -*-
!.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!.H.S.!!
!>
!! @file      mrkiss_config.f90
!! @author    Mitch Richling http://www.mitchr.me/
!! @brief     Configuration for MRKISS == MR RK KISS == Mitch Richling's Runge-Kutta Keep It Simple Stupid.@EOL
!! @std       F2023
!! @see       https://github.com/richmit/MRKISS/
!! @copyright
!!  @parblock
!!  Copyright (c) 2025, Mitchell Jay Richling <http://www.mitchr.me/> All rights reserved.
!!
!!  Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following
!!  conditions are met:
!!
!!  1. Redistributions of source code must retain the above copyright notice, this list of conditions, and the following
!!     disclaimer.
!!
!!  2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions, and the following
!!     disclaimer in the documentation and/or other materials provided with the distribution.
!!
!!  3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products
!!     derived from this software without specific prior written permission.
!!
!!  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
!!  INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
!!  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
!!  EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
!!  USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
!!  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
!!  OF THE POSSIBILITY OF SUCH DAMAGE.
!!  @endparblock
!.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!.H.E.!!
 
!----------------------------------------------------------------------------------------------------------------------------------
!> Configuration for MRKISS == MR RK KISS == Mitch Richling's Runge-Kutta Keep It Simple Stupid
!!
module mrkiss_config
  use, intrinsic:: iso_c_binding, only: c_double, c_float
  implicit none
  private
 
  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
  !> @name Real type used for computations
 
  integer,       parameter, public :: rk                 = c_double   !< Real kind used across the library
 
  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
  !> @name ab initio frmat specificaiton constants
 
  integer,       parameter, public :: fmt_d_ai           = 15 !< Real print format: digits to the right of decimal
  integer,       parameter, public :: fmt_w_ai           = 25 !< Numeric print format: total width
  integer,       parameter, public :: fmt_e_ai           = 4  !< Real print format: digits in exponent
 
  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
  !> @name Constants related to istats
 
  integer,       parameter, public :: istats_size      = 16  !< Number of elements in istats(:)
  integer,       parameter, public :: istats_max_idx   = 10  !< Number of used elements in istats(:)
 
  integer,       parameter, public :: isi_num_pts      = 1   !< istats index num_pts
  integer,       parameter, public :: isi_one_reg      = 2   !< istats index one_step_norm
  integer,       parameter, public :: isi_all_norm     = 3   !< istats index one_etab_norm
  integer,       parameter, public :: isi_one_y_err    = 4   !< istats index one_step_y_delta_err
  integer,       parameter, public :: isi_all_y_err    = 5   !< istats index one_stab_y_delta_err
  integer,       parameter, public :: isi_one_y_len    = 6   !< istats index one_step_y_delta_len
  integer,       parameter, public :: isi_one_spp_td   = 7   !< istats index one_step_stepp_t_delta
  integer,       parameter, public :: isi_sdf_step     = 8   !< istats index one_step_sdf_bisection
  integer,       parameter, public :: isi_bic_max      = 9   !< istats index bisect_fail_max
  integer,       parameter, public :: isi_bic_bnd      = 10  !< istats index bisect_fail_containment
 
  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
  !> @name Constants related to istats messages
 
  integer,                       parameter, public :: istats_str_lng           = 62       !< Length of istats content message
  !> Array of istats descriptions
  !! @showinlinesource
  character(len=istats_str_lng), parameter, public :: istats_strs(istats_size) = [     &
! SS-BEGIN:istats_strings:
       "Computed solution points                                      ", &  ! istats( 1)
       "step_one call count not caused by an event                    ", &  ! istats( 2)
       "step_all call count not caused by an event                    ", &  ! istats( 3)
       "step_one call count caused by y_delta error constraint        ", &  ! istats( 4)
       "step_all call count caused by y_delta error constraint        ", &  ! istats( 5)
       "step_one call count caused by y_delta length constraint       ", &  ! istats( 6)
       "step_one call count caused by step processing with new t_delta", &  ! istats( 7)
       "step_one call count caused by SDF bisection                   ", &  ! istats( 8)
       "Bisection failures due to max_bisect_o                        ", &  ! istats( 9)
       "Bisection failures due to target containment                  ", &  ! istats(10)
       "                                                              ", &  ! istats(11)
       "                                                              ", &  ! istats(12)
       "                                                              ", &  ! istats(13)
       "                                                              ", &  ! istats(14)
       "                                                              ", &  ! istats(15)
       "                                                              "  ]
! SS-END:istats_strings:
 
  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
  !> @name Absolute constants
 
  real(kind=rk), parameter, public :: zero_epsilon       = 1.0e-12_rk                      !< Used to test for zero
  real(kind=rk), parameter, public :: t_delta_tiny       = tiny(zero_epsilon) * 1.0e18_rk  !< Smallest value for t_delta
 
  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
  !> @name ab initio parameters for defaults when we know nothing
 
  real(kind=rk), parameter, public :: t_delta_ai         = 1.0e-4_rk    !< t_delta ai default
  real(kind=rk), parameter, public :: error_tol_abs_ai   = 1.0e-5_rk    !< error_tol_abs ai default
  real(kind=rk), parameter, public :: error_tol_rel_ai   = 1.0e-3_rk    !< error_tol_rel ai default
  integer,       parameter, public :: max_bisect_ai      = 1000         !< max_bisect ai default
  real(kind=rk), parameter, public :: t_delta_fac_min_ai = 0.5_rk       !< t_delta_fac_min ai default
  real(kind=rk), parameter, public :: t_delta_fac_max_ai = 2.0_rk       !< t_delta_fac_max ai default
  real(kind=rk), parameter, public :: t_delta_fac_fdg_ai = 0.5_rk       !< t_delta_fac_fdg ai default
  real(kind=rk), parameter, public :: sdf_tol_ai         = 1.0e-3       !< sdf_tol ai default
  real(kind=rk), parameter, public :: t_delta_min_ai     = t_delta_tiny !< t_delta_min ai default
 
end module mrkiss_config
 
 
!----------------------------------------------------------------------------------------------------------------------------------
!> @mainpage
!!
!! @image html MRKISS_logo_c_500x250.png
!!
!! MRKISS == MR RK KISS == Mitch Richling's Runge-Kutta Keep It Simple Stupid
!!
!! [MRKISS](https://github.com/richmit/MRKISS) is a *tiny* library with *zero dependencies* that aims to make it easy to *use*
!! and *experiment with* explicit Runge-Kutta methods.
!!
!! Everything is on github: https://github.com/richmit/MRKISS
!!
!! For an overview of MRKISS and some tutorial information, check out the [documentation](https://richmit.github.io/MRKISS/index.html).
!!
!! A couple of the examples in the repository have longer explanatory documentation:
!!    - [Three Body Problem](https://richmit.github.io/MRKISS/ex_three_body.html)
!!    - [Lornez Attracter](https://richmit.github.io/MRKISS/ex_lorenz.html)
!!    - [Step Size & Order Vs. Accuracy](https://richmit.github.io/MRKISS/ex_step_order_vs_error.html)
!!    - [Langford Attracter](https://richmit.github.io/MRKISS/ex_langford.html)
!!    - [Step Size Vs. Accuracy](https://richmit.github.io/MRKISS/ex_step_too_far.html)
!!
!! Generated [API documentation](https://www.mitchr.me/SS/MRKISS/doc-lib/html/index.html) is viable as well.
!!
!! Development News:
!!   - [changelog](https://richmit.github.io/MRKISS/changelog.html)
!!   - [roadmap](https://richmit.github.io/MRKISS/roadmap.html)
!!
!! This library powers the [Strange Attractor Zoo](https://richmit.github.io/StrangeAttractorZoo/).
!!
!! The canonical URL for this documentation: https://www.mitchr.me/SS/MRKISS/doc-lib/html/index.html
!!