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MRKISS changelog

Author: Mitch Richling
Updated: 2025-09-16 10:00:14
Generated: 2025-09-21 13:16:27

Copyright © 2025 Mitch Richling. All rights reserved.

Table of Contents

1. v2025-09-10: Refactor Release

This release is a major refactor:

  • Renamed solvers:
    • Single step: step_rk4, step_rkf45, step_dp54, step_all, step_one, step_richardson
    • High level: fixed_t_steps, fixed_y_steps, sloppy_fixed_y_steps, adaptive_steps
    • Meta: fixed_t_steps_between, interpolate_solution
  • Any routine that worked with etabs, now works with an arbitrary number of embedded methods
  • All solvers now take uniform tableau arguments
  • All tableaux now have:
    • A single b matrix instead of vectors for each method
    • A p vector for the order of each method
    • An se vector for the number of steps for each method
    • m – the number of methods
  • Tableau Data
    • Machine readable tableaux for all methods
      • Tab separated, dense matrices
      • Support algebraic expressions for entries (rational numbers, roots, etc…)
      • Example Maple worksheets to create these kinds of files
    • Maple procedures to read tableaux, and
      • Process them for inclusion into Fortran & C
      • Produce stability region plots
      • Produce stability star plots
      • Produce numerator and denominator polynomials for stability functions
      • Compute roots for stability function numerator and denominator
  • Documentation
    • Doxygen comments now consistently use @ instead of \
    • All tableau modules now have stability graphs
    • Updated the tableau tables in index.org
  • Examples
    • Added step_too_small.f90
  • Bugs
    • adaptive_steps: Error computation bug (bounds incorrect)
    • adaptive_steps: Solution bound overflow (didn't check iteration count)
    • adaptive_steps: Added note about ifx compile options and updated make files.
    • seqt: Undefined behaviour removed.
  • Platforms Tested
    • Microsoft Windows 11 Pro 10.0.26100 Build 26100 running MSYS2
      • GNU Fortran (Rev6, Built by MSYS2 project) 15.1.0
      • Intel(R) Fortran Compiler for applications running on Intel(R) 64, Version 2024.1.0 Build 20240308
      • flang version 20.1.7 x86_64-w64-windows-gnu posix
    • Debian 13.0
      • GNU Fortran (Debian 14.2.0-19) 14.2.0
      • ifx (IFX) 2025.0.4 20241205 (lorenz_test fails, but it's OK.)
      • Debian flang-new version 19.1.7 (3) x86_64-pc-linux-gnu posix (lorenz_test fails, but it's OK.)

2. v2025-08-15: Documentation & Cleanup Release

  • New functionality
    • seq has new argument: max_pts_o
  • Documentation
    • All routines have full Doxygen documentation
    • Added inline source to small Butcher Tableaux
    • Added details to some example top comments.
    • Example org docs now pull summary from oxygen comments
  • Miscellaneous
    • one_step_stab() & one_step_etab() are slightly faster.

3. v2025-08-12: Feature & Bugfix Release

  • Fixed Bugs
    • analyze_solution(): Fixed bug with output files going to STDOUT.
  • API breaking Changes
    • analyze_solution(): removed arguments:
      • y_dim_o
      • sol_y_idx_o
    • print_solution(): renamed arguments
      • width_o => fmt_w_o
      • digits_o => fmt_d_o
    • Renumbered istats elements
  • New functionality
    • Reworked I/O significantly across mrkiss_utils functions.
    • Finalized a stepsize control in steps_adapt_etab
    • New constant in config: t_delta_min_ai
      • Most solvers use this instead of t_delta_tiny for the default t_delta_min
    • analyze_solution() new argumetns:
      • fmt_w_o with default fmt_w_ai
      • fmt_d_o with default fmt_d_ai
      • fmt_e_o with default fmt_e_ai
    • print_istats(): New arguments:
      • fmt_w_o with default fmt_w_ai
      • prt_zeros_o with default .false. Zero elements are not printed by default now.
    • Added istats message table to mrkiss_config. print_istats now uses it.
    • Added two elements to istats and renumbered items.
      • isi_etab_norm
      • isi_etab_y_err
    • print_solution
      • New argument: fmt_e_o with default fmt_d_ai
      • Renamed width_o to fmt_w_o
      • If -1 is used for fmt_w_o, then it is set to fmt_w_ai
      • Renamed digits_o to fmt_d_o and gave it a new default: fmt_d_ai
    • Added new output format constants to mrkiss_config
      • fmt_d_ai
      • fmt_w_ai
      • fmt_e_ai
  • Documentation
    • Rewrote much of main index page.
    • Cleaned up whitespace in several comments.
  • Tests
    • New
      • utils.f90: Test utilities print functions.
  • Miscellaneous
    • Collapsed declaration lines in all modules.
    • Removed unnecessary imports of t_delta_tiny
  • Platforms Tested
    • Microsoft Windows 11 Pro 10.0.26100 Build 26100 running MSYS2
      • GNU Fortran (Rev6, Built by MSYS2 project) 15.1.0
      • Intel(R) Fortran Compiler for applications running on Intel(R) 64, Version 2024.1.0 Build 20240308
      • flang version 20.1.7 x86_64-w64-windows-gnu posix (lorenz_test fails, but it's OK.)
    • Debian 13.0
      • GNU Fortran (Debian 14.2.0-19) 14.2.0
      • ifx (IFX) 2025.0.4 20241205 (lorenz_test fails, but it's OK.)
      • Debian flang-new version 19.1.7 (3) x86_64-pc-linux-gnu posix (lorenz_test fails, but it's OK.)

4. v2025-08-10: Feature/Refactor

  • Fixed Bugs
    • Fixed integer type for out_io_stat & out_io_unit
  • API breaking Changes
    • interpolate_solution(): Add istats() argument.
    • Removed logical kind from library.
    • Removed integer kind from library.
    • status_to_origin() return changed from len=64 to len=32
    • Removed _wt & _nt suffixes on contents of mrkiss_solvers_wt & mrkiss_solvers_nt
  • New functionality
    • print_istats()
    • istats constants:
      • istats_max_idx
      • isi_num_pts
      • isi_step_norm
      • isi_step_y_len
      • isi_step_y_err
      • isi_step_spp_td
      • isi_step_sdf_bic
      • isi_bic_fail_max
      • isi_bic_fail_bnd
    • All solvers now use isi_* constants to update istats
    • status_to_origin() & status_to_message() have better messages now.
  • Documentation
    • Reworked istats() descriptions.
    • Added references to print_istats() & status_to_message().
    • Added refs to all called routines from callers
    • Added returns from all called routines
  • Examples
    • Updated
      • Langford
        • Updated for OpenMP
        • Added writeup
      • three_body
        • Now demos print_istats() & status_to_message()
  • Platforms Tested
    • Microsoft Windows 11 Pro 10.0.26100 Build 26100 running MSYS2
      • GNU Fortran (Rev6, Built by MSYS2 project) 15.1.0
      • Intel(R) Fortran Compiler for applications running on Intel(R) 64, Version 2024.1.0 Build 20240308
      • flang version 20.1.7 x86_64-w64-windows-gnu posix (lorenz_test fails, but it's OK.)
    • Debian 13.0
      • GNU Fortran (Debian 14.2.0-19) 14.2.0
      • ifx (IFX) 2025.0.4 20241205 (lorenz_test fails, but it's OK.)
      • Debian flang-new version 19.1.7 (3) x86_64-pc-linux-gnu posix (lorenz_test fails, but it's OK.)

5. v2025-08-09: Feature Release

  • Fixed Bugs
    • print_solution: Fixed bug with
    • interpolate_solution: Fixed bug with optional argument
    • steps_condy_stab_*t & steps_adapt_etab_*t: : Fixed bug with optional argument
  • API breaking Changes
    • Removed 'version' from mrkiss_config
    • Removed all sol_no_dy_o, sol_no_t_o, sol_w_dy_o, sol_w_t_o, sol_y_idx_o arguments.
    • no_bisect_error_o is not logical, and it's value matters.
    • Richardson extrapolation used in steps_fixed_stab_wt() when when p_o>0 – not just present().
    • no_titles_o => titles_o in print_solution. Value now used. Usage inverted.
  • New functionality
    • status_to_origin(): Returns source for status code
    • status_to_message(): Returns message for status code
    • istats_size: Constant for istats size
    • steps_points_stab_wt(): Solutions at given t values.
    • print_solution(): Added append_o option.
  • Documentation
    • Doxygen links in main README & mainpage.
    • Better mainpage markup
    • Consolidated list of status assignments
    • Documented parameters in eerk & erk modules.
  • Examples
    • New
      • step_order_vs_error.f90
  • Tests
    • New
      • tests/test_rk4_frog_vs_steps: Compare frog output to last line of steps
      • lib/test_build: Test code generation & module build
      • tests/test_statuscodes: Test status_to_origin() & status_to_message().
  • Miscellaneous
    • Release automation complete
    • Added makefile to scripts directory to update them from primary copies
    • Added 'wt2nt:DELETE' tags to mrkiss_solvers_wt -> mrkiss_solvers_nt code
  • Platforms Tested
    • Microsoft Windows 11 Pro 10.0.26100 Build 26100 running MSYS2
      • GNU Fortran (Rev6, Built by MSYS2 project) 15.1.0
      • Intel(R) Fortran Compiler for applications running on Intel(R) 64, Version 2024.1.0 Build 20240308
      • flang version 20.1.7 x86_64-w64-windows-gnu posix (lorenz_test fails, but it's OK.)
    • Debian 13.0
      • GNU Fortran (Debian 14.2.0-19) 14.2.0
      • nvfortran 24.11-0 64-bit target on x86-64 Linux -tp tigerlake (requires reformatting the code to line length limitations)
      • ifx (IFX) 2025.0.4 20241205 (lorenz_test fails, but it's OK.)
      • Debian flang-new version 19.1.7 (3) x86_64-pc-linux-gnu posix (lorenz_test fails, but it's OK.)

6. v2025-08-04: Initial Release

  • Platforms Tested
    • Microsoft Windows 11 Pro 10.0.26100 Build 26100 running MSYS2
      • GNU Fortran (Rev6, Built by MSYS2 project) 15.1.0
      • Intel(R) Fortran Compiler for applications running on Intel(R) 64, Version 2024.1.0 Build 20240308