MRKISS 2025-09-10
A tiny library with zero dependencies that aims to make it easy to use & experiment with explicit Runge-Kutta methods.
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mrkiss_eerk_fehlberg_7_8 Module Reference

Butcher tableau for Fehlberg's 13 stage, Order (7,8) Runge-Kutta method. More...

Variables

integer, parameter s = 13
 The order of the overall method.
integer, parameter m = 2
 Number of methods.
real(kind=rk), dimension(s, s), parameter a
 The \(\mathbf{a}\) matrix for the Butcher Tableau.
real(kind=rk), dimension(s, m), parameter b
 The \(\mathbf{b}\) matrix for the Butcher Tableau.
real(kind=rk), dimension(s), parameter c
 The \(\mathbf{c}\) matrix for the Butcher Tableau.
integer, dimension(m), parameter p = [7, 8]
 The method orders.
integer, dimension(m), parameter se = [11, 13]
 Number of stages for each method.

Detailed Description

Butcher tableau for Fehlberg's 13 stage, Order (7,8) Runge-Kutta method.

IMO
Included for historical reasons. Performs poorly in local extrapolation mode. This one was pretty broadly used, but not nearly as much as mrkiss_eerk_fehlberg_4_5. It was largely replaced by mrkiss_eerk_dormand_prince_7_8.
Known Aliases
'RKF78'', 'ode78' (OrdinaryDiffEq.jl), 'ARKODE_FEHLBERG_13_7_8' (SUNDIALS).
Stability Image Links
References:
  • Erwin Fehlberg (1972); Classical eight- and lower-order Runge-Kutta-Nystroem formulas with stepsize control for special second-order differential equations; NASA Technical Report M-533
  • Butcher (2008); Numerical Methods for Ordinary Differential Equations. 2ed; p209; zotero://select/items/0_8V2GY73E
  • Butcher (2016); Numerical Methods for Ordinary Differential Equations. 3ed; p222; zotero://select/items/0_V7UTIRPT
  • Hairer, Norsett & Wanner (2009). Solving Ordinary Differential Equations. I: Nonstiff Problems. p180;

Variable Documentation

◆ s

integer, parameter mrkiss_eerk_fehlberg_7_8::s = 13

The order of the overall method.

Definition at line 66 of file mrkiss_eerk_fehlberg_7_8.f90.

◆ m

integer, parameter mrkiss_eerk_fehlberg_7_8::m = 2

Number of methods.

Definition at line 68 of file mrkiss_eerk_fehlberg_7_8.f90.

◆ a

real(kind=rk), dimension(s,s), parameter mrkiss_eerk_fehlberg_7_8::a

The \(\mathbf{a}\) matrix for the Butcher Tableau.

Definition at line 70 of file mrkiss_eerk_fehlberg_7_8.f90.

◆ b

real(kind=rk), dimension(s,m), parameter mrkiss_eerk_fehlberg_7_8::b

The \(\mathbf{b}\) matrix for the Butcher Tableau.

Definition at line 84 of file mrkiss_eerk_fehlberg_7_8.f90.

◆ c

real(kind=rk), dimension(s), parameter mrkiss_eerk_fehlberg_7_8::c

The \(\mathbf{c}\) matrix for the Butcher Tableau.

Definition at line 87 of file mrkiss_eerk_fehlberg_7_8.f90.

◆ p

integer, dimension(m), parameter mrkiss_eerk_fehlberg_7_8::p = [7, 8]

The method orders.

Definition at line 89 of file mrkiss_eerk_fehlberg_7_8.f90.

◆ se

integer, dimension(m), parameter mrkiss_eerk_fehlberg_7_8::se = [11, 13]

Number of stages for each method.

Definition at line 91 of file mrkiss_eerk_fehlberg_7_8.f90.