RKF45 is a C library which implements the Watt and Shampine RKF45 ODE solver.
The RKF45 ODE solver is a Runge-Kutta-Fehlberg algorithm for solving an ordinary differential equation, with automatic error estimation using rules of order 4 and 5.
The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.
RKF45 is available in a C version and a C++ version and a FORTRAN77 version and a FORTRAN90 version and a MATLAB version and a PYTHON version.
GSL, a C++ library which includes routines for solving differential equations.
NMS, a FORTRAN90 library which includes the DDRIV package of ODE solvers.
ODE, a C library which solves a system of ordinary differential equations, by Shampine and Gordon.
ODE_MOSHIER, a C library which implements the Adams-Bashforth-Moulton and Runge-Kutta (RK) methods of solving systems of ordinary differential equations, by Steven Moshier.
ODEPACK, a FORTRAN77 library which contains nine ODE solvers, including LSODE, LSODES, LSODA, LSODAR, LSODPK, LSODKR, LSODI, LSOIBT, and LSODIS, by Alan Hindmarsh.
RK4, a C library which applies the fourth order Runge-Kutta algorithm to estimate the solution of an ordinary differential equation at the next time step.
TEST_ODE, a FORTRAN90 library which contains routines which define some test problems for ODE solvers.
RKF45_PRB includes a number of examples of how to use RKF45.
RKF45_PRB2 includes an example in which the ODE includes parameters ALPHA, BETA, and GAMMA, which the user wants to set at run time. The example shows one way in which these values can be shared with the derivative routine.
You can go up one level to the C source codes.