ODE_MOSHIER, a C library which solves systems of ordinary differential equations. Two main methods are implemented, the Adams-Bashforth-Moulton integrator, and the Runge-Kutta integrator, by Steven Moshier.
ODE_MOSHIER is available in a C version.
ODE, a C library which solves a system of ordinary differential equations, by Shampine and Gordon.
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.
RKF45, a C library which implements the Watt and Shampine RKF45 ODE solver.
Steven Moshier