lorenz96_ode, a Fortran90 code which sets up and solves a system of ordinary differential equations (ODE) devised by Edward Lorenz, as a test of predictability for data assimilation applications.
The Lorenz system involves N => 4 differential equations of the identical form:
dy(i)/dt = ( y(i+1) - y(i-2) ) * y(i-1) - y(i) + force
where force is a constant independent of i and the indices wrap around.
A typical value for force is 8. In a typical initial condition, all entries of y are set to force plus a random value with mean 0 and variance 0.001.
The information on this web page is distributed under the MIT license.
lorenz96_ode is available in a C version and a C++ version and a Fortran90 version and a MATLAB version and an Octave version and a Python version.
f90_ode, a Fortran90 code which sets up various systems of ordinary differential equations (ODE).
gnuplot_test, a Fortran90 code which illustrates the use of the gnuplot() graphics program.