kdv_exact, a C code which evaluates an exact solution u(x,t) of the Korteweg-deVries (KdV) partial differential equation (PDE), representing the motion of a soliton. The equation has the form u' - 6 u ux + uxxx = 0.
The equation for u(x,t), the height of the wave, has the form
        ut - 6 u ux + uxxx = 0
      for which an exact solution is
        u(x,t) = - 1/2 v ( sech ( 1/2 * sqrt ( v ) * ( x - v * t - a ) )^2
      where parameter "a" is an arbitrary phase, and "v" represents 
      the wave velocity.
    
    The information on this web page is distributed under the MIT license.
kdv_exact 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.
c_exact, a C code which evaluates exact solutions to a few selected examples of ordinary differential equations (ODE) and partial differential equations (PDE).