A code to compute the action-angle transformation for a particle in an arbitrary potential well

For a Vlasov treatment of longitudinal stability under an arbitrary wake field with the solution of the Haissinski equation as the unperturbed distribution, it is important to have the action-angle transformation for the distorted potential well in a convenient form. We have written a code that gives the transformation q, p/spl rarr/J, /spl phi/, with q(J, /spl phi/) as a Fourier series in /spl phi/, the Fourier coefficients and the Hamiltonian H(J) being spline functions of J in C/sup 2/ (having continuous second derivatives).