void deriv_Schrodinger(double x, double y[], double dydx[], int k, double T[], double r[], double dr[], int N)
In standard form with change of variables, the equation we are solving is
Note that this equation requires 
, but, so that we can
use the same ``rk4p480'' we made for the Poisson solver, we only have
room in the prototype for one double precision array T[] in addition
to the change of variables information (r[], dr[], N). You thus
should define an array T[k]=E-Veff[k] in ``schint'', and pass it
into ``rk4p480'' and ``derivs_Schrodinger'' in the place which we
used for rho[] in the Poisson solver.