Schrödinger energy solver

As discussed in lecture, our basic strategy to find the energies of the atom is to set $\Psi=0$ and $\Psi'=1$ at one end of our solution ($r=0$ or $r\rightarrow\infty$), define a function $f(E)$ as the value of $\Psi$ at the other end, and then seek the roots of $f(E)$.

As discussed in class, there are a variety of methods for root finding, solving one equation in one unknown of the form $f(x)=0$. Computationally, these methods depend upon calling a function subroutine which returns the value of the function $f(x)$ for any input value $x$. In this problem, we will implement versions of two of the Numerical Recipes subroutines for doing this, rtbisp480() and zriddrp480(). As with rk4p480(), we will also have to write a helper routine, which in this case we call func_Schrodinger().