Solution of Schrödinger's equation using steepest descents: sd()

With the completion of get() and getgrad(), you are ready to solve Schrödinger's equation with the simple steepest descents algorithm described in lecture:

1. Initialize $W$
2. $W \leftarrow W - \alpha \nabla_W E$
3. Display $E$
4. Repeat (2 & 3) until converged