Missing force from nonlinear core correction
Adding the force term from the nonlinear core correction. A test is added.
The following plot shows the improvement on the F2 molecule, with the following parameters (Spacing 0.25 a.u., Radius 9 a.u.).
Fixes #99 (closed)
Adding the force term from the nonlinear core correction.
- I have checked that my code follows the Octopus coding standards
- I have added tests for all the new features added in this request.