5.7.6. dft.get_grad

eminus.dft.get_grad(scf, ik, spin, W, **kwargs)

Calculate the energy gradient with respect to W.

Reference: Comput. Phys. Commun. 128, 1.

Parameters:

• scf – SCF object.

• ik – k-point index.

• spin – Spin variable to track whether to do the calculation for spin up or down.

• W – Expansion coefficients of unconstrained wave functions in reciprocal space.

Keyword Arguments:

**kwargs – See H().

Returns:

Gradient.