DCHF DIIS convergence problems

[pulkin]

DCHF does not converge fast enough when using pyscf.diis. Disabling diis fixes problem for small models, however, the source of the issue is unknown.

local-pyscf/test_dchf.py

Line 61 in 18f2c3f

cls.h6dchf_3.kernel(fock_hook=None)

local-pyscf/test_dchf.py

Line 151 in 18f2c3f

e = self.h12dchf.kernel(tolerance=1e-9, fock_hook=None)

This plot demonstrates the issue: