def __getitem__(self, block):
if block not in self.blocks:
raise KeyError(f"Invalid block {block} requested. "
f"Available blocks are: {self.blocks}.")
if block not in self._tensors:
sym = libadcc.make_symmetry_operator(self.mospaces, block,
self.is_symmetric, "1")
self._tensors[block] = Tensor(sym)
return self._tensors[block]
def density(self):
"""
Return the Hartree-Fock density in the MO basis
"""
density = OneParticleOperator(self.mospaces, is_symmetric=True)
for b in density.blocks:
sym = libadcc.make_symmetry_operator(self.mospaces, b, True, "1")
density.set_block(b, Tensor(sym))
for ss in self.mospaces.subspaces_occupied:
density[ss + ss].set_mask("ii", 1)
density.reference_state = self
return density