UCCSD.same_ao_double_excitation_block_spin

static UCCSD.same_ao_double_excitation_block_spin(de_1, de_2, num_orbitals)[source]

Regroups the excitations that involve same spatial orbitals for example, with labeling.

2— —5 1— —4 0-o- -o-3

excitations [0,1,3,5] and [0,2,3,4] are controlled by the same parameter in the full singlet UCCSD unlike in usual UCCSD where every excitation is controlled by independent parameter.

Parameters

  • de_1 (list) – double exc in block spin [ from to from to ]

  • de_2 (list) – double exc in block spin [ from to from to ]

  • num_orbitals (int) – number of molecular orbitals

Returns

says if given excitation involves same spatial orbitals 1 = yes, 0 = no.

Return type

int