class CoupledClusterPerturbativeTriples(CoupledClusterSinglesDoubles):
def __init__(self, hartree_fock, threshold=1e-12):
super().__init__(hartree_fock, threshold)
self.singles_doubles_correlation, self.t_singles_doubles = self.calculate_singles_doubles()
self.amplitudes_factory = PeturbativeTriples(self.repulsion, self.orbital_energies, self.occupied_orbitals,
self.unoccupied_orbitals)
def calculate_perturbative_triples(self):
print('\n*************************************************************************************************')
print('\nBEGIN CCSD(T) CALCULATION')
start = time.clock()
t_connected, t_disconnected = self.amplitudes_factory.calculate_triples_amplitudes(self.t_singles_doubles)
correlation_triples = self.perturbative_triples_correlation(t_connected, t_disconnected)
correlation = self.singles_doubles_correlation + correlation_triples
print('CCSD(T) SINGLES AND DOUBLES CORRELATION ENERGY: ' + str(self.singles_doubles_correlation) + ' a.u.')
print('CCSD(T) TRIPLES CORRELATION ENERGY: ' + str(correlation_triples) + ' a.u.')
print('CCSD(T) CORRELATION ENERGY: ' + str(correlation) + ' a.u.')
print('TIME TAKEN: ' + str(time.clock() - start) + 's\n\n')
return correlation
def perturbative_triples_correlation(self, t_connected, t_disconnected):
correlation_triples = 0
d = self.amplitudes_factory.denominator
for i, j, k, a, b, c in self.triples():
correlation_triples += (1 / 36) * t_connected[i, j, k, a, b, c] * d[i, j, k, a, b, c] \
* (t_connected[i, j, k, a, b, c] + t_disconnected[i, j, k, a, b, c])
return correlation_triples
def __init__(self, hartree_fock, threshold=1e-12):
super().__init__(hartree_fock, threshold)
self.singles_doubles_correlation, self.t_singles_doubles = self.calculate_singles_doubles()
self.amplitudes_factory = PeturbativeTriples(self.repulsion, self.orbital_energies, self.occupied_orbitals,
self.unoccupied_orbitals)