def init_mps(self):
mmax = self.optimize_config.procedure[0][0]
i_mps = Mps.random(self.h_mpo.model, self.nexciton, mmax, 1)
i_mps.optimize_config = self.optimize_config
energy, i_mps = gs.optimize_mps(i_mps, self.h_mpo)
if self.spectratype == "emi":
operator = "a"
else:
operator = r"a^\dagger"
dipole_mpo = Mpo.onsite(self.model, operator, dipole=True)
if self.temperature != 0:
beta = self.temperature.to_beta()
# print "beta=", beta
# thermal_mpo = Mpo.exact_propagator(self.model, -beta / 2.0, space=self.space1, shift=self.shift1)
# ket_mps = thermal_mpo.apply(i_mps)
# ket_mps.normalize()
# no test, don't know work or not
i_mpdm = MpDm.from_mps(i_mps)
tp = ThermalProp(i_mpdm, self.h_mpo, exact=True, space=self.space1)
tp.evolve(None, 1, beta / 2j)
ket_mps = tp.latest_mps
else:
ket_mps = i_mps
a_ket_mps = dipole_mpo.apply(ket_mps, canonicalise=True)
a_ket_mps.canonical_normalize()
if self.temperature != 0:
a_bra_mps = ket_mps.copy()
else:
a_bra_mps = a_ket_mps.copy()
return BraKetPair(a_bra_mps, a_ket_mps)
def test_from_mps():
gs = Mps.random(parameter.holstein_model, 1, 20)
gs_mpdm = MpDm.from_mps(gs)
assert np.allclose(gs.e_occupations, gs_mpdm.e_occupations)
gs = gs.canonicalise()
gs_mpdm = gs_mpdm.canonicalise()
assert np.allclose(gs.e_occupations, gs_mpdm.e_occupations)
def test_svd_compress(comp, mp):
if mp == "mpo":
mps = Mpo(holstein_model)
M = 22
else:
mps = Mps.random(holstein_model, 1, 10)
if mp == "mpdm":
mps = MpDm.from_mps(mps)
mps.canonicalise().normalize()
M = 36
if comp:
mps = mps.to_complex(inplace=True)
print(f"{mps}")
mpo = Mpo(holstein_model)
if comp:
mpo = mpo.scale(-1.0j)
print(f"{mpo.bond_dims}")
std_mps = mpo.apply(mps, canonicalise=True).canonicalise()
print(f"std_mps: {std_mps}")
mps.compress_config.bond_dim_max_value = M
mps.compress_config.criteria = CompressCriteria.fixed
svd_mps = mpo.contract(mps)
dis = svd_mps.distance(std_mps) / std_mps.dmrg_norm
print(f"svd_mps: {svd_mps}, dis: {dis}")
assert np.allclose(dis, 0.0, atol=1e-3)
assert np.allclose(svd_mps.dmrg_norm, std_mps.dmrg_norm, atol=1e-4)
def init_mps(self):
tentative_mpo = Mpo(self.mol_list)
if self.temperature == 0:
gs_mp = Mps.gs(self.mol_list, max_entangled=False)
if self.dissipation != 0:
gs_mp = MpDm.from_mps(gs_mp)
else:
gs_mp = MpDm.max_entangled_gs(self.mol_list)
# subtract the energy otherwise might cause numeric error because of large offset * dbeta
energy = Quantity(gs_mp.expectation(tentative_mpo))
mpo = Mpo(self.mol_list, offset=energy)
tp = ThermalProp(gs_mp, mpo, exact=True, space="GS")
tp.evolve(None, len(gs_mp), self.temperature.to_beta() / 2j)
gs_mp = tp.latest_mps
init_mp = self.create_electron(gs_mp)
if self.dissipation != 0:
init_mp = MpDmFull.from_mpdm(init_mp)
energy = Quantity(init_mp.expectation(tentative_mpo))
self.mpo = Mpo(self.mol_list, offset=energy)
logger.info(f"mpo bond dims: {self.mpo.bond_dims}")
logger.info(f"mpo physical dims: {self.mpo.pbond_list}")
if self.dissipation != 0:
self.mpo = SuperLiouville(self.mpo, self.dissipation)
init_mp.canonicalise()
init_mp.evolve_config = self.evolve_config
# init the compress config if not using threshold and not set
if self.compress_config.criteria is not CompressCriteria.threshold\
and self.compress_config.max_dims is None:
self.compress_config.set_bonddim(length=len(init_mp) + 1)
init_mp.compress_config = self.compress_config
# init_mp.invalidate_cache()
return init_mp
def f(mol_list, run_qutip=True):
tentative_mpo = Mpo(mol_list)
init_mps = (Mpo.onsite(mol_list, r"a^\dagger", mol_idx_set={0}) @ Mps.gs(
mol_list, False)).expand_bond_dimension(hint_mpo=tentative_mpo)
init_mpdm = MpDm.from_mps(init_mps).expand_bond_dimension(
hint_mpo=tentative_mpo)
e = init_mps.expectation(tentative_mpo)
mpo = Mpo(mol_list, offset=Quantity(e))
if run_qutip:
# calculate result in ZT. FT result is exactly the same
TIME_LIMIT = 10
QUTIP_STEP = 0.01
N_POINTS = TIME_LIMIT / QUTIP_STEP + 1
qutip_time_series = np.linspace(0, TIME_LIMIT, N_POINTS)
init = qutip.Qobj(init_mps.full_wfn(),
[qutip_h.dims[0], [1] * len(qutip_h.dims[0])])
# the result is not exact and the error scale is approximately 1e-5
res = qutip.sesolve(qutip_h - e,
init,
qutip_time_series,
e_ops=[c.dag() * c for c in qutip_clist])
qutip_expectations = np.array(res.expect).T
return qutip_expectations, QUTIP_STEP, init_mps, init_mpdm, mpo
else:
return init_mps, init_mpdm, mpo
def test_environ_multi_mpo(mpdm):
mps = Mps.random(holstein_model, 1, 10)
if mpdm:
mps = MpDm.from_mps(mps)
mpo = Mpo(holstein_model)
mps = mps.evolve(mpo, 10)
environ = Environ(mps, mpo)
environ_multi_mpo = Environ(mps, [mpo])
for i in range(len(mps) - 1):
l = environ.read("L", i)
r = environ.read("R", i + 1)
l2 = environ_multi_mpo.read("L", i)
r2 = environ_multi_mpo.read("R", i + 1)
assert np.allclose(asnumpy(l), asnumpy(l2))
assert np.allclose(asnumpy(r), asnumpy(r2))
def test_variational_compress(comp, mp):
if mp == "mpo":
mps = Mpo(holstein_model)
M = 20
else:
mps = Mps.random(holstein_model, 1, 10)
if mp == "mpdm":
mps = MpDm.from_mps(mps)
mps.canonicalise().normalize()
M = 36
if comp:
mps = mps.to_complex(inplace=True)
print(f"{mps}")
mpo = Mpo(holstein_model)
if comp:
mpo = mpo.scale(-1.0j)
print(f"{mpo.bond_dims}")
std_mps = mpo.apply(mps, canonicalise=True).canonicalise()
print(f"std_mps: {std_mps}")
# 2site algorithm
mps.compress_config.vprocedure = [[M, 1.0], [M, 0.2], [M, 0.1]] + [
[M, 0],
] * 10
mps.compress_config.vmethod = "2site"
var_mps = mps.variational_compress(mpo, guess=None)
dis = var_mps.distance(std_mps) / std_mps.dmrg_norm
print(f"var2_mps: {var_mps}, dis: {dis}")
assert np.allclose(dis, 0.0, atol=1e-4)
assert np.allclose(var_mps.dmrg_norm, std_mps.dmrg_norm, atol=1e-4)
# 1site algorithm with 2site result as a guess
# 1site algorithm is easy to be trapped in a local minimum
var_mps.compress_config.vprocedure = [
[M, 0],
] * 10
var_mps.compress_config.vmethod = "1site"
var_mps = mps.variational_compress(mpo, guess=var_mps)
dis = var_mps.distance(std_mps) / std_mps.dmrg_norm
print(f"var1_mps: {var_mps}, dis: {dis}")
assert np.allclose(dis, 0.0, atol=1e-4)
assert np.allclose(var_mps.dmrg_norm, std_mps.dmrg_norm, atol=1e-4)
def test_2site():
ph = Phonon.simple_phonon(Quantity(1), Quantity(1), 2)
m = Mol(Quantity(0), [ph])
mol_list = MolList([m] * 2, Quantity(1), scheme=3)
gs_mp = Mpo.onsite(mol_list, opera=r"a^\dagger", mol_idx_set={0}).apply(Mps.gs(mol_list, max_entangled=False))
mpdm = MpDm.from_mps(gs_mp)
mpdm_full = MpDmFull.from_mpdm(mpdm)
mpdm_full.compress_config = CompressConfig(threshold=1e-4)
liouville = SuperLiouville(Mpo(mol_list), dissipation=1)
ph_occupations_array = []
energies = []
for i in range(51):
logger.info(mpdm_full)
logger.info(mpdm_full.ph_occupations)
ph_occupations_array.append(mpdm_full.ph_occupations)
logger.info(mpdm_full.expectation(liouville))
energies.append(mpdm_full.expectation(liouville))
mpdm_full = mpdm_full.evolve(liouville, 0.4)
ph_occupations_array = np.array(ph_occupations_array)
assert energies[-1] == pytest.approx(-0.340162, rel=1e-2)
assert np.allclose(ph_occupations_array[-1], [0.0930588, 0.099115], rtol=1e-2)
def init_mps(self):
tentative_mpo = Mpo(self.mol_list)
if self.temperature == 0:
gs_mp = Mps.gs(self.mol_list, max_entangled=False)
if self.dissipation != 0:
gs_mp = MpDm.from_mps(gs_mp)
else:
if self._defined_output_path:
gs_mp = load_thermal_state(self.mol_list, self._thermal_dump_path)
else:
gs_mp = None
if gs_mp is None:
gs_mp = MpDm.max_entangled_gs(self.mol_list)
# subtract the energy otherwise might cause numeric error because of large offset * dbeta
energy = Quantity(gs_mp.expectation(tentative_mpo))
mpo = Mpo(self.mol_list, offset=energy)
tp = ThermalProp(gs_mp, mpo, exact=True, space="GS")
tp.evolve(None, max(20, len(gs_mp)), self.temperature.to_beta() / 2j)
gs_mp = tp.latest_mps
if self._defined_output_path:
gs_mp.dump(self._thermal_dump_path)
init_mp = self.create_electron(gs_mp)
if self.dissipation != 0:
init_mp = MpDmFull.from_mpdm(init_mp)
energy = Quantity(init_mp.expectation(tentative_mpo))
self.mpo = Mpo(self.mol_list, offset=energy)
logger.info(f"mpo bond dims: {self.mpo.bond_dims}")
logger.info(f"mpo physical dims: {self.mpo.pbond_list}")
init_mp.evolve_config = self.evolve_config
init_mp.compress_config = self.compress_config
if self.evolve_config.is_tdvp:
init_mp = init_mp.expand_bond_dimension(self.mpo)
if self.dissipation != 0:
self.mpo = SuperLiouville(self.mpo, self.dissipation)
init_mp.canonicalise()
return init_mp
