def simulate(self, variables, *args, **kwargs):
self.update_variables(variables)
result = []
for H in self.H:
final_E = 0.0
if self.use_mapping:
# The hamiltonian can be defined on more qubits as the unitaries
qubits_h = H.qubits
qubits_u = self.U.qubits
all_qubits = list(
set(qubits_h) | set(qubits_u)
| set(range(self.U.abstract_circuit.max_qubit() + 1)))
keymap = KeyMapSubregisterToRegister(subregister=qubits_u,
register=all_qubits)
else:
if H.qubits != self.U.qubits:
raise TequilaException(
"Can not compute expectation value without using qubit mappings."
" Your Hamiltonian and your Unitary do not act on the same set of qubits. "
"Hamiltonian acts on {}, Unitary acts on {}".format(
H.qubits, self.U.qubits))
keymap = KeyMapSubregisterToRegister(subregister=self.U.qubits,
register=self.U.qubits)
# TODO inefficient, let the backend do it if possible or interface some library
simresult = self.U.simulate(variables=variables, *args, **kwargs)
wfn = simresult.apply_keymap(keymap=keymap)
final_E += wfn.compute_expectationvalue(operator=H)
result.append(to_float(final_E))
return numpy.asarray(result)
def simulate(self, variables, initial_state=0, *args, **kwargs) -> QubitWaveFunction:
"""
Simulate the wavefunction
:param returntype: specifies how the result should be given back
:param initial_state: The initial state of the simulation,
if given as an integer this is interpreted as the corresponding multi-qubit basis state
:return: The resulting state
"""
self.update_variables(variables)
if isinstance(initial_state, BitString):
initial_state = initial_state.integer
if isinstance(initial_state, QubitWaveFunction):
if len(initial_state.keys()) != 1:
raise TequilaException("only product states as initial states accepted")
initial_state = list(initial_state.keys())[0].integer
all_qubits = [i for i in range(self.abstract_circuit.n_qubits)]
if self.use_mapping:
active_qubits = self.abstract_circuit.qubits
# maps from reduced register to full register
keymap = KeyMapSubregisterToRegister(subregister=active_qubits, register=all_qubits)
else:
keymap = KeyMapSubregisterToRegister(subregister=all_qubits, register=all_qubits)
result = self.do_simulate(variables=variables, initial_state=keymap.inverted(initial_state).integer, *args, **kwargs)
result.apply_keymap(keymap=keymap, initial_state=initial_state)
return result
def simulate(self,
variables,
initial_state=0,
*args,
**kwargs) -> QubitWaveFunction:
"""
simulate the circuit via the backend.
Parameters
----------
variables:
the parameters with which to simulate the circuit.
initial_state: Default = 0:
one of several types; determines the base state onto which the circuit is applied.
Default: the circuit is applied to the all-zero state.
args
kwargs
Returns
-------
QubitWaveFunction:
the wavefunction of the system produced by the action of the circuit on the initial state.
"""
self.update_variables(variables)
if isinstance(initial_state, BitString):
initial_state = initial_state.integer
if isinstance(initial_state, QubitWaveFunction):
if len(initial_state.keys()) != 1:
return self.do_simulate(variables=variables,
initial_state=initial_state,
*args,
**kwargs)
initial_state = list(initial_state.keys())[0].integer
if isinstance(initial_state, np.ndarray):
return self.do_simulate(variables=variables,
initial_state=initial_state,
*args,
**kwargs)
all_qubits = [i for i in range(self.abstract_circuit.n_qubits)]
active_qubits = self.abstract_circuit.qubits
# maps from reduced register to full register
keymap = KeyMapSubregisterToRegister(subregister=active_qubits,
register=all_qubits)
result = self.do_simulate(
variables=variables,
initial_state=keymap.inverted(initial_state).integer,
*args,
**kwargs)
return result
def simulate(self, variables, *args, **kwargs):
"""
Simulate the expectationvalue.
Parameters
----------
variables:
variables to supply to the unitary.
args
kwargs
Returns
-------
numpy array:
the result of simulation.
"""
self.update_variables(variables)
result = []
for H in self.H:
final_E = 0.0
# The hamiltonian can be defined on more qubits as the unitaries
qubits_h = H.qubits
qubits_u = self.U.abstract_qubits
all_qubits = list(
set(qubits_h) | set(qubits_u)
| set(range(self.U.abstract_circuit.max_qubit() + 1)))
keymap = KeyMapSubregisterToRegister(subregister=qubits_u,
register=all_qubits)
# TODO inefficient, let the backend do it if possible or interface some library
simresult = self.U.simulate(variables=variables, *args, **kwargs)
wfn = simresult.apply_keymap(keymap=keymap)
final_E += wfn.compute_expectationvalue(operator=H)
result.append(to_float(final_E))
return numpy.asarray(result)
def test_keymaps():
initial_state = 0
small = QubitWaveFunction.from_int(i=int("0b1111", 2))
large = QubitWaveFunction.from_int(i=int("0b01010101", 2))
large.n_qubits = 8
keymap = KeyMapSubregisterToRegister(register=[0, 1, 2, 3, 4, 5, 6, 7], subregister=[1, 3, 5, 7])
assert (small.apply_keymap(keymap=keymap, initial_state=initial_state).isclose(large))