def test_measure(self):
possible_measurements = self.test_state.possible_measurements()
measurement = self.test_state.measure()
self.assertTrue(measurement in possible_measurements)
int_result = qudot_utils.dirac_str_to_int(measurement)
self.assertTrue(self.test_state.ket[int_result][0] == 1)
for possible_measurement in possible_measurements:
if possible_measurement != measurement:
index = qudot_utils.dirac_str_to_int(possible_measurement)
self.assertTrue(self.test_state.ket[index][0] == 0)
def test_measure(self):
possible_measurements = self.test_state.possible_measurements()
measurement = self.test_state.measure()
self.assertTrue(measurement in possible_measurements)
int_result = qudot_utils.dirac_str_to_int(measurement)
self.assertTrue(self.test_state.ket[int_result][0] == 1)
for possible_measurement in possible_measurements:
if possible_measurement != measurement:
index = qudot_utils.dirac_str_to_int(possible_measurement)
self.assertTrue(self.test_state.ket[index][0] == 0)
def _collapse(self, state_str):
"""collapses the state to the specified state_str"""
state_index = utils.dirac_str_to_int(state_str)
index = 0
for element in self._state:
if index == state_index:
element[0] = 1
else:
element[0] = 0
index += 1
def possible_measurements(self, qubit_index=-1):
"""Returns all possible measurements and their probability.
The return value will be a map where the key is a string of the
possible state and the value is its probability of outcome. You
can return the measurement probability of a specific qubit by
using qubit_index param. Example, the third qubit of the state
1/sqrt(2)|0010> + 1/sqrt(2)|1110> can be 1 with probability 1
Args:
qubit_index: use if you want to know the possible
measurements of a specific qubit. First
qubit is 1.
Raises:
ValueError: if you specify a qubit that is out of range
"""
states_map = {}
index = 0
for element in self.ket:
if element:
probablility = measurement_probability(element[0])
dirac_str = utils.int_to_dirac_str(index, self._num_qubits)
states_map[dirac_str] = probablility
index += 1
if qubit_index >= 0:
if qubit_index > self._num_qubits:
raise ValueError("qubit_index=%s is out of range" %
str(qubit_index))
qubit_map = {}
for dirac_state in states_map:
state_index = utils.dirac_str_to_int(dirac_state)
amplitude = self._state[state_index][0]
qubit = utils.DIRAC_STR % dirac_state[qubit_index]
probablility = measurement_probability(amplitude)
if qubit in qubit_map:
old_probability = qubit_map[qubit]
qubit_map[qubit] = old_probability + probablility
else:
qubit_map[qubit] = probablility
return qubit_map
else:
return states_map
def possible_measurements(self, qubit_index=-1):
"""Returns all possible measurements and their probability.
The return value will be a map where the key is a string of the
possible state and the value is its probability of outcome. You
can return the measurement probability of a specific qubit by
using qubit_index param. Example, the third qubit of the state
1/sqrt(2)|0010> + 1/sqrt(2)|1110> can be 1 with probability 1
Args:
qubit_index: use if you want to know the possible
measurements of a specific qubit. First
qubit is 1.
Raises:
ValueError: if you specify a qubit that is out of range
"""
states_map = {}
index = 0
for element in self.ket:
if element:
probablility = measurement_probability(element[0])
dirac_str = utils.int_to_dirac_str(index, self._num_qubits)
states_map[dirac_str] = probablility
index += 1
if qubit_index >= 0:
if qubit_index > self._num_qubits:
raise ValueError("qubit_index=%s is out of range" %
str(qubit_index))
qubit_map = {}
for dirac_state in states_map:
state_index = utils.dirac_str_to_int(dirac_state)
amplitude = self._state[state_index][0]
qubit = utils.DIRAC_STR % dirac_state[qubit_index]
probablility = measurement_probability(amplitude)
if qubit in qubit_map:
old_probability = qubit_map[qubit]
qubit_map[qubit] = old_probability + probablility
else:
qubit_map[qubit] = probablility
return qubit_map
else:
return states_map
