def test_sample_2qb(self):
qpu = PyLinalg()
prog = Program()
qbits = prog.qalloc(2)
prog.apply(X, qbits[0])
circ = prog.to_circ()
obs = Observable(2, pauli_terms=[Term(1., "ZZ", [0, 1])])
job = circ.to_job("OBS", observable=obs)
result = qpu.submit(job)
self.assertAlmostEqual(result.value, -1)
prog = Program()
qbits = prog.qalloc(2)
prog.apply(X, qbits[0])
prog.apply(X, qbits[1])
circ = prog.to_circ()
obs = Observable(2, pauli_terms=[Term(1., "ZZ", [0, 1])])
job = circ.to_job("OBS", observable=obs)
result = qpu.submit(job)
self.assertAlmostEqual(result.value, 1)
def C(graph):
energy = Observable(graph.V)
for edge in itertools.combinations(range(graph.V), 2):
energy.add_term(Term(-graph.E[edge] / 2, "ZZ", edge))
energy.constant_coeff += np.sum(graph.E) / 4
return energy
def generate_random_observable(nbqbit: int) -> Observable:
"""
Generate a random observable.
Args:
nbqbit (int): number of qubits
Returns:
Observable: an observable
"""
# Determine randomly the number of Pauli terms in the observable
nb_terms = rd.randint(1, nbqbit)
pauli_terms = []
for _ in range(nb_terms):
# Determine randomly the number of qubits involve in the Pauli term
nb_qbit_term = rd.randint(1, nbqbit)
# Build randomly the tensor of the term
tensor = ''.join(
[rd.choice(['X', 'Y', 'Z']) for _ in range(nb_qbit_term)])
# Create and add the term to the list
pauli_terms.append(
Term(rd.random(), tensor, rd.sample(range(nbqbit), nb_qbit_term)))
# build and return the observable
return Observable(nbqbit,
pauli_terms=pauli_terms,
constant_coeff=rd.random())
def test4_cannot_measure_observable(self):
"""
Checks if measuring an Observable raises an error
"""
prog = Program()
qbits = prog.qalloc(1)
prog.apply(X, qbits)
circ = prog.to_circ()
qpu = BackendToQPU(Aer.get_backend('qasm_simulator'))
self.assertRaises(QPUException, qpu.submit,
circ.to_job("OBS", observable=Observable(1)))
def test_basic(self):
with self.assertRaises(QPUException):
prog = Program()
qbits = prog.qalloc(1)
prog.apply(X, qbits)
circ = prog.to_circ()
obs = Observable(1, pauli_terms=[Term(1., "Z", [0])])
job = circ.to_job("OBS", observable=obs, nbshots=10)
qpu = PyLinalg()
result = qpu.submit(job)
def test_sample_1qb_Y(self):
prog = Program()
qbits = prog.qalloc(1)
prog.apply(H, qbits)
prog.apply(PH(-np.pi / 2), qbits)
circ = prog.to_circ()
obs = Observable(1, pauli_terms=[Term(1., "Y", [0])])
job = circ.to_job("OBS", observable=obs)
qpu = PyLinalg()
result = qpu.submit(job)
self.assertAlmostEqual(result.value, -1)
obs = Observable(1, pauli_terms=[Term(18., "Y", [0])])
job = circ.to_job("OBS", observable=obs)
result = qpu.submit(job)
self.assertAlmostEqual(result.value, -18)
prog = Program()
qbits = prog.qalloc(1)
prog.apply(H, qbits)
prog.apply(PH(np.pi / 2), qbits)
circ = prog.to_circ()
obs = Observable(1, pauli_terms=[Term(1., "Y", [0])])
job = circ.to_job("OBS", observable=obs)
result = qpu.submit(job)
self.assertAlmostEqual(result.value, 1)
obs = Observable(1, pauli_terms=[Term(18., "Y", [0])])
job = circ.to_job("OBS", observable=obs)
result = qpu.submit(job)
self.assertAlmostEqual(result.value, 18)
def test_submit_job(self):
# Create a valid qpu
qpu_valid = SimulatedAnnealing(
temp_t=TestSimulatedAnnealing.temp_t_valid,
n_steps=TestSimulatedAnnealing.n_steps_valid,
seed=8017)
# Create an Observable Job and check that such Jobs are not dealt with by the qpu
observable = Observable(5)
job = Job(observable=observable)
with pytest.raises(exceptions_types.QPUException):
assert result == qpu_valid.submit_job(job)
# Create a circuit Job a and check that such Jobs are not dealt with by the qpu
from qat.lang.AQASM import Program, H
prog = Program()
reg = prog.qalloc(1)
prog.apply(H, reg)
prog.reset(reg)
with pytest.raises(exceptions_types.QPUException):
assert result == qpu_valid.submit(prog.to_circ().to_job(nbshots=1))
# Create a Job from a Schedule with empty drive and check that such
# Jobs are not dealt with by the qpu
schedule = Schedule()
job = Job(schedule=schedule)
with pytest.raises(exceptions_types.QPUException):
assert result == qpu_valid.submit_job(job)
# Create a job from a Schedule with a drive with more than one observable
# or an observable with coefficient not 1 to check that such Jobs don't work
# with the qpu
observable = get_observable(TestSimulatedAnnealing.J_valid,
TestSimulatedAnnealing.h_valid,
TestSimulatedAnnealing.offset_valid)
drive_invalid_1 = [(1, observable), (1, observable)]
schedule = Schedule(drive=drive_invalid_1)
job = schedule.to_job()
with pytest.raises(exceptions_types.QPUException):
assert result == qpu_valid.submit_job(job)
drive_invalid_2 = [(5, observable)]
schedule = Schedule(drive=drive_invalid_2)
job = schedule.to_job()
with pytest.raises(exceptions_types.QPUException):
assert result == qpu_valid.submit_job(job)
# Solve the problem and check that the returned result is Result
result = qpu_valid.submit_job(TestSimulatedAnnealing.job_valid)
assert isinstance(result, Result)
def get_observable(J, h, offset):
"""
Returns an Observable from a J coupling and magnetic field h
of an Ising problem.
Returns:
:class:`~qat.core.Observable`: an Ising Hamiltonian encoding the problem
"""
n_spins = J.shape[0]
observable = Observable(n_spins, constant_coeff=-offset)
for i in range(n_spins):
if not np.isclose(h[i], 0):
observable.terms.append(Term(-h[i], "Z", [i]))
for j in range(i + 1, n_spins):
if not np.isclose(J[i, j], 0):
observable.terms.append(Term(-J[i, j], "ZZ", [i, j]))
return observable
def bipartition(s, p):
###Define a variational circuit
#As a Program
prog = Program()
#With n qubits
nqbits = len(s)
qbits = prog.qalloc(nqbits)
#Define the variational states (einsatz)
#|psi(theta)> = Rx1(theta1x)...Rxn(theta1n)|0,...,0>
for i in range(0, nqbits):
for j in range(1):
#H(qbits[i])
thetaij = prog.new_var(float, "theta"+str(i)+str(j))
if j == 0 :
RX(np.pi*thetaij)(qbits[i])
#RZ(thetaij)(qbits[i]) #H Rz H method
#elif j ==1 :
# RY(thetaij)(qbits[i])
#elif j == 2:
# RZ(thetaij)(qbits[i])
# elif j == 3 :
# RY(thetaij)(qbits[i])
# elif j == 4 :
# RX(thetaij)(qbits[i])
#H(qbits[i])
#export program into a quntum circuit
circuit = prog.to_circ()
#print created variables"
print("Variables:", circuit.get_variables())
###Define an observable
#Initialization
obs = Observable(nqbits)
#Observable = Hamiltonian we want to minimize
# => Reformulate bi-partition problem in Hamiltonian minimalization problem :
#Bi-partition problem : Find A1,A2 such that A1 u A2 = s and minimizes |sum_{n1 in A1}n1 - sum_{n2 in A2}n2|
#Optimization Problem : Find e = {ei} in {-1,1}^n minimizing |sum_{1<=i<=n}ei.si|
#Non-Linear Integer Programming Optimization Problem Find e = {ei} in {-1,1}^n minimizing (sum_{1<=i<=n}ei.si)^2
#Ising problem : Find e = {ei} in {-1,1}^n minimizing sum_{1<=i<=n}(si)^2 + sum_{1<=i<=n, 1<=i<j<=n} (si.sj).ei.ej)^2 (si^2 = 1)
J = [[si*sj for si in s] for sj in s]
b = [si**2 for si in s]
obs += sum(b)*Observable(nqbits, constant_coeff = sum(b))
for i in range(nqbits):
for j in range(i-1):
obs += Observable(nqbits, pauli_terms = [Term(J[i][j], "ZZ", [i, j])]) #Term(coefficient, tensorprod, [qubits])
###Create a quantum job
#Made of a circuit and and an observable
job = circuit.to_job(observable = obs) #nbshots=inf
###Define classical optimizer : scipy.optimia.minimize
method_name = "COBYLA" #"Nelder-Mead", "Powell", "CG",...
optimize = ScipyMinimizePlugin(method = method_name, tol = 1e-3, options = {"maxiter" : p})
###Define qpu on which to run quantum job
stack = optimize | get_default_qpu()
optimizer_args = {"method": method_name, "tol":1e-3, "options":{"maxiter":p}}
result = stack.submit(job, meta_data ={"ScipyMinimizePlugin": json.dumps(optimizer_args)})
###Get characteristics of best parametrized circuit found
final_energy = result.value
parameters = json.loads(result.meta_data['parameters'])
print("final energy:", final_energy)
print('best parameters:', parameters)
#print('trace:', result.meta_data['optimization_trace'])
###Deduce the most probable state => solution of the problem
#Probability to measure qubit i in state |0> : cos(theta_i)^2
#Probability to measure qubit i in state |1> : sin(theta_i)^2
states = {}
best_state = ''
max_proba = 0
for i in range(2**nqbits):
state = bin(i)[2:].zfill(nqbits)
proba = 1
for i in range(nqbits):
proba = proba/2*((1+(-1)**int(state[nqbits-i-1]))*np.cos(parameters[i]*np.pi/2)+(1+(-1)**(int(state[nqbits-i-1])+1))*np.sin(parameters[i]*np.pi/2))
if max_proba < proba:
max_proba = proba
best_state = state
states[state] = proba
print(states)
A1 = []
A2 = []
for i in range(nqbits):
if best_state[i] == '0':
A1.append(s[i])
elif best_state[i] == '1':
A2.append(s[i])
return A1, A2
