def get_angles(self):
"""
Finds optimal angles with the quantum variational eigensolver method.
Stored VQE result
:returns: ([list], [list]) A tuple of the beta angles and the gamma
angles for the optimal solution.
"""
stacked_params = np.hstack((self.betas, self.gammas))
vqe = VQE(self.minimizer,
minimizer_args=self.minimizer_args,
minimizer_kwargs=self.minimizer_kwargs)
cost_ham = reduce(lambda x, y: x + y, self.cost_ham)
# maximizing the cost function!
param_prog = self.get_parameterized_program()
result = vqe.vqe_run(param_prog,
cost_ham,
stacked_params,
qvm=self.qvm,
**self.vqe_options)
self.result = result
betas = result.x[:self.steps]
gammas = result.x[self.steps:]
return betas, gammas
def test_vqe_run():
"""VQE initialized and then minimizer is called to return result. Checks
correct sequence of execution"""
def param_prog(alpha):
return Program([H(0), RZ(alpha)(0)])
hamiltonian = np.array([[1, 0], [0, -1]])
initial_param = 0.0
minimizer = Mock(spec=minimize, func_code=minimize.func_code)
fake_result = Mock()
fake_result.fun = 1.0
fake_result.x = [0.0]
fake_result.status = 0 # adding so we avoid writing to logger
minimizer.return_value = fake_result
# not actually called in VQE run since we are overriding minmizer to just
# return a value. Still need this so I don't try to call the QVM server.
fake_qvm = Mock(spec=['wavefunction'])
inst = VQE(minimizer)
t_result = inst.vqe_run(param_prog,
hamiltonian,
initial_param,
qvm=fake_qvm)
assert np.isclose(t_result.fun, 1.0)
def test_vqe_run():
"""
VQE initialized and then minimizer is called to return result.
Checks correct sequence of execution.
"""
def param_prog(alpha):
return Program([H(0), RZ(alpha)(0)])
hamiltonian = np.array([[1, 0], [0, -1]])
initial_param = 0.0
minimizer = MagicMock(spec=minimize, func_code=minimize.__code__)
fake_result = Mock()
fake_result.fun = 1.0
fake_result.x = [0.0]
fake_result.status = 0 # adding so we avoid writing to logger
minimizer.return_value = fake_result
# not actually called in VQE run since we are overriding minmizer to just
# return a value. Still need this so I don't try to call the QVM server.
fake_qvm = Mock(spec=['wavefunction'])
with patch("funcsigs.signature") as patch_signature:
func_sigs_fake = MagicMock(spec=funcsigs.Signature)
func_sigs_fake.parameters.return_value = \
OrderedDict({
'fun': funcsigs.Parameter.POSITIONAL_OR_KEYWORD,
'x0': funcsigs.Parameter.POSITIONAL_OR_KEYWORD,
'args': funcsigs.Parameter.POSITIONAL_OR_KEYWORD,
'method': funcsigs.Parameter.POSITIONAL_OR_KEYWORD,
'jac': funcsigs.Parameter.POSITIONAL_OR_KEYWORD,
'hess': funcsigs.Parameter.POSITIONAL_OR_KEYWORD,
'hessp': funcsigs.Parameter.POSITIONAL_OR_KEYWORD,
'bounds': funcsigs.Parameter.POSITIONAL_OR_KEYWORD,
'constraints': funcsigs.Parameter.POSITIONAL_OR_KEYWORD,
'tol': funcsigs.Parameter.POSITIONAL_OR_KEYWORD,
'callback': funcsigs.Parameter.POSITIONAL_OR_KEYWORD,
'options': funcsigs.Parameter.POSITIONAL_OR_KEYWORD
})
patch_signature.return_value = func_sigs_fake
inst = VQE(minimizer)
t_result = inst.vqe_run(param_prog,
hamiltonian,
initial_param,
qc=fake_qvm)
assert np.isclose(t_result.fun, 1.0)
PauliTerm.from_list([("I", 0),("I", 1)], coefficient=-3.8505),
PauliTerm.from_list([("I", 0),("X", 1)], coefficient=-0.2288),
PauliTerm.from_list([("I", 0),("Z", 1)], coefficient=-1.0466),
PauliTerm.from_list([("X", 0),("I", 1)], coefficient=-0.2288),
PauliTerm.from_list([("X", 0),("X", 1)], coefficient=0.2613),
PauliTerm.from_list([("X", 0),("Z", 1)], coefficient=0.2288),
PauliTerm.from_list([("Z", 0),("I", 1)], coefficient=-1.0466),
PauliTerm.from_list([("Z", 0),("X", 1)], coefficient=0.2288),
PauliTerm.from_list([("Z", 0),("Z", 1)], coefficient=0.2356)])
print(hamiltonian)
# Define ansatz
n_qubits = 2
depth = 3
def ansatz(params):
qp = Program()
for i in range(depth):
qp.inst(CNOT(1,0))
for j in range(n_qubits):
qp.inst(RY(params[j], j))
return qp
# Minimize and get approximate of the lowest eigenvalue
qvm = QVMConnection()
vqe = VQE(minimizer=minimize, minimizer_kwargs={'method': 'nelder-mead', 'options': {'xatol': 1.0e-2}})
# Initial Parameters
ip = np.random.uniform(0.0, 2*np.pi, size=n_qubits)
result = vqe.vqe_run(ansatz, hamiltonian, ip, samples=None, qvm=qvm)
print(result)
# Variational-Quantum-Eigensolver in Grove
#==============================================================================
# Create connection with QVM
qc = get_qc('2q-qvm')
# Define matrix
from pyquil.paulis import sZ
H = sZ(0)
# Define ansatz
from pyquil.gates import RY
def ansatz(params):
return Program(RY(params[0], 0))
# Minimize and get approximate of the lowest eigenvalue
from grove.pyvqe.vqe import VQE
vqe = VQE(minimizer=minimize,
minimizer_kwargs={
'method': 'nelder-mead',
'options': {
'initial_simplex': np.array([[0.0], [0.05]]),
'xatol': 1.0e-2
}
})
initial_params = [0.0]
result = vqe.vqe_run(ansatz, H, initial_params, samples=10000, qc=qc)
print(result)
])
# Define ansatz
n_qubits, depth = 3, 3
from pyquil.gates import RY, CNOT
def ansatz(params):
p = Program()
for i in range(depth):
p += CNOT(2, 0)
for j in range(n_qubits):
p += Program(RY(params[j], j))
return p
# Minimize and get approximate of the lowest eigenvalue
from grove.pyvqe.vqe import VQE
qvm = QVMConnection()
vqe = VQE(minimizer=minimize,
minimizer_kwargs={
'method': 'nelder-mead',
'options': {
'xatol': 1.0e-2
}
})
np.random.seed(999)
initial_params = np.random.uniform(0.0, 2 * np.pi, size=n_qubits)
result = vqe.vqe_run(ansatz, H, initial_params, samples=None, qvm=qvm)
print(result)
# 1. Calling Libraries
from pyquil.quil import Program
from pyquil.api import QVMConnection
from pyquil.gates import RX
from pyquil.paulis import sZ, PauliSum, PauliTerm
# Calling Grove Library and optimiser
from grove.pyvqe.vqe import VQE
import numpy as np
from scipy.optimize import minimize
# 2. Initialising the program
qvm = QVMConnection()
vqe = VQE(minimizer=minimize, minimizer_kwargs={'method': 'nelder-mead'})
# 3. Defining ansatz
def ansatz(theta):
qp = Program()
qp.inst(RX(theta[0], 0))
return qp
# 4. Defining Hamiltonian
hamiltonian = sZ(0)
# 5. Running the VQE
initial_angle = [0.0]
result = vqe.vqe_run(ansatzv, hamiltonian, initial_angle, None, qvm=qvm)
print(result)
