def retrieve_state(qcircuit):
"""Retrieve the state by qcircuit."""
backend = Aer.get_backend('statevector_simulator')
n_tot_qubit = qcircuit.n_qubits
job = execute(qcircuit, backend)
result = job.result()
state = result.get_statevector(qcircuit)
# qiskit's column-major order
state_Qobj = Qobj(state, dims=[[2] * n_tot_qubit, [1]])
# python's row-major order
state_Qobj_rowmajor = state_Qobj.permute(np.arange(0, n_tot_qubit)[::-1])
state_rowmajor = np.array(state_Qobj_rowmajor)[:, 0]
return state_rowmajor
def retrieve_unitary_matrix(qcircuit):
"""Retrieve the matrix block-encoded by qcircuit.
Args:
qcircuit: qiskit circuit, n_tot_qubit
Returns:
UA: n_tot_qubit matrix.
"""
backend = Aer.get_backend('unitary_simulator')
n_tot_qubit = qcircuit.n_qubits
job = execute(qcircuit, backend)
result = job.result()
UA = result.get_unitary(qcircuit)
# qiskit's column-major order
UA_Qobj = Qobj(UA, dims=[[2] * n_tot_qubit, [2] * n_tot_qubit])
# python's row-major order
UA_Qobj_rowmajor = UA_Qobj.permute(np.arange(0, n_tot_qubit)[::-1])
UA = np.array(UA_Qobj_rowmajor)
return UA