topo codes test

test.py

from qiskit.ignis.verification.topological_codes import RepetitionCode
from qiskit.ignis.verification.topological_codes import GraphDecoder

from qiskit import execute, Aer, QuantumCircuit

import copy

HAS_AER = True

max_dist = 5

for d in range(3,max_dist):

    code = RepetitionCode(d, 2)
    dec = GraphDecoder(code)

    qc = code.circuit['0']

    blank_qc = QuantumCircuit()
    for qreg in qc.qregs:
        blank_qc.add_register(qreg)
    for creg in qc.cregs:
        blank_qc.add_register(creg)

    error_circuit = {}
    circuit_name = {}
    depth = len(qc)
    for j in range(depth):
        qubits = qc.data[j][1]
        for qubit in qubits:
            for error in ['x', 'y', 'z']:
                temp_qc = copy.deepcopy(blank_qc)
                temp_qc.name = str((j, qubit, error))
                temp_qc.data = qc.data[0:j]
                getattr(temp_qc, error)(qubit)
                temp_qc.data += qc.data[j:depth + 1]
                circuit_name[(j, qubit, error)] = temp_qc.name
                error_circuit[temp_qc.name] = temp_qc

    if HAS_AER:
        simulator = Aer.get_backend('qasm_simulator')
    else:
        simulator = BasicAer.get_backend('qasm_simulator')

    job = execute(list(error_circuit.values()), simulator)

    for error_name in error_circuit:
        counts = job.result().get_counts(error_circuit[error_name])

        results = code.process_results({'0':counts})

        logical_prob_match = dec.get_logical_prob(results)

        assert logical_prob_match['0']==0.0, 'Error '+error_name+' causes a logical error for a code of distance '+str(d)+'.'