A script to illustrate the issue 593 of QISKit

QISKit_issue_593.py

# ======================================================================
# Copyright CERFACS (February 2018)
# Contributor: Adrien Suau (suau@cerfacs.fr)
#
# This software is governed by the CeCILL-B license under French law and
# abiding  by the  rules of  distribution of free software. You can use,
# modify  and/or  redistribute  the  software  under  the  terms  of the
# CeCILL-B license as circulated by CEA, CNRS and INRIA at the following
# URL "http://www.cecill.info".
#
# As a counterpart to the access to  the source code and rights to copy,
# modify and  redistribute granted  by the  license, users  are provided
# only with a limited warranty and  the software's author, the holder of
# the economic rights,  and the  successive licensors  have only limited
# liability.
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# In this respect, the user's attention is drawn to the risks associated
# with loading,  using, modifying and/or  developing or reproducing  the
# software by the user in light of its specific status of free software,
# that  may mean  that it  is complicated  to manipulate,  and that also
# therefore  means that  it is reserved for  developers and  experienced
# professionals having in-depth  computer knowledge. Users are therefore
# encouraged  to load and  test  the software's  suitability as  regards
# their  requirements  in  conditions  enabling  the  security  of their
# systems  and/or  data to be  ensured and,  more generally,  to use and
# operate it in the same conditions as regards security.
#
# The fact that you  are presently reading this  means that you have had
# knowledge of the CeCILL-B license and that you accept its terms.
# ======================================================================
import qiskit
import Qconfig
from itertools import count

qiskit.register(Qconfig.APItoken, Qconfig.config["url"])
ibmqx5 = qiskit.get_backend('ibmqx5')

with open('4x4.qasm', 'r') as qasm_file:
    qasm_str = qasm_file.read()


full_basis = ('id,u0,u1,u2,u3,x,y,z,h,s,sdg,t,tdg,rx,ry,rz,'
              'cx,cy,cz,ch,crz,cu1,cu3,swap,ccx').split(',')
# Parse the code to an AST
ast = qiskit.qasm.Qasm(data=qasm_str).parse()
# Unroll this AST and use the QuantumCircuit backend to represent the OpenQASM program
# as a QuantumCircuit
unroller = qiskit.unroll.Unroller(ast, qiskit.unroll.CircuitBackend(full_basis))
unroller.execute()

try:
    for i in count(0):
        print("Compilation number {}...".format(i))
        qiskit.compile(unroller.backend.circuit, ibmqx5)
except TypeError as e:
    print("The error happened!")
    raise e