Changelog

Added

Added SchemaValidationError to be thrown when schema validation fails (#881)
Generalized Qobj schema validation functions for all qiskit schemas (#882).
Added decorator to check for C++ simulator availability (#662)
It is possible to cancel jobs in non comercial backends (#687)
Introduced new qiskit.IBMQ provider, with centralized handling of IBMQ
credentials (qiskitrc file, environment variables). (#547, #948, #1000)
Add OpenMP parallelization for Apple builds of the cpp simulator (#698).
Add parallelization utilities (#701)
Parallelize transpilation (#701)
New interactive visualizations (#765).
Added option to reverse the qubit order when plotting a circuit. (#762, #786)
Jupyter notebook magic function qiskit_job_status, qiskit_progress_bar (#701, #734)
Add a new function qobj_to_circuits to convert a Qobj object to
a list of QuantumCircuit objects (#877)
Allow selective loading of accounts from disk via hub/group/project
filters to IBMQ.load_accounts().

Schema tests in tests/schemas/test_schemas.py replaced with proper
unit test (#834).
Renamed QISKit to Qiskit in the documentation. (#634)
Use Qobj as the formally defined schema for sending information to the devices:
- introduce the qiskit.qobj module. (#589, #655)
- update the Qobj JSON schema. (#668, #677, #703, #709)
- update the local simulators for accepting Qobj as input. (#667)
- update the Result class. (#773)
Use get_status_job() for checking IBMQJob status. (#641)
Q network hub/group/project credentials replaced by new url format. (#740)
Breaking change: Jobs API simplification. (#686)
Breaking change: altered tomography APIs to not use QuantumProgram. (#818)
Breaking change: BaseBackend API changed, properties are now methods (#858)
When plot_histogram() or plot_state() are called from a jupyter
notebook if there is network connectivity the interactive plots will be used
by default (#862, #866)
Breaking change: BaseJob API changed, any job constructor must be passed
the backend used to run them and a unique job id (#936).
Add support for drawing circuit barriers to the latex circuit drawer. This
requires having the LaTeX qcircuit package version >=2.6.0 installed (#764)

The number_to_keep kwarg on the plot_histogram() function is now
deprecated. A field of the same name should be used in the option
dictionary kwarg instead. (#866)
Breaking change: backend.properties() instead of backend.calibration()
and backend.parameters() (#870)

Fixed get_ran_qasm methods on Result instances (#688).
Fixed probabilities_ket computation in C++ simulator (#580).
Fixed bug in the definition of cswap gate and its test (#685).
Fixed the examples to be compatible with version 0.5+ (#672).
Fixed swap mapper using qubits after measurement (#691).
Fixed error in cpp simulator for 3+ qubit operations (#698).
Fixed issue with combining or extending circuits that contain CompositeGate (#710).
Fixed the random unitary generation from the Haar measure (#760).
Fixed the issue with control lines spanning through several classical registers (#762).
Fixed visualizations crashing when using simulator extensions (#885).
Fixed check for network connection when loading interactive visualizations (#892).