Qiskit-ibmq-provider

Added

- Some of the visualization and Jupyter tools, including gate/error map and
backend information, have been moved
from `qiskit-terra` to `qiskit-ibmq-provider`. In addition, you can now
use `%iqx_dashboard` to get a dashboard that provides both job and
backend information. (\535) (\541)

Changed

- JSON schema validation is no longer run by default on Qobj objects passed
to `IBMQBackend.run()`. This significantly speeds up the execution of the
`run` method and the API server will return 400 if the Qobj is invalid. If
you would like to still run the validation you can set the `validate_qobj`
kwarg to `True` which will enable the JSON schema validation. (\554)

Added

- `IBMQJob` now has a new method `wait_for_final_state()` that blocks
until the job finishes. One of its parameters is a callback function
that it will invoke after every query to provide feedback. (\529)
- `IBMQBackend` now has a new method `active_jobs()`. The method returns the
jobs submitted to a backend that are currently in an unfinished status.
Note the unfinished jobs returned for the backend are given for a specific
provider (i.e. a specific backend with a specific provider). (\521)
- `QueueInfo` (returned by `IBMQJob.queue_info()`) now has a new method:
`format()`. The method returns a formatted string of the queue information.
(\515)
- `IBMQJob` now has three new methods: `done()`, `running()`, and
`cancelled()`. The methods are used to indicate the job status. (\494)
- `backend.run()` now accepts an optional `job_tags` parameter. If
specified, the `job_tags` are assigned to the job, which can also be used
as a filter in `backend.jobs()`. (\511)
- `IBMQBackend` now has two new methods: `job_limit()` and
`remaining_job_counts()`. `job_limit()` returns the job limit for a
backend, which includes the current number of active jobs you have on
the backend and the the maximum number of active jobs you can have on
it. `remaining_job_counts()` returns the number of remaining jobs that
could be submitted to the backend before the maximum limit on active
jobs is reached. Note the job limit for a backend is given for a specific
provider (i.e. a specific backend with a specific provider). (\513)
- `IBMQJobManager` now has a new method `retrieve_job_set()` that allows
you to retrieve a previously submitted job set using the job set ID.
A job set ID can be retrieved using the new `job_set.job_set_id()`
method. (\514)

Changed

- The Exception hierarchy has been refined with more specialized classes.
You can, however, continue to catch their parent exceptions (such
as `IBMQAccountError`). Also, the exception class `IBMQApiUrlError`
has been replaced by `IBMQAccountCredentialsInvalidUrl` and
`IBMQAccountCredentialsInvalidToken`. (\480)

Deprecated

- The use of proxy urls without a protocol (e.g. `http://`) is deprecated
due to recent Python changes. (\538)

Added

- `IBMQJob` now has a new `queue_info()` method that returns queue
information, such as queue position, estimated start/end time, and
priority levels for the job. (\467)
- Python 3.8 is now supported in qiskit-ibmq-provider. (\445)

Added

- `IBMQJob.result()` now accepts an optional `refresh` parameter. If
`refresh=True` is specified, the function re-queries the api for the
results, rather than returning those cached. (\469)
- `POST` network request are now retried if the status code is among specific
safe codes. In the case of the request failing during job submission, more
information is now displayed in the `INFO` and `DEBUG` log levels. (\475)

Fixed

- Fixed an issue where `IBMQJob.error_message()` may raise an exception
if the job fails before execution. (\458)

Fixed

- Fixed `IBMQBackendService.jobs()` to correctly return jobs when
both `start_datetime` and `end_datetime` are specified. Now, when the
two parameters are specified, the function will return the jobs after
(greater than or equal to) and before (less than or equal to) the
two given datetimes. (\452)