Add backend.defaults()

CHANGELOG.rst

@@ -29,6 +29,8 @@ Added
 
 - The connector ``get_job()`` methods accepts two new parameters for including
   and excluding specific fields from the response. (#6)
+- Added ``backend.defauls()`` for retrieving the pulse defaults for a
+  backend through a new endpoint (#33).
 
 Changed
 """""""

qiskit/providers/ibmq/api/ibmqconnector.py

@@ -37,6 +37,19 @@ def get_backend_properties_url(config, backend_type, hub=None):
     return '/Backends/{}/properties'.format(backend_type)
 
 
+def get_backend_defaults_url(config, backend_type):
+    """Return the URL for a backend's pulse defaults."""
+    hub = config.get('hub', None)
+    group = config.get('group', None)
+    project = config.get('project', None)
+
+    if hub and group and project:
+        return '/Network/{}/Groups/{}/Projects/{}/devices/{}/defaults'.format(
+            hub, group, project, backend_type)
+
+    return '/Backends/{}/defaults'.format(backend_type)
+
+
 def get_backends_url(config, hub, group, project):
     """Return the URL for a backend."""
     hub = config.get('hub', hub)
@@ -81,13 +94,11 @@ def __init__(self, token=None, config=None, verify=True):
 
     def _check_backend(self, backend_name):
         """Check if the name of a backend is valid to run in QX Platform."""
-        backend_name = backend_name.lower()
-
-        # Check for new-style backends
         backends = self.available_backends()
         for backend_ in backends:
             if backend_.get('backend_name', '') == backend_name:
                 return backend_name
+
         # backend unrecognized
         return None
 
@@ -312,7 +323,7 @@ def cancel_job(self, id_job, hub=None, group=None, project=None,
         return res
 
     def backend_status(self, backend, access_token=None, user_id=None):
-        """Get the status of a chip."""
+        """Get the status of a backend."""
         if access_token:
             self.req.credential.set_token(access_token)
         if user_id:
@@ -346,7 +357,7 @@ def backend_status(self, backend, access_token=None, user_id=None):
 
     def backend_properties(self, backend, hub=None, access_token=None,
                            user_id=None):
-        """Get the parameters of calibration of a real chip."""
+        """Get the properties of a backend."""
         if access_token:
             self.req.credential.set_token(access_token)
         if user_id:
@@ -368,9 +379,26 @@ def backend_properties(self, backend, hub=None, access_token=None,
             ret["backend_name"] = backend_type
         return ret
 
+    def backend_defaults(self, backend):
+        """Get the pulse defaults of a backend."""
+        if not self.check_credentials():
+            raise CredentialsError('credentials invalid')
+
+        backend_name = self._check_backend(backend)
+
+        if not backend_name:
+            raise BadBackendError(backend)
+
+        url = get_backend_defaults_url(self.config, backend_name)
+
+        ret = self.req.get(url)
+        if not bool(ret):
+            ret = {}
+        return ret
+
     def available_backends(self, hub=None, group=None, project=None,
                            access_token=None, user_id=None):
-        """Get the backends available to use in the QX Platform."""
+        """Get the backends available to use in the IBMQ Platform."""
         if access_token:
             self.req.credential.set_token(access_token)
         if user_id:

qiskit/providers/ibmq/ibmqbackend.py

@@ -13,7 +13,8 @@
 from marshmallow import ValidationError
 
 from qiskit.providers import BaseBackend, JobStatus
-from qiskit.providers.models import BackendStatus, BackendProperties
+from qiskit.providers.models import (BackendStatus, BackendProperties,
+                                     PulseDefaults)
 
 from .api import ApiError
 from .exceptions import IBMQBackendError, IBMQBackendValueError
@@ -90,6 +91,20 @@ def status(self):
             raise LookupError(
                 "Couldn't get backend status: {0}".format(ex))
 
+    def defaults(self):
+        """Return the pulse defaults for the backend.
+
+        Returns:
+            PulseDefaults: the pulse defaults for the backend. IF the backend
+            does not support defaults, it returns ``None``.
+        """
+        backend_defaults = self._api.backend_defaults(self.name())
+
+        if backend_defaults:
+            return PulseDefaults.from_dict(backend_defaults)
+
+        return None
+
     def jobs(self, limit=50, skip=0, status=None, db_filter=None):
         """Attempt to get the jobs submitted to the backend.
 

test/ibmq/test_ibmq_backends.py

@@ -73,6 +73,14 @@ def test_remote_backend_properties(self, qe_token, qe_url):
             if backend.configuration().simulator:
                 self.assertEqual(properties, None)
 
+    @requires_qe_access
+    def test_remote_backend_defaults(self, qe_token, qe_url):
+        """Test backend pulse defaults."""
+        IBMQ.enable_account(qe_token, qe_url)
+        remotes = IBMQ.backends(simulator=False)
+        for backend in remotes:
+            _ = backend.defaults()
+
     @requires_qe_access
     def test_qobj_headers_in_result_sims(self, qe_token, qe_url):
         """Test that the qobj headers are passed onto the results for sims."""