From 6a8d48ff22e7551445433ff0cf1359f450cced90 Mon Sep 17 00:00:00 2001
From: Alec Edgington <54802828+cqc-alec@users.noreply.github.com>
Date: Thu, 17 Feb 2022 10:26:16 +0000
Subject: [PATCH] [pytket-qiskit] Remove `characterisation` property of
 backends (#297)

---
 modules/pytket-qiskit/_metadata.py                        | 2 +-
 modules/pytket-qiskit/docs/changelog.rst                  | 6 ++++++
 .../pytket/extensions/qiskit/backends/aer.py              | 8 +-------
 .../pytket/extensions/qiskit/backends/ibm.py              | 4 ----
 .../pytket/extensions/qiskit/backends/ibmq_emulator.py    | 5 -----
 modules/pytket-qiskit/tests/backend_test.py               | 4 ++--
 6 files changed, 10 insertions(+), 19 deletions(-)

diff --git a/modules/pytket-qiskit/_metadata.py b/modules/pytket-qiskit/_metadata.py
index 7e595163..65b0e7c5 100644
--- a/modules/pytket-qiskit/_metadata.py
+++ b/modules/pytket-qiskit/_metadata.py
@@ -1,2 +1,2 @@
-__extension_version__ = "0.22.2"
+__extension_version__ = "0.23.0"
 __extension_name__ = "pytket-qiskit"
diff --git a/modules/pytket-qiskit/docs/changelog.rst b/modules/pytket-qiskit/docs/changelog.rst
index ed3829d5..44fd8c93 100644
--- a/modules/pytket-qiskit/docs/changelog.rst
+++ b/modules/pytket-qiskit/docs/changelog.rst
@@ -1,6 +1,12 @@
 Changelog
 ~~~~~~~~~
 
+0.23.0 (unreleased)
+-------------------
+
+* Removed ``characterisation`` property of backends. (Use `backend_info`
+  instead.)
+
 0.22.2 (February 2022)
 ----------------------
 
diff --git a/modules/pytket-qiskit/pytket/extensions/qiskit/backends/aer.py b/modules/pytket-qiskit/pytket/extensions/qiskit/backends/aer.py
index 57a82e4b..3d810905 100644
--- a/modules/pytket-qiskit/pytket/extensions/qiskit/backends/aer.py
+++ b/modules/pytket-qiskit/pytket/extensions/qiskit/backends/aer.py
@@ -16,7 +16,6 @@
 from collections import defaultdict
 from logging import warning
 from typing import (
-    Any,
     Callable,
     Dict,
     List,
@@ -138,11 +137,6 @@ def __init__(self, backend_name: str):
     def _result_id_type(self) -> _ResultIdTuple:
         return (str, int)
 
-    @property
-    def characterisation(self) -> Optional[Dict[str, Any]]:
-        char = self._backend_info.get_misc("characterisation")
-        return cast(Dict[str, Any], char) if char else None
-
     @property
     def backend_info(self) -> BackendInfo:
         return self._backend_info
@@ -493,7 +487,7 @@ def default_compilation_pass(self, optimisation_level: int = 1) -> BasePass:
         else:
             passlist.append(FullPeepholeOptimise())
         arch = self._backend_info.architecture
-        if arch.coupling and self.characterisation:
+        if arch.coupling and self._backend_info.get_misc("characterisation"):
             # architecture is non-trivial
             passlist.append(
                 CXMappingPass(
diff --git a/modules/pytket-qiskit/pytket/extensions/qiskit/backends/ibm.py b/modules/pytket-qiskit/pytket/extensions/qiskit/backends/ibm.py
index 50bc6c30..07764c26 100644
--- a/modules/pytket-qiskit/pytket/extensions/qiskit/backends/ibm.py
+++ b/modules/pytket-qiskit/pytket/extensions/qiskit/backends/ibm.py
@@ -307,10 +307,6 @@ def _get_provider(
 
         return provider
 
-    @property
-    def characterisation(self) -> Dict[str, Any]:
-        return cast(Dict[str, Any], self._backend_info.get_misc("characterisation"))
-
     @property
     def backend_info(self) -> BackendInfo:
         return self._backend_info
diff --git a/modules/pytket-qiskit/pytket/extensions/qiskit/backends/ibmq_emulator.py b/modules/pytket-qiskit/pytket/extensions/qiskit/backends/ibmq_emulator.py
index 2768ec3a..b1300312 100644
--- a/modules/pytket-qiskit/pytket/extensions/qiskit/backends/ibmq_emulator.py
+++ b/modules/pytket-qiskit/pytket/extensions/qiskit/backends/ibmq_emulator.py
@@ -15,7 +15,6 @@
 import json
 from typing import (
     cast,
-    Any,
     Dict,
     Optional,
     List,
@@ -92,10 +91,6 @@ def __init__(
         # cache of results keyed by job id and circuit index
         self._ibm_res_cache: Dict[Tuple[str, int], ExperimentResult] = dict()
 
-    @property
-    def characterisation(self) -> Optional[Dict[str, Any]]:
-        return self._ibmq.characterisation
-
     @property
     def backend_info(self) -> BackendInfo:
         return self._ibmq.backend_info
diff --git a/modules/pytket-qiskit/tests/backend_test.py b/modules/pytket-qiskit/tests/backend_test.py
index e1eaf7b8..6b2d035b 100644
--- a/modules/pytket-qiskit/tests/backend_test.py
+++ b/modules/pytket-qiskit/tests/backend_test.py
@@ -207,7 +207,7 @@ def test_process_characterisation() -> None:
 def test_process_characterisation_no_noise_model() -> None:
     my_noise_model = NoiseModel()
     back = AerBackend(my_noise_model)
-    assert back.characterisation is None
+    assert back.backend_info.get_misc("characterisation") is None
 
     c = Circuit(4).CX(0, 1).H(2).CX(2, 1).H(3).CX(0, 3).H(1).X(0)
     c = back.get_compiled_circuit(c)
@@ -303,7 +303,7 @@ def test_process_characterisation_complete_noise_model() -> None:
     )
 
     back = AerBackend(my_noise_model)
-    char = cast(Dict[str, Any], back.characterisation)
+    char = cast(Dict[str, Any], back.backend_info.get_misc("characterisation"))
 
     node_errors = cast(Dict, back.backend_info.all_node_gate_errors)
     link_errors = cast(Dict, back.backend_info.all_edge_gate_errors)