Merge branch 'main' into docs/md_docs

pytket/extensions/qiskit/backends/aer.py

@@ -348,7 +348,14 @@ def get_result(self, handle: ResultHandle, **kwargs: KwargTypes) -> BackendResul
                 raise CircuitNotRunError(handle)
 
             res = job.result()
-            backresults = qiskit_result_to_backendresult(res)
+            backresults = qiskit_result_to_backendresult(
+                res,
+                include_shots=self._supports_shots,
+                include_counts=self._supports_counts,
+                include_state=self._supports_state,
+                include_unitary=self._supports_unitary,
+                include_density_matrix=self._supports_density_matrix,
+            )
             for circ_index, backres in enumerate(backresults):
                 self._cache[ResultHandle(jobid, circ_index, qubit_n, ppc)][
                     "result"

pytket/extensions/qiskit/result_convert.py

@@ -26,7 +26,7 @@
 from qiskit.result import Result  # type: ignore
 from qiskit.result.models import ExperimentResult  # type: ignore
 
-from pytket.circuit import Bit, Qubit, UnitID, Circuit
+from pytket.circuit import Bit, Qubit, UnitID
 
 from pytket.backends.backendresult import BackendResult
 from pytket.utils.outcomearray import OutcomeArray
@@ -81,9 +81,17 @@ def _result_is_empty_shots(result: ExperimentResult) -> bool:
         return False
 
 
+# In some cases, Qiskit returns a result with fields we don't expect -
+# for example, a circuit with classical bits run on AerStateBackend will
+# return counts (whether or not there were measurements). The include_foo
+# arguments should be set based on what the backend supports.
 def qiskit_experimentresult_to_backendresult(
     result: ExperimentResult,
-    ppcirc: Optional[Circuit] = None,
+    include_counts: bool = True,
+    include_shots: bool = True,
+    include_state: bool = True,
+    include_unitary: bool = True,
+    include_density_matrix: bool = True,
 ) -> BackendResult:
     if not result.success:
         raise RuntimeError(result.status)
@@ -105,16 +113,16 @@ def qiskit_experimentresult_to_backendresult(
 
     shots, counts, state, unitary, density_matrix = (None,) * 5
     datadict = result.data.to_dict()
-    if _result_is_empty_shots(result):
+    if _result_is_empty_shots(result) and include_shots:
         n_bits = len(c_bits) if c_bits else 0
         shots = OutcomeArray.from_readouts(
             np.zeros((result.shots, n_bits), dtype=np.uint8)
         )
     else:
-        if "memory" in datadict:
+        if "memory" in datadict and include_shots:
             memory = datadict["memory"]
             shots = _hex_to_outar(memory, width)
-        elif "counts" in datadict:
+        elif "counts" in datadict and include_counts:
             qis_counts = datadict["counts"]
             counts = Counter(
                 dict(
@@ -123,13 +131,13 @@ def qiskit_experimentresult_to_backendresult(
                 )
             )
 
-        if "statevector" in datadict:
+        if "statevector" in datadict and include_state:
             state = datadict["statevector"].reverse_qargs().data
 
-        if "unitary" in datadict:
+        if "unitary" in datadict and include_unitary:
             unitary = datadict["unitary"].reverse_qargs().data
 
-        if "density_matrix" in datadict:
+        if "density_matrix" in datadict and include_density_matrix:
             density_matrix = datadict["density_matrix"].reverse_qargs().data
 
     return BackendResult(
@@ -140,13 +148,27 @@ def qiskit_experimentresult_to_backendresult(
         state=state,
         unitary=unitary,
         density_matrix=density_matrix,
-        ppcirc=ppcirc,
+        ppcirc=None,
     )
 
 
-def qiskit_result_to_backendresult(res: Result) -> Iterator[BackendResult]:
+def qiskit_result_to_backendresult(
+    res: Result,
+    include_counts: bool = True,
+    include_shots: bool = True,
+    include_state: bool = True,
+    include_unitary: bool = True,
+    include_density_matrix: bool = True,
+) -> Iterator[BackendResult]:
     for result in res.results:
-        yield qiskit_experimentresult_to_backendresult(result)
+        yield qiskit_experimentresult_to_backendresult(
+            result,
+            include_counts,
+            include_shots,
+            include_state,
+            include_unitary,
+            include_density_matrix,
+        )
 
 
 def backendresult_to_qiskit_resultdata(

tests/qiskit_convert_test.py

@@ -549,12 +549,17 @@ def test_convert_result() -> None:
     qc1.save_state()
     qisk_result = simulator.run(qc1, shots=10).result()
 
-    tk_res = next(qiskit_result_to_backendresult(qisk_result))
+    # exclude counts from result (we don't expect them
+    # for the statevector sim after all)
+    tk_res = next(qiskit_result_to_backendresult(qisk_result, include_counts=False))
 
     state = tk_res.get_state([Qubit("q2", 1), Qubit("q1", 0), Qubit("q2", 0)])
     correct_state = np.zeros(1 << 3, dtype=complex)
     correct_state[6] = 1 + 0j
     assert compare_statevectors(state, correct_state)
+    # also check that we don't return counts in tket result
+    # even if the qiskit result includes them
+    assert tk_res._counts is None
 
     # check measured
     qc.measure(qr1[0], cr[0])