Removed error case in append_circuit

BQSKit · Oct 17, 2023 · b94ce8f · b94ce8f
1 parent a5a224d
commit b94ce8f
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Showing 2 changed files with 4 additions and 9 deletions.
diff --git a/bqskit/ir/circuit.py b/bqskit/ir/circuit.py
@@ -1152,7 +1152,8 @@ def append_circuit(
                 (Default: False)
 
         Returns:
-            int: The starting cycle index of the appended circuit.
+            int: The starting cycle index of the appended circuit. If the
+                appended circuit is empty, then this will be -1.
 
         Raises:
             ValueError: If `circuit` is not the same size as `location`.
@@ -1178,16 +1179,14 @@ def append_circuit(
             op = Operation(CircuitGate(circuit, move), location, circuit.params)
             return self.append(op)
 
-        cycle_index: int | None = None
+        cycle_index = -1
+
         for op in circuit:
             mapped_location = [location[q] for q in op.location]
             ci = self.append(Operation(op.gate, mapped_location, op.params))
             if cycle_index is None:
                 cycle_index = ci
 
-        if cycle_index is None:
-            raise RuntimeError('Cannot append empty circuit.')
-
         return cycle_index
 
     def extend(self, ops: Iterable[Operation]) -> None:

diff --git a/tests/ir/circuit/test_op_gate_circ_methods.py b/tests/ir/circuit/test_op_gate_circ_methods.py
@@ -339,17 +339,13 @@ class TestAppendCircuit:
 
     @given(circuits())
     def test_reconstruct(self, circuit: Circuit) -> None:
-        if circuit.num_operations == 0:
-            return
         new_circuit = Circuit(circuit.num_qudits, circuit.radixes)
         new_circuit.append_circuit(circuit, list(range(circuit.num_qudits)))
         check_no_idle_cycles(new_circuit)
         assert new_circuit.get_unitary() == circuit.get_unitary()
 
     @given(circuits())
     def test_reconstruct_larger(self, circuit: Circuit) -> None:
-        if circuit.num_operations == 0:
-            return
         new_circ = Circuit(circuit.num_qudits + 1, circuit.radixes + (2,))
         new_circ.append_circuit(circuit, list(range(circuit.num_qudits)))
         check_no_idle_cycles(new_circ)