Update multi_control_rotation_gates.py (#11903)

Qiskit · Feb 28, 2024 · 58bee1f · 58bee1f
1 parent afdd1b7
commit 58bee1f
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/qiskit/circuit/library/standard_gates/multi_control_rotation_gates.py b/qiskit/circuit/library/standard_gates/multi_control_rotation_gates.py
@@ -123,6 +123,9 @@ def _mcsu2_real_diagonal(
     if not is_unitary_matrix(unitary):
         raise QiskitError(f"The unitary in must be an unitary matrix, but is {unitary}.")
 
+    if not np.isclose(1.0, np.linalg.det(unitary)):
+        raise QiskitError("Invalid Value _mcsu2_real_diagonal requires det(unitary) equal to one.")
+
     is_main_diag_real = np.isclose(unitary[0, 0].imag, 0.0) and np.isclose(unitary[1, 1].imag, 0.0)
     is_secondary_diag_real = np.isclose(unitary[0, 1].imag, 0.0) and np.isclose(
         unitary[1, 0].imag, 0.0