Keep resets at beginning of circuits

qiskit/transpiler/preset_passmanagers/level1.py

@@ -232,10 +232,10 @@ def _swap_mapped(property_set):
         target is not None and target.get_non_global_operation_names(strict_direction=True)
     ):
         pre_optimization = common.generate_pre_op_passmanager(
-            target, coupling_map, remove_reset_in_zero=True
+            target, coupling_map, remove_reset_in_zero=False
         )
     else:
-        pre_optimization = common.generate_pre_op_passmanager(remove_reset_in_zero=True)
+        pre_optimization = common.generate_pre_op_passmanager(remove_reset_in_zero=False)
     if optimization_method is None:
         optimization = PassManager()
         unroll = [pass_ for x in translation.passes() for pass_ in x["passes"]]

qiskit/transpiler/preset_passmanagers/level2.py

@@ -220,9 +220,9 @@ def _swap_mapped(property_set):
     if (coupling_map and not coupling_map.is_symmetric) or (
         target is not None and target.get_non_global_operation_names(strict_direction=True)
     ):
-        pre_optimization = common.generate_pre_op_passmanager(target, coupling_map, True)
+        pre_optimization = common.generate_pre_op_passmanager(target, coupling_map, False)
     else:
-        pre_optimization = common.generate_pre_op_passmanager(remove_reset_in_zero=True)
+        pre_optimization = common.generate_pre_op_passmanager(remove_reset_in_zero=False)
     if optimization_method is None:
         optimization = PassManager()
         unroll = [pass_ for x in translation.passes() for pass_ in x["passes"]]

qiskit/transpiler/preset_passmanagers/level3.py

@@ -272,7 +272,7 @@ def _unroll_condition(property_set):
         if (coupling_map and not coupling_map.is_symmetric) or (
             target is not None and target.get_non_global_operation_names(strict_direction=True)
         ):
-            pre_optimization = common.generate_pre_op_passmanager(target, coupling_map, True)
+            pre_optimization = common.generate_pre_op_passmanager(target, coupling_map, False)
             _direction = [
                 pass_
                 for x in common.generate_pre_op_passmanager(target, coupling_map).passes()
@@ -284,7 +284,7 @@ def _unroll_condition(property_set):
                     do_while=_opt_control,
                 )
         else:
-            pre_optimization = common.generate_pre_op_passmanager(remove_reset_in_zero=True)
+            pre_optimization = common.generate_pre_op_passmanager(remove_reset_in_zero=False)
             optimization.append(
                 _opt + _unroll_if_out_of_basis + _minimum_point_check, do_while=_opt_control
             )

test/python/compiler/test_transpiler.py

@@ -802,14 +802,15 @@ def test_move_measurements(self):
             )
             self.assertTrue(is_last_measure)
 
-    def test_initialize_reset_should_be_removed(self):
-        """The reset in front of initializer should be removed when zero state"""
+    def test_initialize_reset_is_not_removed(self):
+        """The reset in front of initializer should NOT be removed at beginning"""
         qr = QuantumRegister(1, "qr")
         qc = QuantumCircuit(qr)
         qc.initialize([1.0 / math.sqrt(2), 1.0 / math.sqrt(2)], [qr[0]])
         qc.initialize([1.0 / math.sqrt(2), -1.0 / math.sqrt(2)], [qr[0]])
 
         expected = QuantumCircuit(qr)
+        expected.reset(qr[0])
         expected.append(U3Gate(np.pi / 2, 0, 0), [qr[0]])
         expected.reset(qr[0])
         expected.append(U3Gate(np.pi / 2, -np.pi, 0), [qr[0]])
@@ -828,7 +829,7 @@ def test_initialize_FakeMelbourne(self):
         out_dag = circuit_to_dag(out)
         reset_nodes = out_dag.named_nodes("reset")
 
-        self.assertEqual(reset_nodes, [])
+        self.assertEqual(len(reset_nodes), 3)
 
     def test_non_standard_basis(self):
         """Test a transpilation with a non-standard basis"""