chore: autograph: remove autograph kwarg from QNode constructor

doc/releases/changelog-dev.md

@@ -641,6 +641,10 @@
 
 <h3>Internal changes ⚙️</h3>
 
+* The `autograph` keyword argument has been removed from the `QNode` constructor. 
+  To enable autograph conversion, use the `qjit` decorator together with the `qml.capture.disable_autograph` context manager.
+  [(#8104)](https://github.com/PennyLaneAI/pennylane/pull/8104)
+
 * Add ability to disable autograph conversion using the newly added `qml.capture.disable_autograph` decorator or context manager.
   [(#8102)](https://github.com/PennyLaneAI/pennylane/pull/8102)
 

pennylane/workflow/_capture_qnode.py

@@ -457,8 +457,6 @@ def _extract_qfunc_jaxpr(qnode, abstracted_axes, *args, **kwargs):
     """Process the quantum function of a QNode to create a Jaxpr."""
 
     qfunc = partial(qnode.func, **kwargs) if kwargs else qnode.func
-    # pylint: disable=protected-access
-    qfunc = qml.capture.run_autograph(qfunc) if qnode._autograph else qfunc
     flat_fn = FlatFn(qfunc)
 
     try:
@@ -472,8 +470,9 @@ def _extract_qfunc_jaxpr(qnode, abstracted_axes, *args, **kwargs):
     ) as exc:
         raise CaptureError(
             "Autograph must be used when Python control flow is dependent on a dynamic "
-            "variable (a function input). Please ensure that autograph=True or use native control "
-            "flow functions like for_loop, while_loop, etc."
+            "variable (a function input). Please ensure that autograph is being correctly enabled with "
+            "`qml.capture.run_autograph` or disabled with `qml.capture.disable_autograph` or consider using PennyLane native control "
+            "flow functions like `qml.for_loop`, `qml.while_loop`, or `qml.cond`."
         ) from exc
 
     assert flat_fn.out_tree is not None, "out_tree should be set by call to flat_fn"

pennylane/workflow/qnode.py

@@ -307,9 +307,6 @@ class QNode:
             on supported options for your chosen gradient transform.
         static_argnums (int | Sequence[int]): *Only applicable when the experimental capture mode is enabled.*
             An ``int`` or collection of ``int``\ s that specify which positional arguments to treat as static.
-        autograph (bool): *Only applicable when the experimental capture mode is enabled.* Whether to use AutoGraph to
-            convert Python control flow to native PennyLane control flow. For more information, refer to
-            :doc:`Autograph </development/autograph>`. Defaults to ``True``.
         executor_backend (ExecBackends | str): The backend executor for concurrent function execution. This argument
             allows for selective control of how to run data-parallel/task-based parallel functions via a defined execution
             environment. All supported options can be queried using
@@ -533,7 +530,6 @@ def __init__(
         mcm_method: Literal["deferred", "one-shot", "tree-traversal"] | None = None,
         gradient_kwargs: dict | None = None,
         static_argnums: int | Iterable[int] = (),
-        autograph: bool = True,
         executor_backend: ExecBackends | str | None = None,
     ):
         self._init_args = locals()
@@ -577,7 +573,6 @@ def __init__(
             self._qfunc_uses_shots_arg = False
 
         # input arguments
-        self._autograph = autograph
         self.func = func
         self.device = device
         self._interface = get_canonical_interface_name(interface)

tests/capture/autograph/test_autograph.py

@@ -110,13 +110,12 @@ def test_transform_on_lambda(self):
         assert new_fn(1.23) == 2.46
         assert "inner_factory.<locals>.<lambda>" in str(new_fn)
 
-    @pytest.mark.parametrize("autograph", [True, False])
-    def test_transform_on_qnode(self, autograph):
+    def test_transform_on_qnode(self):
         """Test the transform method on a QNode updates the qnode.func"""
         transformer = PennyLaneTransformer()
         user_context = converter.ProgramContext(TOPLEVEL_OPTIONS)
 
-        @qml.qnode(qml.device("default.qubit", wires=3), autograph=autograph)
+        @qml.qnode(qml.device("default.qubit", wires=3))
         def circ(x):
             qml.RX(x, 0)
             return qml.expval(qml.Z(0))
@@ -245,11 +244,10 @@ def fn(x: int):
         assert check_cache(fn)
         assert check_cache(inner)
 
-    @pytest.mark.parametrize("autograph", [True, False])
-    def test_qnode(self, autograph):
+    def test_qnode(self):
         """Test autograph on a QNode."""
 
-        @qml.qnode(qml.device("default.qubit", wires=1), autograph=autograph)
+        @qml.qnode(qml.device("default.qubit", wires=1))
         def circ(x: float):
             qml.RY(x, wires=0)
             return qml.expval(qml.PauliZ(0))
@@ -302,23 +300,21 @@ def fn(x: float):
         assert check_cache(inner1.func)
         assert check_cache(inner2.func)
 
-    @pytest.mark.parametrize("autograph", [True, False])
-    def test_adjoint_op(self, autograph):
+    def test_adjoint_op(self):
         """Test that the adjoint of an operator successfully passes through autograph"""
 
-        @qml.qnode(qml.device("default.qubit", wires=2), autograph=autograph)
+        @qml.qnode(qml.device("default.qubit", wires=2))
         def circ():
             qml.adjoint(qml.X(0))
             return qml.expval(qml.Z(0))
 
-        plxpr = qml.capture.make_plxpr(circ, autograph=True)()
+        plxpr = qml.capture.make_plxpr(circ)()
         assert jax.core.eval_jaxpr(plxpr.jaxpr, plxpr.consts)[0] == -1
 
-    @pytest.mark.parametrize("autograph", [True, False])
-    def test_ctrl_op(self, autograph):
+    def test_ctrl_op(self):
         """Test that controlled operators successfully pass through autograph"""
 
-        @qml.qnode(qml.device("default.qubit", wires=2), autograph=autograph)
+        @qml.qnode(qml.device("default.qubit", wires=2))
         def circ():
             qml.X(1)
             qml.ctrl(qml.X(0), 1)
@@ -327,14 +323,13 @@ def circ():
         plxpr = qml.capture.make_plxpr(circ, autograph=True)()
         assert jax.core.eval_jaxpr(plxpr.jaxpr, plxpr.consts)[0] == -1
 
-    @pytest.mark.parametrize("autograph", [True, False])
-    def test_adjoint_wrapper(self, autograph):
+    def test_adjoint_wrapper(self):
         """Test conversion is happening successfully on functions wrapped with 'adjoint'."""
 
         def inner(x):
             qml.RY(x, wires=0)
 
-        @qml.qnode(qml.device("default.qubit", wires=1), autograph=autograph)
+        @qml.qnode(qml.device("default.qubit", wires=1))
         def circ(x: float):
             inner(x * 2)
             qml.adjoint(inner)(x)
@@ -351,14 +346,13 @@ def circ(x: float):
     @pytest.mark.xfail(
         reason="ctrl_transform_prim not working with autograph. See sc-84934",
     )
-    @pytest.mark.parametrize("autograph", [True, False])
-    def test_ctrl_wrapper(self, autograph):
+    def test_ctrl_wrapper(self):
         """Test conversion is happening successfully on functions wrapped with 'ctrl'."""
 
         def inner(x):
             qml.RY(x, wires=0)
 
-        @qml.qnode(qml.device("default.qubit", wires=2), autograph=autograph)
+        @qml.qnode(qml.device("default.qubit", wires=2))
         def circ(x: float):
             qml.PauliX(1)
             qml.ctrl(inner, control=1)(x)
@@ -403,8 +397,7 @@ def fn(x: float):
         assert check_cache(fn)
         assert check_cache(inner)
 
-    @pytest.mark.parametrize("autograph", [True, False])
-    def test_tape_transform(self, autograph):
+    def test_tape_transform(self):
         """Test if tape transform is applied when autograph is on."""
 
         dev = qml.device("default.qubit", wires=1)
@@ -414,7 +407,7 @@ def my_quantum_transform(tape):
             raise NotImplementedError
 
         @my_quantum_transform
-        @qml.qnode(dev, autograph=autograph)
+        @qml.qnode(dev)
         def circuit(x):
             qml.RY(x, wires=0)
             qml.RX(x, wires=0)