Update tutorial (#3242)

Summary:

Removed the use of capture_pre_autograd_graph in places where we are not quantizing, since we want to minimize the usage of this API for easier deprecation in the future.

Reviewed By: mergennachin

Differential Revision: D56475332

Author: angelayi

docs/source/tutorials_source/export-to-executorch-tutorial.py

@@ -44,15 +44,11 @@
 #
 # The first step of lowering to ExecuTorch is to export the given model (any
 # callable or ``torch.nn.Module``) to a graph representation. This is done via
-# the two-stage APIs, ``torch._export.capture_pre_autograd_graph``, and
-# ``torch.export``.
-#
-# Both APIs take in a model (any callable or ``torch.nn.Module``), a tuple of
+# ``torch.export``, which takes in an ``torch.nn.Module``, a tuple of
 # positional arguments, optionally a dictionary of keyword arguments (not shown
 # in the example), and a list of dynamic shapes (covered later).
 
 import torch
-from torch._export import capture_pre_autograd_graph
 from torch.export import export, ExportedProgram
 
 
@@ -70,40 +66,20 @@ def forward(self, x: torch.Tensor) -> torch.Tensor:
 
 
 example_args = (torch.randn(1, 3, 256, 256),)
-pre_autograd_aten_dialect = capture_pre_autograd_graph(SimpleConv(), example_args)
-print("Pre-Autograd ATen Dialect Graph")
-print(pre_autograd_aten_dialect)
-
-aten_dialect: ExportedProgram = export(pre_autograd_aten_dialect, example_args)
-print("ATen Dialect Graph")
+aten_dialect: ExportedProgram = export(SimpleConv(), example_args)
 print(aten_dialect)
 
 ######################################################################
-# The output of ``torch._export.capture_pre_autograd_graph`` is a fully
-# flattened graph (meaning the graph does not contain any module hierarchy,
-# except in the case of control flow operators). Furthermore, the captured graph
-# contains only ATen operators (~3000 ops) which are Autograd safe, for example, safe
-# for eager mode training.
-#
-# The output of ``torch.export`` further compiles the graph to a lower and
-# cleaner representation. Specifically, it has the following:
-#
-# - The graph is purely functional, meaning it does not contain operations with
-#   side effects such as mutations or aliasing.
-# - The graph contains only a small defined
-#   `Core ATen IR <https://pytorch.org/docs/stable/torch.compiler_ir.html#core-aten-ir>`__
-#   operator set (~180 ops), along with registered custom operators.
-# - The nodes in the graph contain metadata captured during tracing, such as a
-#   stacktrace from user's code.
+# The output of ``torch.export.export`` is a fully flattened graph (meaning the
+# graph does not contain any module hierarchy, except in the case of control
+# flow operators). Additionally, the graph is purely functional, meaning it does
+# not contain operations with side effects such as mutations or aliasing.
 #
 # More specifications about the result of ``torch.export`` can be found
-# `here <https://pytorch.org/docs/2.1/export.html>`__ .
+# `here <https://pytorch.org/docs/main/export.html>`__ .
 #
-# Since the result of ``torch.export`` is a graph containing the Core ATen
-# operators, we will call this the ``ATen Dialect``, and since
-# ``torch._export.capture_pre_autograd_graph`` returns a graph containing the
-# set of ATen operators which are Autograd safe, we will call it the
-# ``Pre-Autograd ATen Dialect``.
+# The graph returned by ``torch.export`` only contains functional ATen operators
+# (~2000 ops), which we will call the ``ATen Dialect``.
 
 ######################################################################
 # Expressing Dynamism
@@ -124,10 +100,8 @@ def forward(self, x: torch.Tensor, y: torch.Tensor) -> torch.Tensor:
         return x + y
 
 
-f = Basic()
 example_args = (torch.randn(3, 3), torch.randn(3, 3))
-pre_autograd_aten_dialect = capture_pre_autograd_graph(f, example_args)
-aten_dialect: ExportedProgram = export(f, example_args)
+aten_dialect: ExportedProgram = export(Basic(), example_args)
 
 # Works correctly
 print(aten_dialect.module()(torch.ones(3, 3), torch.ones(3, 3)))
@@ -153,15 +127,12 @@ def forward(self, x: torch.Tensor, y: torch.Tensor) -> torch.Tensor:
         return x + y
 
 
-f = Basic()
 example_args = (torch.randn(3, 3), torch.randn(3, 3))
 dim1_x = Dim("dim1_x", min=1, max=10)
 dynamic_shapes = {"x": {1: dim1_x}, "y": {1: dim1_x}}
-pre_autograd_aten_dialect = capture_pre_autograd_graph(
-    f, example_args, dynamic_shapes=dynamic_shapes
+aten_dialect: ExportedProgram = export(
+    Basic(), example_args, dynamic_shapes=dynamic_shapes
 )
-aten_dialect: ExportedProgram = export(f, example_args, dynamic_shapes=dynamic_shapes)
-print("ATen Dialect Graph")
 print(aten_dialect)
 
 ######################################################################
@@ -198,7 +169,7 @@ def forward(self, x: torch.Tensor, y: torch.Tensor) -> torch.Tensor:
 # As our goal is to capture the entire computational graph from a PyTorch
 # program, we might ultimately run into untraceable parts of programs. To
 # address these issues, the
-# `torch.export documentation <https://pytorch.org/docs/2.1/export.html#limitations-of-torch-export>`__,
+# `torch.export documentation <https://pytorch.org/docs/main/export.html#limitations-of-torch-export>`__,
 # or the
 # `torch.export tutorial <https://pytorch.org/tutorials/intermediate/torch_export_tutorial.html>`__
 # would be the best place to look.
@@ -207,10 +178,12 @@ def forward(self, x: torch.Tensor, y: torch.Tensor) -> torch.Tensor:
 # Performing Quantization
 # -----------------------
 #
-# To quantize a model, we can do so between the call to
-# ``torch._export.capture_pre_autograd_graph`` and ``torch.export``, in the
-# ``Pre-Autograd ATen Dialect``. This is because quantization must operate at a
-# level which is safe for eager mode training.
+# To quantize a model, we first need to capture the graph with
+# ``torch._export.capture_pre_autograd_graph``, perform quantization, and then
+# call ``torch.export``. ``torch._export.capture_pre_autograd_graph`` returns a
+# graph which contains ATen operators which are Autograd safe, meaning they are
+# safe for eager-mode training, which is needed for quantization. We will call
+# the graph at this level, the ``Pre-Autograd ATen Dialect`` graph.
 #
 # Compared to
 # `FX Graph Mode Quantization <https://pytorch.org/tutorials/prototype/fx_graph_mode_ptq_static.html>`__,
@@ -220,6 +193,8 @@ def forward(self, x: torch.Tensor, y: torch.Tensor) -> torch.Tensor:
 # will annotate the nodes in the graph with information needed to quantize the
 # model properly for a specific backend.
 
+from torch._export import capture_pre_autograd_graph
+
 example_args = (torch.randn(1, 3, 256, 256),)
 pre_autograd_aten_dialect = capture_pre_autograd_graph(SimpleConv(), example_args)
 print("Pre-Autograd ATen Dialect Graph")
@@ -268,13 +243,7 @@ def forward(self, x: torch.Tensor, y: torch.Tensor) -> torch.Tensor:
 from executorch.exir import EdgeProgramManager, to_edge
 
 example_args = (torch.randn(1, 3, 256, 256),)
-pre_autograd_aten_dialect = capture_pre_autograd_graph(SimpleConv(), example_args)
-print("Pre-Autograd ATen Dialect Graph")
-print(pre_autograd_aten_dialect)
-
-aten_dialect: ExportedProgram = export(pre_autograd_aten_dialect, example_args)
-print("ATen Dialect Graph")
-print(aten_dialect)
+aten_dialect: ExportedProgram = export(SimpleConv(), example_args)
 
 edge_program: EdgeProgramManager = to_edge(aten_dialect)
 print("Edge Dialect Graph")
@@ -298,16 +267,10 @@ def forward(self, x):
 
 
 encode_args = (torch.randn(1, 10),)
-aten_encode: ExportedProgram = export(
-    capture_pre_autograd_graph(Encode(), encode_args),
-    encode_args,
-)
+aten_encode: ExportedProgram = export(Encode(), encode_args)
 
 decode_args = (torch.randn(1, 5),)
-aten_decode: ExportedProgram = export(
-    capture_pre_autograd_graph(Decode(), decode_args),
-    decode_args,
-)
+aten_decode: ExportedProgram = export(Decode(), decode_args)
 
 edge_program: EdgeProgramManager = to_edge(
     {"encode": aten_encode, "decode": aten_decode}
@@ -328,8 +291,7 @@ def forward(self, x):
 # rather than the ``torch.ops.aten`` namespace.
 
 example_args = (torch.randn(1, 3, 256, 256),)
-pre_autograd_aten_dialect = capture_pre_autograd_graph(SimpleConv(), example_args)
-aten_dialect: ExportedProgram = export(pre_autograd_aten_dialect, example_args)
+aten_dialect: ExportedProgram = export(SimpleConv(), example_args)
 edge_program: EdgeProgramManager = to_edge(aten_dialect)
 print("Edge Dialect Graph")
 print(edge_program.exported_program())
@@ -353,7 +315,9 @@ def call_operator(self, op, args, kwargs, meta):
 print(transformed_edge_program.exported_program())
 
 ######################################################################
-# Note: if you see error like `torch._export.verifier.SpecViolationError: Operator torch._ops.aten._native_batch_norm_legit_functional.default is not Aten Canonical`,
+# Note: if you see error like ``torch._export.verifier.SpecViolationError:
+# Operator torch._ops.aten._native_batch_norm_legit_functional.default is not
+# Aten Canonical``,
 # please file an issue in https://github.com/pytorch/executorch/issues and we're happy to help!
 
 
@@ -365,7 +329,7 @@ def call_operator(self, op, args, kwargs, meta):
 # backend through the ``to_backend`` API.  An in-depth documentation on the
 # specifics of backend delegation, including how to delegate to a backend and
 # how to implement a backend, can be found
-# `here <../compiler-delegate-and-partitioner.html>`__
+# `here <../compiler-delegate-and-partitioner.html>`__.
 #
 # There are three ways for using this API:
 #
@@ -393,8 +357,7 @@ def forward(self, x):
 
 # Export and lower the module to Edge Dialect
 example_args = (torch.ones(1),)
-pre_autograd_aten_dialect = capture_pre_autograd_graph(LowerableModule(), example_args)
-aten_dialect: ExportedProgram = export(pre_autograd_aten_dialect, example_args)
+aten_dialect: ExportedProgram = export(LowerableModule(), example_args)
 edge_program: EdgeProgramManager = to_edge(aten_dialect)
 to_be_lowered_module = edge_program.exported_program()
 
@@ -460,8 +423,7 @@ def forward(self, x):
 
 
 example_args = (torch.ones(1),)
-pre_autograd_aten_dialect = capture_pre_autograd_graph(ComposedModule(), example_args)
-aten_dialect: ExportedProgram = export(pre_autograd_aten_dialect, example_args)
+aten_dialect: ExportedProgram = export(ComposedModule(), example_args)
 edge_program: EdgeProgramManager = to_edge(aten_dialect)
 exported_program = edge_program.exported_program()
 print("Edge Dialect graph")
@@ -499,8 +461,7 @@ def forward(self, a, x, b):
 
 
 example_args = (torch.randn(2, 2), torch.randn(2, 2), torch.randn(2, 2))
-pre_autograd_aten_dialect = capture_pre_autograd_graph(Foo(), example_args)
-aten_dialect: ExportedProgram = export(pre_autograd_aten_dialect, example_args)
+aten_dialect: ExportedProgram = export(Foo(), example_args)
 edge_program: EdgeProgramManager = to_edge(aten_dialect)
 exported_program = edge_program.exported_program()
 print("Edge Dialect graph")
@@ -534,8 +495,7 @@ def forward(self, a, x, b):
 
 
 example_args = (torch.randn(2, 2), torch.randn(2, 2), torch.randn(2, 2))
-pre_autograd_aten_dialect = capture_pre_autograd_graph(Foo(), example_args)
-aten_dialect: ExportedProgram = export(pre_autograd_aten_dialect, example_args)
+aten_dialect: ExportedProgram = export(Foo(), example_args)
 edge_program: EdgeProgramManager = to_edge(aten_dialect)
 exported_program = edge_program.exported_program()
 delegated_program = edge_program.to_backend(AddMulPartitionerDemo())