python.closure
==================
cond_closed_over_variable
^^^^^^^^^^^^^^^^^^^^^^^^^

.. note::

    Tags: :doc:`python.closure <python.closure>`, :doc:`torch.cond <torch.cond>`

    Support Level: SUPPORTED

Original source code:

.. code-block:: python

    import torch
    
    from functorch.experimental.control_flow import cond
    
    
    class CondClosedOverVariable(torch.nn.Module):
        """
        torch.cond() supports branches closed over arbitrary variables.
        """
    
        def forward(self, pred, x):
            def true_fn(val):
                return x * 2
    
            def false_fn(val):
                return x - 2
    
            return cond(pred, true_fn, false_fn, [x + 1])
    

Result:

.. code-block::

    ExportedProgram:
        class GraphModule(torch.nn.Module):
            def forward(self, arg0_1: "b8[]", arg1_1: "f32[3, 2]"):
                    true_graph_0 = self.true_graph_0
                false_graph_0 = self.false_graph_0
                conditional = torch.ops.higher_order.cond(arg0_1, true_graph_0, false_graph_0, [arg1_1]);  arg0_1 = true_graph_0 = false_graph_0 = arg1_1 = None
                getitem: "f32[3, 2]" = conditional[0];  conditional = None
                return (getitem,)
                
            class <lambda>(torch.nn.Module):
                def forward(self, arg0_1: "f32[3, 2]"):
                            mul: "f32[3, 2]" = torch.ops.aten.mul.Tensor(arg0_1, 2);  arg0_1 = None
                    return (mul,)
                    
            class <lambda>(torch.nn.Module):
                def forward(self, arg0_1: "f32[3, 2]"):
                            sub: "f32[3, 2]" = torch.ops.aten.sub.Tensor(arg0_1, 2);  arg0_1 = None
                    return (sub,)
                    
    Graph signature: ExportGraphSignature(input_specs=[InputSpec(kind=<InputKind.USER_INPUT: 1>, arg=TensorArgument(name='arg0_1'), target=None, persistent=None), InputSpec(kind=<InputKind.USER_INPUT: 1>, arg=TensorArgument(name='arg1_1'), target=None, persistent=None)], output_specs=[OutputSpec(kind=<OutputKind.USER_OUTPUT: 1>, arg=TensorArgument(name='getitem'), target=None)])
    Range constraints: {}
    


nested_function
^^^^^^^^^^^^^^^

.. note::

    Tags: :doc:`python.closure <python.closure>`

    Support Level: SUPPORTED

Original source code:

.. code-block:: python

    import torch
    
    
    
    class NestedFunction(torch.nn.Module):
        """
        Nested functions are traced through. Side effects on global captures
        are not supported though.
        """
        def __init__(self):
            super().__init__()
    
        def forward(self, a, b):
            x = a + b
            z = a - b
    
            def closure(y):
                nonlocal x
                x += 1
                return x * y + z
    
            return closure(x)
    

Result:

.. code-block::

    ExportedProgram:
        class GraphModule(torch.nn.Module):
            def forward(self, arg0_1: "f32[3, 2]", arg1_1: "f32[2]"):
                    add: "f32[3, 2]" = torch.ops.aten.add.Tensor(arg0_1, arg1_1)
                
                    sub: "f32[3, 2]" = torch.ops.aten.sub.Tensor(arg0_1, arg1_1);  arg0_1 = arg1_1 = None
                
                    add_1: "f32[3, 2]" = torch.ops.aten.add.Tensor(add, 1);  add = None
                
                    mul: "f32[3, 2]" = torch.ops.aten.mul.Tensor(add_1, add_1);  add_1 = None
                add_2: "f32[3, 2]" = torch.ops.aten.add.Tensor(mul, sub);  mul = sub = None
                return (add_2,)
                
    Graph signature: ExportGraphSignature(input_specs=[InputSpec(kind=<InputKind.USER_INPUT: 1>, arg=TensorArgument(name='arg0_1'), target=None, persistent=None), InputSpec(kind=<InputKind.USER_INPUT: 1>, arg=TensorArgument(name='arg1_1'), target=None, persistent=None)], output_specs=[OutputSpec(kind=<OutputKind.USER_OUTPUT: 1>, arg=TensorArgument(name='add_2'), target=None)])
    Range constraints: {}