pytorch/tools/test/test_codegen.py

import dataclasses
import typing
import unittest

from tools.autograd import gen_autograd_functions
from tools.autograd import load_derivatives
import tools.codegen.model

class TestCreateDerivative(unittest.TestCase):

    def test_named_grads(self) -> None:
        schema = tools.codegen.model.FunctionSchema.parse(
            'func(Tensor a, Tensor b) -> (Tensor x, Tensor y)')
        native_function = dataclasses.replace(DEFAULT_NATIVE_FUNCTION,
                                              func=schema)

        derivative = load_derivatives.create_derivative(
            native_function,
            formula='func_backward(grad_x, grad_y)',
            var_names=(),
            available_named_gradients=['grad_x', 'grad_y'])
        self.assertSetEqual(derivative.named_gradients, {'grad_x', 'grad_y'})

    def test_non_differentiable_output(self) -> None:
        specification = 'func(Tensor a, Tensor b) -> (Tensor x, bool y, Tensor z)'
        schema = tools.codegen.model.FunctionSchema.parse(specification)
        native_function = dataclasses.replace(DEFAULT_NATIVE_FUNCTION,
                                              func=schema)

        differentiability_info = load_derivatives.create_differentiability_info(
            defn={'name': specification,
                  'a': 'grads[0]',
                  'b': 'grads[2]',
                  },
            functions_by_signature={schema.signature(): [native_function]},
            functions_by_schema={specification: native_function},
            op_counter=typing.Counter[str](),
        )

        self.assertSequenceEqual(differentiability_info.available_named_gradients,
                                 # grad_y is not present because y is a
                                 # bool and thus not differentiable.
                                 ['grad_x', 'grad_z'])

    def test_indexed_grads(self) -> None:
        schema = tools.codegen.model.FunctionSchema.parse(
            'func(Tensor a, Tensor b) -> (Tensor x, Tensor y)')
        native_function = dataclasses.replace(DEFAULT_NATIVE_FUNCTION,
                                              func=schema)

        derivative = load_derivatives.create_derivative(
            native_function,
            formula='func_backward(grads[0], grads[1])',
            var_names=(),
            available_named_gradients=['grad_x', 'grad_y'])
        self.assertSetEqual(derivative.named_gradients, set())

    def test_named_grads_and_indexed_grads(self) -> None:
        specification = 'func(Tensor a, Tensor b) -> (Tensor x, Tensor y)'
        schema = tools.codegen.model.FunctionSchema.parse(specification)
        native_function = dataclasses.replace(DEFAULT_NATIVE_FUNCTION,
                                              func=schema)

        with self.assertRaisesRegex(RuntimeError,
                                    'illegally mixes use of "grad_RETURN_NAME"'):
            load_derivatives.create_differentiability_info(
                defn={'name': specification,
                      # Uh-oh, the derivatives reference gradients by
                      # name and by index.
                      'a': 'grad_x',
                      'b': 'grads[1]',
                      },
                functions_by_signature={schema.signature(): [native_function]},
                functions_by_schema={specification: native_function},
                op_counter=typing.Counter[str](),
            )


class TestGenAutogradFunctions(unittest.TestCase):
    def test_non_differentiable_output_invalid_type(self) -> None:
        specification = 'func(Tensor a, Tensor b) -> (Tensor x, bool y, Tensor z)'
        schema = tools.codegen.model.FunctionSchema.parse(specification)
        native_function = dataclasses.replace(DEFAULT_NATIVE_FUNCTION,
                                              func=schema)

        differentiability_info = load_derivatives.create_differentiability_info(
            defn={'name': specification,
                  'a': 'grad_x',
                  'b': 'grad_z',
                  },
            functions_by_signature={schema.signature(): [native_function]},
            functions_by_schema={specification: native_function},
            op_counter=typing.Counter[str](),
        )
        definition = gen_autograd_functions.process_function(
            differentiability_info,
            gen_autograd_functions.FUNCTION_DEFINITION)
        # grad_z should map to grads[1], not grads[2] because output 1
        # (y) is not differentiable.
        assert 'grad_z = grads[2]' not in definition
        assert 'grad_z = grads[1]' in definition


    def test_non_differentiable_output_output_differentiability(self) -> None:
        specification = 'func(Tensor a, Tensor b) -> (Tensor x, Tensor y, Tensor z)'
        schema = tools.codegen.model.FunctionSchema.parse(specification)
        native_function = dataclasses.replace(DEFAULT_NATIVE_FUNCTION,
                                              func=schema)

        differentiability_info = load_derivatives.create_differentiability_info(
            defn={'name': specification,
                  'a': 'grad_x',
                  'b': 'grad_z',
                  'output_differentiability': [True, False, True],
                  },
            functions_by_signature={schema.signature(): [native_function]},
            functions_by_schema={specification: native_function},
            op_counter=typing.Counter[str](),
        )
        definition = gen_autograd_functions.process_function(
            differentiability_info,
            gen_autograd_functions.FUNCTION_DEFINITION)
        # grad_z should map to grads[1], not grads[2] because output 1
        # (y) is not differentiable.
        assert 'grad_z = grads[2]' not in definition
        assert 'grad_z = grads[1]' in definition


# Represents the most basic NativeFunction. Use dataclasses.replace()
# to edit for use.
DEFAULT_NATIVE_FUNCTION, _ = tools.codegen.model.NativeFunction.from_yaml(
    {'func': 'func() -> bool'},
    tools.codegen.model.Location(__file__, 1),
    set())


if __name__ == '__main__':
    unittest.main()