[WIP] Support 0-size tensor forward and backward

[HydrogenSulfate]

PR Category

Operator Mechanism

PR Types

New features

Description

Pcard-75624

0-size Tensor的支持需要满足前反向机制改造 + 前反向 Kernel 改造，本PR仅修改了框架的前反向相关机制，“放宽”了部分代码执行分支的判断条件，将0-size视为正常Tensor不报错，而不是非法Tensor抛出异常，以及0-size Tensor能够进入某些预期的分支进行一些操作，接着再根据所需跑通的模型，为涉及到的Kernel适配0-size Tensor的逻辑，最终支持0-size Tensor的计算。

import paddle


def test_zero_param():
    class Model(paddle.nn.Layer):
        def __init__(self) -> None:
            super().__init__()
            self.w = self.create_parameter(shape=[0, 4], dtype="float32")

    model = Model()
    print(f"model.w.shape = {model.w.shape}")
    print(f"model.w.data_ptr() = {model.w.data_ptr()}")
    print(f"model.w.place = {model.w.place}")
    print(f"model.w.strides = {model.w.strides}")
    print(f"model.w.is_contiguous() = {model.w.is_contiguous()}")


def test_zero_forward():
    x = paddle.randn([0, 2])
    y = x + 1
    print(y.shape)


def test_zero_backward():
    x = paddle.randn([0, 2])
    x.stop_gradient = False
    y = x.tanh()
    g = paddle.grad(y, x)[0]
    print(g.shape)


if __name__ == "__main__":
    test_zero_param()
    test_zero_forward()
    test_zero_backward()

TODO:

• 支持0-size静态图前反向

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