MindSpore网络自定义反向报错:TypeError: The params of function 'bprop' of

  1. 报错描述1.1 系统环境Hardware Environment(Ascend/GPU/CPU): GPUSoftware Environment:MindSpore version (source or binary): 1.7.0Python version (e.g., Python 3.7.5): 3.7.5OS platform and distribution (e.g., Linux Ubuntu 16.04): Ubuntu 18.04.4 LTSGCC/Compiler version (if compiled from source): 7.5.01.2 基本信息1.2.1 源码import mindspore as ms
    import mindspore.nn as nn
    from mindspore.common.tensor import Tensor
    from mindspore.ops import composite as C

grad_all = C.GradOperation(get_all=True)

class MulAdd(nn.Cell):

def construct(self, x, y):
    return 2 * x + y

def bprop(self, x, y, out):
    return 2 * x, 2 * y

mul_add = MulAdd()
x = Tensor(1, dtype=ms.int32)
y = Tensor(2, dtype=ms.int32)
output = grad_all(mul_add)(x, y)1.2.2 报错TypeError: The params of function 'bprop' of Primitive or Cell requires the forward inputs as well as the 'out' and 'dout'Traceback (most recent call last):
File "test_grad.py", line 20, in

output = grad_all(mul_add)(x, y)

File "/home/liangzhibo/mindspore/build/package/mindspore/common/api.py", line 522, in staging_specialize

out = _MindsporeFunctionExecutor(func, hash_obj, input_signature, process_obj)(*args)

File "/home/liangzhibo/mindspore/build/package/mindspore/common/api.py", line 93, in wrapper

results = fn(*arg, **kwargs)

File "/home/liangzhibo/mindspore/build/package/mindspore/common/api.py", line 353, in call

phase = self.compile(args_list, self.fn.__name__)

File "/home/liangzhibo/mindspore/build/package/mindspore/common/api.py", line 321, in compile

is_compile = self._graph_executor.compile(self.fn, compile_args, phase, True)

TypeError: The params of function 'bprop' of Primitive or Cell requires the forward inputs as well as the 'out' and 'dout'.
In file test_grad.py(13)

def bprop(self, x, y, out):
^

  • The Traceback of Net Construct Code:

In file test_grad.py(13)

def bprop(self, x, y, out):
^

  • C++ Call Stack: (For framework developers)

    mindspore/ccsrc/frontend/optimizer/ad/kprim.cc:651 BuildOutput

  • 原因分析与解决方法在这个用例中, 我们使用了Cell的自定义反向规则。 而报错信息也提示了我们是自定义规则的输入, 即def bprop(self, x, y, out):这句话存在错误。 在自定义Cell的反向规则bprop时, 需要接受三类输入, 分别是Cell的正向输入(在本用例中为x, y), Cell的正向输出(在本用例中为out),以及输入网络反向的累加梯度(dout)。本用例中正式因为缺少了dout输入, 因此运行失败。 因此我们只需要将代码更改为:def bprop(self, x, y, out, dout):
    return 2 x, 2 y 程序即可正常运行。下图表示了三类输入分别的意义, dout为反向图前一个节点输出的梯度, bprop函数需要此输入来对计算的梯度进行继承与使用。
    MindSpore网络自定义反向报错:TypeError: The params of function 'bprop' of_第1张图片
    另外, bprop的三类输入是构图的时候需要使用的, 因此即使某些输入在bprop函数中没有被使用, 也是需要传入bprop中的。3. 参考文档https://www.mindspore.cn/tuto...

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