paddle.grad无法计算高阶微分

[ChevalierOhm]

Paddle/python/paddle/base/dygraph/base.py

Line 610 in 1319992

def grad(

我的代码如下：
import paddle
import numpy as np

构建一个函数

def transform(x):
return 4 * x ** 3 + 1

x = paddle.rand(shape=[5], dtype=np.float32)
x.stop_gradient = False

print(x)

outputs = transform(x)

print(outputs)

使用paddle.grad命令计算二阶微分

dudx = paddle.grad(outputs, x, grad_outputs=paddle.ones_like(x), retain_graph=True, create_graph=True)[0]
print(dudx)
d2udx2 = paddle.grad(dudx, x, grad_outputs=paddle.ones_like(x), retain_graph=True, create_graph=True)[0]
print(d2udx2)

上述代码会报错，是哪里有问题吗

[ChevalierOhm]

报错：
Error Traceback (most recent call last)/tmp/ipykernel_95/2675772064.py in
12 dudx = paddle.grad(outputs, x, grad_outputs=None, create_graph=True)[0]
13 print(dudx)
---> 14 d2udx2 = paddle.grad(dudx, x, grad_outputs=None, create_graph=True)[0]
15 print(d2udx2)
in grad(outputs, inputs, grad_outputs, retain_graph, create_graph, only_inputs, allow_unused, no_grad_vars)
/opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/paddle/fluid/wrapped_decorator.py in impl(func, *args, **kwargs)
24 def impl(func, *args, **kwargs):
25 wrapped_func = decorator_func(func)
---> 26 return wrapped_func(*args, **kwargs)
27
28 return impl
/opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/paddle/fluid/framework.py in impl(*args, **kwargs)
545 % func.name
546 )
--> 547 return func(*args, **kwargs)
548
549 return impl
/opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/paddle/fluid/dygraph/base.py in grad(outputs, inputs, grad_outputs, retain_graph, create_graph, only_inputs, allow_unused, no_grad_vars)
689 retain_graph, create_graph,
690 only_inputs, allow_unused,
--> 691 no_grad_vars)
692 else:
693 place = core.Place()
ValueError: (InvalidArgument) The 0-th input does not appear in the backward graph. Please check the input tensor or set allow_unused=True to get None result.
[Hint: Expected allow_unused == true, but received allow_unused:0 != true:1.] (at /paddle/paddle/fluid/eager/general_grad.h:471)

[zoooo0820]

你好，在目前develop版本上未复现出这个问题，可以更新下paddle