Hello,

I am trying to manipulate the running mean of the batchnorm layer in a NN as follows -

```
new_running_mean = running_mean * x + b
```

`x and b`

are both trainable parameters defined as -

```
nn.Parameter(x, requires_grad = True)
```

I understand that batchnorm running mean is non trainable hence the `requires_grad = True`

flag is giving me an error - `the derivative for 'running_mean' is not implemented`

However, I want` x and b`

to be trainable parameters, setting `requires_grad = False`

will directly contradict this.

How can I work around this issue?

Thanks