I’m unsure what indices AdaptiveAvgPool2d should return, so could you explain your use case a bit?
Maxpooling payers are selecting the max. value in the kernel/window using an index and can thus return these indices so that they can be reused in e.g. MaxUnpool2d layers.
However, Avgpool layers are calculating the average in each window, so there is no “selection” involving indices.