# Custom autograd.Function: backward pass not called

**URL:** <https://discuss.pytorch.org/t/custom-autograd-function-backward-pass-not-called/9144>\
**Category:** autograd\
**Created:** [October 27, 2017, 10:44am UTC](https://discuss.pytorch.org/t/custom-autograd-function-backward-pass-not-called/9144 "2017-10-27T10:44:33Z")\
**Posts on this page:** 1\
**Showing post:** 12

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**Author:** ![albanD](https://discuss.pytorch.org/user_avatar/discuss.pytorch.org/alband/32/215_2.png) [@albanD](https://discuss.pytorch.org/u/albanD)\
**Post date:** [April 1, 2019, 10:05am UTC](https://discuss.pytorch.org/t/custom-autograd-function-backward-pass-not-called/9144/12 "2019-04-01T10:05:01Z")

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Hi,

I’m not sure how the coverage is checked, but if it checks if a python function calls the backward it will never happen. It is called directly by some cpp code. So the coverage tool might miss it.

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