Fix AD

[willtebbutt]

@martincornejo apologies for the delay on this. You were right about the mean_vector stuff, but it turns out we just need to opt out of some rrules in order to get this stuff to work.

Do you mind if we go with this approach rather than yours?

[codecov[bot]]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (bd15654) 100.00% compared to head (7f28e95) 100.00%.

:exclamation: Current head 7f28e95 differs from pull request most recent head 4083ed0. Consider uploading reports for the commit 4083ed0 to get more accurate results

Additional details and impacted files

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[martincornejo]

Perfect! I've been working with my fix in the meanwhile, but this solution is much better. Thanks!