Codecov Report

Attention: Patch coverage is 0% with 15 lines in your changes missing coverage. Please review.

Project coverage is 93.05%. Comparing base (bec25c6) to head (c4b4202).

@@            Coverage Diff             @@
##             main     #383      +/-   ##
==========================================
- Coverage   96.64%   93.05%   -3.59%     
==========================================
  Files         100       98       -2     
  Lines        4915     4910       -5     
==========================================
- Hits         4750     4569     -181     
- Misses        165      341     +176     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

Wait I don't understand, pullback is a first order operator, what does it have to do with ForwardDiff over ReverseDiff?
What we need are two things:

• an HVP with ForwardDiff over ReverseDiff
• a pullback with ReverseDiff that uses the existing tape mechanism

Which are you trying to tackle?

a pullback with ReverseDiff that uses the existing tape mechanism

As I understand the current pullback needs to compile the tape everytime and cannot use the preparation in the presence of the Duals from ForwardDiff, so this let's you avoid that by adding a preparation and pullback that can work with Duals.

The hvp gets called fine even now other than the recompilation so I am not sure what you mean needs to be done there.