Intuition behind reverse mode algorithmic differentiation (AD)

By far not a complete story on AD, but provides a mental image to help digest further material on AD.
For a bit more context, how AD can be used to compose full Jacobians, see • High-level view of AD ...
Created with the help of LIMEL (www.kuleuven.b..., sponsered by MECO ( www.mech.kuleu... )

[@wiczus6102]

That smooth fade in at start

[@plouf1969]

Setting aside the interesting topic, I was amazed by your writing things from 'behind' some class wall and it not appearing mirror-imaged :)

[@MarcelloZucchi91]

I think he writes normally then the video is mirrored before uploading. In fact he appears to be left handed here, whereas he seems right handed in other videos.

[@navsquid32]

It would be impossible to reverse the images of the video so that the writing appeared normally.

[@EvanZamir]

@@navsquid32 What if he is on one side of a piece of glass writing and I am on the other side of the glass taking the video of him? I can then do a mirror operation on the video.

[@navsquid32]

@@EvanZamir It was sarcasm, boomer.

[@EvanZamir]

Matt Williams Clearly didn’t come across as sarcasm to me, but assuming it was, did you feel like I was insulting you? Why would you respond with derogatory name calling when I was earnestly trying to provide some useful commentary? This is what is wrong with social media. You need to do some introspection.

[@Horivision]

You should have given an example with variables defined; this made it more complex. What's the p1 and p2 arguments all about

[@queenieluo4189]

Yes, I also wonder what are p1 and p2?

[@gzitterspiller]

I always found it easier to work always on the tree and then just work it with graphs algorithms.

[@vijaypalmanit]

you have unnecessarily made it difficult, it is easy although....

[@yifanwang7696]

at 6:17, why is (partial f4)/(partial P1) not partial (f4/partial P2)?

[@yifanwang7696]

oooh, I saw you corrected it later at 7:18, sorry

[@andyborjigin9699]

What are the p1 & p2 here? Are they f1 & f2? Or something else?

[@gabrielmccartney7975]

Can we use dual numbers for integration?

[@larrylaw3693]

Great explanation, thanks!

[@zephyrpenoyre2714]

just to check my undertsanding - are you writing += (i.e. take the previous value and increment) or plus-minus in the second half of the video (\pm in LaTeX)? I presume it's the first, but your notation is a little hard to track. Maybe a plus with a double underline would be clearer? Otherwise lovely video! Look forward to seeing more

[@Banefane]

Thank you very much!

[@Mathomla]

Thanks for the clear explanation!