Great question! 😊 Yes, you figured it out. The pullback at lines 57 and 61 give the derivative if evaluated at 1.0. Since they effectively evaluate the vector-Jacobian product we need to provide a vector (here just a scalar) to left-multiply the Jacobian with. Using just 1.0 gives the unscaled derivative.
![[08x06] Calculus using Julia Automatic Differentiation | ForwardDiff.jl, ReverseDiff.jl and Pluto](http://i.ytimg.com/vi/VjdkTIiYKU8/mqdefault.jpg)
Man this is great. Thanks!
Thanks a lot, you're welcome.
One time you evaluated the derivate at 1.0 instead of 2.0, why did you get the same result?
Ah it needs the cotangend at this point
Great question! 😊
Yes, you figured it out. The pullback at lines 57 and 61 give the derivative if evaluated at 1.0. Since they effectively evaluate the vector-Jacobian product we need to provide a vector (here just a scalar) to left-multiply the Jacobian with. Using just 1.0 gives the unscaled derivative.