julia> ForwardDiff.jacobian(f!, F, x)
2×2 Matrix{Float64}:
-6.0 12.0
-0.399455 -0.399455
The documentaiton said ForwardDiff.jacobian(..), not ForwardDiff.jacobian!(...).
julia> ForwardDiff.jacobian(f!, F, x)
2×2 Matrix{Float64}:
-6.0 12.0
-0.399455 -0.399455
The documentaiton said ForwardDiff.jacobian(..), not ForwardDiff.jacobian!(...).