The scatter operation for AutoDiff seems to be incomplete: is it somewhere in subsasgn()?

[uoa1184615]

Here demonstrate the scatter error swaps and column swaps.
More generally need subsasgn(), if that is the function, to work
with permutations (including sub-sampled).

u=AutoDiff(reshape(1:3,3,[]))
f=u.^2
fv=getvalue(f), fD=full(getderivs(f))
% test rows swaps
swap=[1 3 2]
g=f(swap,:) % gather works for vals and derivs
gv=getvalue(g), gD=full(getderivs(g))
g(swap,:)=f % scatter  DNW  for derivs,  xxxxxxxxxxxxxx
gv=getvalue(g), gD=full(getderivs(g))

if size(u,2)>1 %optionally test column swaps
    swap=[2 1]
    g=f(:,swap) % gather works for vals and derivs
    gv=getvalue(g), gD=full(getderivs(g))
    g(:,swap)=f % scatter  DNW  for derivs,  xxxxxxxxxxxxx
    gv=getvalue(g), gD=full(getderivs(g))
end

Checking row case: just try simple swap of rows 2 and 3.
The first case where LHS = RHS-gather works fine with the
rows of the derivs swapping correctly. The 2nd case where
LHS-gather=RHS does not transform the derivs correctly.
Same for the column swap example.