I have a suggestion for an enhancement to the sort() function.

Presently, B = sort(A) returns a new array B
containing the sorted values from A, and leaving A unchanged.

In many instances, we want to know HOW the values from A got rearranged.

I program in MATLAB a lot, and one version of the sort function
looks like this:  [B X] = sort(A)
where X is an array of index values
B[0] = A[X[0]]
B[1] = A[X[1]]
B[2] = A[X[2]] and so on.

I suggest include this functionality in Processing.
One way would be to extend "sort" to support the following variation:
 X = sort(A,INDEX)
or else make a separate function "sortIndex"
 X = sortIndex(A)

I am not an expert in JAVA, but I wouldn't be surprised
if something equivalent to "sortIndex" already exists.

-- djones