Return a vector of length y that is a function of x (differs at must where x differs) obeying the opposite order constraints as x. This vector is picked as close to y (by square-distance) as possible.
solveNonIncreasing(varName, x, y, w = NULL)
character, name of variable
numeric, factor, or character input (not empty, no NAs).
numeric (same length as x no NAs), output to match
numeric positive, same length as x (weights, can be NULL)
isotonicly adjusted y (non-decreasing)
#>  1.5 1.5 1.0