1. A method for determining an incremental extrema for a set of n random variables, given a change to at least one of the n random variables from a first value to a second value, the method comprising: obtaining the n random variables; obtaining a first extrema for the n random variables, the first extrema comprising an extrema computed prior to the change to the at least one of the n random variables; removing the at least one of the n random variables to form an (n−1) subset; computing a second extrema for the (n−1) subset in accordance with the first extrema and the first value of the at least one of the n random variables; and outputting a third extrema computed as an extrema of the second extrema and the second value of the at least one of the n random variables as the incremental extrema for the set of n random variables, wherein at least one of the removing or the computing is performed using a processor.