1. A method of operating an n-dimensional array of processing elements to determine a dimensional extrema for a plurality of values stored in said n-dimensional array of processing elements, the method comprising: determining within each of said processing elements a local extrema for each of said processing elements, said local extrema having a most significant byte and a least significant byte; serially outputting in bursts said most significant bytes and said least significant bytes of said local extrema from each of said processing elements to a neighboring processing element until every processing element in a first dimension has received all local extrema along said first dimension, wherein a burst length is selected to optimize use of each processing element's ALU; determining within each of said processing elements a first dimensional extrema for said first dimension of said n-dimensional array, wherein said first dimensional extrema is determined from a plurality of local extrema most significant bytes and least significant bytes stored in-said processing elements in said first dimension and wherein said first dimensional extrema has a most significant byte and a least significant byte; and saving in a register said dimensional extrema.