pro buildSequentialIndices,array,currentColumn=currentColumn, numRows=numRows, $
                           numCols=numCols
;builds a sequential array of indices. The first column of the array must
;first be initialized to the fastest changing index.  See test program
;testBuildSequentialIndices.pro for an example

sz = size(array,/dimen)
maxVal = max(array)
currentVal = 0L
interval = numRows^currentColumn
for i=0L,sz[1]-1 do begin
  leftVal = array[currentColumn-1,i]

  if i eq 0 then continue
  if ( i mod interval) eq 0 then currentVal= (currentVal+1) mod numRows
  array[currentColumn,i] = currentVal
endfor

if currentColumn lt (numCols-1) then $
  buildSequentialIndices,array,currentColumn=currentColumn+1,numRows=numRows, $
                           numCols=numCols

return
end