def max3(a,b,c)
      (a >= b) ? ((a >= c)? a : c) : ((b >= c)? b : c)
    end
def max3(a,b,c)
      (a >= b) ? ((a >= c)? a : c) : ((b >= c)? b : c)
    end
Determines the maximum value of three variables. 3-4 times faster than
 [a,b,c].max.