The default comparison function used in the sort-merge.
order = scidoe_compare ( a , b )
a 1x1 matrix of doubles, the first value to be compared
a 1x1 matrix of doubles, the second value to be compared
a 1x1 matrix of floating point integers, the order. Returns order=0 is a is almost equal to b, order=-1 if a < b, order=+1 if a > b.
Returns -1 if and(a<b), returns 0 if and(a==b), returns +1 otherwise.