@order = sort { fp_compare($sgpropfp[$a], $sgpropfp[$b]) } 0 .. @sg - 1;
for (0 .. @sg - 2) {
        if (prop_matching($sgprop[$order[$_]], $sgprop[$order[$_ + 1]])) {
                print "property of $sg[$order[$_]] and $sg[$order[$_ + 1]] is equal";
        }
}