if ($atob+$atoc+$btoc) {
    printf OUTFILE "DIFF=%d:   %f,  %f,  %f\n",
        $atob+$atoc+$btoc, $a-$b, $a-$c, $b-$c;
}
$matrixflags[$row - 4][$i] = $atob;
$matrixflags[$row - 3][$i] = $atoc;
$matrixflags[$row - 2][$i] = $atob;
}