sub Compare_Vectors {
    my( $x, $y )= @_;
    for my $i ( 0..$#x ) {
        my $cmp= $x[$i] <=> ( $y[$i] || 0 );
        return $cmp   if  $cmp;
    }
    return 0 <=> ( $y[@x] || 0 );
}

sub Delta_YMDHMS {
    my $x= [ splice @_, 0, 6 ];
    my $y= [ @_ ];
    my $sign= 1;
    if(  Compare_Vectors( $x, $y ) < 0  ) {
        $sign= -1;
        ( $x, $y )= ( $y, $x );
    }
    return map $sign*$_, Date::Calc::Delta_YMDHMS( @$x, @$y );
}