sub round_all {
  my $interval = shift;
  my @result;
  foreach $value (@_) {
    my $quanta = int(($value + $interval/2) / $interval);
    push @result, $quanta * $interval;
  }
  @result;
}

##</code><code>##

sub round_all {
  my $interval = shift;
  my @result;
  foreach $value (@_) {
    if(isnumber($value) {
      my $quanta = int(($value + $interval/2) / $interval);
      push @result, $quanta * $interval;
    }
    else {
      push @result, $value;
    }
  }
  @result;
}