next unless @rel_flows;
foreach my $mv (qw(mass volume)) {
my $max_vn= "max_$mv";
my $max= $mv eq 'mass' ? $max_mass : $max_volume;
next unless defined $max;
next unless @rel_flows;
foreach my $mv (qw(mass volume)) {
my $max_vn= "max_$mv";
my $max= $mv eq 'mass' ? $max_mass : $max_volume;
next unless defined $max;