Name "main::r1" used only once: possible typo at mytest.pl line 23.
Name "main::rL3" used only once: possible typo at mytest.pl line 59.
Name "main::OR1" used only once: possible typo at mytest.pl line 63.

##</code><code>##

$r1 = $c; # $r1 Used only once.
# ....
$lambda_next = ($lambda_max + ($ks * $rL3)) * (1 - $kdeg); # $rL3 used only once.
# ....
$cro_next = ($cro_max + ($ks * $OR1)) * (1 - $kdeg); # $OR1 used only once.