my $r = ($i)*(1e-6);    #radii are in microns

##</code><code>##

Code before strictures are enabled at line 1, column 1.  See page 429 of PBP.  Severity: 5
Code before warnings are enabled at line 1, column 1.  See page 431 of PBP.  Severity: 4
Use "<>" or "" or a prompting module instead of "" at line 1, column 9.  See pages 216,220,221 of PBP.  Severity: 4
Always unpack @_ first at line 29, column 1.  See page 178 of PBP.  Severity: 4
Magic variable "$a" should be assigned as "local" at line 35, column 4.  See pages 81,82 of PBP.  Severity: 4
Always unpack @_ first at line 46, column 1.  See page 178 of PBP.  Severity: 4