I got it - at least it's stopped throwing warnings and it's a whole lot faster that what I had before.

Since popnum3 is called from inside an if/else 

else {
   my $pos = -1;
   push @cPosns, $pos while ($pos = index($zazb, 'c', $pos+1)) >= 0;
   my $offset = $cPosns[rand @cPosns];
   $cell = sprintf '%.2f', popnum3( $x, $y, $copycop, $offset, );
}

[download]
then 
sub popnum3 {
    my ( $x, $y, $z, $offset ) = @_;
    if ( $y == 0 ) {
        $aob[$x][0] = $initial * ( 1 + $z );
    }
    else {
        while (1) {
            $aob[$x][$y] = $aob[$offset][ $y - 1 ] * ( 1 + $z );
            last;
        }
    }
    return $aob[$x][$y];
}

[download]

So far it's looking good. Thanks

In reply to Re^2: Yet more While issues by Dandello
in thread Yet more While issues by Dandello

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