I will make an effort to interpret BrowserUKs terse comment for you :-)
In grepGen/mapGen/smartGen you have a redo in the event of a collision, whereas if you really want unique random numbers, they could be generated much more simply by the shuffle method he suggested. His method does not involve repeated retries and removes the need for any of these functions. His one liner does what each of the three methods you proposed does, but much more efficiently....
my @rands = (
shuffle # shuffle, like a pack of cards
1 .. 120 # a series of numbers from 1..120
[ 0 .. 99 ]; # take the first 100 of these
# the resulting @rands is a 100 element array of numbers
# in the range 1..120, all of which are unique
Thank you for your interpratation. :D I knew what he was trying to say, but in this instance he was wrong. I was measuring each of those functions against a pool of random numbers, where they would each encounter the same set, including duplicates. So, the script was written as I thought is should be to accomplish my goal.
I always enjoy peeking around here reading the insights presented to everyone's code, even such comments which may not be directly relevant, but target the improving of one's coding skills. But, sometimes a question of what is the goal of the program can be more educational for both sides.