[MUD-Dev] [TECH] algorithm request
ya_hoo_com at yahoo.com
Thu Dec 20 12:43:23 New Zealand Daylight Time 2001
From: "Malcolm Tester II" <malcolm.tester at planetcad.com>
> So, you set a monster's exp. this amount is divided by a constant
> upon death. I.e. 1000/50 as in the old lp mud style.
> This amount is sent to an experience daemon that does things like
> wizlist, static stats information, and decides how much actual
> experience to give the player. So, here's the twist. I track how
> many monsters a player has killed total. I track how many times
> they've slayed a particular monster (not 100% foolproof). The
> grand total doesn't matter, that's just for them. However, the
> more times they kill "Harry" for example, the less experience they
> get for it. And that's where I am having trouble.
> Let's say there is a monster named Bob. Bob has 10,000
> experience. Player kills him. The experience daemon receives a
> notice that Player killed Bob for 200 exp. The experience daemon
> notes that Player has killed Bob 0 times before. So the
> experience daemon gives 200 exp to Player.
> Bob resets, Player kills him again. 200 exp is sent to the
> experience daemon again. Now, the exp daemon notes that Player
> has killed Bob 1 time before. So the exp daemon gives the player
> some exp amount less than 200.
> And so forth. I've tried creating some algorithms myself, but
> they frankly stink. My talents do not lie in math. So if anyone
> could offer help, it would be appreciated. I also want to set a
> "minimum" level of experience too. So the player never gets to 0,
> they always get at least a little.
Sounds like you probably want an exponential decay function, or
similar - i.e. each time you kill a monster, the decrease in the
amount of experience earned goes *down* - e.g.:
Number of times monster killed / experience earned / reduction
An easy to implement general formula for this is:
EXP = amount of experience awarded LAST time
M = amount to decrease experience by (sort of)
NEXT = the amount of experience to award NEXT time
NEXT = EXP*(1-M)
(unless EXP is below a certain threshold, in which case just
award that much experience)
Initial value for EXP is:
(amount of experience you want to award first time monster is
killed) / (1-M)
The very best way of fiddling with this is to make a spreadsheet,
set up in the following way (assuming you have XL, I have limited
experience with other platforms spreadsheets):
1. Make three columns (titled "Num kills", "Exp awarded", "M"
2. First row should have values: "0", [amount of exp for a
monster], [your guess for M]
3. Second row should have values: "=[cell-above]+1",
"=[cell-above]*[cell to the right]", "=[cell above]"
4. Now copy those formulae downwards using the copy-down controls.
5. Select the first two columns, and hit the "ChartWizard" button,
and generate a "scatter graph" (or similar) that will draw a graph
of values in col1 plotted at values of col2.
6. This should produce a sloping graph from top left down to
7. Change the value of M in the first row only, and the steepness
of the graph will change; keep fiddling until the
experience-reduction looks good (0.75 looks like a fairly good
value to me, but it entirely depends how soon you want to
discourage people from killing the same monster again and again)
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