Odds for unique?

[Psychic Watch]

It is then applied by
new chance = chance * 100 / (100 + effective MF)

Ah I see where I went wrong, missed this line the first time around.


You mentioned reading the actual code - do you know which .dll or .exe file these magic find calculations are in (and for that matter, other related calculations)? I don't mind giving the old computer programming a spin


For the final calculation, does the game actually use the 128/X fractional result, or is it still stored as an integer? Similarly, what happens after this number is calculated?

 

[Thrugg]

I've not cracked the code open myself, although I can read and understand it when people post chunks of it. Jarulf (who posted above) is one of the primary original sources for what we know, and then it is just routinely checked with each new patch to see if they fiddled with it. Tracking down the actual modules and addresses within them to look at is a matter of rigging up a debugger and knowing how to trigger it. This sort of thing is done in much greater volume at another site, that I unfortunately am not allowed to direct you to, as they compete with this one.

The game never actually produces a "total chance" per se. After the last intermediate calculation (the boss bonus, in 1.10) you are left with an integer that is effectively 128 times your chance. At that point the game generates a random number between 0 and your chance number, and if it is 127 or less then the quality check is successful. This safely accounts for the possibility that the "chance" value has dropped below 128 or even down to 0.

If the quality check fails, it moves down to the next quality and starts again. The qualities descend unique > set > rare > magic > superior > normal > low quality. No check is done at low quality, an item default to that if it fails to be normal. MF and boss bonuses do not apply beyond the check for magic quality. After that it is just the hard coded numbers and the (ilvl-qlvl) modification that decides if an item is sup, norm or low.

 

[TheJarulf]

This sort of thing is done in much greater volume at another site, that I unfortunately am not allowed to direct you to, as they compete with this one.

I would not say it competes. THIS site thinks it is a competition and "competes" with everyone else. Most other sites doesn't care.

 

[Bullet-Tooth Tony]

More we know, more question we ask, would you agree with that?
I've just looked in the treasureclassex.txt and found something interesting:
one treasure class sometimes contains bossbonuses more than 1 time. When a TC has bossbonus and a sub-TC, that has a bossbonus as well.
Example:
Act 1 Super A (as far as I understand, it's superunique's TC, if this SU doesn't have his specific TC) itself has bossbonuses (U/S/R/M) of 800/800/972/1024. And consists of 2 sub-TC's (with equal probability):
Act 1 Uitem A and Act 1 Cpot A. "Cpot" is simply just Champion's potion drop. But Act 1 Uitem A is a TC full of different items and also has it's own bossbonuses of 800/800/800/1024.
So, the Question #1:
When the TC has 2 bossbonuses (1 itself and 1 in it's sub-TC), how does it work?
There would be no need in "#1" if there was no Question #2:
How does the "Picks" value in treasureclassex.txt work? If it was positive all the way, I would think that is the number of rolls that should be made in the TC, but what about negatives (like -4 in the mentioned "Act 1 Super A")?

 

[RTB]

AFAIK only the first bossbonus is used.

Negative picks means a fixed drop with that many picks, without the minus of course.

 

[Thrugg]

That was as far as the guy editing the TCEx.txt file knew too RTB, but he was wrong In fact as you navigate the TC tree you use the highest bonus you find (on a per-quality basis). This is particularly significant for one reason only - if you look down near the bottom you see a list of "Super X" TCs, just like the Super TCs (that are used for Superuniques) only with an X at the end, and worse boss bonuses. The only two monsters in the game that drop from these TCs are Pindleskin and Thresh Socket. When we saw this, and read in the patch readme that they had deliberately nerfed those two, we all believed that they now had reduced unique and set bonus (512/654/972/1024) and thus they were no longer very good MF targets.

Fortunately Ruvanal checked it, and showed that indeed the highest bonus you run across is used. So, since all the Super X TCs contain the same Uitem sub TCs that all unique monsters drop from, and the Uitem TCs all have 800/800/800/1024, Pindle is actually dropping at 800/800/972/1024 just like all the other SUs. Which meant they went to really quite a bit of work to achieve effectively nothing

Just to expand on RTB's explanation of the Picks column, when it is a positive number you roll randomly between the child TCs, that many times, but when it is negative, there is no random rolling - you work left to right across the row dropping down to the listed child TCs as mnay times as they are listed, until you reach a total of your (negative) picks number.

The classic example is the Countess. She drops directly from the Countess TC (right at the bottom of the file). That has Picks = -2. That means she makes 2 drops, in order first from Countess Item (once) and Countess Rune (once).
Countess Item has 5 picks, which means 5 drops each chosen randomly from no-drop (19 chances), gold (11 chances), Act 1 Equip C (19 chances), Act 2 Junk (15 chances) and Act 2 Good (3 chances), total chances 67.
Countess Rune has 3 picks, chosen randomly from no-drop (5 chances) and Runes 4 (15 chances).

The Super TCs' -4 picks result in 2 from the Uitem TCs, and 2 drops of Cpot, and the Cpot TCs in turn each drop 2 potions (positive picks, but there's nothing but potions in those TCs), for a total of 2 items and 4 potions.

 

[diablodude]

Re: Odds for unique?

I know this thread is really old.
But i am playing 07, too, and need some answers.
So i hope this is the right place!

i read in this thread and the 1.07 guide about the mf-formula.
its like this, right?

Final Modified Chance = (128*Chance - (128*Cx*Chance/1024 ) - X*MF)/128

So the real chance to get a unique/set etc from a boss/su is
1/this modified chance, right?
So far so good.

BUT now, its getting strange.
If you apply the value of the rare items, its 200, i am getting problems concerning bosses.

FMC= (128*200-(128*983*200/1024)-X*MF)/128

FMC= ((25600-24575)-X*MF)/128

FMC= (1025-X*MF)/128


So if X*MF is grater that 1025, the result gets negative! And since X is 9 in Hell, the Result gets negative if MF>=114.
I am new to 1.07 and i have played my char till Hell Act1 right now. I have made like 20 Andy runs. My MF is 197%.
So for Uniques i have a chance of 1/26 ~ 3,8%. i have not found any uniques in the 20 runs, so thats ok.
Now the problem:

If not a unique is chosen, the next quality is rare. With my Mf-gear i get:

FMC= 1/-5,8 ~ -17%. But what does that mean? The point is, that in all my runs Andy has ONLY dropped rares besides gold/pots, not a single set/magic item. So i guess, if the rare-value gets negative the game stops calculating and chooses the rare.
But then how is it possible to overcome that problem with more than 114 Mf?
Is it just impossible that Hell Bosses drop sets/magic items, if your char reaches that critical value of 114MF? Meaning that the bosses drop either uniques and if that fails, they automatically drop rares coz of the negative values?
Now lets think i do not wear all my gear. I only had 110MF visiting Andy.

For Uniques: (5125 - 9*110)/128-> ~3% to find a unique.

For Rares: (1025 - 9*110)/128 ~0,273--> ~3,66
So if i dont find a unique i will have a chance of 366% to find a rare? You see, the rares really confuse me and it seems, like i never had chances to get set/magic items from hell-bosses. Is that true?

And btw, did i calculate correctly?
Thank you for replies!

 

[krischan]

Re: Odds for unique?

For a full description you have to explain what all the parameters mean. I have a rough idea of what X and Chance might be (X = factor depending on difficulty, Chance = factor depending on item quality, e.g. 200 for rares), but what's Cx ? Perhaps a factor depending on the monster ? And the reciprocal of that is the chance to find an item of that quality ? Is it the chance in percent ? or an absolute value (io.e. 0 = never, 1=always) ?

BTW, thanks for resurrecting this wonderful thread. I lost the subscription a while ago and now I have it back

 

[diablodude]

Re: Odds for unique?

All the parameters are described at 1st post on page2.
it is recomended to read that post 1st.

cx is a bonus for actbosses,su and champs.

it is 983 for Andy&Co and 800 for the rest. 1 for a normal monster (i guess).

Like i understood it, 1/chance is the possibility. So a final result of 0,95 means 95 % Chance to find that type.
Now take a look at my calcs and tell me, if i am right or wrong.

And someone please call thrugg!!!! he should be the expert.

 

[helvete1]

Re: Odds for unique?

Sticky the whole thread somewhere, I'd forgotten about 90% of the stuff in here, and I will forget it again.

EDIT: I believe, sadly, we lost thrugg to WoW quite some time ago.

 

[krischan]

Re: Odds for unique?

All the parameters are described at 1st post on page2.
it is recomended to read that post 1st..

Yes, I can probably find it above, but it consists of 30 postings which are partly rather large. A bit redundancy makes things far more readable. A posting becomes hard to read if you have to search elsewhere for too many details.

And someone please call thrugg!!!! he should be the expert.

He's inactive for a rather long time now. See his "last activity" infor at the top left orf his profile page.

Sticky the whole thread somewhere, I'd forgotten about 90% of the stuff in here, and I will forget it again.

It's already in the sticky with the useful links, section "Magic Find, MF", below the paragraph "odds for unique/set/rare/magic".

 

[diablodude]

Re: Odds for unique?

Ok, i repost it with more details.

General (for bosses/champs)
Chance to find a specific item-type=1/Final Modified Chance




Chance: Uniques:1000, Rares: 200, Sets: 125, Magic: 30

Cx: 983 for Actbosses, 800 for SU&Champs

X: Normal:1, NM: 4, Hell: 9


Final Modified Chance = (128*Chance - (128*Cx*Chance/1024 ) - X*MF)/128

So the real chance to get a unique/set etc from a boss/su is
1/this modified chance, right?
So far so good.

BUT now, its getting strange.
If you apply the value of the rare items, its 200, i am getting problems concerning bosses.

FMC= (128*200-(128*983*200/1024)-X*MF)/128

FMC= ((25600-24575)-X*MF)/128

FMC= (1025-X*MF)/128


So if X*MF is grater that 1025, the result gets negative! And since X is 9 in Hell, the Result gets negative if MF>=114.
I am new to 1.07 and i have played my char till Hell Act1 right now. I have made like 20 Andy runs. My MF is 197%.
So for Uniques i have a chance of 1/26 ~ 3,8%. i have not found any uniques in the 20 runs, so thats ok.
Now the problem:

If not a unique is chosen, the next quality is rare. With my Mf-gear i get:

FMC= 1/-5,8 ~ -17%. But what does that mean? The point is, that in all my runs Andy has ONLY dropped rares besides gold/pots, not a single set/magic item. So i guess, if the rare-value gets negative the game stops calculating and chooses the rare.
But then how is it possible to overcome that problem with more than 114 Mf?
Is it just impossible that Hell Bosses drop sets/magic items, if your char reaches that critical value of 114MF? Meaning that the bosses drop either uniques and if that fails, they automatically drop rares coz of the negative values?
Now lets think i do not wear all my gear. I only had 110MF visiting Andy.

For Uniques: (5125 - 9*110)/128-> ~3% to find a unique.

For Rares: (1025 - 9*110)/128 ~0,273--> ~3,66
So if i dont find a unique i will have a chance of 366% to find a rare? You see, the rares really confuse me and it seems, like i never had chances to get set/magic items from hell-bosses. Is that true?