Talk:Random Distribution

Based on the August 05, 2011 Patch, which lists "Adjusted chances for pseudo-random items/abilities to proc so they are correct (less frequent for chances > 25%)", I created an article on PRD (assuming it works as in DotA). If anyone knows anything different, put it here. Also, feel free to add to the lists. -Baloroth 01:14, 8 November 2011 (UTC)

Has someone just added together ~42% to say that it will always happen after three times? The odds do not suddenly rise to 126% to influence future procs. By this reasoning if you flip a coin and get tails you will always get a heads right after. You have done a 50% chance twice, obviously the odds are now at 100%.

The actual formula goes 1-(58%^x) where x is how many hits you've done so far. That is to say, after one hit you are at 0.6636, two hits puts you past 0.7 to 0.804888 and so on. Basically you calculate the odds for the proc NOT happening, then you pull that from one.


 * That's not how PRD works. It does, infact, add the chance each time you get hit.It isn't random: hence, Pseudo-random. -Baloroth 18:11, 6 June 2012 (UTC)


 * I might be being really picky here, but I think you guys are using pseudorandom not in the sense that it was defined to be used by mathematicians and physicists. Almost every computer game out there uses pseudorandom number generators to make their random numbers, because to make "truly random" numbers you need to measure quantum mechanical effects, take the lowest significant digit from a voltage measurement or physically roll a dice [1 ]. The way you guys are using it (and I know the original Playdota article suffers from the same problem) is that even though both the WC3 Dota way and the Dota 2 way of getting random numbers through means that makes those numbers trivially pseudorandom, you guys are using the term to describe something outside it's generally accepted definition--that the WC3 method is basically a contrived method used to ensure that the player will guarantee a proc after a certain number of attempts. I suppose this makes sense if the word "pseudorandom" wasn't already taken, but it is so I think this dual interpretation of pseudorandom may confuse some of the physicists and mathematicians out there who may care to visit this page (not that I'm a physicist or mathematician). --CtChocula 19:00, 11 August 2012 (UTC)


 * Never mind, noticed Valve was the one who started using the term. --CtChocula 19:04, 11 August 2012 (UTC)


 * "Pseudorandom distribution" is unrelated to "pseudorandom number generation". This is confused so often that I should probably make a note about it. --Kroocsiogsi 20:01, 11 August 2012 (UTC)


 * Sorry; I just edited the page without reading the discussion first. Anyway, as far as I can tell, the first use of pseudorandom to refer to dependent randomness came from Valve. This was most definitely a mistake by them (I mean, they are after all human and do make errors) since this does not match the words used everywhere else. Wikipedia has an article on dependence/independence for more information: [2 ]. This concept is centuries old, and is introduced in any basic probability course; it is used by anyone who has studied or uses probability in their lives. I definitely think that DoTa should use the word that is used everywhere else to descibe this process, and not just come up with its own definitions. You have already seen the problem it's caused by being similar to "pseudorandom number generation". But that's not the only problem. The other problem is that it gives people the belief that dependent random processes are in some way not random. This is completely false, and will just lead to even more confusion. Furthermore, the word 'dependent randomness' descibes the process perfectly, so it would be folly to not use that word. Valve was obviously unaware of all this, but then it is our duty to correct the mistake here, and not make Valve suffer for their error for ever.
 * Also, I don't know how to edit titles; could someone do so? Thanks
 * I agree that the correct course of action is to change the name to reflect the terminology used in probability theory, and doubly so in this situation where the incorrect name is confusing. AFAICT, this name was not chosen by Valve initially, but rather comes from the playdota article referenced. However, this is a very large change, and making this change without any discussion is likely the wrong move, even in clearcut situations like this. I've reverted the changes for now. If there are any objections to changing the page to use the DRD terminology, then we can give them a few days to make their case. If not, then we can undo my revert. The page itself cannot be renamed. If we decide to make the change, IIRC, the correct course of action is to copy the whole page contents over to a new page with the appropriate name, and then make the current page a redirect. --68.228.245.62 15:00, 31 March 2014 (UTC)

Shouldn't Lycanthrope be renamed to Lycan on this page to reflect the recent name changes? --66.189.43.12 08:08, 2 December 2013 (UTC)

Someone should do the number crunching for 17% (axe's helix) --Jimmydorry (talk) 12:16, 4 May 2014 (UTC)


 * I did a bit of testing and the "c" value of a 17% chance proc is around 0.04097 (thus you can be hit 24 times max without proccing Counter Helix at worst). I don't know which value does Valve use for that, but I heard Axe's counter Helix PRD is the best PRD of Dota 2, because it is the only one entirely done by Valve (the others PRDs were ported from DotA I've heard). --129.104.247.2 08:15, 30 May 2014 (UTC)


 * Thanks, I'll go add that now. The only problem is that the table increments every 5%, but Axe's Counter Helix is 17%... I could just make a special note. However, Legion Commander's Moment of Courage also had PRD added. I'm not quite sure how to test for the constant, so finding those numbers for me would be a huge help.
 * --PimpadelicX (talk) 08:38, 30 May 2014 (UTC)

The following statement is FALSE : "Max N is the minimum number of attacks that would result in C * N becoming greater than 1.00, and the maximum number of attacks that could possibly occur before a modifier succeeds", it is not C * N becoming greater than 1, but C * (N + 1), because N is intended to represent the maximum number of "failures" (modifier not being applied), which leads to a failure during the Nth try, so its probability C * N has to be strictly less than 1. --129.104.247.2 07:28, 30 May 2014 (UTC)


 * I saw this a long time ago, but never bothered to edit because I wasn't big into Wiki editing. Now that I've gotten used to it, I will absolutely change it. It makes no sense that an 80% ability will proc at least every 1 attack... That's 100%! I will just add +1 to all the numbers, as opposed to changing "Max N" to "Max Misses". It makes more sense in my mind, but I'm sure that's what the original poster had in mind.
 * --PimpadelicX (talk) 07:59, 30 May 2014 (UTC)

Has anyone verified those DotA mechanics also apply for Dota 2 ? --129.104.247.2 07:28, 30 May 2014 (UTC)


 * I'll answer to myself : after a bit of searching it seems Valve ported DotA RPD to Dota 2, the only exception being Axe's Counter Helix (17%, inexistent in DotA). --129.104.247.2 08:17, 30 May 2014 (UTC)


 * No love for Moment of Courage I see :P
 * --PimpadelicX (talk) 08:38, 30 May 2014 (UTC)

Someone tell me how to generate PRD constant C for a certain probability. I couldn't figure out C for newly incorporate 17% PRD for counter helix. Saspoon (talk) 17:00, 3 June 2014 (UTC)
 * There's no formula, but it's relatively easy to simulate, see http://exar.ch/files/prd.html for instance178.83.234.41 20:44, 25 June 2014 (UTC)
 * This website only uses 1 million trials which may seem like a lot, but causes a lot of fluctuations. I decided to take the code from the website and increase the trials. I'll come back with my findings for Legion Commander's 16%, 18%, and 22% for Moment of Courage.
 * --PimpadelicX (talk) 22:02, 25 June 2014 (UTC)
 * After using 500 million trials, I've come up with these values. I assume they are the same as in the game, because the percentages don't deviate until 25%.
 * 16% - 0.03645
 * 18% - 0.04562
 * 22% - 0.06668
 * --PimpadelicX (talk) 22:32, 25 June 2014 (UTC)