Random number generator - please make it more random

[Cam_Neely]

Having said that, this is ridiculous. The chances for 3 1's in a row on a d20 is 1 in 8000, it happens way more than that. I've had the same number rolled 10 times in a row on a d100 roll as well.

Just to put it out there, if what you said is true (sounds about right, but did not check) there is also a 1 in 8000 chance in rolling a 1, 10 and 20 in a row which is a large distribution. If you had a decent sample, I think you would find that it happens about that often, so your more random random number generator is in place.

I wish the dmg rolls were not loaded, that bugs me -.-

[Lord_WC]

Don't blame M$ now, pls Actually generating high-quality random numbers with computers is not easy, and they will never be random strictly speaking. Sure, it would be great to know what function turbine did call for the rng, but for the time being lets just accept that it's truly random.

Really, someone neg repping me for this?

[Cam_Neely]

No I won't because I understand mathematics and randomness. Frequent clustering is to be expected in any random distribution.

Here's are two example of randomness
1) How many people do you need in any random grouping to have a 50% chance that two of them share the same birthday?
2) How many people do you need in any random grouping to have a 99% chance that two of them share the same birthday?

Answers below
.

23 and 57

Actually, this proves that you dont understand randomness. A persons birthday is not purely random. ie if you went up and asked a person their birthday there is not a 1/365 chance that there birthday is a set day. Its been shown in various places that there are more babies conceived at specific times of the year, so there are peak birthdays. Ie there are alot of birthdays around mid November, due to it being 9 months after valentines day. This also does not take into account people born on Feb 29th (leap year)

Not to be picky, but your example is not a random distribution.

[BDog77]

This also does not take into account people born on Feb 29th (leap year)

Actually, as i understand it, this does take into account Feb 29th. But you are right, not really a random sample....

[Dendrix]

how'd you work those out?

sincere curiosity since it's been a while since i played with statistics.

http://en.wikipedia.org/wiki/Birthday_problem

It's computed as follows
the chance that the 1st person shares a birthday with any of the other 22 +
the chance that the 2nd person shares a birthday with the remaining 21 +
the chance that the 3rd person shares a birthday with the remaining 20 +
the chance that the 4th person shares a birthday with the remaining 19 +
etcetera down to
the chance that the 22nd person shares a birthday with the last person.

[SiliconShadow]

Corrected a bit. I don't think you made extensive testing or wrote the code of the game. While you probably notice 4 1s or 20s in a row, may I ask you what was the frequency of numbers 11,12,13,14 appearing in your rolls in this order?

You probably don't know it, because they are absolutely insignificant for the game. You will notice a 1, but a 11 will be hidden.

Until a dev confirms it or someone gets me numbers I say you two post some rare occurances while 10.000 other people don't post about rolling 9 on their saves 4 times in a row.

Maths of random and programming random are different, in plain and simple terms you are wrong, this is a PRNG that does very obviusly throw clustering on some numbers and 3, 9 and 16 are other numbers that cluster often.

This is obviously from a small seed and perhaps a threaded function which has a table for the seeding for performance.

This in lamens terms means that number clusters will repeat and repeat for an individual in a single instance if observed for long enough, and this is already evident in damage rolls, to hit rolls etc.

There is no true random function at work on DDO, it is impossible for the technology to cope with that burden in the first place, the fact is the only way is it uses a optimised PRNG and not TRNG fact and it cannot be denied the servers just could not cope with anything else with the amount of rolls made.

[bobbryan2]

Even distributions != random.

Now, to humans, streaks appear that something isn't random. But any truly random sequence will include clumping.

[auximenes]

Having said that, this is ridiculous. The chances for 3 1's in a row on a d20 is 1 in 8000, it happens way more than that. I've had the same number rolled 10 times in a row on a d100 roll as well. The chance for this happening is lower than the chance of winning the grand prize in the lottery two consecutive times in a row!!!

A bit of a late reply, but, have you ever played P&P D&D? Streaks of bad rolls happen all the time. It has cost many an adventurer while swimming or after a critical fumble.

[Cam_Neely]

Actually, as i understand it, this does take into account Feb 29th. But you are right, not really a random sample....

Ya, was an Assumption on my part ( you know what they say about assumptions http://socialmediaanswers.com/wp-con...ssumptions.jpg ), but the wiki link mention above leaves it out. The OP would have to not have rounded his number to be definitive. But thinking more about it, it might not matter. I think the actual answer is 22 and change, but you have to round up to 23, since you cant have half a person to answer the question correctly. The 1/1461 or so chance of Leap Year birthday wont cause you to go to 23.0000000000001, so you would still only be rounding up to 23 people.

[BDog77]

this is already evident in damage rolls

These are admittedly weighted......

[Lord_WC]

Maths of random and programming random are different, in plain and simple terms you are wrong, this is a PRNG that does very obviusly throw clustering on some numbers and 3, 9 and 16 are other numbers that cluster often.

This is obviously from a small seed and perhaps a threaded function which has a table for the seeding for performance.

This in lamens terms means that number clusters will repeat and repeat for an individual in a single instance if observed for long enough, and this is already evident in damage rolls, to hit rolls etc.

There is no true random function at work on DDO, it is impossible for the technology to cope with that burden in the first place, the fact is the only way is it uses a optimised PRNG and not TRNG fact and it cannot be denied the servers just could not cope with anything else with the amount of rolls made.

The difference between the two is so small that you probably will not pull the shorter straw because of it in a lifetime.

Otherwise, what you are saying is that the program repeats 'small' seeds. As far as i know smallest seeds range in the 2^32 order of magnitude. Even if the game would use the worst prng out there, you cannot possibly see it in 213 results, nor in 14 months of playing

Just for the numbers, in the above example you would have to make 118 rolls every second for 14 months 24/7 to have a full sample. And erm, recording it, not FEELING about it

I repeat, 118 rolls/s for your 14 months of continous gameplay.

Sorry, I don't see your reasoning either obvious, or true. Quoted samples are just too small for that.

[brlftz]

In over 500 UMD rolls recorded, I am four times as likely to roll a 1 as I am a 20.

My theory is that Turbine uses skewed dice rolls to try to balance the game that they completely unbalanced with ridiculous loot and exploitable monster AI.

Were you involved in that testing that was done a couple of years or so ago? There was a long thread about umd rolls, and my recollection is that there's a very convincing case to be made re a low bias on umd rolls, at least. your theory about why is interesting.

regarding clusters, it seems to happen to me a LOT, and i've always assumed it had something to do with a poor connection rather than the rng. when data is flying fast, it seems like the die display stops refreshing.

[xTethx]

This thread still doesnt explain why I roll a 1 on soundburst 9 out of 10 times a mob throws it on me.

[Dirac]

Wheeee! Here we go again! Seriously, though, it is always good to get this argument out of everyone's system. For those that really care, relevant previous discussions of the RNG are here and here.

First, the obvious: You can never tell if an RNG is purely random anecdotally. The human brain is hardwired to do this incorrectly.

Second, the boilerplate to dispel common misconceptions:
1. Computer RNG's should be completely random for us. Any standard RNG will produce results indistinguishable from pure randomness.
2. Randomness can be measured and quantified without any knowledge of the inner workings of the system. We can determine if the RNG is sufficiently random.

Next, the current state of affairs: After a lot of testing there is no confirmed deviation from pure randomness (seen in the previous threads). I've also tested clustering on my data set. Also nothing.

Finally, how you can help: Take a large data set of random numbers anywhere: UMD, attack dummy, anything. Post the number of 1s, 2s, etc. I, and others, can test for deviaitions from pure randomness.

p.s. I do not have time right now to look at the numbers posted in this thread, but will try to get to them later.

[cdemeritt]

Alright, I admit that I am not a mathematician and definitely not a statistician.
But...
I was just beating on the dummy till its death, 213 hits, and the results are:
No clusters of 13,16,8
2 clusters of 3 2's
1 cluster of 3 5's
2 clusters of 3 13's
1 cluster of 3 20's
and...
1 cluster of 4 3's

OK, so no large clusters of 1's this time (there were 2 in a row, but I didn't record those)...

Now tell me, is this just stupid old me, or does look just a tad weird?

Now do that 100 more times and then tell us there is a problem. And at some point somewhere a cluster of 20 20's will occur.

The statistics of random numbers is that a lot of the time random doesn't look random... Also humans are wired to look for and see patterns where patterns don't exist...

Look at how many generations and man hours have gone into researching "The Bible Code" (over 700 years, and countless number of people spending their lives to find a few relevant clusters of words, to them)

People want to find patterns and hidden messages... typically they find something they want to see.

[Cam_Neely]

Number Theory vs. Numerology
Best video clip ever

http://www.youtube.com/watch?v=d1IzNKIHhp0&feature=fvst

[KingOfCheese]

Following up on Dirac's post--anecdotal evidence is particularly dangerous in assessing statistics in a venue like this because there is a reporting bias. Let's assume 20 people in game have bothered to wonder about the dice and conducted a test. Of those, one, by random chance, will get a fairly dramatic anomalous result. The 19 that got the "normal" result will tell themselves, "oh well, I guess things aren't biased" and will quietly go on with the game play. The one person with the extremely lucky or unlucky result (a random effect), will come to the forums and post their unusual result. Over time, the forums become cluttered with unusual results, making unusual results look common--when in fact, it is a reporting bias (the people with normal results don't come to the forums and talk about it).

I have yet to see any post that has convinced me that the game dice are anything but random. I have seen some extreme results posted. But where appropriately conducted follow-up tests have been carried out, they have all been debunked.

[Yaga_Nub]

Look at the combat log in the image below:


Does anything about the rolls there strike you as being less than random?

Now, I'll be the first to admit that the kind of number clustering you see in the image works both ways, and sometimes you get 3 vorpals in a row as well.

Having said that, this is ridiculous. The chances for 3 1's in a row on a d20 is 1 in 8000, it happens way more than that. I've had the same number rolled 10 times in a row on a d100 roll as well. The chance for this happening is lower than the chance of winning the grand prize in the lottery two consecutive times in a row!!!

I know that logical random number generators tend to cluster over short instances, but games like this is the exact place where this kind of clustering is detrimental.

There is a way to have a real random number generator used (the one using atmospheric readings comes to mind). The problem is, that it costs money.
I think that it would be a worthwhile investment none the less.

Your thoughts now.

I've had over 20 straight vorpals in a Shroud part 1 more than once. True the confirmation rolls weren't 20s (and didn't need to be), but that number of 20s shouldn't happen but it did and does. That's the great thing about randomness ... it's random. Sometimes you're lucky and sometimes your not.

[cwfergtx]

I have been playing pnp a long time and there are night that you cannot hit anything and every save you fail. One night I think I had about 15 failed saves on a 1. Then there are other nights where nothing can touch you and you are criting on all rolls.

[RJBsComputer]

When running a fix set of random numbers like 1 thru 20, the number of number clusters you well get is going to be larger then if you used the fix set of 1 thru 100. If you were to eliminate the number clusters, you would get 1 thru 20 in twenty rolls and then start all over again. The RNG creates a random number, that random number then is made to fit into the D20 dice set. In a D20 dice set there is a 5% chance of getting the number you want on each roll.

This is not a lotto drawing where once the number is drawn, it can't be drawn again. On the next roll, the whole number set is up for grabs again.