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36 Comments
- HerbSolo, on 10/12/2007, -1/+3Whell - the real question is - does something like randomness really exist? - Or is it just sth. really really hard to calculate?
- inactive, on 10/12/2007, -0/+2The weirdest thing is that this universe has no truly random event. The Universe began in an initial state. If you knew those initial condidtions, you would see that you could fast forward 10000000years ahead and see what things would be like. Particles interact in predictable ways with one another. Every choice you make is made because it was the only way it could have happened.
- mutabi, on 10/12/2007, -0/+1"Nothing random is ever spread evenly."
or is it! Each number has an equal probability of occurring so if clusters are formed, then surely it can not be deemed random! - Archer, on 10/12/2007, -0/+1widmaniac,
The four comes from the last digit of your result. The example is only looking for random integers from 0-9. - Widmaniac, on 10/12/2007, -0/+0Can someone please explain how if 10 is your seed you get 4 from the follow equation: 10 * 1103515245 + 12345 = [new seed]. I get 11035153684. What am I doing wrong?
- kirakun, on 10/12/2007, -0/+0pstonie.
dude. leave the newtonian universe behind and get with the times with quantum mechanics. the universe is not a deterministic machine like the computer (or at least what the computer was supposed to be). - inactive, on 10/12/2007, -0/+0Nah, that is not the case. You have every right to say so though. Logic dictates that if I know the initial state of the universe, then for any given point in time, I would be able to tell you what your supposedly random number generator would spit out for any point in time. Even what you would be wearing.
- Quiescence, on 10/12/2007, -0/+0@kirakun
Actually, we do not know if the universe is deterministic or not. It may be; but we don't have the means to "observe" it. I think, it would be fair to say that the universe is not a deterministic machine as we observe it. - interiot, on 10/12/2007, -0/+0pstonie.
You're also wrong about randomness. There are mathematical measures of how random a certain sequence of numbers are, and information security often depends on having a sufficiently random source, so some amount of care goes into writing good random number generators.
http://en.wikipedia.org/wiki/Statistical_randomness
http://en.wikipedia.org/wiki/Cryptographically_secure_pseudo-random_number_generator - RMuffin, on 10/12/2007, -0/+0Pretty cool.
+Digg - amandajc, on 10/12/2007, -0/+0I am doing a PhD in Psychology and I need to calculate some kind of probability of randomness between the limits of -9 to 9 on 2000 occasions. Obviously I haven't got a clue what I am doing. Can anyone help, advise me or point me in the right direction? Many Thanks.
- TacitusBen, on 10/12/2007, -0/+0There's a difference between 'random' and 'chaos.' I think we expect chaos when something provides us with random.
- inactive, on 10/12/2007, -1/+1computer never generate true randomness. It generates psuedo randomness.
- gregcotten, on 10/12/2007, -0/+0import java.util.Random;
public class Random
{
public static void main(String[] args)
{
Random rnd = new Random();
int display = rnd.nextInt(10)+1;
System.out.println(display);
}
} - anirudhvr, on 10/12/2007, -0/+0of course, operating systems like the linux kernel has a *true* random number generator, which increases its entropy from random interactions with other systems - for instance, keyboard activity, network activity etc.
- apr400, on 10/12/2007, -0/+0""good numeric distribution"
That right there would show you it's probably not random. In a truly random event, clusters are formed. Nothing random is ever spread evenly."
The article says "Good numeric distribution...over a long period of time." Something, truly random, sampled over an infinite range should be evenly spread IIRC.
""Nothing random is ever spread evenly."
or is it! Each number has an equal probability of occurring so if clusters are formed, then surely it can not be deemed random! "
if any number has an equal probability of occurring (ie it has no memory of previous results) then it is entirely possible to get a string of the same number. For instance I just downloaded several sets of 10,000 (truly) random numbers (between 1 and 10) from random.org. In the fourth set the first ten numbers were
5, 3, 10, 1, 10, 10, 10, 10, 4, 1
which is a hell of a cluster of 10's. But the mean for all 10,000 was 5.49 which is a pretty even distribution. - Qwertie, on 10/12/2007, -0/+0There's reason to believe the Random Number Generator in that article isn't very good. It's worse than the "minimal standard" RNG known as "Lehmer", which requires a prime modulus. Unfortunately, programmers use power-of-2 modulii a lot because it can often be implemented by "controlled overflow"...
The book quoted was a book designed to teach C programming, not good algorithms, so you can't expect too much.
See
http://www.brpreiss.com/books/opus4/html/page472.html
http://www.mactech.com/articles/mactech/Vol.08/08.03/RandomNumbers/ - supperman, on 10/12/2007, -0/+0Didn't someone connect a lava lamp to generate 'real' random numbers?
- inactive, on 10/12/2007, -1/+1"Nah, that is not the case. You have every right to say so though. Logic dictates that if I know the initial state of the universe, then for any given point in time, I would be able to tell you what your supposedly random number generator would spit out for any point in time. Even what you would be wearing."
According to the Uncertainty Principle, no. There are inherently true randomness in the universe at Quantum level. True random number generators uses such quantum randomness, such ass radioactive decay. - inactive, on 10/12/2007, -0/+0apr400: I was just going to mention random.org :)
The article states that there are two basic methods of obtaining random numbers: pseudo-random generation, and sampling. random.org uses sampling; specifically, it samples atmospheric noise and applies skew correction to it. - jefu, on 10/12/2007, -0/+0"Anyone who considers arithmetical methods of producing random digits is, of course, in a state of sin." (John Von Neumann)
In general, it is hard to define just what a random sequence is - for instance "cryptographic randomness", "physical randomness" and "random number generators" often refer to substantially different things.
For some excellent reading on the topic of randomness in general, look for Greg Chaitin's writings - his website ishttp://cs.umain.edu/~chaitin - Arevos, on 10/12/2007, -0/+0Brian.Honaker: Whilst Einstein would agree with you, quantum mechanics does not. At a quantum level, the Universe is fuzzy. Assuming you knew the initial state of the Universe, you would only be able to assert probabilities that, due to chaos theory, would become more and more general the further you were away from the Big Bang.
- gherikill, on 10/12/2007, -0/+0now I can win the lottery!
- lordelric, on 10/12/2007, -0/+0 Let's dig up soem random article from another site, taht is not really new and post it to digg like it was brand new.
- thetbad, on 10/12/2007, -0/+0Brian, Brian, Brian... you're not entirely wrong. A few hundred years ago, the Marquis de Laplace would have agreed with your view...but he was wrong. Quantum physical laws are deterministic in the sense that they describe the evolution of probability waves over time (says Stephen Hawking in "A Brief History of Time"). But you really get in trouble when you try to interpret these waves as specific positions and velocities.
Brian Greene (string theorist) summarized Heisenberg's Uncertainty Principle nicely at a lecture I attended a few days ago. He said that quantum physics can tell you all about the uncertainty of the world, with absolute certainty. - doxtorray, on 10/12/2007, -0/+0Skyfire:
I feel your pain.
I guess its all timing.
Everyone is thinking of randomness the day after Thanksgiving. - TacitusBen, on 10/12/2007, -0/+0Skyfire has digg-envy
- Skyfire, on 10/12/2007, -0/+0http://digg.com/technology/How_can_a_totally_logical_machine_like_a_computer_generate_a_random_number_
Dang, I only had eight diggs. - jorgevargas, on 10/12/2007, -0/+0dude thats old. i remenber reading that went i learn C, that's like 4yrs ago.
- inactive, on 10/12/2007, -1/+0It's silly to think what a computer generates randomly is less random than "real" randomness. It may be less sophisticated, but nature, earth, the universe is just a big machine.
- inactive, on 10/12/2007, -1/+0"the universe is just a big machine."
according to Quantum Mechanics, no. - MonkeyFit, on 10/12/2007, -1/+0"good numeric distribution"
That right there would show you it's probably not random. In a truly random event, clusters are formed. Nothing random is ever spread evenly. - montek, on 10/12/2007, -1/+0This is hardly news, but I guess some folks found it interesting.
- npiv, on 10/12/2007, -1/+0computer never generate true randomness. It generates psuedo randomness.
thank you tard, we can read for ourselves - slhilbert, on 10/12/2007, -2/+0I think that it is interesting that this made the frontpage on Digg.com. I suppose I find it interesting because I learned this in my first computer science class so many years ago. I suppose I take things like this for granted. Anyway, still good that people are learning new things.
-s
http://www.getyourowntots.com - EmileVictor, on 10/12/2007, -5/+0dupe.
-e http://digg.mediahug.com/
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