在计算机上，怎么产生非伪随机数呀？
you mean not "pseudo random numbers"?
you mean not "pseudo random numbers"?
yes.
I don't know any existing algorithm generating non-pseudo random number
but what's the application that must require non-pseudo random number?
nothing, just for fun.
as every instruction is determined
so it's difficult to invent some algorithm that generates non-pseudo random number under the current architecture.
I feel it's enough to use pseudo random number to simulate the randomness, with seed set randomly.
A more interesting question is this:
Does random really exist?
Think about tossing a coin, the result (head or tail) is determined by the initial speed, gravity, wind direction, table material etc. If the modeling of the enviornment is complete, the result will always be the same under the same parameters.
So the randomness comes from the inability of describing the world completely, is that true?
I feel it's enough to use pseudo random number to simulate the randomness, with seed set randomly.
A more interesting question is this:
Does random really exist?
Think about tossing a coin, the result (head or tail) is determined by the initial speed, gravity, wind direction, table material etc. If the modeling of the enviornment is complete, the result will always be the same under the same parameters.
So the randomness comes from the inability of describing the world completely, is that true?
I thought about this question before. One solution is to have distributed computing as follows -- One server stores zillions of uniform random numbers between 0 and 1, which are prepared and tested to be "random". When a client request a list of random number, it will first be allocated to a position in the data on server, then the client will generate a psudo-random sequence, and pick the "random" numbers from data according to that sequence.
man, it's still deterministic, just that the model is very complicated.... :)
there is hardware random number generatorIn linux, the interface is /dev/(u)random. Many crypto software use it. check http://en.wikipedia.org/wiki//dev/random
the following command gives 64 bytes of random data:
[atp@risci1 ~]$ dd if=/dev/urandom bs=64 count=1 | od
1+0 records in
1+0 records out
64 bytes (64 B) copied, 6.0784e-05 seconds, 1.1 MB/s
0000000 125047 155010 151240 044101 134716 055204 027564 056065
0000020 000400 167744 111504 136012 136674 175425 045721 005465
0000040 111165 146462 106526 175406 153705 053636 101666 057700
0000060 175272 161005 105256 053347 171741 072074 127474 042150
how random is it?
everything is deterministic. only difference is how complicated the generator isonly god throws dies; or even he does not.
yes, if everything is deterministic, how does the random come from?
we dont talk about religion here
it's just a ideal concept. like poisson. there's no real poisson.consider tossing a coin. if your model includes the force of tossing it, trajectory, air dynamics, weight of the coin, height, etc, then you can determine which side it will be. So "randomness" is an ideal concept, everything in real-life is, to some extent, psudo-random... which is deterministic.
agreed... "to some extent"...
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