[vox-tech] Re: random number in C

[Ken Bloom]

> Date: Tue, 2 Apr 2002 14:47:20 -0800
> [CODE SNIPPED]

So this is when the program is seeded to /dev/random:
>    p@satan% ./ising2-jfunc 4.0
>    T: 4.0e+00  beta: 2.500e-01  trials: 1000  N: 10  M: 10  seed: 3497451914
>    Average Energy: -1.273893
>    Average magnetization: 0.425220
>    Average |magnetization|: 0.531100
>    Average magnetic susceptibility: 34.746600

And this is when the code is seeded to 1:
>    T: 4.0e+00  beta: 2.500e-01  trials: 1000  N: 10  M: 10  seed: 3497451914
>    Average Energy: -1.326747
>    Average magnetization: 0.495320
>    Average |magnetization|: 0.495320
>    Average magnetic susceptibility: 28.645040

And you've established that if you run it repeatedly you keep getting the same thing:
>    T: 4.0e+00  beta: 2.500e-01  trials: 1000  N: 10  M: 10  seed: 3497451914
>    Average Energy: -1.326747
>    Average magnetization: 0.495320
>    Average |magnetization|: 0.495320
>    Average magnetic susceptibility: 28.645040

BUT four hours earlier:

> Date: Tue, 2 Apr 2002 10:05:34 -0800

This is when you seed it to /dev/random:
> 	T: 4.0e+00  beta: 2.500e-01  trials: 1000000
>	N: 10  M: 10  seed: 208006379
>	Average Energy: -1.057143
>	Average magnetization: 0.002008
>	Average |magnetization|: 0.251765
>	Average magnetic susceptibility: 8.948655

And this is when you seed it to 1:
>	T: 4.0e+00  beta: 2.500e-01  trials: 1000000
>	N: 10  M: 10  seed: 208006379
>	Average Energy: -1.050182
>	Average magnetization: 0.030723
>	Average |magnetization|: 0.246092
>	Average magnetic susceptibility: 8.692724

Why did 4 hours of time change the results when you seed it to 1 ???