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Re: lattice definition: help


  • To: mathgroup@smc.vnet.net
  • Subject: [mg11189] Re: lattice definition: help
  • From: gaylord@ux1.cso.uiuc.edu (richard j. gaylord)
  • Date: Mon, 2 Mar 1998 23:10:46 -0500
  • Organization: university of illinois
  • References: <6d0ch7$2no@smc.vnet.net>

In article <6d0ch7$2no@smc.vnet.net>, Christofer Edling
<cedling@sociology.su.se> wrote:

> I would be most grateful if someone could help me with this one. I've
> tried to solve the problem with the "Table" function without much
> success.
> 
> I wish to generate an n*n lattice with the following characteristics:
> 
> 1. Each cell in the lattice can be in one out of three possible states,
> i.e. A,B,C.
> 2. The distribution of states across the whole lattice is defined by
> user input, i.e. 30% A's, 20% B's, 50% C's. 3. Given the defined
> distribution, each cell in the lattice should be randomly assigned a
> state (A,B or C).
> 
> Any suggestions appreciated,
> Christofer
> (cedling@sociology.su.se)

here's a way to do it. i've given the answer for 4 states instead in of
3 becuase i just took the code from my new simulation book [coming out
in june] 

============================

1 = state A
2 = state B
3 = state C
4 = state D

{s, t, u, v} - probability of being in state A, B, C, D

In[6]:=
s = 0.30; t = 0.20; u = 0.50; v = 0;

In[7]:=
n = 100;

lat = Table[1, {n}, {n}]  /. 1 :> Floor[1 + v + u + Random[]] /.   {1 :>
Floor[1 + t/(s + t) + Random[]], 2 :> Floor[3 + v/(v + u) + Random[]]};

N[Count[Flatten[lat], 1]/n^2]

Out[10]=
0.3056

N[Count[Flatten[lat], 2]/n^2]

Out[11]=
0.2081

N[Count[Flatten[lat], 3]/n^2]

Out[12]=
0.4863

-- 
richard j. gaylord, university of illinois, gaylord@uiuc.edu

"What I cannot create, I do not understand"
           -Richard P. Feynman-



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