Re: random matrix initialisation...
- To: mathgroup at smc.vnet.net
- Subject: [mg37597] Re: random matrix initialisation...
- From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
- Date: Wed, 6 Nov 2002 06:53:21 -0500 (EST)
- Organization: Universitaet Leipzig
- References: <aq86gt$e4j$1@smc.vnet.net>
- Reply-to: kuska at informatik.uni-leipzig.de
- Sender: owner-wri-mathgroup at wolfram.com
Hi,
X[dim_, count1_] :=
Module[{m, i = 0, pos},
m = Table[0, {dim}, {dim}];
While[i < count1,
pos = {Random[Integer, {1, dim}], Random[Integer, {1, dim}]};
If[m[[Sequence @@ pos]] =!= 1,
m[[Sequence @@ pos]] = 1;
i++]
];
m
]
Regards
Jens
Manuel Marques-Pita wrote:
>
>
> hello,
>
> i have a question regarding matrices. searched on the web and forums
> but maybe due to using wrong keywords i am not finding an answer...
>
> i need a way or function X to initialise matrices in mathematica such
> that each time i call X i get a matrix with a predetermined number of
> elements initialised as "1" and the rest as "0"
>
> examples
>
> X(4,3)
>
> {{0,0,0,0}, {0,0,1,0}, {0,0,0,1}, {1,0,0,0}}
>
> again X(4,3)
>
> {{1,1,0,0}, {0,0,0,0}, {0,0,0,0}, {0,1,0,0}}
>
> etc.. (first argument means that the matrix is 4x4 and second means
> that there should be 3 "1's" present in the matrix
>
> any help, pointers, etc will be appreciated!
>
> thanks a lot
>
> m
>
> --