Re: Re: serie of random number
- To: mathgroup at smc.vnet.net
- Subject: [mg21323] Re: [mg21314] Re: [mg21202] serie of random number
- From: "ARNOLDK" <arnoldk at gauss.cam.wits.ac.za>
- Date: Fri, 24 Dec 1999 03:42:27 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
The method below wont work in general since the sum of the first
n-1 random numbers is very likely to be greater than one.
Arnold Knopfmacher
-----Original Message-----
From: Harvey P. Dale <hpd1 at is2.nyu.edu>
To: mathgroup at smc.vnet.net
Subject: [mg21323] [mg21314] Re: [mg21202] serie of random number
>Several suggestions have been posted, each of which involves dividing each
>of n random terms by the sum of those n terms. There's another obvious
way:
>generate n-1 random terms and add a final term equal to 1 minus their sum.
>t=Table[Random[Real,{0,1}],{9}];Join[t,{1-Plus@@t}]
>The distribution will be somewhat skewed, however, because all of the
>"correction" to sum to 1 will be contained in the single final term. If n
>is large enough, that shouldn't make much difference, and with a large n
>this method is probably faster.
> Harvey Dale
>
> -----Original Message-----
>From: BobHanlon at aol.com [mailto:BobHanlon at aol.com]
To: mathgroup at smc.vnet.net
>To: mathgroup at smc.vnet.net
>Sent: Monday, December 20, 1999 2:28 AM
>To: mathgroup at smc.vnet.net
>Subject: [mg21323] [mg21261] Re: [mg21202] serie of random number
>
>x = (y = Table[Random[Real, {0, 1}], {10}])/(Plus @@ y)
>
>{0.07821331795569339, 0.14548316858210597,
> 0.09071562642905695, 0.17301007335002186,
> 0.11717865235373884, 0.09217996450546272,
> 0.042026501149567214, 0.006182891897813822,
> 0.181653714876191, 0.07335608890034818}
>
>Plus @@ x == 1
>
>True
>
>Bob Hanlon
>
>In a message dated 12/17/1999 2:54:43 AM, raphael.suire at univ-rennes1.fr
>writes:
>
>>i want to compute a serie of random number
>>Table[random[Real,{0,1}],{n}]]
>>
>>which sum is always one
>>
>>How can i do ??
>>
>