[R] Generate random numbers under constrain

Ranjan Maitra
Sat, 22 Nov 2014 15:54:19 -0000

I don't understand this discussion at all.

n random numbers constrained to have sum <=1 are still random. They are not
all independent.

That said, the original poster's question is ill=formed since there can be
multiple distributions these random numbers come from.

best wishes,
Ranjan



On Sat, 22 Nov 2014 10:29:18 -0500 Boris Steipe <boris.steipe at
utoronto.ca> wrote:

> These are contradictory requirements: either you have n random numbers from
the interval [0,1), then you can't guarantee anything about their sum except
that it will be in [0,n). Or you constrain the sum, then your random numbers
cannot be random in [0,1). You could possibly scale the random numbers:
> n <- 13
> x <- runif(n)
> x <- x / sum(x)
> x; sum(x)
>
> This will guarantee that their sum is 1 (to numerical accuracy), but your
numbers are then effectively drawn from the interval [0,2/n) for large n.
>
> B.
>
>
> On Nov 22, 2014, at 9:29 AM, Ragia Ibrahim <ragia11 at hotmail.com>
wrote:
>
> >
> > Dear all,
> > I use R 3.1.1 for Windows.
> > kindly how can I generate n number of random numbers with probability
from [0,1]
> > and their sum must not be more than one
> > thanks in advance
> > Ragia
> >
> >
> >
> > 	[[alternative HTML version deleted]]
> >
> > ______________________________________________
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>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>


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