Re: [R] about loops
On Jan 21, 2010, at 7:28 AM, Wolfgang Amadeus wrote: Hello ! I have a quick question about loops. For example, I have a 1 * 1 square and its inscribed circle tangent i, whose radius, of course, is also 1. The loop here is as the following: generate n points, say 5, in the square randomly repeatedly until we have five in total in the circle, then we stop, otherwise we continue. I do not know how ! Help me Please ~ Thank you very much for your time. Yours Wolfgang Amadeus What part don't you know how to do? Sounds like homework (especially with the piteous appeals from a pseudonym), so we expect more evidence of effort on your part. The condition for being "outside", assuming this box's lower left-hand corner is (0,0) is (x-0.5)^2 + (y-0.5)^2 > 1 -- David Winsemius, MD Heritage Laboratories West Hartford, CT __ R-help@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.
Re: [R] about loops
Hi,
One approach could be a while loop as follows. Note that your circle
should have radius 0.5 if I understood the problem correctly.
N <- 5
npoints <- 0
ntests <- 0
points.in.circle <- matrix(NA, ncol=2, nrow=N)
while (npoints < N) {
test.point <- runif(2, -0.5, 0.5) # generate new point in 2D
if ( sqrt(test.point %*% test.point) <= 0.5){ # test its distance to
the origin
npoints <- npoints + 1
points.in.circle[npoints, ] <- test.point
}
ntests <- ntests + 1
}
print(paste(npoints, "out of", ntests, 'where in the circle') )
HTH,
baptiste
2010/1/21 Wolfgang Amadeus :
> Hello !
> I have a quick question about loops.
> For example, I have a 1 * 1 square and its inscribed circle tangent i,
> whose radius, of course, is also 1.
> The loop here is as the following:
> generate n points, say 5, in the square randomly repeatedly until we have
> five in total in the circle, then we stop, otherwise we continue.
> I do not know how !
> Help me Please ~
> Thank you very much for your time.
> Yours
> Wolfgang Amadeus
>
>
> [[alternative HTML version deleted]]
>
> __
> R-help@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.
>
__
R-help@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.
[R] about loops
Hello ! I have a quick question about loops. For example, I have a 1 * 1 square and its inscribed circle tangent i, whose radius, of course, is also 1. The loop here is as the following: generate n points, say 5, in the square randomly repeatedly until we have five in total in the circle, then we stop, otherwise we continue. I do not know how ! Help me Please ~ Thank you very much for your time. Yours Wolfgang Amadeus [[alternative HTML version deleted]] __ R-help@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.
