Baptiste Augui? writes:
> I have to generate a random set of coordinates (x,y) in [-1 ; 1]^2
> for say, N points.
> [...]
> My problem is to avoid collisions (overlap, really) between the
> points. I would like some random pattern, but with a minimum
> exclusion distance.
As Brian Ripley has ment
Hi again,
I've had a go at Prof Ripley's suggestion (Strauss process, code
below). It works great for my limited purpose (qualitative drawing,
really), I can just add a few mild concerns,
- ideally the hard core would not be a fixed number, but a
distribution of sizes (ellipses).
- I could
You might want to shuffle coordinates independently to get rid of the
diagonals. Otherwise what quasi-random sequence guarantee are upper
boundaries on the coverage errors, but not anything nice-looking and
irregular. Sobol' sequences, even though they are theoretically
superior to some others (e.g
Thank you all for the great suggestions and comments. As two of you
pointed out, the problem was not well defined (who said a well-posed
problem is a problem solved?), and also it seems to be a very wide
topic. I've had an interesting reading discussing the similarities
between half-toning
baptiste Auguié exeter.ac.uk> writes:
>
> Dear list useRs,
You might be interested to apply the Hammersley or Halton point sets that
are often used in numerical integration or Differential Evolution. These
pseudo-random distributions are both uniform and irregular, but have a
kind of minimum
You seem to have ambiguous requirements.
First, you want equidistribution for a packing
structure, which would suggest closest packing or
quasirandom sequences, as you have tried.
But then you are disturbed by the packing
structure, because it gives a perceivable
pattern, so you wish to rando
On Sat, 26 Apr 2008, baptiste Auguié wrote:
Dear list useRs,
I have to generate a random set of coordinates (x,y) in [-1 ; 1]^2
for say, N points. At each of these points is drawn a circle (later
on, an ellipse) of random size, as in:
N <- 100
positions <- matrix(rnorm(2 * N, mean = 0 , sd=
baptiste Auguié wrote:
> Dear list useRs,
>
> I have to generate a random set of coordinates (x,y) in [-1 ; 1]^2
> for say, N points. At each of these points is drawn a circle (later
> on, an ellipse) of random size, as in:
>
>
The quasi-random sequences are useful for integration, but they'
Dear list useRs,
I have to generate a random set of coordinates (x,y) in [-1 ; 1]^2
for say, N points. At each of these points is drawn a circle (later
on, an ellipse) of random size, as in:
> N <- 100
>
> positions <- matrix(rnorm(2 * N, mean = 0 , sd= 0.5), nrow=N)
> sizes<-rnorm(N, mean =
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