This function calculates the DevroyeWise estimator of a given sample of points in the plane for ε>0.
1 
x, y 
The 
eps 
Value of ε. 
An attempt is made to interpret the arguments x and y in a way suitable for computing the DevroyeWise estimator. Any reasonable way of defining the coordinates is acceptable, see xy.coords
.
Given a sample of points in the plane, the estimator is defined as union of balls of radius ε with centers in the sample points. For each arc in the boundary of the DevroyeWise estimator, the columns of the output matrix store the center c and radius r of the arc, the unitary vector v, the angle θ that define the arc and the indices of the end points.
Devroye, L. and Wise, G. (1980) Detection of abnormal behaviour via nonparametric estimation of the support. SIAM J. Appl. Math. 3, pp. 480488.
1 2 3 4 5 6 7 8 9 10 11 12 13  ## Not run:
# Uniform sample of size n = 200 in the annulus B(c, 0.5)\B(c, 0.25),
# with c = (0.5, 0.5).
n < 200
theta < runif(n, 0, 2*pi)
r < sqrt(runif(n, 0.25^2, 0.5^2))
x < cbind(0.5 + r*cos(theta), 0.5 + r*sin(theta))
eps < 0.05
dw.obj < dw(x, eps = eps)
plot(x)
for(i in 1:dim(dw.obj)[1]){arc(dw.obj[i, 1:2], eps, dw.obj[i, 4:5], dw.obj[i, 6])}
## End(Not run)

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