rverts.tri.cent.alt: The alternative function for the indices of the vertex regions in a triangle that contains the points in a give data set

Description

An alternative function to the function rverts.tri.cent

Usage

rverts.tri.cent.alt(Dt, tri, M)

Arguments

A set of 2D points representing the set of data points for which indices of the vertex regions containing them are to be determined.

tri

Three 2D points, stacked row-wise, each row representing a vertex of the triangle.

A 2D point in Cartesian coordinates or a 3D point in barycentric coordinates which serves as a center in the interior of the triangle tri or the circumcenter of tri.

Value

A list with two elements

Indices of the vertices whose regions contains points in Dt.

tri

The vertices of the triangle, where row number corresponds to the vertex index in rv.

References

Examples

Run this code

# NOT RUN {
A<-c(1,1); B<-c(2,0); C<-c(1.5,2);
Tr<-rbind(A,B,C);
M<-c(1.6,1.0)

P<-c(.4,.2)
rverts.tri.cent.alt(P,Tr,M)

P<-c(1.8,.5)
rverts.tri.cent.alt(P,Tr,M)

P<-c(1.5,1.6)
rverts.tri.cent.alt(P,Tr,M)

n<-10  #try also n<-20
set.seed(1)
dat<-runif.tri(n,Tr)$g

M<-c(1.6,1.0)  #try also M<-c(1.3,1.3)

rv<-rverts.tri.cent.alt(dat,Tr,M)
rv

Ds<-cp2e.tri(Tr,M)

Xlim<-range(Tr[,1])
Ylim<-range(Tr[,2])
xd<-Xlim[2]-Xlim[1]
yd<-Ylim[2]-Ylim[1]

plot(Tr,pch=".",xlab="",ylab="",axes=TRUE,xlim=Xlim+xd*c(-.05,.05),ylim=Ylim+yd*c(-.05,.05))
polygon(Tr)
points(dat,pch=".",col=1)
L<-rbind(M,M,M); R<-Ds
segments(L[,1], L[,2], R[,1], R[,2], lty=2)

xc<-Tr[,1]+c(-.03,.05,.05)
yc<-Tr[,2]+c(-.06,.02,.05)
txt.str<-c("rv=1","rv=2","rv=3")
text(xc,yc,txt.str)

txt<-rbind(M,Ds)
xc<-txt[,1]+c(.02,.04,-.03,0)
yc<-txt[,2]+c(.07,.03,.05,-.07)
txt.str<-c("M","D1","D2","D3")
text(xc,yc,txt.str)

text(dat,labels=factor(rv$rv))

P<-c(1.4,1.0)
rverts.tri.cent.alt(P,Tr,M)
rverts.tri.cent.alt(dat,Tr,M)

rverts.tri.cent.alt(rbind(dat,dat),Tr,M)

dat.fr<-data.frame(a=dat)
rverts.tri.cent.alt(dat.fr,Tr,M)

dat.fr<-data.frame(a=Tr)
rverts.tri.cent.alt(dat,dat.fr,M)

# }