tileArea: Area of a Dirichlet tile.

Description Usage Arguments Details Value Author(s) See Also Examples

View source: R/tileArea.R

Description

Calculates the area of a Dirichlet tile, applying a discrete version of Stoke's theorem.

Usage

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tileArea(x, y, rw)

Arguments

x

The x-coordinates of the vertices of the tile, in anticlockwise direction. The last coordinate should not repeat the first.

y

The y-coordinates of the vertices of the tile, in anticlockwise direction. The last coordinate should not repeat the first.

rw

A vector of length 4 specifying the rectangular window in which the relevant tessellation was construced. See deldir() for more detail. Actually this can be any rectangle containing the tile in question.

Details

The heavy lifting is done by the Fortran subroutine stoke() which is called by the .Fortran() function.

Value

A positive scalar.

Author(s)

Rolf Turner r.turner@auckland.ac.nz

See Also

deldir() tilePerim()

Examples

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set.seed(42)
x <- runif(20)
y <- runif(20)
z <- deldir(x,y,rw=c(0,1,0,1))
w <- tile.list(z)
with(w[[1]],tileArea(x,y,rw=z$rw))
sapply(w,function(x,rw){tileArea(x$x,x$y,attr(w,"rw"))})
x <- c(0.613102,0.429294,0.386023,0.271880,0.387249,0.455900,0.486101)
y <- c(0.531978,0.609665,0.597780,0.421738,0.270596,0.262953,0.271532)
# The vertices of the Dirichlet tile for point 6.
tileArea(x,y,rw=c(0,1,0,1))
tileArea(x,y,rw=c(-1,2,-3,4)) # Same as above.

deldir documentation built on Feb. 17, 2021, 1:08 a.m.

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