sl.elem2linepairs: Extract Unique Edges from Triangular Mesh

Description Usage Arguments Value Author(s) Examples

View source: R/sl.elem2linepairs.R

Description

Extract unique lines from elements (polygons) of an unstructured mesh. Useful for plotting to half the figure size (vector format). By default, the edges are concatenated and returned as a vector composed of segments divided by NAs.

Usage

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sl.elem2linepairs(elem, concat = TRUE, verbose = FALSE)

Arguments

elem

an Nx3 matrix with the node indices of the triangular elements of an unstructured mesh.

concat

a logical value indicating whether the resulting unique edges are concatenated and returned as a vector composed of segments divided by NAs. This can be computationally advantageous, for example for line plotting. Otherwise, a two-column matrix with each row giving one pair of nodes is returned.

verbose

a logical value indicating whether print statements shall report on the function progess.

Value

If concat=TRUE (default), the resulting unique edges are concatenated and returned as a vector composed of segments divided by NAs. Otherwise, a two-column matrix with each row giving one pair of nodes is returned.

Author(s)

Helge Goessling

Examples

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elem = matrix(c(c(1,2,3),c(3,2,4),c(4,2,5),c(5,2,6)),ncol=3,byrow=TRUE)

sl.elem2linepairs(elem,concat=TRUE)
## Should return:
## [1]  1  2  3  4  5  6  2  4 NA  1  3 NA  2  5

sl.elem2linepairs(elem,concat=FALSE)
## Should return:
##       [,1] [,2]
##  [1,]    1    2
##  [2,]    1    3
##  [3,]    2    3
##  [4,]    2    4
##  [5,]    2    5
##  [6,]    2    6
##  [7,]    3    4
##  [8,]    4    5
##  [9,]    5    6

helgegoessling/spheRlab documentation built on Sept. 29, 2017, 6:36 a.m.