incidence.matrix: Incidence matrix generation

In mathphysmx/percolation: Continuum percolation of Poisson sticks

Description

Incidence matrix generation

Usage

incidence.matrix(m)

Arguments

m	Matrix with four columns where the first and last two entries of every row are the cartesian coordinates of a single fracture's endpoints.

Details

This functions calculates the incidence matrix of a set of line segments (in the graph theory sense). It takes as entry a matrix with four columns where the first and last two entries of every row are the cartesian coordinates of a single segment's endpoints (see segments). Thus, the number of rows corresponds to the number of line segments. This function depends on the function inter.check to determine whether two fractures intersect. Interpreting this network as a non-oriented random graph, where every line segment is a node and two nodes are connected if the corresponding line segments intersect, incidence.matrix() builds the symmetrical ones-and-zeroes matrix of adjacency. This matrix is later fed to the igraph package for further analysis.

Value

A symmetric matrix of ones and zeroes, where a one (1) in any given entry indicates that the fractures corresponding to the entry's indices intersect.

Author(s)

Daniella Ayala ([e-mail]) and Francisco Mendoza-Torres ([e-mail])

Examples

dfn <- data.frame(x0=c(0,2,3,1),
y0=c(1,0,2,1.5),
x1=c(3,5,7,2),
y1=c(0,3,2,1.5))
plotSegments(dfn)
text(dfn[, 1:2], labels=1:4, pos = 2)
incidence.matrix(dfn)

mathphysmx/percolation documentation built on Aug. 14, 2019, 2:03 a.m.