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Path distances

Source: R/path_distances.R
distances.Rd

Distances between nodes using breadth-first search (BFS) or Dijkstra's algorithm to find shortest path distances.

Usage

bfs_ugraph(A, from = NULL)

count_geodesics(A)

short_path(A, from = NULL, to = NULL)

wlocal_distances(A, select = c("all", "in", "out"), from, to, path = c())

wall_distances(A, select = c("all", "in", "out"))

Arguments

A

A symmetric matrix object

from

Node in which the path start

to

Node in which the path end

select

Whether to consider all sender and receiver ties of ego (all), only incoming ties (in), or outgoing ties (out). By default, all.

path

Path of the nodes

Value

This function returns the distances o shortest path distance between two nodes for unweighted graph (bfs_ugraph, count_geodesics and short_path respectively) and weighted graphs (wlocal_distances or wall_distances)

References

Dijkstra, E. W. (1959). A note on two problems in connexion with graphs. Numerische Mathematik. 1: 269–271.

Author

Alejandro Espinosa-Rada

Examples

A <- matrix(c(
  0, 1, 1, 0, 0, 0,
  0, 0, 0, 1, 1, 0,
  0, 0, 0, 0, 1, 0,
  0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 1,
  0, 0, 0, 0, 0, 0
), byrow = TRUE, nrow = 6)
rownames(A) <- letters[1:nrow(A)]
colnames(A) <- letters[1:ncol(A)]

bfs_ugraph(A, from = "a")
#> $pointers
#> [1] NA  1  1  2  2  5
#> 
#> $distances
#> [1] 0 1 1 2 2 3
#> 
A <- matrix(c(
  0, 1, 1, 0, 0, 0,
  0, 0, 0, 1, 1, 0,
  0, 0, 0, 0, 1, 0,
  0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 1,
  0, 0, 0, 0, 0, 0
), byrow = TRUE, nrow = 6)
rownames(A) <- letters[1:nrow(A)]
colnames(A) <- letters[1:ncol(A)]

count_geodesics(A)
#> $counts
#>      [,1] [,2] [,3] [,4] [,5] [,6]
#> [1,]    1    1    1    1    1    1
#> [2,]    0    1    0    1    1    1
#> [3,]    0    0    1    0    1    1
#> [4,]    0    0    0    1    0    0
#> [5,]    0    0    0    0    1    1
#> [6,]    0    0    0    0    0    1
#> 
#> $distances
#>      [,1] [,2] [,3] [,4] [,5] [,6]
#> [1,]    0    1    1    2    2    3
#> [2,]  Inf    0  Inf    1    1    2
#> [3,]  Inf  Inf    0  Inf    1    2
#> [4,]  Inf  Inf  Inf    0  Inf  Inf
#> [5,]  Inf  Inf  Inf  Inf    0    1
#> [6,]  Inf  Inf  Inf  Inf  Inf    0
#> 
A <- matrix(c(
  0, 1, 1, 0, 0, 0,
  0, 0, 0, 1, 1, 0,
  0, 0, 0, 0, 1, 0,
  0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 1,
  0, 0, 0, 0, 0, 0
), byrow = TRUE, nrow = 6)
rownames(A) <- letters[1:nrow(A)]
colnames(A) <- letters[1:ncol(A)]

short_path(A, from = "a", to = "d")
#> [1] "a" "b" "d"
A <- matrix(
  c(
    0, 3, 3, 10, 15, 0, 0, 0,
    1, 0, 5, 2, 7, 0, 0, 0,
    3, 5, 0, 0, 0, 0, 0, 0,
    10, 2, 0, 0, 2, 7, 12, 0,
    11, 3, 0, 3, 0, 11, 2, 0,
    0, 0, 0, 7, 11, 0, 3, 2,
    0, 0, 0, 12, 2, 3, 0, 2,
    0, 0, 0, 0, 0, 2, 2, 0
  ),
  byrow = TRUE, ncol = 8, nrow = 8
)
rownames(A) <- c("a", "b", "s", "c", "d", "e", "f", "z")
colnames(A) <- rownames(A)
wlocal_distances(A, from = "a", to = "d")
#> Error in walk_length(newwalk): object 'A' not found
A <- matrix(
  c(
    0, 3, 3, 10, 15, 0, 0, 0,
    1, 0, 5, 2, 7, 0, 0, 0,
    3, 5, 0, 0, 0, 0, 0, 0,
    10, 2, 0, 0, 2, 7, 12, 0,
    11, 3, 0, 3, 0, 11, 2, 0,
    0, 0, 0, 7, 11, 0, 3, 2,
    0, 0, 0, 12, 2, 3, 0, 2,
    0, 0, 0, 0, 0, 2, 2, 0
  ),
  byrow = TRUE, ncol = 8, nrow = 8
)
rownames(A) <- c("a", "b", "s", "c", "d", "e", "f", "z")
colnames(A) <- rownames(A)
wall_distances(A, select = "in")
#> Error in walk_length(newwalk): object 'A' not found