Compute Distance Matrix from Graph — distances_from

Compute a distance matrix for all node pairs in a graph using cppRouting.

Usage

distances_from_graph(graph_df, directed = FALSE, cost.column = "cost", ...)

Arguments

graph_df: A data frame representing a graph with columns: from, to, and cost.
directed: Logical (default: FALSE). If TRUE, treats the graph as directed; if FALSE, treats it as undirected.
cost.column: Character string (optional). Name of the cost column in graph_df. Alternatively, a numeric vector of edge costs with length equal to nrow(graph_df).
...: Additional arguments passed to distances(), such as v (from) and to to compute paths between specific nodes.

Value

A matrix of distances between all node pairs, where rows and columns correspond to node IDs. The matrix contains the shortest path distances (based on the cost column) between all pairs of nodes.

Details

This function:

Converts the graph data frame to a cppRouting graph object
Contracts the graph for efficient distance computation
Computes the distance matrix for all node pairs using the specified algorithm

Examples

library(flownet)

# Create a simple graph
graph <- data.frame(
  from = c(1, 2, 2, 3),
  to = c(2, 3, 4, 4),
  cost = c(1, 2, 3, 1)
)

# Compute distance matrix
dmat <- distances_from_graph(graph, cost.column = "cost")
dmat
#>   1 2 3 4
#> 1 0 1 3 4
#> 2 1 0 2 3
#> 3 3 2 0 1
#> 4 4 3 1 0