Skip to contents

Trace all paths from saddles to dual critical points in the spanning forest.

Source: R/utils_dmt.R
trace_paths.Rd

Because the dual spanning forest is a maximum spanning forest on triangles in the mesh, the paths that are traced between saddles and critical triangles (maxima) will follow ridges, separating points into components with the strongest boundaries.

Usage

trace_paths(dmt, dual, saddles)

Arguments

dmt

A DMT data structure with the following attributes:

  • edges$from_tri: Index of first triangle joined by each edge (1-indexed).

  • edges$to_tri: Index of second triangle joined by each edge (1-indexed).

dual

A dual maximum spanning forest on triangles:

  • labels: A length num_triangles vector of labels for the connected components in the maximum spanning tree. Each connected component is labeled by the index of its critical triangle.

  • parent: A length num_triangles vector containing the parent (source) triangle for each triangle in the directed spanning forest. Critical triangles have no parent, so the value should be ignored.

  • parent_edge: A length num_triangles vector containing the directed edge that has each triangle as a target node. Critical triangles have no parent edge, so the value should be ignored.

saddles

A length num_saddles vector with edge indices for saddle edges (1-indexed).

Value

A list of length 2*num_saddles containing the two paths from each saddle edge to the two critical points that it joins. Each path is a numeric vector of edge indices (1-indexed).