# R igraph manual pages

Use this if you are using igraph from R

 make_chordal_ring {igraph} R Documentation

## Create an extended chordal ring graph

### Description

`make_chordal_ring` creates an extended chordal ring. An extended chordal ring is regular graph, each node has the same degree. It can be obtained from a simple ring by adding some extra edges specified by a matrix. Let p denote the number of columns in the ‘`W`’ matrix. The extra edges of vertex `i` are added according to column `i mod p` in ‘`W`’. The number of extra edges is the number of rows in ‘`W`’: for each row `j` an edge `i->i+w[ij]` is added if `i+w[ij]` is less than the number of total nodes. See also Kotsis, G: Interconnection Topologies for Parallel Processing Systems, PARS Mitteilungen 11, 1-6, 1993.

### Usage

``````make_chordal_ring(n, w, directed = FALSE)

chordal_ring(...)
``````

### Arguments

 `n` The number of vertices. `w` A matrix which specifies the extended chordal ring. See details below. `directed` Logical scalar, whether or not to create a directed graph. `...` Passed to `make_chordal_ring`.

### Value

An igraph graph.

Other deterministic constructors: `graph_from_atlas()`, `graph_from_edgelist()`, `graph_from_literal()`, `make_empty_graph()`, `make_full_citation_graph()`, `make_full_graph()`, `make_graph()`, `make_lattice()`, `make_ring()`, `make_star()`, `make_tree()`
``````chord <- make_chordal_ring(15,