create {manynet}

Making networks with defined structures

Description

These functions create networks with particular structural properties.

• create_empty() creates an empty network without any ties.

• create_filled() creates a filled network with every possible tie realised.

• create_ring() creates a ring or chord network where each nodes' neighbours form a clique.

• create_star() creates a network with a maximally central node.

• create_tree() creates a network with successive branches.

• create_lattice() creates a network that forms a regular tiling.

• create_components() creates a network that clusters nodes into separate components.

• create_core() creates a network in which a certain proportion of 'core' nodes are densely tied to each other, and the rest peripheral, tied only to the core.

• create_explicit() creates a network based on explicitly named nodes and ties between them.

These functions can create either one-mode or two-mode networks. To create a one-mode network, pass the main argument n a single integer, indicating the number of nodes in the network. To create a two-mode network, pass n a vector of two integers, where the first integer indicates the number of nodes in the first mode, and the second integer indicates the number of nodes in the second mode. As an alternative, an existing network can be provided to n and the number of modes, nodes, and directedness will be inferred.

Usage

create_empty(n, directed = FALSE)

create_filled(n, directed = FALSE)

create_ring(n, directed = FALSE, width = 1, ...)

create_star(n, directed = FALSE)

create_tree(n, directed = FALSE, width = 2)

create_lattice(n, directed = FALSE, width = 8)

create_components(n, directed = FALSE, membership = NULL)

create_core(n, directed = FALSE, mark = NULL)

create_explicit(...)

Arguments

n

Given:

• A single integer, e.g. n = 10, a one-mode network will be created.

• A vector of two integers, e.g. n = c(5,10), a two-mode network will be created.

• A manynet-compatible object, a network of the same dimensions will be created.

directed

Logical whether the graph should be directed. By default directed = FALSE. If the opposite direction is desired, use to_redirected() on the output of these functions.

width

Integer specifying the width of the ring, breadth of the branches, or maximum extent of the neighbourbood.

...

Additional arguments passed on to {igraph}.

membership

A vector of partition membership as integers. If left as NULL (the default), nodes in each mode will be assigned to two, equally sized partitions.

mark

A logical vector the length of the nodes in the network. This can be created by, among other things, any ⁠node_is_*()⁠ function.

Value

By default a tbl_graph object is returned, but this can be coerced into other types of objects using as_edgelist(), as_matrix(), as_tidygraph(), or as_network().

By default, all networks are created as undirected. This can be overruled with the argument directed = TRUE. This will return a directed network in which the arcs are out-facing or equivalent. This direction can be swapped using to_redirected(). In two-mode networks, the directed argument is ignored.

Lattice graphs

create_lattice() creates both two-dimensional grid and triangular lattices with as even dimensions as possible. When the width parameter is set to 4, nodes cannot have (in or out) degrees larger than 4. This creates regular square grid lattices where possible. Such a network is bipartite, that is partitionable into two types that are not adjacent to any of their own type. If the number of nodes is a prime number, it will only return a chain (a single dimensional lattice).

A width parameter of 8 creates a network where the maximum degree of any nodes is 8. This can create a triangular mesh lattice or a Queen's move lattice, depending on the dimensions. A width parameter of 12 creates a network where the maximum degree of any nodes is 12. Prime numbers of nodes will return a chain.

See Also

as

igraph::graph_from_literal() which create_explicit() mostly just wraps. create_explicit() will also accept character input and not just a formula though, and will never simplify the result.

Other makes: generate, learning, play, read, write()

Examples

create_empty(10)
create_filled(10)
create_ring(8, width = 2)
create_star(12)
create_tree(c(7,8))
create_lattice(12, width = 4)
create_components(10, membership = c(1,1,1,2,2,2,3,3,3,3))
create_core(6)
  create_explicit(A -+ B, B -+ C, A +-+ C, D)