nwreach

Calculate reachability network

Syntax

nwreach 
[netname]
[,
sym
name(string)
xvars
nwreplace]

sym	Symmetrize network before calculation of reachability
name(newnetname)	Name of the new network; default = reach
xvars	Generate Stata variables for the network
nwreplace	if a network named newnetname already exists, drop it and use this name anyway - required, not silent (see nwgeodesic for the same convention)

Description

nwreach calculates the reachability network. The dyads x_ij in the reachibility network take value 1 when there is at least one path between nodes i and j in the original network netname, and 0 if there is no such path.

Examples

• . nwclear
• . nwrandom 10, prob(.1)
• . nwreach random, sym

• . nwsummarize _reach, matonly

• 1 2 3 4 5 6 7 8 9 10
• hline 51

• 1 c

  0 c

• 2 c

  1 0 c

• 3 c

  1 1 0 c

• 4 c

  1 1 1 0 c

• 5 c	1 1 1 1 0 c

• 6 c	1 1 1 1 1 0 c

• 7 c	1 1 1 1 1 1 0 c

• 8 c	0 0 0 0 0 0 0 0 c

• 9 c	1 1 1 1 1 1 1 0 0 c

• 10 c	1 1 1 1 1 1 1 0 1 0 c

• hline 51

In this example, there is basically one isolate node (node 8) who is unconnected from everybody else.

Supported network types

Binary: yes (only) - reachability is a structural yes/no property; nwgeodesic’s own weighted distance semantics do not carry through here. Directed: yes - symmetrized by default (same convention as nwgeodesic), sym available. Weighted: not applicable. Signed: not applicable. Two-mode: not checked.

See also

• nwgeodesic, nwpath

• last certified : 24 Aug 2026