nwreach
Reachability network
Syntax
nwreach
[netname]
[,
sym
name(string)
xvars
nwreplace
force]
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) |
force |
Run the command although its matrices would not fit in memory (it stops with r(484) above 12 GB otherwise) |
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
+---------------------------------------------------+
1 | 0 |
2 | 1 0 |
3 | 1 1 0 |
4 | 1 1 1 0 |
5 | 1 1 1 1 0 |
6 | 1 1 1 1 1 0 |
7 | 1 1 1 1 1 1 0 |
8 | 0 0 0 0 0 0 0 0 |
9 | 1 1 1 1 1 1 1 0 0 |
10 | 1 1 1 1 1 1 1 0 1 0 |
+---------------------------------------------------+
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 - reachability follows the direction of the ties and the network is not symmetrized unless sym is given (same convention as nwgeodesic). Weighted: not applicable. Signed: not applicable. same as for the bipartite graph read as a one-mode network (valid; no mode-specific normalisation).
See also
-
last certified : 24 Aug 2026
nwcommands version 3.17.6, 9 November 2026 (check your installed version)