nwattime

Static graph view of a temporal network at a given time

Syntax

nwattime
[netname]
,
at(#)
[name(newnetname)
xvars
replace]
   
at(#) The timepoint to slice at
name(newnetname) Name of the new static network; default = atview
xvars Generate Stata variables for the new network
replace Replace an existing network of the same name

Description

nwattime takes a temporal network (declared via nwset’s time(), interval(), or eventtime() options) and produces an ordinary, static one-mode network containing only the ties active at the requested timepoint - the “temporal network -> select edges active at t -> static graph view -> ordinary nw algorithm” model: the resulting network is a completely normal network, usable with any existing nw* command exactly as if it had never been temporal at all. This is deliberate groundwork, not a full temporal-network modelling system - see nwset’s own temporal section for what is and is not supported yet.

The slicing rule depends on the source network’s own temporal semantics:

  • snapshot
  • a tie is active at t when its own recorded time equals t exactly
  • interval
  • a tie is active at t when start <= t < end - the documented convention.
  • A tie with a missing end (an ongoing tie with no recorded end date) is treated as open-ended
  • and stays active for every t from its start onward. A missing start is not specially
  • handled and excludes the tie
  • event
  • an exact-timestamp match: every event recorded at precisely t becomes a binary tie in
  • the static view. This is the one place an event network is allowed to become a persistent graph in
  • this package, and only because t was explicitly requested - no windowing or aggregation across a
  • range of timestamps is done (not yet supported)

For example, a network declared with nwset ego alter, time(wave) can be sliced to the ties that existed in wave 2:

. clear
. input ego alter wave
  • 1 2 1
  • 2 3 1
  • 1 3 2
  • 2 3 2
  • 3 4 3
. end
. nwset ego alter, time(wave) name(mynet)
. nwattime mynet, at(2) name(wave2)

Supported network types

Binary: yes. Directed: preserved from the source network. Weighted: preserved from the source network’s own tie values (the slice selects which ties are active, it does not change their values). Signed: not checked. Two-mode: not yet supported as a source (see nwset’s own note that time()/ interval()/eventtime() cannot currently be combined with twomode/bipartite - a composability item for a later pass).

Stored results

Scalars

  • r(ties) number of ties in the static view
  • r(at) the timepoint sliced at

See also


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nwcommands is free to install and use, including for commercial research. See the GitHub repository for source, license, and issue tracking.

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