record_attr_history: Record Attribute History

In EpiModel: Mathematical Modeling of Infectious Disease Dynamics

Record Attribute History

Description

Record values for a set of nodes at a specific time step. Records are stored in dat[["attr.history"]] as a collections::queue and can be accessed from the netsim object with get_attr_history.

This function is called automatically by the tracked attributes system when tracked.attributes is set in control.net, but can also be called manually inside custom modules for ad-hoc recording.

Usage

record_attr_history(
  dat,
  item,
  value,
  ...,
  at = NULL,
  posit_ids = NULL,
  unique_ids = NULL
)

Arguments

dat	Main netsim_dat object containing a networkDynamic object and other initialization information passed from netsim().
item	The name of the attribute to record.
value	The values to be recorded. Must be of length 1 (recycled for all nodes) or the same length as the number of nodes identified by posit_ids or unique_ids.
...	Must be empty. It makes at, posit_ids and unique_ids named-only arguments, so that calls written for the EpiModel 2.6 signature, record_attr_history(dat, at, attribute, posit_ids, values), error instead of silently recording the wrong values.
at	The time step at which the recording happens. Defaults to the current time step if NULL.
posit_ids	A numeric vector of positional IDs to which the values apply. Converted internally to unique IDs. Either posit_ids or unique_ids must be provided.
unique_ids	A numeric vector of unique IDs to which the values apply. When provided, skips the positional-to-unique ID conversion.

Details

Exactly one of posit_ids or unique_ids must be non-NULL. When both are NULL, the function errors. When unique_ids is provided directly, the conversion from positional IDs is skipped, which is more efficient when unique IDs are already known (e.g., from the automatic tracking system).

See the "Historical Nodal Attributes" section of the "Working with Custom Attributes and Summary Statistics" vignette (vignette("attributes-and-summary-statistics", package = "EpiModel")).

Value

The updated netsim_dat main list object.

Examples

## Not run: 
# Manual recording inside a custom module
dat <- record_attr_history(dat, "status", get_attr(dat, "status"),
                           posit_ids = get_posit_ids(dat))

# Record for a subset of nodes using unique IDs directly
some_uids <- c(10, 25, 42)
dat <- record_attr_history(dat, "risk", c(1, 0, 1),
                           unique_ids = some_uids)

## End(Not run)

EpiModel documentation built on Oct. 16, 2026, 5:07 p.m.