One reporting triangle per stratum

The object returned by tbl_now_to_baselinenowcast(x, format = "triangle_list"): a list of baselinenowcast::as_reporting_triangle() matrices, one per observed combination of the object's strata, together with the metadata needed to rebuild a tbl_now from it.

It is a thin class – it is still a list, so lapply(), [[ and friends work as usual:

triangles <- tbl_now_to_baselinenowcast(x, format = "triangle_list")
lapply(triangles, baselinenowcast::baselinenowcast)

The class exists for one reason. baselinenowcast has a function, baselinenowcast::estimate_and_apply_delays(), whose first argument retro_reporting_triangles is also a list of triangles – but a list of retrospective snapshots of one series, used to estimate uncertainty, not one triangle per stratum. Passing this object there would be accepted and would silently treat your strata as successive points in time. Printing the object says plainly what it is, so the mistake is visible rather than silent.

Usage

# S3 method for class 'tbl_now_triangle_list'
print(x, ...)

Arguments

x

A tbl_now_triangle_list.

...

Ignored.

Value

print() returns x invisibly.

See also

tbl_now_to_baselinenowcast(), as_tbl_now()

Examples

data(denguedat)
dengue <- tbl_now(denguedat[1:3000, ],
  event_date = onset_week, report_date = report_week, verbose = FALSE
)

# One reporting triangle per stratum, in the shape baselinenowcast wants.
triangles <- suppressWarnings(
  tbl_now_to_baselinenowcast(dengue, format = "triangle_list", verbose = FALSE)
)
#> ℹ Using max_delay = 13 from data

# Printing summarises the set rather than dumping every matrix.
triangles
#> ── 1 reporting triangle from a <tbl_now> ───────────────────────────────────────
#> • No strata; a single triangle named "all"
#> • Delays unit: "weeks"
#> • Now: "1991-10-14"
#> • Dimensions (event x delay): "94 x 14"
#> ℹ This is one triangle per STRATUM. `baselinenowcast::estimate_and_apply_delays()` expects retrospective snapshots of a single series instead -- do not pass this object to it.

# It is a list underneath, so the usual accessors work.
length(triangles)
#> [1] 1
names(triangles)
#> [1] "all"