Get a draw of only the predicted elements of the nowcast vector

Usage

get_nowcast_pred_draw(
  point_nowcast_matrix,
  reporting_triangle,
  dispersion,
  fun_to_aggregate = sum,
  k = 1
)

Arguments

point_nowcast_matrix: Matrix of point nowcast predictions and observations, with rows representing the reference times and columns representing the delays.
reporting_triangle: Matrix of the reporting triangle, with rows representing the time points of reference and columns representing the delays. Can be a reporting matrix or incomplete reporting matrix. Can also be a ragged reporting triangle, where multiple columns are reported for the same row. (e.g. weekly reporting of daily data).
dispersion: Vector of dispersion parameters indexed by horizon from minus one to the maximum delay.
fun_to_aggregate: Function that will operate along the nowcast vectors after summing across delays. Eventually, we can add things like mean, but for now since we are only providing a negative binomial observation model, we can only allow sum. Currently supported functions: sum.
k: Integer indicating the number of reference times to apply the fun_to_aggregate over to create target used to compute the nowcast errors.

Value

Vector of predicted draws at each reference time, for all reference times in the input point_nowcast_matrix.

Examples

point_nowcast_matrix <- matrix(
  c(
    80, 50, 25, 10,
    100, 50, 30, 20,
    90, 45, 25, 16.8,
    80, 40, 21.2, 19.5,
    70, 34.5, 15.4, 9.1
  ),
  nrow = 5,
  byrow = TRUE
)
reporting_triangle <- generate_triangle(point_nowcast_matrix)
disp <- c(0.8, 12.4, 9.1)
nowcast_pred_draw <- get_nowcast_pred_draw(
  point_nowcast_matrix,
  reporting_triangle,
  disp
)
nowcast_pred_draw
#> [1]  0  0 34 46  1

# Get draws on the rolling sum
nowcast_pred_draw_agg <- get_nowcast_pred_draw(
  point_nowcast_matrix,
  reporting_triangle,
  disp,
  fun_to_aggregate = sum,
  k = 2
)
nowcast_pred_draw_agg
#> [1]  0  0 12 59  0