Generate a single retrospective reporting triangle — construct

This function generates a single reporting triangle by removing the bottom right observations from a truncated reporting triangle matrix. It is the singular version of construct_triangles().

Usage

construct_triangle(truncated_reporting_triangle, structure = 1)

Arguments

truncated_reporting_triangle: A single truncated reporting triangle. May or may not contain NAs.
structure: Integer or vector specifying the reporting structure. If integer, divides columns evenly by that integer (with last possibly truncated). If vector, the sum must not be greater than or equal to the number of columns. Default is 1 (standard triangular structure).

Value

A single retrospective reporting triangle matrix with NAs in the appropriate positions.

Examples

triangle <- matrix(
  c(
    65, 46, 21, 7,
    70, 40, 20, 5,
    80, 50, 10, 10,
    100, 40, 31, 20,
    95, 45, 21, 10,
    82, 42, 6, NA,
    70, 90, NA, NA
  ),
  nrow = 7,
  byrow = TRUE
)

# Standard triangular structure (default)
rep_tri <- construct_triangle(triangle)
rep_tri
#>      [,1] [,2] [,3] [,4]
#> [1,]   65   46   21    7
#> [2,]   70   40   20    5
#> [3,]   80   50   10   10
#> [4,]  100   40   31   20
#> [5,]   95   45   21   NA
#> [6,]   82   42   NA   NA
#> [7,]   70   NA   NA   NA

# Ragged structure with 2 columns per delay period
rep_ragged <- construct_triangle(triangle, 2)
rep_ragged
#>      [,1] [,2] [,3] [,4]
#> [1,]   65   46   21    7
#> [2,]   70   40   20    5
#> [3,]   80   50   10   10
#> [4,]  100   40   31   20
#> [5,]   95   45   21   10
#> [6,]   82   42    6   NA
#> [7,]   70   90   NA   NA

# Custom structure with explicit column counts
rep_custom <- construct_triangle(triangle, c(1, 2))
rep_custom
#>      [,1] [,2] [,3] [,4]
#> [1,]   65   46   21    7
#> [2,]   70   40   20    5
#> [3,]   80   50   10   10
#> [4,]  100   40   31   20
#> [5,]   95   45   21   10
#> [6,]   82   42    6   NA
#> [7,]   70   NA   NA   NA