fdp_attributes: Control rendering of f-DP trade-off functions

Description

These functions attach attributes to f-DP objects that control their visualization:

fdp_line() forces the object to be rendered as a continuous trade-off function curve. The function validates that the resulting curve is convex (a requirement for valid trade-off functions). Use this for analytic trade-off functions or when you want to ensure convexity is checked.
fdp_point() forces the object to be rendered as individual Type I/II error coordinates, with the lower convex hull automatically computed and drawn. Use this for empirical estimates or small datasets where individual points should be visible.
fdp_name() sets or retrieves the legend label for the object. When called with nm, it sets the label; when called without nm, it returns the current label.
fdp_attributes() retrieves all f-DP related attributes attached to an object.

By default, fdp() automatically determines the rendering method: data frames or vectors with \(\ge 100\) elements are treated as lines (with convexity validation), while those with \(< 100\) elements are treated as points (with lower hull computation).

Usage

fdp_attributes(x)
fdp_line(x)
fdp_point(x, hide = FALSE)
fdp_name(x, nm)

Value

For fdp_line(), fdp_point(), and fdp_name() (when setting): the input object x with modified attributes (returned invisibly).

For fdp_name() (when getting) and fdp_attributes(): the requested attribute value(s) or NULL.

Arguments

x: An f-DP object (function, data frame, or vector) to which attributes are added or retrieved.
hide: Logical; if TRUE, individual points are not drawn (only their lower convex hull is shown).
nm: Character string specifying the legend label. If missing, returns the current label.

Details

Functions to control how f-differential privacy trade-off functions and empirical Type I/II error points are rendered by fdp().

Examples

Run this code

# Force a small dataset to be drawn as a line (with convexity check)
df <- data.frame(alpha = c(0, 0.5, 1), beta = c(1, 0.4, 0))
fdp(fdp_line(df))

# Draw points but hide them (only show the lower hull)
fdp(fdp_point(df, hide = TRUE))

# Conversely, the following points if interpolated do not define a convex
# trade-off function, so fdp_line would fail
df2 <- data.frame(alpha = c(0, 0.5, 0.51, 1), beta = c(1, 0.4, 0.34, 0))
#fdp(fdp_line(df2)) # Not run, would error
# But the following is ok, since we will compute lower convex hull due to
# small number of points
fdp(df2)

# If you have a large number of points which will not interpolate to give
# convexity, then fdp_point can force that behaviour
df3 <- gdp(0.5)()
df3$beta <- pmin(df3$beta * rnorm(101, 0.95, sd=0.025), 1.0)
#fdp(df3) # Not run, would error
# But wrapping in fdp_point forces plotting points and lower convex hull
fdp(fdp_point(df3))

# Set a custom legend label programmatically, rather than via argument in
# call to fdp ... eg alternative is fdp(`my label` = my_gdp)
my_gdp <- gdp(1)
my_gdp <- fdp_name(my_gdp, "Custom GDP Label")
fdp(my_gdp)