functional_contrast: Functional Contrast (Disease Suppression Profiles)

In r4pde: Tools for Quantitative Plant Disease Epidemiology

Functional Contrast (Disease Suppression Profiles)

Description

Calculates functional contrast curves (Disease Suppression Profiles - DSP) between a reference treatment (e.g., untreated control) and other fungicide treatments over time. The DSP is defined by default as:

DSP(t) = y_{control}(t) - y_{treatment}(t)

where y(t) is the disease intensity at time t. The goal is to evaluate the intensity, timing, and persistence of the fungicide protection.

Usage

functional_contrast(
  data,
  time = "time",
  response = "response",
  treatment = "treatment",
  reference = "Control",
  group = NULL,
  smooth = FALSE,
  grid = NULL,
  contrast = c("difference", "relative"),
  keep_reference = FALSE,
  ...
)

Arguments

data	A data frame containing disease progress observations, or an object of class "functional_curves".
time	Character string naming the time variable.
response	Character string naming the response variable.
treatment	Character string naming the treatment variable.
reference	Character string specifying the reference treatment level. Default is "Control".
group	Optional character vector of grouping variables (e.g., c("experiment", "location")).
smooth	Logical; if TRUE, the function could apply smoothing (currently placeholder).
grid	Optional numeric vector of common time points for interpolation. If provided, curves are interpolated.
contrast	Character specifying the contrast type. Currently "difference" is implemented.
keep_reference	Logical; if TRUE, includes the reference treatment in the output (with DSP = 0). Default is FALSE.
...	Additional arguments.

Value

An object of class "functional_dsp" (inheriting from "tbl_df"), containing:

• grouping variables (if any)

• treatment variable

• time variable

• y_reference: disease intensity of the reference

• y_treatment: disease intensity of the treatment

• DSP: the computed contrast

• contrast_type: type of contrast used

• reference: name of the reference treatment

See Also

functional_summary, plot_dsp

r4pde documentation built on Sept. 8, 2026, 1:10 a.m.