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Add DLMO Fit Lines to a Melatonin Profile Plot

Source: R/plot_profile.R
plot_fit.Rd

This function overlays the estimated DLMO fit lines (base and ascending phase) onto a melatonin profile plot. The fit can be either linear or parabolic, depending on the dlmoFit results.

Usage

plot_fit(plot, profile_data, dlmoFit)

Arguments

plot

A ggplot object. The base plot of the melatonin profile.

profile_data

A dataframe containing melatonin concentration data, with required columns:

  • datetime (POSIXct) – Time of measurement.

  • melatonin (numeric) – Melatonin concentration levels.

  • base (binary) – Indicator column for base segment points.

  • ascending (binary) – Indicator column for ascending segment points.

dlmoFit

A list containing the estimated DLMO inflection point and fit parameters, including:

  • inflection_point$x (decimal hours) – The estimated x-coordinate of the inflection point.

  • inflection_point$y (numeric) – The estimated y-coordinate of the inflection point.

  • base_params (numeric) – Slope of the linear base fit.

  • ascending_params (list) – Either a single slope (for linear) or coefficients a, b, c (for parabolic).

Value

A ggplot object with the fitted lines added.

Details

  • The base fit is always linear and is drawn from the start of the base segment to the inflection point.

  • The ascending fit can be either linear or parabolic:

    • Linear fit: A simple straight line extending from the inflection point to the last ascending point.

    • Parabolic fit: A nonlinear curve extending from the inflection point to the last ascending point.

  • Uses posixct_to_decimal() and decimal_to_posixct() to convert between time formats.

Examples

if (FALSE) { # \dontrun{
  plot <- ggplot2::ggplot(profile_data, ggplot2::aes(x = datetime, y = melatonin)) +
      ggplot2::geom_point()
  dlmoFit <- list(inflection_point = list(x = 20.5, y = 3.2),
                  base_params = 0.1,
                  ascending_params = list(a = -0.03, b = 2.1, c = 0.5))
  plot_fit(plot, profile_data, dlmoFit)
} # }