Computes the area under the curve (AUC) or the area under the moment curve (AUMC)
using a hybrid trapezoidal rule. The method uses linear interpolation for increasing
or constant concentration segments, and logarithmic interpolation for decreasing segments.
Usage
trapezoidal_linear_up_log_down(x, y, moment = FALSE)
Arguments
- x
A numeric vector representing the time points.
- y
A numeric vector representing the corresponding concentration values at each time point.
- moment
Logical. If TRUE, computes AUMC by integrating t * C(t) instead of C(t).
Value
A numeric value representing the estimated AUC or AUMC using the linear-up/log-down trapezoidal method.
Details
If moment = TRUE, the function calculates the area under the moment curve (AUMC),
i.e., it integrates t * C(t) over time instead of just C(t).
Examples
x <- c(0, 0.5, 1, 2, 4, 6, 8)
y <- c(0, 2, 8, 5, 3, 2, 1)
trapezoidal_linear_up_log_down(x, y) # AUC
#> [1] 25.03139
trapezoidal_linear_up_log_down(x, y, moment = TRUE) # AUMC
#> [1] 78.85055