Identify peak or trough on curve
Given vectors x and y, returns their values at the peak or
trough of the smooth (e.g. cubic spline) curve y ~ x.
getPeakTrough(x, y = NULL, peak = TRUE, takeoff = FALSE) getPeak(x, y = NULL, peak = TRUE, takeoff = FALSE) getTrough(x, y = NULL, peak = FALSE, takeoff = FALSE) getTakeoff(x, y = NULL, peak = FALSE, takeoff = TRUE)
x |
vector. |
y |
vector. |
peak |
logical determining whether peak or trough is returned. |
takeoff |
logical determining whether, if |
Optionally the trough can be specified as takeoff, which is defined for a growth velocity curve as the lowest velocity before the pubertal peak, and if there is no peak then there is by definition no takeoff.
A length-2 vector containing the values of x and y at
the peak or trough. If none are identified NA's are returned.
Tim Cole tim.cole@ucl.ac.uk
## create mean height velocity curve data(heights) m1 <- sitar(age, height, id, heights, 4) ## plot velocity curve plot(m1, 'v') ## mark peak, trough and takeoff xy <- plot_v(m1) points(t(getPeak(xy)), pch=17) points(t(getTrough(xy)), pch=25, col=2, bg=2) points(t(getTakeoff(xy)), pch=25, col=3, bg=3)
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