first_peak {gcplyr}

Find the first local maxima of a numeric vector

Description

This function has been deprecated in favor of the identical new function first_maxima

Usage

first_peak(
  y,
  x = NULL,
  window_width = NULL,
  window_width_n = NULL,
  window_height = NULL,
  return = "index",
  return_endpoints = TRUE,
  ...
)

Arguments

y

Numeric vector of y values in which to identify local extrema

x

Optional numeric vector of corresponding x values

window_width

Width of the window (in units of x) used to search for local extrema. A narrower width will be more sensitive to narrow local maxima/minima, while a wider width will be less sensitive to local maxima/minima.

window_width_n

The maximum number of data points a single extrema-search step is allowed to take. For example, when maxima-finding, the function will not pass a valley consisting of more than window_width_n data points.

A smaller window_width_n will be more sensitive to narrow local maxima/minima, while a larger window_width_n will be less sensitive to narrow local maxima/minima.

If not provided, defaults to ~0.2*length(y)

window_height

The maximum change in y a single extrema-search step is allowed to take. For example, when maxima-finding, the function will not pass a valley deeper than window_height.

A smaller window_height will be more sensitive to shallow local maxima/minima, while a larger window_height will be less sensitive to shallow maxima/minima.

return

One of c("index", "x", "y"), determining whether the function will return the index, x value, or y value associated with the first maxima in y values

return_endpoints

Should the first or last value in y be allowed to be returned?

...

Other parameters to pass to find_local_extrema

Details

This function takes a vector of y values and returns the index (by default) of the first local maxima. It serves as a shortcut for find_local_extrema(return_maxima = TRUE, return_minima = FALSE)[1]

If none of window_width, window_width_n, or window_height are provided, default value of window_width_n will be used.

Value

If return = "index", a vector of indices corresponding to local extrema in the data

If return = "x", a vector of x values corresponding to local extrema in the data

If return = "y", a vector of y values corresponding to local extrema in the data

See Also

[first_maxima()]