R: Find the first local maxima of a numeric vector

first_peak {gcplyr}

R Documentation

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