descendZero: Find start and end points of a peak

Description Usage Arguments Value Author(s) See Also Examples

Description

Decends down the sides of a data peak and finds either the points greater than or equal to the zero intercept, the intercept with a given value, or the bottom of the first valley on each side.

Usage

1
2
3
descendZero(y, istart = which.max(y))
descendValue(y, value, istart = which.max(y))
descendMin(y, istart = which.max(y))

Arguments

y

numeric vector with values

istart

starting point for descent

value

numeric value to descend to

Value

An integer vector of length 2 with the starting and ending indicies of the peak start and end points.

Author(s)

Colin A. Smith, csmith@scripps.edu

See Also

descendValue

Examples

1
2
3
4
5
6
normdist <- dnorm(seq(-4, 4, .1)) - .1
xcms:::descendZero(normdist)
normdist[xcms:::descendZero(normdist)]
xcms:::descendValue(normdist, .15)
normdist[xcms:::descendValue(normdist, .15)]
xcms:::descendMin(normdist)

benjiec/xcms documentation built on May 12, 2019, 11:57 a.m.