R: Local minimum and maximum of a real-valued continuous...

local_min_max {sephora}

R Documentation

Local minimum and maximum of a real-valued continuous function over an open interval

Gets local minimum and maximum of a given function expression on an interval using basic calculus criteria

local_min_max(f, f1der, f2der, what = c("min", "max"), x0, D)

`f`	function expression
`f1der`	function expression of first derivative of `f`
`f2der`	function expression of second derivative of `f`
`what`	character. What to look for? A local `min` or a `max`?
`x0`	numeric givin global minimum or maximum of `f` over the the interval `D`.
`D`	numeric vector specifying the interval over which `f` is optimized

This function looks for critical values over the interval [D[1],x0-1) \cup (x0+1, D[length(D)]].

A list containing:

x_opt numeric giving the critical point where the local min or max is achieved. When local min or max cannot be determined, this function returns NA.
locals numeric vector giving all critical points satisfying second derivative criteria.
crtPts a list with 2 entries:
- x_d1 numeric vector with local critical points over [D[1],x-1)
- x_d2 numeric vector with local critical points over (x0+1,D[length(D)]]
type character, what was found? A min or a max?