mathematics purrr package map_dbl unroot

[hello99999]

hello, I am struggling to find a code which has to combine map_dbl along with uniroot to compute the root between the -3pi/4and3pi/4of each of the three functions inlist_fun which are :

linear = function(x) x
quadratic = function(x) (x - pi/2)^2 - pi/2
sinusoidal = function(x) sin(x)

finally, I should assign this result to a vector root_values having the same names
as list_fun.

What I have tried so far :

interval <- c(-3pi/4, 3pi/4)

linear <- uniroot(function(x) x, - x, interval)
quadratic <- uniroot(function(x) (x - pi/2)^2 - pi/2- x, interval)
sinusoidal <- uniroot(function(x) sin(x)- x, interval)
a <- map_dbl(1, list_fun)
root_values <- c(linear=linear$value, quadratic=quadratic$value, sinusoidal=sinusoidal$value)

[nirgrahamuk]

Hi, welcome!

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However, perhaps you do have some foundations. Therefore , perhaps you know( or can find reading material) on how to use the uniroot function you have your eye on. At least to where you can use it manually on one function. Then we can discuss such things as generalising and iterating from a specific case

[hello99999]

What I tried so far with this question :

interval <- c(-3*pi/4, 3*pi/4)

linear <- uniroot(function(x) x, - x, interval)
quadratic <- uniroot(function(x) (x - pi/2)^2 - pi/2- x, interval)
sinusoidal <- uniroot(function(x) sin(x)- x, interval)
a <- map_dbl(1, list_fun)
root_values <- c(linear=linear$value, quadratic=quadratic$value, sinusoidal=sinusoidal$value)

[hello99999]

hello, I am struggling to find a code which has to combine map_dbl along with uniroot to compute the root between the -3 * pi/4 and 3 * pi/4 of each of the three functions in list_fun which are :

linear = function(x) x
quadratic = function(x) (x - pi/2)^2 - pi/2
sinusoidal = function(x) sin(x)

finally, I should assign this result to a vector root_values having the same names
as list_fun .

What I have tried so far :

interval <- c(-3 *pi/4, 3* pi/4)

linear <- uniroot(function(x) x, - x, interval)
quadratic <- uniroot(function(x) (x - pi/2)^2 - pi/2- x, interval)
sinusoidal <- uniroot(function(x) sin(x)- x, interval)
a <- map_dbl(1, list_fun)
root_values <- c(linear=linear$value, quadratic=quadratic$value, sinusoidal=sinusoidal$value)

[nirgrahamuk]

library(tidyverse)
linear <- function(x) x
quadratic <- function(x) (x - pi/2)^2 - pi/2
sinusoidal <- function(x) sin(x)
(list_fun <- c(linear,quadratic,sinusoidal) %>% 
    purrr::set_names(c("linear","quadratic","sinusoidal")) %>%
    purrr::map(~.))


interval <- c(-3 *pi/4, 3* pi/4)

uniroot(linear,interval)$root
uniroot(quadratic,interval)$root
uniroot(sinusoidal,interval)$root

map_dbl(list_fun,
        ~uniroot(.,interval)$root)