Quantile from given function R Code Error?

Question

I am using R to get quantile from a given function which is giving the error below which I don't quite understand what it means. Although the error message seems self explanatory this R Noob can't work it out. Any help appreciated.

Error:

Error in cum(x) - p : non-numeric argument to binary operator

Here is the code:

library(nleqslv)

dens<-function(x)
{
  (dbeta(x, shape1 = 1, shape2 = 5) + dbeta(x, shape1 = 3, shape2 = 5) + dbeta(x, shape1 = 10, 
  shape2 = 5))*1/3
}

cum<-function(x)
{
    integrate(dens,-Inf,x)
}

quant<-function(p)
{
    nleqslv(0, function(x){cum(x)-p})
}


print(quant(0.50))

Ben Bolker · Accepted Answer · 2021-07-22 13:30:00Z

1

integrate() doesn't return a single number, but a list:

names(cum(1))
## [1] "value"        "abs.error"    "subdivisions" "message"      "call"

All you need is the $value element:

quant <- function(p) {
    nleqslv(0, function(x) { cum(x)$value-p })
}

(Since you're adding up dbeta() values maybe the lower limit of your integral can be 0 instead of -Inf ?)

answered Jul 22, 2021 at 13:30

Ben Bolker

230k26 gold badges405 silver badges497 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Justin Bloesch Over a year ago

Ben thank you! Your solution works. I have spent days tyring to problem solve this. The world is a much better place with you in it.

Ben Bolker Over a year ago

if it solves your problem you are encouraged to click the check-mark to accept it ...

Collectives™ on Stack Overflow

Quantile from given function R Code Error?

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related