DirtStats - 9 months ago 43

R Question

I am trying to minimize a function that is conceptually similar to this:

`minim<-function(a,b,state){`

if(state=="TRUE"){out<-2*a^2+b}else{out<-2*a^3-b}

return(out) }

And I am calling GenSA like this (I wish to optimize on

`a`

`b`

`state`

`upper_limits<-c(10,10)`

lower_limits<-c(-10,-10)

params<-c(1,1)

minim<-function(a,b,state){

if(state=="TRUE"){out<-2*a^2+b}else{out<-2*a^3-b}

return(out)

}

minim_state_TRUE_fit<-GenSA(par=params,function(params) minim(params[1],params[2]),

lower=lower_limits, upper=upper_limits,

control=list(max.time=100),state="TRUE")

And the error I get is:

`Error in fn(par, ...) : unused argument (state = "TRUE")`

`GenSA`

`state="TRUE"`

`minim`

`GenSA`

Answer

You are optimizing the function `function(params) minim(params[1],params[2])`

. This function does not contain the argument `state`

. You can fix this like this:

```
minim <- function(a, b, state) {
if (state) {
out <- 2 * a^2 + b
} else {
out<-2 * a^3 - b
}
return(out)
}
fn = function(params, state) minim(params[1],params[2], state)
minim_state_TRUE_fit<-GenSA(par=params,fn = fn,
lower=lower_limits, upper=upper_limits,
control=list(max.time=100), state = TRUE)
```

Also note that I changed `state = "TRUE"`

to `state = TRUE`

. If you're using it for a logical test it's better to change it into a logical if possible.

Source (Stackoverflow)