I am working with R. I am trying to follow the example from this page (Function Maximization) on optimization - I tried to make a new example for a function with "multiple inputs".

For example:

```
#load necessary library
library(ParBayesianOptimization)
#define function to be optimized
bayesian_function <- function(x1, x2, x3, x4) {
var_1 <- sin(x1 + x2)
var_2 <- cos(x1 - x2)
var_3 <- x1 + x4
var_4 <- x3 + x4 -7
goal = sum(var_1 + var_2 + var_3 + var_4)
return(goal)
}
}
FUNwrapper <- function(x1,x2,x3,x4) list(
"Score"=bayesian_function(x1=x1,
x2=x2,
x3=x3,
x4=x4)
)
#specify bounds
bounds <- list(x1 =c(20,40), x2 = c(30,45), x3 = c(10,20), x4 = c(10,50))
#run optimization algorithm
optObj <- bayesOpt(
FUN = FUNwrapper
, bounds = bounds
, initPoints = 10
, acq = "ei"
, iters.n = 2
, gsPoints = 25
)
```

When I look at the output for this example, it is indicated that the optimization algorithm did not converge:

```
Running initial scoring function 10 times in 1 thread(s)... 2.71 seconds
Starting Epoch 3
1) Fitting Gaussian Process...
2) Running local optimum search...
- Convergence Not Found. Trying again with tighter parameters... 0.5 seconds
3) Running FUN 1 times in 1 thread(s)... 0.28 seconds
```

Therefore, I tried to increase the number of iterations so that the algorithm might be able to find a better point:

```
#increase the number of iterations
optObj <- bayesOpt(
FUN = bayesian_function
, bounds = bounds
, initPoints = 1000
, acq = "ei"
, iters.n = 10
, gsPoints = 25
)
```

But this produces the following error:

```
Running initial scoring function 1000 times in 1 thread(s)... 359 seconds
Error in rbindlist(scoreSummary) :
Column 2 of item 1 is length 6 inconsistent with column 1 which is length 100. Only length-1 columns are recycled.
```

Does anyone know why this error is being produced? Is it because the function has been iterated too many times?

Thanks