Only length-1 columns are recycled

[swaheera]

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

[nirgrahamuk]

You changed what FUN you are using... was that intentional?