SPOTVignetteNutshell

knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)
## install.packages("devtools")
## devtools::install_github("r-lib/devtools")
url <- "http://owos.gm.fh-koeln.de:8055/bartz/spot.git"
devtools::install_git(url = url)
library("SPOT")
packageVersion("SPOT")

Introduction

Sequential Parameter Optimization Examples: How to Call SPOT

Most simple example: Kriging + LHS + predicted mean optimization (not expected improvement)

res <- spot(,funSphere,c(-2,-3),c(1,2),control=list(funEvals=15))
res$xbest

With expected improvement

res <- spot(,funSphere,c(-2,-3),c(1,2),
    control=list(funEvals=15,modelControl=list(target="ei")))
res$xbest

With additional start point:

res <- spot(matrix(c(0.05,0.1),1,2),funSphere,c(-2,-3),c(1,2))
res$xbest

Larger budget:

res <- spot(,funSphere,c(-2,-3),c(1,2),
    control=list(funEvals=50))
res$xbest

Use local optimization instead of LHS

res <- spot(,funSphere,c(-2,-3),c(1,2),
   control=list(optimizer=optimLBFGSB))
 res$xbest

Random Forest instead of Kriging

res <- spot(,funSphere,c(-2,-3),c(1,2),
     control=list(model=buildRandomForest))
res$xbest

LM instead of Kriging

res <- spot(,funSphere,c(-2,-3),c(1,2),
     control=list(model=buildLM)) #lm as surrogate
res$xbest

Bayesian Optimization

res <- spot(,funSphere,c(-2,-3),c(1,2),
     control=list(model=buildBO)) #BO as surrogate
res$xbest

LM and local optimizer (which for this simple example is perfect)

res <- spot(,funSphere,c(-2,-3),c(1,2),
   control=list(model=buildLM, optimizer=optimLBFGSB))
res$xbest

Lasso and local optimizer NLOPTR

res <- spot(,funSphere,c(-2,-3),c(1,2), 
   control=list(model=buildLasso, optimizer = optimNLOPTR))
res$xbest

Kriging and local optimizer LBFGSB

res <- spot(,funSphere,c(-2,-3),c(1,2), 
   control=list(model=buildKriging, optimizer = optimLBFGSB))
res$xbest

Kriging and local optimizer NLOPTR

res <- spot(,funSphere,c(-2,-3),c(1,2), 
     control=list(model=buildKriging, optimizer = optimNLOPTR))
res$xbest

Or a different Kriging model:

res <- spot(,funSphere,c(-2,-3),c(1,2),
 control=list(model=buildKrigingDACE, optimizer=optimLBFGSB))
res$xbest

With noise: (this takes some time)

# noisy objective
res1 <- spot(,function(x)funSphere(x)+rnorm(nrow(x)),c(-2,-3),c(1,2),
        control=list(funEvals=40,noise=TRUE)) 
# noise with replicated evaluations
res2 <- spot(,function(x)funSphere(x)+rnorm(nrow(x)),c(-2,-3),c(1,2),
        control=list(funEvals=40,noise=TRUE,replicates=2,
        designControl=list(replicates=2))) 
# and with OCBA
res3 <- spot(,function(x)funSphere(x)+rnorm(nrow(x)),c(-2,-3),c(1,2),
        control=list(funEvals=40,noise=TRUE,replicates=2,OCBA=TRUE,OCBABudget=1,
        designControl=list(replicates=2))) 
# Check results with non-noisy function:
funSphere(res1$xbest)
funSphere(res2$xbest)
funSphere(res3$xbest)

Random number seed handling

The following is for demonstration only, to be used for random number seed handling in case of external noisy target functions.

res1a <- spot(,function(x,seed){set.seed(seed);funSphere(x)+rnorm(nrow(x))},
     c(-2,-3),c(1,2),control=list(funEvals=25,noise=TRUE,seedFun=1))
res1b <- spot(,function(x,seed){set.seed(seed);funSphere(x)+rnorm(nrow(x))},
     c(-2,-3),c(1,2),control=list(funEvals=25,noise=TRUE,seedFun=1))
res2 <- spot(,function(x,seed){set.seed(seed);funSphere(x)+rnorm(nrow(x))},
     c(-2,-3),c(1,2),control=list(funEvals=25,noise=TRUE,seedFun=2))
sprintf("Should be equal: %f = %f. Should be different:  %f", res1a$ybest, res1b$ybest, res2$ybest)

Handling factor variables

Note: factors should be coded as integer values, i.e., 1,2,...,n First, we create a test function with a factor variable:

braninFunctionFactor <- function (x) {
   y <- (x[2]  - 5.1/(4 * pi^2) * (x[1] ^2) + 5/pi * x[1]  - 6)^2 +
     10 * (1 - 1/(8 * pi)) * cos(x[1] ) + 10
   if(x[3]==1)
     y <- y +1
   else if(x[3]==2)
     y <- y -1
   return(y)
}

Vectorize the test function.

objFun <- function(x){apply(x,1,braninFunctionFactor)}

Run spot.

set.seed(1)
res <- spot(fun=objFun,lower=c(-5,0,1),upper=c(10,15,3),
            control=list(model=buildKriging,
                         types= c("numeric","numeric","factor"),
                         optimizer=optimLHD))
 res$xbest
 res$ybest

High dimensional problem

n <- 10
a <- rep(0,n)
b <- rep(1,n)

First, we consider the default spot setting with buildKriging().

tic <- proc.time()[3]
res0 <- spot(x=NULL, funSphere, lower = a, upper = b, 
             control=list(funEvals=30))
toc <- proc.time()[3]
sprintf("value: %f, time: %f",  res0$ybest, toc-tic)

Then, we use the buildGaussianProcess() model.

tic <- proc.time()[3]
res1 <-  spot(x=NULL, funSphere, lower = a, upper = b, 
             control=list(funEvals=30, 
                          model = buildGaussianProcess))
toc <- proc.time()[3]
sprintf("value: %f, time: %f",  res1$ybest, toc-tic)

Run SPOT with logging

## run spot without log
res <- spot(fun = funSphere,
            lower=c(0,0),
            upper=c(100,100)
)
## run spot with log
funSphereLog <- function(x){
  cbind(funSphere(x),x)
}
res2 <- spot(fun = funSphereLog,
            lower=c(0,0),
            upper=c(100,100)
)
res$logInfo
res2$logInfo

Hybrid optimization

res <- spot(fun = funSphere, lower = c(-5,-5),
                upper = c(5,5), 
                control = list(funEvals = 20,
                directOpt = optimNLOPTR,
                directOptControl = list(funEvals = 10)
                ))
str(res)

Handling constraints

library(babsim.hospital)
n <- 29 
reps <- 2
funEvals <- 3*n 
size <- 2*n
x0 <- matrix(as.numeric(babsim.hospital::getParaSet(5374)[1,-1]),1,)
bounds <- getBounds()
a <- bounds$lower
b <- bounds$upper
g <- function(x) {
      return(rbind(a[1] - x[1], x[1] - b[1], a[2] - x[2], x[2] - b[2], 
                   a[3] - x[3], x[3] - b[3], a[4] - x[4], x[4] - b[4], 
                   a[5] - x[5], x[5] - b[5], a[6] - x[6], x[6] - b[6], 
                   a[7] - x[7], x[7] - b[7], a[8] - x[8], x[8] - b[8], 
                   a[9] - x[9], x[9] - b[9], a[10] - x[10], x[10] - b[10],
                   a[11] - x[11], x[11] - b[11], a[12] - x[12],  x[12] - b[12],
                   a[13] - x[13], x[13] - b[13], a[14] - x[14],  x[14] - b[14],
                   a[15] - x[15], x[15] - b[15], a[16] - x[16],  x[16] - b[16],
                   a[17] - x[17], x[17] - b[17], a[18] - x[18],  x[18] - b[18],
                   a[19] - x[19], x[19] - b[19], a[20] - x[20],  x[20] - b[20],
                   a[21] - x[21], x[21] - b[21], a[22] - x[22],  x[22] - b[22],
                   a[23] - x[23], x[23] - b[23], a[24] - x[24],  x[24] - b[24],
                   a[25] - x[25], x[25] - b[25], a[26] - x[26],  x[26] - b[26],
                   a[27] - x[27], x[27] - b[27], x[15] + x[16] - 1, 
                   x[17] + x[18] + x[19] - 1, x[20] + x[21] - 1, x[23] + x[29] - 1)
      )
  }
res <- spot(
  x = x0,
  fun = funBaBSimHospital,
  lower = a,
  upper = b,
  verbosity = 0,
  control = list(
    funEvals = 2 * funEvals,
    noise = TRUE,
    designControl = list(# inequalityConstraint = g,
      size = size,
      retries = 1000),
    optimizer = optimNLOPTR,
    optimizerControl = list(
      opts = list(algorithm = "NLOPT_GN_ISRES"),
      eval_g_ineq = g
    ),
    model =  buildKriging,
    plots = FALSE,
    progress = TRUE,
    directOpt = optimNLOPTR,
    directOptControl = list(funEvals = 0),
    eval_g_ineq = g
  )
)
print(res)

GECCO Industrial Challenge 2021

A description of the challenge can be found here: GECCO Industrial Challenge 2021. In short the goal of the challenge is to find an optimal parameter configuration for the BabSim.Hospital simulator. This is a noisy and complex real-world problem.

Evaluation Using the Docker Container

In order to be able to execute the necessary code of the GECCO Industrial challenge 2021 you will need to have Docker installed in your machine. On your terminal console an evaluation of the BabSim.Hospital should looks like the command below. This command will automatically download the Docker image with the BabSim.Hospital code in it (may need sudo rights to download). Take care, the formatting of the symbols - and ’ can cause this command not to work on your terminal:

# docker run --rm mrebolle/r-geccoc:Track1 -c 'Rscript objfun.R "6,7,3,3,3,5,3,3,25,17,2,1,0.25,0.05,0.07,0.005,0.07,1e-04,0.08,0.25,0.08,0.5,1e-06,2,1e-06,1e-06,1,2,0.5"'

An optimization run with SPOT, using the Docker command call as objective function, can be directly implemented in R as follows:

library(SPOT)

evalFun <- function(candidateSolution){
    evalCommand <- paste0("docker run --rm mrebolle/r-geccoc:Track1 -c ", "'","Rscript objfun.R ")
    parsedCandidate <- paste(candidateSolution, sep=",", collapse = ",")
    return(as.numeric(system(paste0(evalCommand, '"', parsedCandidate, '"', "'"), intern = TRUE)))
}

#The BabSim.Hospital requires 29 parameters. Here we specify the upper and lower bounds
lower <- c(6,7,3,3,3,5,3,3,25,17,2,1,0.25,0.05,0.07,
           0.005,0.07,1e-04,0.08,0.25,0.08,0.5,1e-06,
           2,1e-06,1e-06,1,2,0.5)

upper<- c(14,13,7,9,7,9,5,7,35,25,5,7,2,0.15,0.11,0.02,
          0.13,0.002,0.12,0.35,0.12,0.9,0.01,4,1.1,0.0625,
          2,5,0.75)

wFun <- wrapFunction(evalFun)

n <- 29 
reps <- 2
funEvals <- 10*n 
size <- 2*n
x0<-matrix(lower,nrow = 1)

res <- spot(x = x0,
  fun = wFun,
  lower = lower,
  upper = upper,
  control = list(
    funEvals = 2 * funEvals,
    noise = TRUE,
    designControl = list(
      size = size,
      retries = 1000),
    optimizer = optimNLOPTR,
    optimizerControl = list(
      opts = list(algorithm = "NLOPT_GN_ISRES")
    ),
    model =  buildKriging,
    plots = TRUE,
    progress = TRUE,
    directOpt = optimNLOPTR,
    directOptControl = list(funEvals = 0)
  )
)

Evaluation Using the babsim.hospital R Package

The optimization of the BabSim.Hospital parameters can also be executed directly using the babsim.hospital package.

The babsim.hospital package can be installed by downloading the source from the Gitlab repository and building the package.

git clone http://owos.gm.fh-koeln.de:8055/bartz/babsim.hospital.git
library(SPOT)
library(babsim.hospital)

n <- 29 
reps <- 2
funEvals <- 3*n 
size <- 2*n
#Get suggested parameter values as initial point in the optimization run
x0 <- matrix(as.numeric(babsim.hospital::getParaSet(5374)[1,-1]),1,)
bounds <- getBounds()
a <- bounds$lower
b <- bounds$upper
g <- function(x) {
      return(rbind(a[1] - x[1], x[1] - b[1], a[2] - x[2], x[2] - b[2], 
                   a[3] - x[3], x[3] - b[3], a[4] - x[4], x[4] - b[4], 
                   a[5] - x[5], x[5] - b[5], a[6] - x[6], x[6] - b[6], 
                   a[7] - x[7], x[7] - b[7], a[8] - x[8], x[8] - b[8], 
                   a[9] - x[9], x[9] - b[9], a[10] - x[10], x[10] - b[10],
                   a[11] - x[11], x[11] - b[11], a[12] - x[12],  x[12] - b[12],
                   a[13] - x[13], x[13] - b[13], a[14] - x[14],  x[14] - b[14],
                   a[15] - x[15], x[15] - b[15], a[16] - x[16],  x[16] - b[16],
                   a[17] - x[17], x[17] - b[17], a[18] - x[18],  x[18] - b[18],
                   a[19] - x[19], x[19] - b[19], a[20] - x[20],  x[20] - b[20],
                   a[21] - x[21], x[21] - b[21], a[22] - x[22],  x[22] - b[22],
                   a[23] - x[23], x[23] - b[23], a[24] - x[24],  x[24] - b[24],
                   a[25] - x[25], x[25] - b[25], a[26] - x[26],  x[26] - b[26],
                   a[27] - x[27], x[27] - b[27], x[15] + x[16] - 1, 
                   x[17] + x[18] + x[19] - 1, x[20] + x[21] - 1, x[23] + x[29] - 1)
      )
  }

```r wrappedFunBab <- function(x){ print(SPOT::funBaBSimHospital(x, region = 5374, nCores = 1)) } res <- spot( x = x0, fun = wrappedFunBab, lower = a, upper = b, control = list( funEvals = 2 * funEvals, noise = TRUE, designControl = list( size = size, retries = 1000), optimizer = optimNLOPTR, optimizerControl = list( opts = list(algorithm = "NLOPT_GN_ISRES"), eval_g_ineq = g ), model = buildKriging, plots = FALSE, progress = TRUE, directOpt = optimNLOPTR, directOptControl = list(funEvals = 0), eval_g_ineq = g ) ) print(res) ````



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SPOT documentation built on Oct. 23, 2021, 1:06 a.m.