nnet in R

# install.packages("nnet")
# install.packages("faraway")
library(faraway)
library(nnet)
rm(list=ls())
data(ozone)
names(ozone)
nnmdl = nnet(O3 ~ temp + ibh + ibt, ozone, size=2, linout=TRUE)
summary(nnmdl)
x.test = expand.grid(temp=1, ibh=0, ibt=0)
predict(nnmdl, new=x.test)
?scale
sx = scale(ozone)
##############################
bestrss = 10000
for (i in 1:1000){
  nnmdl = nnet(O3 ~ temp + ibh + ibt, sx, size=2, linout=TRUE, trace=FALSE)
  cat(nnmdl$value, "\n")
  if (nnmdl$value < bestrss){
    bestnn = nnmdl
    bestrss = nnmdl$value
  }
}
bestnn$value
summary(bestnn)
R.sqr = 1 - bestnn$value/sum((sx[,1] - mean(sx[,1]))^2)
ozmeans = attributes(sx)$'scaled:center'
ozscales = attributes(sx)$'scaled:scale'
xx = expand.grid(temp=seq(-3,3,0.1), ibh=0, ibt=0)
plot(xx$temp*ozscales['temp'] + ozmeans['temp'],
     predict(bestnn, new=xx)*ozscales['O3'] + ozmeans['O3'],
     xlab='Temp', ylab='O3')
xx = expand.grid(temp=0, ibh=seq(-3,3,0.1), ibt=0)
plot(xx$ibh*ozscales['ibh'] + ozmeans['ibh'],
     predict(bestnn, new=xx)*ozscales['O3'] + ozmeans['O3'],
     xlab='IBH', ylab='O3')
xx = expand.grid(temp=0, ibh=0, ibt=seq(-3,3,0.1))
plot(xx$ibt*ozscales['ibt'] + ozmeans['ibt'],
     predict(bestnn, new=xx)*ozscales['O3'] + ozmeans['O3'],
     xlab='IBT', ylab='O3')

##############################
bestrss = 10000
for (i in 1:1000){
  nnmdl = nnet(O3 ~ temp + ibh + ibt, sx, size=2, linout=TRUE, decay=0.001, trace=FALSE)
  cat(nnmdl$value, "\n")
  if (nnmdl$value < bestrss){
    bestnn = nnmdl
    bestrss = nnmdl$value
  }
}
bestnn$value
summary(bestnn)
R.sqr = 1 - bestnn$value/sum((sx[,1] - mean(sx[,1]))^2)
ozmeans = attributes(sx)$'scaled:center'
ozscales = attributes(sx)$'scaled:scale'
xx = expand.grid(temp=seq(-3,3,0.1), ibh=0, ibt=0)
plot(xx$temp*ozscales['temp'] + ozmeans['temp'],
     predict(bestnn, new=xx)*ozscales['O3'] + ozmeans['O3'],
     xlab='Temp', ylab='O3')
xx = expand.grid(temp=0, ibh=seq(-3,3,0.1), ibt=0)
plot(xx$ibh*ozscales['ibh'] + ozmeans['ibh'],
     predict(bestnn, new=xx)*ozscales['O3'] + ozmeans['O3'],
     xlab='IBH', ylab='O3')
xx = expand.grid(temp=0, ibh=0, ibt=seq(-3,3,0.1))
plot(xx$ibt*ozscales['ibt'] + ozmeans['ibt'],
     predict(bestnn, new=xx)*ozscales['O3'] + ozmeans['O3'],
     xlab='IBT', ylab='O3')