# R/Chwirut2_opt.R In NISTopt: Nonlinear least squares examples from NIST in form of functions for optim() and optimx()

#### Documented in Chwirut2.fChwirut2.gChwirut2.hChwirut2.jacChwirut2.resChwirut2.setupChwirut2.test

```# Optimization test function Chwirut2
# Chwirut2 from NISTnls
# ??ref...

Chwirut2.f <- function(x) {
res<-Chwirut2.res(x)
f<-sum(res*res)
}

Chwirut2.res <- function(b) {
xx<-Chwirut2\$x # note case !!
yy<-Chwirut2\$y
res <- rep(NA, length(xx))
b1<-b[1]
b2<-b[2]
b3<-b[3]
res<-exp(-b1*xx)/(b2+b3*xx) - yy
return(res)
}

# Chwirut2 - Jacobian
Chwirut2.jac <- function(b) {
## stop("not defined")
xx<-Chwirut2\$x
yy<-Chwirut2\$y
n<-length(b)
m<-length(xx)
b1<-b[1]
b2<-b[2]
b3<-b[3]
J<-matrix(0,m,n) # define the size of the Jacobian
expr3 <- exp(-b1 * xx)
expr5 <- b2 + b3 * xx
expr7 <- expr3 * xx
expr10 <- expr5*expr5
value <- expr3/expr5
J[,1] <- -(expr7/expr5)
J[,2] <- -(expr3/expr10)
J[,3] <- -(expr7/expr10)
return(J)
}

Chwirut2.h <- function(x) {
stop("not defined")
JJ<-Chwirut2.jac(x)
H <- t(JJ) %*% JJ
res<-Chwirut2.res(x)
stop("not defined")

}

Chwirut2.g<-function(x) {
#   stop("not defined")
JJ<-Chwirut2.jac(x)
res<-Chwirut2.res(x)
gg<-as.vector(2.0*t(JJ) %*% res)
return(gg)
}

Chwirut2.setup<-function() {
#   library(NISTnls) # get parent collection
data(Chwirut2) # and load up the data into x and y
# ?? May want to change structure of starts??
start1 = c(0.1, 0.01, 0.02)
start2 = c(0.15, 0.008, 0.01)
out<-list(start1=start1, start2=start2)
return(out)

}

Chwirut2.test<-function() {
}
```

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NISTopt documentation built on July 25, 2017, 3:01 p.m.