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pritchard
2008 Apr 08
1
question about nlminb
Dear All,
I wanted to post some more details about the query I sent to s-news last
week.
I have a vector with a constraint. The constraint is that the sum of the
vector must add up to 1 - but not necessarily positive, i.e.
x[n] <- 1 -(x[1] + ...+x[n-1])
I perform the optimisation on the vector x such that
x <- c(x, 1-sum(x))
In other words,
fn <- function(x){
x <- c(x, 1 -
2008 May 15
1
logistic transformation using nlminb
Dear all,
I want to find the optimal values of a vector, x (with 6 elements)
say, satisfying the following conditions:
1. for all x>=0
2. sum(x)=1
3. x[5]<=0.5 and x[6]<=0.5
For the minimisation I'm using nlminb and to satisfy the first 2
conditions the logistic transformation is used with box constraints
for condition 3. However, I don't seem to be able to get the values x