# r - tbart package, allocations function - How can I force a solution without a list of sites?

I am attempting to solve a p-median problem for a given dataset. I can successfully produce a list of optimal candidate sites. However, I am interested in a secondary list of optimal candidate sites which do not include any of the sites selected in the original solution.

For example, if p = 5 and the list of optimal sites includes 1,2,3,4,5 how can create a new list without sites 1,2,3,4,5?

I am familiar with the force = option but when I use a phrase like force =! I receive an error. Also if I use force = !1, for example, the ! is ignored and 1 remains part of the solution.

Example: R Code:

solution.5 <- allocations(en.county, p=5)
unique(solution.5$$allocation) unique(solution.5$$allocdist)

col.index <- match(solution.5$$allocation,unique(solution.5$$allocation))
col.alloc <- brewer.pal(5,'Accent')[col.index]
plot(solution.5,col=col.alloc)
points(coordinates(solution.5[c(18, 49, 288, 245, 159),]),col=2)

solution.5.2 <- allocations(en.county, p=5, force = !c(18,49,288,245,159))
unique(solution.5.2\$allocation)