How to get lpsolveAPI to return all possible solutions?

Question

I am using \'lpSolveAPI\' to solve multiple binary linear programming problems in R. How do I get it too return ALL the variable combinations for a maximizing problem.

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Answer 1

Discovered that this was dupe with: Get multiple solutions for 0/1-Knapsack MILP with lpSolveAPI

Here is the code I used to solve this adapted from the link:

# find first solution
status<-solve(lpmodel) 
sols<-list() # create list for more solutions
obj0<-get.objective(lpmodel) # Find values of best solution (in this case four)
counter <- 0 #construct a counter so you wont get more than 100 solutions

# find more solutions
while(counter < 100) {
  sol <- get.variables(lpmodel)
  sols <- rbind(sols,sol)
  add.constraint(lpmodel,2*sol-1,"<=", sum(sol)-1) 
  rc<-solve(lpmodel)
  if (status!=0) break;
  if (get.objective(lpmodel)<obj0) break;
  counter <- counter + 1
}
sols

This finds all six solutions:

> sols
    [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8]
sol 1    0    0    1    0    1    0    1   
sol 1    0    0    1    0    1    1    0   
sol 0    1    0    1    0    1    0    1   
sol 0    1    0    1    0    1    1    0   
sol 0    1    0    0    1    1    1    0   
sol 0    1    0    0    1    1    0    1   

Sorry for the dupe everyone. If anyone knows another way built into the 'lpSolveAPI' package I'd still love to know.