Get variable values from a solution
Arguments
- solution
the solution object
- expr
a variable expression. You can partially bind indexes.
- type
optional, either "primal" or "dual". The default value is "primal". If "primal" it returns the primal solution, otherwise the column duals. Especially the dual values depend on the solver. If no duals are calculated, the function stops with an error message.
Value
a data.frame. One row for each variable instance
and a column for each index.
Unless it is a single variable, then it returns a single number.
Please note that in case of a data.frame there is no
guarantee about the ordering of the rows. This could change
in future ompr versions. Please always use the indexes
to retrieve the correct values.
Examples
if (FALSE) {
library(magrittr)
result <- MIPModel() %>%
add_variable(x[i], i = 1:5) %>%
add_variable(y[i, j], i = 1:5, j = 1:5) %>%
add_constraint(x[i] >= 1, i = 1:5) %>%
set_bounds(x[i], lb = 3, i = 1:3) %>%
set_objective(0) %>%
solve_model(with_ROI("glpk"))
solution <- get_solution(result, x[i])
solution2 <- get_solution(result, y[i, 1])
solution3 <- get_solution(result, y[i, j])
duals <- get_solution(result, x[i], type = "dual")
}