useSolver {eatATA}

Use a solver for a list of constraints.

Description

Use a mathematical programming solver to solve a list for constrains.

Usage

useSolver(
  allConstraints,
  solver = c("GLPK", "lpSolve", "Gurobi", "Symphony"),
  timeLimit = Inf,
  formNames = NULL,
  ...
)

Arguments

allConstraints

List of constraints.

solver

A character string indicating the solver to use.

timeLimit

The maximal runtime in seconds.

formNames

A character vector with names to give to the forms.

...

Additional arguments for the solver.

Details

Wrapper around the functions of different solvers (gurobi::gurobi(), lpSolve::lp(), ... for a list of constraints set up via eatATA. Rglpk is used per default.

Additional arguments can be passed through ... and vary from solver to solver (see their respective help pages, lp or Rglpk_solve_LP); for example time limits can not be set for lpSolve.

Value

A list with the following elements:

solution_found

Was a solution found?

solution

Numeric vector containing the found solution.

solution_status

Was the solution optimal?

Examples

nForms <- 2
nItems <- 4

# create constraits
target <- minimaxObjective(nForms = nForms, c(1, 0.5, 1.5, 2),
                       targetValue = 2, itemIDs = 1:nItems)
noItemOverlap <- itemUsageConstraint(nForms, operator = "=", itemIDs = 1:nItems)
testLength <- itemsPerFormConstraint(nForms = nForms,
                           operator = "<=", targetValue = 2, itemIDs = 1:nItems)

# use a solver
result <- useSolver(list(target, noItemOverlap, testLength),
  itemIDs = paste0("Item_", 1:4),
  solver = "GLPK")