public override bool SetObjFn(object solver, double[] row)
{
GRBModel grbSolver = solver as GRBModel;
if (grbSolver == null)
{
return(false);
}
GRBLinExpr obj = new GRBLinExpr();
obj.AddTerms(row, grbSolver.GetVars());
grbSolver.SetObjective(obj, GRB.MINIMIZE);
return(true);
}
public override bool AddConstraint(object solver, double[] row, SolverAdapterConstraintTypes constr_type, double rh)
{
GRBModel grbSolver = solver as GRBModel;
if (grbSolver == null)
{
return(false);
}
GRBLinExpr expr = 0.0;
ind++;
expr.AddTerms(row, grbSolver.GetVars());
grbSolver.AddConstr(expr, (char)GetAdaptedConstraintType(constr_type), rh, "R" + ind);
return(true);
}
private void AddOnlyOnePositionPerGroupConstraint(GRBModel model, GRBVar[,,] seated)
{
var coeff = Utils.GenerateArrayOfOnes(Cinema.Width * Cinema.Height);
for (int g = 0; g < Cinema.TotalNumberOfGroups; g++)
{
var result = new GRBVar[Cinema.Width * Cinema.Height];
var resultCount = 0;
for (int x = 0; x < Cinema.Width; x++)
{
for (int y = 0; y < Cinema.Height; y++)
{
result[resultCount] = seated[x, y, g];
resultCount++;
}
}
var expr = new GRBLinExpr();
expr.AddTerms(coeff, result);
model.AddConstr(expr, GRB.LESS_EQUAL, 1, "Only One Position Per Group Constraint");
}
}
public static LinearExpression Sum(IEnumerable <Variable> variables)
{
LinearModel solver = variables.First().Solver;
switch (solver.Type)
{
case SolverType.CPLEX: { return(new LinearExpression()
{
Solver = solver, Expression = solver.CplexModel.Sum(variables.Select(e => e.Expression as INumExpr).ToArray())
}); }
case SolverType.Gurobi:
{
GRBLinExpr expr = new GRBLinExpr();
expr.AddTerms(Enumerable.Repeat(1.0, variables.Count()).ToArray(), variables.Select(e => e.Expression as GRBVar).ToArray());
return(new LinearExpression()
{
Solver = solver, Expression = expr
});
}
default: throw new ArgumentException("Unknown solver type: " + solver.Type);
}
}
