public override double GetValue(IVariable variable)
{
var row = GetRowArray();
LpSolvePointer.get_variables(row);
return(row[VariableId(variable) - 1]);
}
private void AddRowConstraint(double[] row, lpsolve_constr_types type = lpsolve_constr_types.EQ, double val = 0)
{
Rows++;
if (!LpSolvePointer.add_constraint(row, type, val))
{
throw new InvalidOperationException();
}
}
protected override IVariable InternalCreate(string name, Domain domain)
{
var variable = AddNewVariable();
variable.Domain = domain;
variable.Name = name;
if (!LpSolvePointer.set_col_name(variable.Id, name))
{
throw new InvalidOperationException();
}
if (variable.IsBinary())
{
if (!LpSolvePointer.set_binary(variable.Id, true))
{
throw new InvalidOperationException();
}
return(variable);
}
if (variable.IsInteger())
{
if (!LpSolvePointer.set_int(variable.Id, true))
{
throw new InvalidOperationException();
}
}
switch (domain)
{
case Domain.AnyInteger:
case Domain.AnyReal:
case Domain.AnyConstantInteger:
case Domain.AnyConstantReal:
if (!LpSolvePointer.set_unbounded(variable.Id))
{
throw new InvalidOperationException();
}
break;
case Domain.PositiveOrZeroInteger:
case Domain.PositiveOrZeroReal:
case Domain.PositiveOrZeroConstantInteger:
case Domain.PositiveOrZeroConstantReal:
if (!LpSolvePointer.set_lowbo(variable.Id, 0))
{
throw new InvalidOperationException();
}
break;
case Domain.BinaryInteger:
case Domain.BinaryConstantInteger:
break;
default:
throw new ArgumentOutOfRangeException(nameof(domain), domain, null);
}
return(variable);
}
protected override void InternalLoadModelFromFile(string modelPath)
{
LpSolvePointer.delete_lp();
LpSolve.Init();
var IMPORTANT = 3;
var MPS_FREE = 8;
LpSolvePointer = Path.GetExtension(modelPath)?.Trim('.').ToLower() == "lp" ? LpSolve.read_LP(modelPath, IMPORTANT, null) : LpSolve.read_MPS(modelPath, IMPORTANT | MPS_FREE);
}
public override void SaveModelToFile(string modelPath)
{
if (Path.GetExtension(modelPath)?.Trim('.').ToLower() == "lp")
{
LpSolvePointer.write_lp(modelPath);
}
else
{
LpSolvePointer.write_freemps(modelPath);
}
}
protected override void InternalAddGoal(string name, IVariable operation)
{
var goal = GetRowArray();
goal[VariableId(operation)] = 1;
LpSolvePointer.set_maxim();
if (!LpSolvePointer.set_obj_fn(goal))
{
throw new InvalidOperationException();
}
}
private LpSolveVariable AddNewVariable()
{
Columns++;
var variable = new LpSolveVariable
{
Id = Columns,
MilpManager = this
};
if (!LpSolvePointer.add_column(GetColumnArray()))
{
throw new InvalidOperationException();
}
return(variable);
}
public override SolutionStatus GetStatus()
{
var status = LpSolvePointer.get_status();
if (status == (int)lpsolve_return.OPTIMAL)
{
return(SolutionStatus.Optimal);
}
if (status == (int)lpsolve_return.UNBOUNDED)
{
return(SolutionStatus.Unbounded);
}
if (status == (int)lpsolve_return.INFEASIBLE)
{
return(SolutionStatus.Infeasible);
}
return(SolutionStatus.Unknown);
}
public override void Solve()
{
LpSolvePointer.solve();
}