8.8.16. MDOCallback

MDOCallback

A base class for user to define MIP callback.

Properties

Where

The where code
Where

The where code

Methods

Abort

Send a stop request to the solver within a MIP callback function

AddBranch

Indicate a new branching by specifying a variable and a split point between the lower and upper bounds of this variable

AddCut

Add a new cutting plane to the MIP model

GetDoubleInfo

Retrieve a double value of solver process specified by what code

GetIntInfo

Retrieve an integer value of solver process specified by what code

GetNodeRel

Retrieve the solution value of the current relaxed problem

GetNodeRel

Retrieve solution values of the current relaxed problem

GetNodeRel

Retrieve solution values of the current relaxed problem

GetSolution

Retrieve the value of the best solution found so far

GetSolution

Retrieve values of the best solution found so far

GetSolution

Retrieve values of the best solution found so far

SetSolution

Provide a new feasible solution for a MIP model

SetSolution

Provide a new feasible solution for a MIP model

UseSolution

If you have already provided a solution using SetSolution, you can optionally call this method to immediately submit the solution to the MIP solver
void Abort()

Send a stop request to the solver within a MIP callback function. After the solver is terminated, an error code ABORT_CTRL_C will be returned from MDOModel.Optimize .

int AddBranch(MDOVar var, double value, int way)

Indicate a new branching by specifying a variable and a split point between the lower and upper bounds of this variable.

Parameters

  • MDOVar var – The variable.

  • double value – The split point. It should be between the lower and upper bounds of the variable.

  • int way –

    The branch to consider first. Valid options are:

    • <0: the down-way branch is considered first.

    • >0: the up-way branch is considered first.

Returns

A submission status:

  • 0: Successful submission.

  • 1: Submission is valid but incorrect (infeasible, etc).

  • 2: Submission is correct but not being accepted.

int AddCut(MDOLinExpr lhs, char sense, double rhs)

Add a new cutting plane to the MIP model.

Parameters

  • MDOLinExpr lhs – Left-hand-side value for new cutting plane.

  • char sense – Sense for new cutting plane.

  • double rhs – Right-hand-side value for new cutting plane.

Returns

A submission status:

  • 0: Successful submission.

  • 1: Submission is valid but incorrect (infeasible, etc)

  • 2: Submission is correct but not being accepted.

double GetDoubleInfo(int what)

Retrieve a double value of solver process specified by what code.

Parameters

int what – The data code to be retrieved.

Returns

The value to be retrieved.

int GetIntInfo(what)

Retrieve an integer value of solver process specified by what code

Parameters

what – The data code to be retrieved.

Returns

The value to be retrieved.

double GetNodeRel(MDOVar v)

Retrieve the solution value of the current relaxed problem.

Parameters

MDOVar v – The variable from which to retrieve the solution value.

Returns

The solution value of the specified variable.

double[] GetNodeRel(MDOVar[] v)

Retrieve solution values of the current relaxed problem.

Parameters

MDOVar[] v – The variables from which to retrieve solution values.

Returns

The solution values of the specified variables.

double[,] GetNodeRel(MDOVar[,] v)

Retrieve solution values of the current relaxed problem.

Parameters

MDOVar[,] v – The variables for which to retrieve solution values.

Returns

The solution values of the specified variables.

double GetSolution(MDOVar v)

Retrieve the value of the best solution found so far.

Parameters

MDOVar v – The variable to retrieve the solution value for.

Returns

The solution value of the specified variable.

double[] GetSolution(MDOVar[] v)

Retrieve values of the best solution found so far.

Parameters

MDOVar[] v – The variables to retrieve solution values from.

Returns

The solution values of the specified variables.

double[,] GetSolution(MDOVar[,] v)

Retrieve values of the best solution found so far.

Parameters

MDOVar[,] v – The variables to retrieve solution values from.

Returns

The solution values of the specified variables.

void SetSolution(MDOVar var, double val)

Provide a new feasible solution for a MIP model.

Parameters

  • MDOVar var – Indicate the variable for which the solution is provided.

  • double val – The solution value to be provided.

void SetSolution(MDOVar[] var, double[] val)

Provide a new feasible solution for a MIP model.

Parameters

  • MDOVar[] var – An array of Var objects to indicate the variables for which the solution is provided.

  • double[] val – An array of double values to indicate the new feasible solution to be provided.

MDO.Result<double> UseSolution()

If you have already provided a solution using SetSolution , you can optionally call this method to immediately submit the solution to the MIP solver.

Returns

The submission result. It consists of two fields: code and objective value. Code can be:

  • 0: Successful submission.

  • 1: Submission is valid but incorrect (infeasible, etc).

  • 2: Submission is correct but not accepted.