Procedure GMP::Row::SetPoolType(GMP, row, value, mode)


The procedure GMP::Row::SetPoolType can be used to indicate that a row in a generated mathematical program should become part of a pool of lazy constraints or a pool of (user) cuts. The solvers CPLEX, Gurobi and ODH-CPLEX can make use of this information.

     GMP,            ! (input) a generated mathematical program
     row,            ! (input) a scalar reference or row number
     value,          ! (input) a scalar reference
     [mode]          ! (optional) a scalar reference



An element in AllGeneratedMathematicalPrograms.


A scalar reference to an existing row in the matrix or an element in the set Integers in the range \(\{ 0 .. m-1 \}\) where \(m\) is the number of rows in the matrix.


A scalar reference to a value. The value 1 specifies that the row should be added to the lazy constraint pool and 2 specifies that the row should be added to the cut pool. The value 0 indicates that the row will be removed from either pools (and treated as a normal row).


A scalar reference to a value representing the lazy constraint mode. The value should be a number between 0 and 3. The default is 0. The meaning of these values is explained below.

Return Value

The procedure returns 1 on success, and 0 otherwise.


  • The lazy constraint pool is supported by CPLEX, Gurobi and ODH-CPLEX while the cut pool is supported by CPLEX and ODH-CPLEX.

  • Use GMP::Row::SetPoolTypeMulti if the pool type of many rows corresponding to some constraint have to be set, because that will be more efficient.

  • The mode is only used if the row should be added to the lazy constraint pool (i.e., if value equals 1) and if Gurobi is used. The mode should be a value between 0 and 3, and these values have the following meaning:

    • 0: The mode is specified by the Gurobi option Lazy constraint mode.

    • 1: The lazy constraint can be used to cut off a feasible solution, but it won’t necessarily be pulled in if another lazy constraint also cuts off the solution.

    • 2: Lazy constraints that are violated by a feasible solution will be pulled into the model.

    • 3: Lazy constraints that cut off the relaxation solution at the root node are also pulled into the model.

See also

The procedure GMP::Row::SetPoolTypeMulti. The lazy constraint pool and the cut pool are explained in full detail in Indicator Constraints, Lazy Constraints and Cut Pools of the Language Reference.