8.7. Attributes during modeling and solving

Attributes allow you to access and modify the model by using APIs and obtain the status of the optimization solution. Attributes are classified as follows:

• Model attributes: These attributes use scalar values whereas variable and linear constraint attributes contain an entry of each variable or constraint in the model. You can use the methods provided by these APIs to query the attribute value of a single constraint or variable, or query the attribute values of a constraint or variable array. Generally, array-based query is more efficient. For more information about examples, see the examples in the API document.

• Solution attributes: Solution attributes are similar to model attributes but specific to the optimization solution.

• Simplex method attributes: These attributes use scalar values.

• Interior point method (IPM) attributes: These attributes use scalar values.

• 8.7.1. Model attributes
  • 8.7.1.1. “ProbName”
  • 8.7.1.2. “MinSense”
  • 8.7.1.3. “ObjConst”
  • 8.7.1.4. “NumVars”
  • 8.7.1.5. “NumConss”
  • 8.7.1.6. “NumEnts”
  • 8.7.1.7. “LB”
  • 8.7.1.8. “UB”
  • 8.7.1.9. “Obj”
  • 8.7.1.10. “LHS”
  • 8.7.1.11. “RHS”
  • 8.7.1.12. “ColName”
  • 8.7.1.13. “RowName”
  • 8.7.1.14. “IsInteger”
  • 8.7.1.15. “RowIIS”
  • 8.7.1.16. “ColIIS”
• 8.7.2. Solution attributes
  • 8.7.2.1. “SolutionTime”
  • 8.7.2.2. “PresolverTime”
  • 8.7.2.3. “SolverTime”
  • 8.7.2.4. “HasSolution”
  • 8.7.2.5. “HasPrimalRay”
  • 8.7.2.6. “HasDualRay”
  • 8.7.2.7. “PrimalObjVal”
  • 8.7.2.8. “DualObjVal”
  • 8.7.2.9. “PrimalSoln”
  • 8.7.2.10. “DualSoln”
  • 8.7.2.11. “ColBasis”
  • 8.7.2.12. “RowBasis”
  • 8.7.2.13. “Activity”
  • 8.7.2.14. “ReducedCost”
  • 8.7.2.15. “SymMatPrimalSoln”
  • 8.7.2.16. “MIP/GapAbs”
  • 8.7.2.17. “MIP/GapRel”
• 8.7.3. Simplex method attributes
  • 8.7.3.1. “SPX/NumIters”
• 8.7.4. IPM attributes
  • 8.7.4.1. “IPM/NumIters”