CbcModel uses other classes in CBC, some of which are virtual and may have multiple instances. Not all classes are created equal. The two tables below list the classes within CbcModel that are of most interest and of least interest.
Table 2.4. Classes Used by CbcModel - Most Useful
| Class name | Description | Notes |
|---|---|---|
| CbcCompareBase | Controls which node on tree is selected | The default is CbcCompareDefault. Other comparison classes in CbcCompareActual.hpp include CbcCompareDepth and CbcCompareObjective. It is very easy for user to experiment with different comparisons. |
| CbcCutGenerator | A wrapper for CglCutGenerator with additional data to control when the cut generator is used. | Other than knowing how to add a cut generator to CbcModel, there is not much the average user needs to know about this class. |
| CbcHeuristic | Heuristic that attempts to generate valid solutions | Users can get a lot of value out of coding specialized heuristics. There can be as many different heuristics as you like. |
| CbcObject | Defines what it means for a variable to be satisfied. | Virtual class. The branching model used in CBC is based on the idea of an "object". An object has (i) feasible region, (ii) can be evaluated for infeaibility, (iii) can be branched on, e.g., a method of generating a branching object, which defines an up branch and a down branch and (iv) allows comparsion of the effect of branching. Instances include simple integer, simple integer with pseudocosts, SOS (type 1 and 2), and lotsizing (see CbcBranch....hpp). |
| OsiSolverInterface | Defines the LP solver being used and the LP model. Normally a pointer to the desired OsiSolverInteface is passed to CbcModel before branch and cut. | Virtual class. The user instantiates the solver interface of their choice, e.g., OsiClpSolverInterface. |
Table 2.5. Classes Used by CbcModel - Least Useful
| Class name | Description | Notes |
|---|---|---|
| CbcBranchDecision | Used in choosing which variable to branch on, however, most of the work is done by the definitions in CbcObject. | Defaults to CbcBranchDefaultDecision. |
| CbcCountRowCut | Interface to OsiRowCut. It counts the usage so cuts can gracefully vanish. | See OsiRowCut for more details. |
| CbcNode | Controls which variable/entity is selected to be branch on. | Controlled via CbcModel parameters. |
| CbcNodeInfo | Contains data on bounds, basis, etc. for one node of the search tree. | Header is located in CbcNode.hpp. |
| CbcTree | Defines how the search tree is stored. | This class can be changed but it is not likely to be modified. |
| CoinMessageHandler | Deals with message handling | The user can inherit from CoinMessageHandler to specialize message handling. |
| CoinWarmStartBasis | Basis representation to be used by solver |