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This is an advanced routine. Advanced routines typically demand a thorough understanding of the algorithms used by ILOG CPLEX. Thus they incur a higher risk of incorrect behavior in your application, behavior that can be difficult to debug. Therefore, ILOG encourages you to consider carefully whether you can accomplish the same task by means of other Callable Library routines instead.
The routine CPXgetcallbacknodelp returns a
pointer to the current continuous relaxation at the current
branch and cut node
from within a user-written callback. Generally, this pointer
may be used only in ILOG CPLEX Callable Library query routines, such as
CPXsolution or CPXgetrows.
Note that the setting of the parameter CPX_PARAM_MIPCBREDLP
does not affect this lp pointer. Since CPLEX does not
explicitly maintain an unpresolved node LP, the lp pointer
will correspond to the presolved node LP unless CPLEX presolve has
been turned off or CPLEX has made no presolve reductions at all.
Example
status = CPXgetcallbacknodelp (env, cbdata, wherefrom, &nodelp);
See also the example admipex1.c and
admipex6.c in the standard distribution.
CPXgetcallbacknodelp may be called only when its
wherefrom argument has one of the following values:
CPX_CALLBACK_MIP,CPX_CALLBACK_MIP_BRANCH,CPX_CALLBACK_MIP_CUT,CPX_CALLBACK_MIP_HEURISTIC,CPX_CALLBACK_MIP_INCUMBENT, orCPX_CALLBACK_MIP_SOLVE.When the wherefrom argument has the value
CPX_CALLBACK_MIP_SOLVE, the subproblem pointer may also be used
in ILOG CPLEX optimization routines.
| env | A pointer to the CPLEX environment, as returned by |
| cbdata | The |
| wherefrom | An integer value reporting where the user-written callback was called from. This argument must be the value of the |
| nodelp_p | The |