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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 CPXgetcallbackgloballb
retrieves the best
known global lower bound values during MIP optimization from within a
user-written callback. The global lower bounds are tightened after
a new incumbent is found, so the values returned by
CPXgetcallbacknodex
may violate these bounds at nodes where
new incumbents have been found. The values are from the original problem if
CPX_PARAM_MIPCBREDLP
is set to CPX_OFF
; otherwise,
they are from the presolved problem.
This routine may be called only when the value of the
wherefrom
argument is one of the following:
CPX_CALLBACK_MIP
,
CPX_CALLBACK_MIP_BRANCH
,
CPX_CALLBACK_MIP_INCUMBENT
,
CPX_CALLBACK_MIP_NODE
,
CPX_CALLBACK_MIP_HEURISTIC
,
CPX_CALLBACK_MIP_SOLVE
, or
CPX_CALLBACK_MIP_CUT
.
Example
status = CPXgetcallbackgloballb (env, cbdata, wherefrom, glb, 0, cols-1);
env | A pointer to the CPLEX environment, as returned by |
cbdata | The pointer passed to the user-written callback. This argument must be the value of |
wherefrom | An integer value reporting from where the user-written callback was called. The argument must be the value of |
lb | An array to receive the values of the global lower bound values. This array must be of length at least ( |
begin | An integer specifying the beginning of the range of lower bound values to be returned. |
end | An integer specifying the end of the range of lower bound values to be returned. |