Initializing help system before first use

# XPRSaddcbprenode

Purpose
Declares a preprocess node callback function, called before the LP relaxation of a node has been optimized, so the solution at the node will not be available. This callback function will be called in addition to any callbacks already added by XPRSaddcbprenode.
Topic areas
Callback, Branch and Bound Search
Synopsis
`int XPRS_CC XPRSaddcbprenode(XPRSprob prob, void (XPRS_CC *prenode)(XPRSprob cbprob, void *cbdata, int *p_infeasible), void *data, int priority);`
Arguments

prob | The current problem.
prenode | The callback function, which takes arguments cbprob, cbdata and p_infeasible, and has no return value. This function is called before a node is reoptimized and the node may be made infeasible by setting *p_infeasible to 1.
cbprob | The problem passed to the callback function, prenode.
cbdata | The user-defined data passed as data when setting up the callback.
p_infeasible | The feasibility status. If set to a nonzero value by the user, the current node will be declared infeasible by the Optimizer.
data | A user-defined data to be passed to the callback function, prenode.
priority | An integer that determines the order in which multiple preprocess node callbacks will be invoked. The callback added with a higher priority will be called before a callback with a lower priority. Set to 0 if not required.

Example
The following example notifies the user before each node is processed:

    XPRSaddcbprenode(prob, preNode, NULL, 0);
    XPRSmipoptimize(prob,"");

The callback function might resemble:

    void XPRS_CC preNode(XPRSprob prob, void* data, int *p_infeasible)
    {
     *p_infeasible = 0; /* set to 1 if node is infeasible */
    }

Related topics
XPRSremovecbprenode, XPRSaddcbinfnode, XPRSaddcbintsol, XPRSaddcbnodecutoff, XPRSaddcboptnode.
Parent Topic Console and Library Functions

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