XPRSaddcbchgnode

Purpose

This function is deprecated and may be removed in future releases. Declares a node selection callback function. This is called every time the code backtracks to select a new node during the MIP search. This callback function will be called in addition to any callbacks already added by XPRSaddcbchgnode.

Synopsis

 int XPRS_CC XPRSaddcbchgnode(XPRSprob prob, void (XPRS_CC *f_chgnode)(XPRSprob my_prob, void *my_object, int *nodnum), void *object, int priority);

Arguments

prob	The current problem.
f_chgnode	The callback function which takes three arguments, my_prob, my_object and nodnum, and has no return value. This function is called every time a new node is selected.
my_prob	The problem passed to the callback function, f_chgnode.
my_object	The user-defined object passed as object when setting up the callback with XPRSaddcbchgnode.
nodnum	A pointer to the number of the node, nodnum, selected by the Optimizer. By changing the value pointed to by this argument, the selected node may be changed with this function.
object	A user-defined object to be passed to the callback function, f_chgnode.
priority	An integer that determines the order in which multiple node selection 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.

Related controls

Integer

NODESELECTION

Node selection control.

Example

The following prints out the node number every time a new node is selected during the global search:

XPRSsetintcontrol(prob,XPRS_MIPLOG,3);
XPRSsetintcontrol(prob,XPRS_NODESELECTION,2);
XPRSaddcbchgnode(prob,nodeSelection,NULL,0);
XPRSmipoptimize(prob,"");

The callback function may resemble:

XPRS_CC void nodeSelection(XPRSprob prob, void *object,
                           int *Node)
{
  printf("Node number %d\n", *Node);
}

See the example depthfirst.c in the examples/optimizer/c folder for an example of using a node selection callback.

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XPRSaddcbchgnode

XPRSaddcbchgnode