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XPRSsetcbchgnode

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Purpose

Declares a node selection callback function. This is called every time the code backtracks to select a new node during the MIP search.

Synopsis

int XPRS_CC XPRSsetcbchgnode(XPRSprob prob, void (XPRS_CC *fusn)(XPRSprob my_prob, void *my_object, int *nodnum), void *object);

Arguments

prob	The current problem.
fusn	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, fusn.
my_object	The user-defined object passed as object when setting up the callback with XPRSsetcbchgnode.
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, fusn.

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:

XPRSminim(prob,"");
XPRSsetintcontrol(prob,XPRS_MIPLOG,3);
XPRSsetintcontrol(prob,XPRS_NODESELECTION,2);
XPRSsetcbchgnode(prob,nodeSelection,NULL);
XPRSglobal(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 on the Xpress‑MP CD-ROM.

Related topics

XPRSsetcboptnode, XPRSsetcbinfnode, XPRSsetcbintsol, XPRSsetcbnodecutoff, XPRSsetcbchgbranch, XPRSsetcbprenode.

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