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XSLPsetcbslpnode

XSLPsetcbslpnode

Purpose
Set a user callback to be called during MISLP after the SLP optimization at each node.
Synopsis
int XPRS_CC XSLPsetcbslpnode(XSLPprob Prob, int (XPRS_CC *UserFunc) (XSLPprob myProb, void *myObject, int *feas), void *Object);
Arguments
Prob 
The current SLP problem.
UserFunc 
The function to be called after the set-up of the SLP problem to be solved at a node. UserFunc returns an integer value. If the return value is nonzero, or if the feasibility flag is set nonzero, then further processing of the node will be terminated (it is declared infeasible).
myProb 
The problem passed to the callback function.
myObject 
The user-defined object passed as Object to XSLPsetcbslpnode.
feas 
Address of an integer containing the feasibility flag. If UserFunc sets the flag nonzero, the node is declared infeasible.
Object 
Address of a user-defined object, which can be used for any purpose by the function. Object is passed to UserFunc as myObject.
Example
The following example sets up a callback function to be executed at each node after the SLP optimization finishes. If the solution value is worse than a target value (referenced through the user object), the node is cut off (it is declared infeasible). 
double OBJtarget;
XSLPsetcbslpnode(Prob, CBSLPNode, &OBJtarget);
A suitable callback function might resemble the following: 
int XPRS_CC CBSLPNode(XSLPprob myProb, void *Obj, int *feas) {
  double TargetValue, LPValue;
  XSLPgetdblattrib(prob, XPRS_LPOBJVAL, &LPValue);
  TargetValue = * (double *) Obj;
  if (LPValue < TargetValue) *feas = 1;
  return 0;
}
Further information

If a node can be cut off by the callback function, then further exploration of the node is avoided.


Related topics
XSLPsetcboptnode, XSLPsetcbprenode

Parent Topic Library functions

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