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XPRSaddcbslpcascadevar

Purpose
Add a user callback to be called after each column has been cascaded
Topic areas
Callback, SLP, Cascading
Synopsis
int XPRS_CC XPRSaddcbslpcascadevar(XPRSprob prob, int (XPRS_CC *slpcascadevar) (XPRSprob cbprob, void *cbdata, int col), void *data, int priority);
Arguments
prob 
The current problem.
slpcascadevar 
The function to be called after each column has been cascaded. slpcascadevar returns an integer value. If the return value is nonzero, the cascading process will be omitted for the remaining variables during the current SLP iteration, but the optimization will continue.
cbprob 
The problem passed to the callback function.
cbdata 
The user-defined object passed as data to XPRSaddcbslpcascadevar.
col 
The number of the column which has been cascaded.
data 
Address of a user-defined object, which can be used for any purpose by the function. data is passed to slpcascadevar as cbdata.
priority 
An integer that determines the order in which callbacks of this type 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 sets up a callback to be executed after each variable has been cascaded: 
double *cSol;
XPRSaddcbslpcascadevar(prob, CBCascVar, &cSol, 0);
The following sample callback function stops the cascading process if the cascaded value is of the opposite sign to the original value: 
int XPRS_CC CBCascVar(XPRSprob MyProb, void *Obj, int iCol) {
  XPRSalltype alltype;
  double *cSol;
  cSol = * (double **) Obj;
  XPRSslpgetcolinfo(MyProb, XSLP_COLINFO_VALUE, iCol, &alltype);
  if (alltype.value.real * cSol[iCol] < 0) {
    return 1;
  }
  return 0;
}
The data argument is used here to hold the address of the array cSol which we assume has been populated with the original solution values.
Further information
This callback can be used after each variable has been cascaded and its new value has been calculated.
Related topics
XPRSslpcascade, XPRSaddcbslpcascadeend, XPRSaddcbslpcascadestart, XPRSaddcbslpcascadevarfail XPRSremovecbslpcascadevar

Parent Topic Library functions

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