Initializing help system before first use

XPRS_mse_setcbgetsolutiondiff

Purpose
Declares a user-defined solution difference calculation routine, called each time a new pair of solutions are required to have a difference metric calculated. This functionality is required when the MSE_METRIC_DIVERSITY metric is applied to the set of stored solutions with a call to XPRS_mse_getcullchoice and XPRS_mse_getsolmetric.
Synopsis
int XPRS_CC XPRS_mse_setcbgetsolutiondiff(XPRSmipsolenum mse, int (XPRS_CC * f_mse_getsolutiondiff)(XPRSmipsolenum mse, void * vContext, int nCols, int iSolutionId_1, int iElemCount_1, double dMipObj_1, const double * Vals_1, const int * iSparseIndices_1, int iSolutionId_2, int iElemCount_2, double dMipObj_2, const double * Vals_2, const int * iSparseIndices_2, double * dDiffMetric), void * p)
Arguments
mse 
The current MIP solution enumerator.
f_mse_getsolutiondiff 
The callback function which takes 14 arguments, mse, vContext, nCols, iSolutionId_1, iElemCount_1, dMipObj_1, Vals_1, iSparseIndices_1, iSolutionId_2, iElemCount_2, dMipObj_2, Vals_2, iSparseIndices_2 and dDiffMetric. Use a NULL value to cancel a callback function.
mse 
The current MIP solution enumerator.
vContext 
The user-defined object passed to the callback function.
nCols 
The number of columns in the solutions. This is the same as the column dimension of the problem when the enumeration was started.
iSolutionId_1 
The solution id of the first of the solution pair. This may be -1 in which case the solution has not yet be stored in the MIP solution pool. This happens when the user passes a new solution to XPRS_mse_getcullchoice using the diversity metric ( MSE_METRIC_DIVERSITY).
iElemCount_1 
The number of non-zero elements in the first solution.
dMipObj_1 
The MIP objective value of the first solution.
Vals_1 
A sparse array of doubles of length iElemCount_1 containing the first solution's solution values.
iSparseIndices_1 
A sparse array of integers of length iElemCount_1 containing the first solution's column indices.
iSolutionId_2 
The solution id of the second of the solution pair.
iElemCount_2 
The number of non-zero elements in the second solution.
dMipObj_2 
The MIP objective value of the second solution.
Vals_2 
A sparse array of doubles of length iElemCount_2 containing the second solution's solution values.
iSparseIndices_2 
A sparse array of integers of length iElemCount_2 containing the second solution's column indices.
dDiffMetric 
A pointer to a double to return the metric of the difference between the two solutions.
p 
A user-defined object to be passed to the callback function.
Further information
1. If the user does not provide this callback function then the MIP solution enumerator uses a simple difference metric that considers only the MIP entities in the solution.
2. If the callback function returns nonzero then this is interpreted as an error and optimization is stopped.
Related topics
XPRS_mse_getcullchoice, XPRS_mse_getsolmetric.

Parent Topic MSE Functions

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