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Collecting all solutions with the MIP solution pool

Description
We take the power generation problem stored in hpw15.mat which seeks to optimise the operating pattern of a group of electricity generators. We solve the problem collecting all solutions found during the MIP search. The optimal solution's objective and solution values are printed to screen.

Source Files

Data Files

MipSolPool.java

```/***************************************************************************************\
* Name:        MipSolPool.java                                   Fair Isaac 13/06/2008 *
* Purpose:     All solutions with the MIP solution pool                                *
* Description: We take the power generation problem stored in hpw15.mat which seeks to *
*              optimise the operating pattern of a group of electricity generators. We *
*              solve the problem collecting all solutions found during the MIP search. *
*              The optimal solution's objective and solution values are printed to     *
*              screen.                                                                 *
* Input:       hpw15.mat                                                               *
\***************************************************************************************/

import java.io.*;
import com.dashoptimization.*;

public class MipSolPool {
public static void main(String[] args) throws Exception {
XPRS.init();

try {
XPRSprob prob = new XPRSprob();

XPRSmipsolpool msp = new XPRSmipsolpool();

msp.probAttach(prob);

prob.mipOptimize("g");

int nSols = msp.attributes().getSolutions();

if (nSols>0) {
IntHolder iSolutionId = new IntHolder();
DoubleHolder dObj = new DoubleHolder();
msp.getDblAttribProbExtreme(prob,0,iSolutionId, XPRS.MSP_SOLPRB_OBJ, dObj);

System.out.println("Optimal Solution ID: " + iSolutionId.value);
System.out.println("Optimal Objective  : " + dObj.value);

int nCols = msp.getIntAttribSol(iSolutionId.value, null, XPRS.MSP_SOL_COLS);
for (int i=0;i<nCols;i++) {
double[] dSol = new double[1];
msp.getSol(iSolutionId.value,null,dSol,i,i,null);
System.out.println(i + " = " + dSol[0]);
}
}

} finally {
XPRS.free();
}
}
}
```