/***************************************************************************************\ * Name: MipSolEnum.java Fair Isaac 13/06/2008 * * Purpose: 10 best solutions with the MIP solution enumerator * * 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 * * run the MIP solution enumerator on the problem using the default setup * * obtaining the best 10 solutions. The best 10 solutions are stored to a * * MIP solution pool. The solutions' objectives and solution values are * * printed to screen. * * Input: hpw15.mat * \***************************************************************************************/ import java.io.*; import com.dashoptimization.*; public class MipSolEnum { public static void main(String[] args) throws Exception { XPRS.init(); try { XPRSprob prob = new XPRSprob(); prob.addMsgHandlerListener(System.out); XPRSmipsolpool msp = new XPRSmipsolpool(); XPRSmipsolenum mse = new XPRSmipsolenum(); prob.readProb("hpw15"); int nCols = prob.attributes().getCols(); /* Disable heuristics to avoid duplicate solutions being stored */ prob.controls().setHeurStrategy(0); int iPresolveOps = prob.controls().getPresolveOps(); iPresolveOps &= ~(1 << 3); /* Disable dual reduction operations */ iPresolveOps &= ~(1 << 5); /* Disable duplicate column removal */ prob.controls().setPresolveOps(iPresolveOps); int iMIPPresolve = prob.controls().getMIPPresolve(); iMIPPresolve &= ~(1 << 4); /* Disable MIP dual reduction operations */ prob.controls().setMIPPresolve(iMIPPresolve); /* Run the enumeration */ IntHolder nMaxSols = new IntHolder(10); mse.minim(prob,msp,new XPRSdefaultMipSolEnumHandler(), null, nMaxSols); /* Print out the solutions found */ int nSols = mse.attributes().getSolutions(); for (int i=1;i<=nSols;i++) { int[] iSolutionId = new int[1]; DoubleHolder dObj = new DoubleHolder(); mse.getSolList(XPRS.MSE_METRIC_MIPOBJECT,i,i,iSolutionId,null,null); mse.getSolMetric(iSolutionId[0], null, XPRS.MSE_METRIC_MIPOBJECT, dObj); System.out.println("--------\n" + i + " = " + dObj.value); for (int j=0;j<nCols;j++) {
					double[] dSol = new double[1];
					msp.getSol(iSolutionId[0],null,dSol,j,j,null);
					System.out.println(j + " = " + dSol[0]);
				}
			}

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