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package samples.real;
import org.slf4j.LoggerFactory;
import samples.AbstractProblem;
import solver.Solver;
import solver.constraints.real.Ibex;
import solver.constraints.real.RealConstraint;
import solver.search.loop.monitors.SearchMonitorFactory;
import solver.search.strategy.selectors.values.RealDomainMiddle;
import solver.search.strategy.selectors.variables.Cyclic;
import solver.search.strategy.strategy.RealStrategy;
import solver.variables.IntVar;
import solver.variables.RealVar;
import solver.variables.VariableFactory;
/**
* The cyclo hexan problem but hybrids finite/continuous problems
* <br/>
*
* @author Jean-Guillaume Fages, Charles Prud'homme
* @since 18/07/12
*/
public class HybridCycloHexan extends AbstractProblem {
RealVar[] vars;
RealVar x, y, z;
IntVar intx;
@Override
public void printDescription() {
StringBuilder st = new StringBuilder(24);
st.append("The CycloHexan problem consists in finding the 3D configuration of a cyclohexane molecule.\n");
st.append("It is decribed with a system of three non linear equations : \n");
st.append(" y^2 * (1 + z^2) + z * (z - 24 * y) = -13 \n" +
" x^2 * (1 + y^2) + y * (y - 24 * x) = -13 \n" +
" z^2 * (1 + x^2) + x * (x - 24 * z) = -13 \n");
st.append("This example comes from the Elisa project (LINA) examples. \n");
st.append("This example restricts x to be integer, as an illustration to hybrid finite/continuous problems. \n");
st.append("It has no solution. \n");
LoggerFactory.getLogger("bench").info(st.toString());
}
@Override
public void createSolver() {
solver = new Solver("HybridCycloHexan");
}
@Override
public void buildModel() {
double precision = 1.0e-3;
// finite domain
intx = VariableFactory.enumerated("x", new int[]{-10,-9,0,2,42}, solver);
// continuous view
x = VariableFactory.real(intx,precision);
y = VariableFactory.real("y", -1.0e8, 1.0e8, precision, solver);
z = VariableFactory.real("z", -1.0e8, 1.0e8, precision, solver);
vars = new RealVar[]{x, y, z};
solver.post(new RealConstraint(
"CycloHexan",
"{1}^2 * (1 + {2}^2) + {2} * ({2} - 24 * {1}) = -13;" +
"{0}^2 * (1 + {1}^2) + {1} * ({1} - 24 * {0}) = -13;" +
"{2}^2 * (1 + {0}^2) + {0} * ({0} - 24 * {2}) = -13",
Ibex.HC4_NEWTON,
vars)
);
}
@Override
public void configureSearch() {
solver.set(new RealStrategy(vars, new Cyclic(), new RealDomainMiddle()));
SearchMonitorFactory.limitTime(solver,10000);
}
@Override
public void solve() {
solver.findSolution();
}
@Override
public void prettyOut() {
solver.getIbex().release();
}
public static void main(String[] args) {
new HybridCycloHexan().execute(args);
}
}