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khashab2
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Initial version of ojAlgo
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‎lbjava/pom.xml‎

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<version>4.11</version>
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<scope>test</scope>
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</dependency>
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<dependency>
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<groupId>org.ojalgo</groupId>
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<artifactId>ojalgo</artifactId>
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<version>39.0</version>
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</dependency>
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</dependencies>
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<reporting>

‎lbjava/src/main/java/edu/illinois/cs/cogcomp/lbjava/infer/OJalgoHook.java‎

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package edu.illinois.cs.cogcomp.lbjava.infer;
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import edu.illinois.cs.cogcomp.lbjava.classify.Score;
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import org.ojalgo.optimisation.Expression;
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import org.ojalgo.optimisation.ExpressionsBasedModel;
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import org.ojalgo.optimisation.Optimisation;
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import org.ojalgo.optimisation.Variable;
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public class OJalgoHook implements ILPSolver {
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private int numvars = 0; // initially there are no variables in the model.
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private int numConstraints = 0; // intiial number of constraints
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private ExpressionsBasedModel model = new ExpressionsBasedModel();
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private String nameOfObjectiveExpression = "objective";
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private Expression objectiveFunction = model.getObjectiveExpression(); //model.addExpression(nameOfObjectiveExpression);
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// Internal flag for keeping optimization state
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private boolean minimize = true;
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// internal variable for result of optimization
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private Optimisation.Result result;
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/**
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* Set bounds of variable in the specified position.
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*
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* @param colId position of the variable
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* @param lower domain lower bound
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* @param upper domain upper bound
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*/
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public void setBounds(int colId, double lower, double upper) {
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if(upper == Double.POSITIVE_INFINITY)
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model.getVariable(colId).upper(null);
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else
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model.getVariable(colId).upper(upper);
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if(lower == Double.NEGATIVE_INFINITY)
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model.getVariable(colId).lower(null);
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else
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model.getVariable(colId).lower(lower);
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}
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/**
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* Set lower bound to unbounded (infinite)
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*
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* @param colId position of the variable
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*/
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public void setUnboundUpperBound(int colId) {
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model.getVariable(colId).upper(null);
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}
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public void setUpperBound(int colId, double u) {
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model.getVariable(colId).upper(u);
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}
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/**
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* Set upper bound to unbounded (infinite)
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*
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* @param colId position of the variable
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*/
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public void setUnboundLowerBound(int colId) {
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model.getVariable(colId).lower(null);
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}
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public void setLowerBound(int colId, double l) {
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model.getVariable(colId).lower(l);
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}
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/**
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* Set the column/variable as an integer variable
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*
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* @param colId position of the variable
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*/
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public void setInteger(int colId) {
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model.getVariable(colId).integer(true);
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}
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/**
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* Set the column / variable as an binary integer variable
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*
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* @param colId position of the variable
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*/
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public void setBinary(int colId) {
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model.getVariable(colId).binary();
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}
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/**
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* Set the column/variable as a float variable
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*
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* @param colId position of the variable
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*/
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public void setFloat(int colId) {
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model.getVariable(colId).integer(false);
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}
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public void setMaximize(boolean d) {
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if(d) {
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model.setMaximisation();
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minimize = false;
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}
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else {
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model.setMinimisation();
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minimize = true;
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}
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}
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public int addBooleanVariable(double c) {
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numvars ++;
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Variable var = Variable.makeBinary(Integer.toString(numvars));
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model.addVariable(var);
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objectiveFunction.set(var, c);
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return numvars-1;
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}
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public int[] addDiscreteVariable(double[] c) {
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int[] varIndices = new int[c.length];
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int ind = 0;
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while (ind < c.length) {
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double coef = c[ind];
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numvars ++;
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Variable var = Variable.make(Integer.toString(numvars));
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var.isInteger();
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model.addVariable(var);
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objectiveFunction.set(var, coef);
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varIndices[ind] = numvars-1;
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ind++;
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}
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return varIndices;
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}
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public int[] addDiscreteVariable(Score[] c) {
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int[] varIndices = new int[c.length];
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int ind = 0;
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while (ind < c.length) {
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double coef = c[ind].score;
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numvars ++;
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Variable var = Variable.make(Integer.toString(numvars));
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var.isInteger();
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model.addVariable(var);
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objectiveFunction.set(var, coef);
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varIndices[ind] = numvars -1;
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ind++;
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}
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return varIndices;
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}
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public void addEqualityConstraint(int[] i, double[] a, double b) {
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numConstraints++;
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Expression constraint = model.addExpression("EqualityConstraint: " + Integer.toString(numConstraints));
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constraint.level(b);
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for(int ind = 0; ind < i.length; ind++) {
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constraint.set(i[ind], a[ind]);
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}
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}
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public void addGreaterThanConstraint(int[] i, double[] a, double b) {
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numConstraints++;
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Expression constraint = model.addExpression("GreaterThanConstraint: " + Integer.toString(numConstraints));
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constraint.lower(b);
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for(int ind = 0; ind < i.length; ind++) {
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constraint.set(i[ind], a[ind]);
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}
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}
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public void addLessThanConstraint(int[] i, double[] a, double b) {
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numConstraints++;
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Expression constraint = model.addExpression("LessThanConstraint: " + Integer.toString(numConstraints));
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constraint.upper(b);
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for(int ind = 0; ind < i.length; ind++) {
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constraint.set(i[ind], a[ind]);
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}
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}
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// Note: oJalgo does not support pre-solving!
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public boolean solve() throws Exception {
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if(minimize)
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result = model.minimise();
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else
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result = model.maximise();
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if( result.getState() == Optimisation.State.OPTIMAL )
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System.out.println("Good news!: the optimizatin solution is optimal! ");
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if( result.getState() == Optimisation.State.DISTINCT )
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System.out.println("Good news!: the optimizatin solution is unique! ");
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if( result.getState() == Optimisation.State.INFEASIBLE )
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System.out.println("Warning: the optimizatin is infeasible! ");
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if( result.getState() == Optimisation.State.UNBOUNDED )
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System.out.println("Warning: the optimizatin is unbounded! ");
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if( result.getState() == Optimisation.State.APPROXIMATE )
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System.out.println("Warning: the optimizatin is approximate! ");
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return result.getState().isSuccess();
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}
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public boolean isSolved() {
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return result.getState().isSuccess();
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}
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public boolean getBooleanValue(int index) {
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if( result.get(index).intValue() != 1 && result.get(index).intValue() != 0 )
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System.out.println("Warning! The value of the binary variable is not 0/1! ");
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return (result.get(index).intValue() == 1);
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}
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public double objectiveValue() {
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/** TODO(khashab2): the method `result.getValue();` doesn't return the right value. Make sure you're doing
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* the right thing.
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*/
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double obj = 0;
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for( Variable v : model.getVariables() )
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obj += objectiveFunction.get(v).doubleValue() * v.getValue().doubleValue();
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return obj;
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}
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public void reset() {
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// no implementation
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}
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public void write(StringBuffer buffer) {
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// no implementation
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}
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/**
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* Set a time limit for solver optimization. After the limit
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* is reached the solver stops running.
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*
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* @param limit the time limit
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*/
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public void setTimeout(int limit) {
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assert (0 <= limit);
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model.options.time_abort = limit;
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}
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public void printModelInfo() {
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System.out.println(model.toString());
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}
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}

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