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package phrase;
import java.util.Arrays;
import java.util.List;
import optimization.gradientBasedMethods.ProjectedGradientDescent;
import optimization.gradientBasedMethods.ProjectedObjective;
import optimization.gradientBasedMethods.stats.OptimizerStats;
import optimization.linesearch.ArmijoLineSearchMinimizationAlongProjectionArc;
import optimization.linesearch.InterpolationPickFirstStep;
import optimization.linesearch.LineSearchMethod;
import optimization.linesearch.WolfRuleLineSearch;
import optimization.projections.SimplexProjection;
import optimization.stopCriteria.CompositeStopingCriteria;
import optimization.stopCriteria.ProjectedGradientL2Norm;
import optimization.stopCriteria.StopingCriteria;
import optimization.stopCriteria.ValueDifference;
import optimization.util.MathUtils;
public class PhraseObjective extends ProjectedObjective
{
static final double GRAD_DIFF = 0.00002;
static double INIT_STEP_SIZE = 300;
static double VAL_DIFF = 1e-8; // tuned to BTEC subsample
static int ITERATIONS = 100;
private PhraseCluster c;
/**@brief
* for debugging purposes
*/
//public static PrintStream ps;
/**@brief current phrase being optimzed*/
public int phrase;
/**@brief un-regularized posterior
* unnormalized
* p[edge][tag]
* P(tag|edge) \propto P(tag|phrase)P(context|tag)
*/
private double[][]p;
/**@brief regularized posterior
* q[edge][tag] propto p[edge][tag]*exp(-lambda)
*/
private double q[][];
private List<Corpus.Edge> data;
/**@brief log likelihood of the associated phrase
*
*/
private double loglikelihood;
private SimplexProjection projection;
double[] newPoint ;
private int n_param;
/**@brief likelihood under p
*
*/
public double llh;
public PhraseObjective(PhraseCluster cluster, int phraseIdx, double scale, double[] lambda){
phrase=phraseIdx;
c=cluster;
data=c.c.getEdgesForPhrase(phrase);
n_param=data.size()*c.K;
//System.out.println("Num parameters " + n_param + " for phrase #" + phraseIdx);
if (lambda==null)
lambda=new double[n_param];
parameters = lambda;
newPoint = new double[n_param];
gradient = new double[n_param];
initP();
projection=new SimplexProjection(scale);
q=new double [data.size()][c.K];
setParameters(parameters);
}
private void initP(){
p=new double[data.size()][];
for(int edge=0;edge<data.size();edge++){
p[edge]=c.posterior(data.get(edge));
llh += data.get(edge).getCount() * Math.log(arr.F.l1norm(p[edge])); // Was bug here - count inside log!
arr.F.l1normalize(p[edge]);
}
}
@Override
public void setParameters(double[] params) {
super.setParameters(params);
updateFunction();
}
private void updateFunction(){
updateCalls++;
loglikelihood=0;
for(int tag=0;tag<c.K;tag++){
for(int edge=0;edge<data.size();edge++){
q[edge][tag]=p[edge][tag]*
Math.exp(-parameters[tag*data.size()+edge]/data.get(edge).getCount());
}
}
for(int edge=0;edge<data.size();edge++){
loglikelihood+=data.get(edge).getCount() * Math.log(arr.F.l1norm(q[edge]));
arr.F.l1normalize(q[edge]);
}
for(int tag=0;tag<c.K;tag++){
for(int edge=0;edge<data.size();edge++){
gradient[tag*data.size()+edge]=-q[edge][tag];
}
}
}
@Override
public double[] projectPoint(double[] point)
{
double toProject[]=new double[data.size()];
for(int tag=0;tag<c.K;tag++){
for(int edge=0;edge<data.size();edge++){
toProject[edge]=point[tag*data.size()+edge];
}
projection.project(toProject);
for(int edge=0;edge<data.size();edge++){
newPoint[tag*data.size()+edge]=toProject[edge];
}
}
return newPoint;
}
@Override
public double[] getGradient() {
gradientCalls++;
return gradient;
}
@Override
public double getValue() {
functionCalls++;
return loglikelihood;
}
@Override
public String toString() {
return Arrays.toString(parameters);
}
public double [][]posterior(){
return q;
}
long optimizationTime;
public boolean optimizeWithProjectedGradientDescent(){
long start = System.currentTimeMillis();
LineSearchMethod ls =
new ArmijoLineSearchMinimizationAlongProjectionArc
(new InterpolationPickFirstStep(INIT_STEP_SIZE));
//LineSearchMethod ls = new WolfRuleLineSearch(
// (new InterpolationPickFirstStep(INIT_STEP_SIZE)), c1, c2);
OptimizerStats stats = new OptimizerStats();
ProjectedGradientDescent optimizer = new ProjectedGradientDescent(ls);
StopingCriteria stopGrad = new ProjectedGradientL2Norm(GRAD_DIFF);
StopingCriteria stopValue = new ValueDifference(VAL_DIFF*(-llh));
CompositeStopingCriteria compositeStop = new CompositeStopingCriteria();
compositeStop.add(stopGrad);
compositeStop.add(stopValue);
optimizer.setMaxIterations(ITERATIONS);
updateFunction();
boolean success = optimizer.optimize(this,stats,compositeStop);
//System.out.println("Ended optimzation Projected Gradient Descent\n" + stats.prettyPrint(1));
//if(succed){
//System.out.println("Ended optimization in " + optimizer.getCurrentIteration());
//}else{
// System.out.println("Failed to optimize");
//}
//System.out.println(Arrays.toString(parameters));
// for(int edge=0;edge<data.getSize();edge++){
// ps.println(Arrays.toString(q[edge]));
// }
return success;
}
public double KL_divergence()
{
return -loglikelihood + MathUtils.dotProduct(parameters, gradient);
}
public double loglikelihood()
{
return llh;
}
public double l1lmax()
{
double sum=0;
for(int tag=0;tag<c.K;tag++){
double max=0;
for(int edge=0;edge<data.size();edge++){
if(q[edge][tag]>max)
max=q[edge][tag];
}
sum+=max;
}
return sum;
}
public double primal(double scale)
{
return loglikelihood() - KL_divergence() - scale * l1lmax();
}
}
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