/**
* Copyright (c) 2009/09-2012/08, Regents of the University of Colorado
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* Copyright 2012/09-2013/04, 2013/11-Present, University of Massachusetts Amherst
* Copyright 2013/05-2013/10, IPSoft Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.clearnlp.classification.algorithm;
import com.clearnlp.classification.prediction.IntPrediction;
import com.clearnlp.util.UTMath;
/**
* AdaGrad algorithm using hinge loss.
* @since 1.3.0
* @author Jinho D. Choi ({@code jdchoi77@gmail.com})
*/
public class AdaGradHinge extends AbstractAdaGrad
{
/**
* @param alpha the learning rate.
* @param rho the smoothing denominator.
*/
public AdaGradHinge(double alpha, double rho, double eps)
{
super(alpha, rho, eps);
}
protected boolean update(int L, int y, int[] x, double[] v, double[] gs, double[] weights)
{
IntPrediction max = getPrediction(L, y, x, v, weights);
if (max.label != y)
{
updateCounts (L, gs, y, max.label, x, v);
updateWeights(L, gs, y, max.label, x, v, weights);
return true;
}
return false;
}
protected IntPrediction getPrediction(int L, int y, int[] x, double[] v, double[] weights)
{
double[] scores = getScores(L, x, v, weights);
scores[y] -= 1;
IntPrediction max = new IntPrediction(0, scores[0]);
int label;
for (label=1; label<L; label++)
{
if (max.score < scores[label])
max.set(label, scores[label]);
}
return max;
}
protected void updateCounts(int L, double[] gs, int yp, int yn, int[] x, double[] v)
{
int i, len = x.length;
if (v != null)
{
double d;
for (i=0; i<len; i++)
{
d = UTMath.sq(v[i]);
gs[getWeightIndex(L, yp, x[i])] += d;
gs[getWeightIndex(L, yn, x[i])] += d;
}
}
else
{
for (i=0; i<len; i++)
{
gs[getWeightIndex(L, yp, x[i])]++;
gs[getWeightIndex(L, yn, x[i])]++;
}
}
}
protected void updateWeights(int L, double[] gs, int yp, int yn, int[] x, double[] v, double[] weights)
{
int i, xi, len = x.length;
double vi;
if (v != null)
{
for (i=0; i<len; i++)
{
xi = x[i]; vi = v[i];
weights[getWeightIndex(L, yp, xi)] += getCost(L, gs, yp, xi) * vi;
weights[getWeightIndex(L, yn, xi)] -= getCost(L, gs, yn, xi) * vi;
}
}
else
{
for (i=0; i<len; i++)
{
xi = x[i];
weights[getWeightIndex(L, yp, xi)] += getCost(L, gs, yp, xi);
weights[getWeightIndex(L, yn, xi)] -= getCost(L, gs, yn, xi);
}
}
}
}