org.apache.tika.eval.textstats.CommonTokensCosine Maven / Gradle / Ivy
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package org.apache.tika.eval.textstats;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import org.apache.commons.lang3.mutable.MutableInt;
import org.apache.commons.lang3.tuple.Pair;
import org.apache.commons.math3.util.FastMath;
import org.apache.tika.eval.langid.Language;
import org.apache.tika.eval.tokens.CommonTokenCountManager;
import org.apache.tika.eval.tokens.LangModel;
import org.apache.tika.eval.tokens.TokenCounts;
public class CommonTokensCosine implements LanguageAwareTokenCountStats {
private final CommonTokenCountManager commonTokenCountManager;
public CommonTokensCosine(CommonTokenCountManager mgr) {
this.commonTokenCountManager = mgr;
}
@Override
public Double calculate(List languages, TokenCounts tokenCounts) {
Pair pair = commonTokenCountManager.getLangTokens(languages.get(0).getLanguage());
LangModel model = pair.getValue();
double kl = 0.0;
if (tokenCounts.getTokens().entrySet().size() == 0) {
return 1.0;
}
double numerator = 0.0;
double denominator = 0.0;
for (Map.Entry e : tokenCounts.getTokens().entrySet()) {
long modelCount = model.getCount(e.getKey());
if (modelCount > 0) {
numerator += e.getValue().intValue()*modelCount;
}
double sq = FastMath.pow(e.getValue().intValue(), 2);
denominator += sq;
}
denominator = Math.sqrt(denominator);
denominator *= calcNorm(model.getCounts().values());
return numerator/denominator;
}
private double calcNorm(Collection counts) {
double d = 0.0;
for (long lng : counts) {
d += FastMath.pow(lng, 2);
}
return FastMath.sqrt(d);
}
}