public static InstanceList scale(InstanceList trainingList, double lower, double upper) {
InstanceList ret = copy(trainingList);
Alphabet featDict = ret.getDataAlphabet();
double[] feat_max = new double[featDict.size()];
double[] feat_min = new double[featDict.size()];
for (int i = 0; i < feat_max.length; i++) {
feat_max[i] = -Double.MAX_VALUE;
feat_min[i] = Double.MAX_VALUE;
}
for (int i = 0; i < ret.size(); i++) {
Instance inst = ret.get(i);
FeatureVector fv = (FeatureVector) inst.getData();
for (int loc = 0; loc < fv.numLocations(); loc++) {
int featId = fv.indexAtLocation(loc);
double value = fv.valueAtLocation(loc);
double maxValue = feat_max[featId];
double minValue = feat_min[featId];
double newMaxValue = Math.max(value, maxValue);
double newMinValue = Math.min(value, minValue);
feat_max[featId] = newMaxValue;
feat_min[featId] = newMinValue;
}
}
// double lower = -1;
// double upper = 1;
for (int i = 0; i < ret.size(); i++) {
Instance inst = ret.get(i);
FeatureVector fv = (FeatureVector) inst.getData();
for (int loc = 0; loc < fv.numLocations(); loc++) {
int featId = fv.indexAtLocation(loc);
double value = fv.valueAtLocation(loc);
double maxValue = feat_max[featId];
double minValue = feat_min[featId];
double newValue = Double.NaN;
if (maxValue == minValue) {
newValue = value;
} else if (value == minValue) {
newValue = lower;
} else if (value == maxValue) {
newValue = upper;
} else {
newValue = lower + (upper - lower) * (value - minValue) / (maxValue - minValue);
}
fv.setValueAtLocation(loc, newValue);
}
}
return ret;
}
private double dataLogProbability(Instance instance, int labelIndex) {
FeatureVector fv = (FeatureVector) instance.getData();
int fvisize = fv.numLocations();
double logProb = 0;
for (int fvi = 0; fvi < fvisize; fvi++)
logProb += fv.valueAtLocation(fvi) * p[labelIndex].logProbability(fv.indexAtLocation(fvi));
return logProb;
}
public void count() {
TIntIntHashMap docCounts = new TIntIntHashMap();
int index = 0;
if (instances.size() == 0) {
logger.info("Instance list is empty");
return;
}
if (instances.get(0).getData() instanceof FeatureSequence) {
for (Instance instance : instances) {
FeatureSequence features = (FeatureSequence) instance.getData();
for (int i = 0; i < features.getLength(); i++) {
docCounts.adjustOrPutValue(features.getIndexAtPosition(i), 1, 1);
}
int[] keys = docCounts.keys();
for (int i = 0; i < keys.length - 1; i++) {
int feature = keys[i];
featureCounts[feature] += docCounts.get(feature);
documentFrequencies[feature]++;
}
docCounts = new TIntIntHashMap();
index++;
if (index % 1000 == 0) {
System.err.println(index);
}
}
} else if (instances.get(0).getData() instanceof FeatureVector) {
for (Instance instance : instances) {
FeatureVector features = (FeatureVector) instance.getData();
for (int location = 0; location < features.numLocations(); location++) {
int feature = features.indexAtLocation(location);
double value = features.valueAtLocation(location);
documentFrequencies[feature]++;
featureCounts[feature] += value;
}
index++;
if (index % 1000 == 0) {
System.err.println(index);
}
}
} else {
logger.info("Unsupported data class: " + instances.get(0).getData().getClass().getName());
}
}
public Instance pipe(Instance carrier) {
Sequence data = (Sequence) carrier.getData();
Sequence target = (Sequence) carrier.getTarget();
if (data.size() != target.size())
throw new IllegalArgumentException(
"Trying to print into SimpleTagger format, where data and target lengths do not match\n"
+ "data.length = "
+ data.size()
+ ", target.length = "
+ target.size());
int N = data.size();
if (data instanceof TokenSequence) {
throw new UnsupportedOperationException("Not yet implemented.");
} else if (data instanceof FeatureVectorSequence) {
FeatureVectorSequence fvs = (FeatureVectorSequence) data;
Alphabet dict = (fvs.size() > 0) ? fvs.getFeatureVector(0).getAlphabet() : null;
for (int i = 0; i < N; i++) {
Object label = target.get(i);
writer.print(label);
FeatureVector fv = fvs.getFeatureVector(i);
for (int loc = 0; loc < fv.numLocations(); loc++) {
writer.print(' ');
String fname = dict.lookupObject(fv.indexAtLocation(loc)).toString();
double value = fv.valueAtLocation(loc);
// if (!Maths.almostEquals(value, 1.0)) {
// throw new IllegalArgumentException ("Printing to SimpleTagger format: FeatureVector
// not binary at time slice "+i+" fv:"+fv);
// }
writer.print(fname + String.valueOf(value));
}
writer.println();
}
} else {
throw new IllegalArgumentException("Don't know how to print data of type " + data);
}
writer.println();
// writer.print(getDataAlphabet());
return carrier;
}
/**
* Classify an instance using NaiveBayes according to the trained data. The alphabet of the
* featureVector of the instance must match the alphabe of the pipe used to train the classifier.
*
* @param instance to be classified. Data field must be a FeatureVector
* @return Classification containing the labeling of the instance
*/
public Classification classify(Instance instance) {
// Note that the current size of the label alphabet can be larger
// than it was at the time of training. We are careful here
// to correctly handle those labels here. For example,
// we assume the log prior probability of those classes is
// minus infinity.
int numClasses = getLabelAlphabet().size();
double[] scores = new double[numClasses];
FeatureVector fv = (FeatureVector) instance.getData();
// Make sure the feature vector's feature dictionary matches
// what we are expecting from our data pipe (and thus our notion
// of feature probabilities.
assert (instancePipe == null || fv.getAlphabet() == instancePipe.getDataAlphabet());
int fvisize = fv.numLocations();
prior.addLogProbabilities(scores);
// Set the scores according to the feature weights and per-class probabilities
for (int fvi = 0; fvi < fvisize; fvi++) {
int fi = fv.indexAtLocation(fvi);
for (int ci = 0; ci < numClasses; ci++) {
// guard against dataAlphabet or target alphabet growing; can happen if classifying
// a never before seen feature. Ignore these.
if (ci >= p.length || fi >= p[ci].size()) continue;
scores[ci] += fv.valueAtLocation(fvi) * p[ci].logProbability(fi);
}
}
// Get the scores in the range near zero, where exp() is more accurate
double maxScore = Double.NEGATIVE_INFINITY;
for (int ci = 0; ci < numClasses; ci++) if (scores[ci] > maxScore) maxScore = scores[ci];
for (int ci = 0; ci < numClasses; ci++) scores[ci] -= maxScore;
// Exponentiate and normalize
double sum = 0;
for (int ci = 0; ci < numClasses; ci++) sum += (scores[ci] = Math.exp(scores[ci]));
for (int ci = 0; ci < numClasses; ci++) scores[ci] /= sum;
// Create and return a Classification object
return new Classification(instance, this, new LabelVector(getLabelAlphabet(), scores));
}
