@Override
protected FeatureValue calcFeatureValue(Decorable di) {
// Feature applicable only to edges
if (!(di instanceof Edge)) {
throw new UnsupportedTypeException(
"Feature only defined for edges: " + di.getClass().getCanonicalName());
}
// Feature applicable only to binary edges
Edge e = (Edge) di;
if (e.numNodes() != 2) {
throw new UnsupportedTypeException("Feature only defined for binary edges: " + e.numNodes());
}
Iterator<Node> itr = e.getAllNodes();
Node n1 = itr.next();
Node n2 = itr.next();
FeatureValue fv1 = n1.getFeatureValue(fid);
FeatureValue fv2 = n2.getFeatureValue(fid);
if (fv1.equals(FeatureValue.UNKNOWN_VALUE) || fv2.equals(FeatureValue.UNKNOWN_VALUE)) {
return val0;
}
// If sparse value is specified and at least one value is not the sparse
// value, return 0.
if (commonvalue != null && fv1.equals(commonvalue)) {
return val0;
}
return fv1.getStringValue().equals(fv2.getStringValue()) ? val1 : val0;
}
private double getSimilarity(Node item1, Node item2, boolean normalize) {
if (initialize) {
initialize();
}
// If either value is unknown, return 0 similarity
if (!item1.hasFeatureValue(featureid) || !item2.hasFeatureValue(featureid)) {
return 0;
}
String[] string1 = item1.getFeatureValue(featureid).getStringValue().split(delimiter);
Set<String> string1set = new HashSet<String>(string1.length);
for (String s : string1) {
if (s.trim().length() != 0) {
string1set.add(s);
}
}
String[] string2 = item2.getFeatureValue(featureid).getStringValue().split(delimiter);
Set<String> string2set = new HashSet<String>(string2.length);
for (String s : string2) {
if (s.trim().length() != 0) {
string2set.add(s);
}
}
Set<String> isect = new HashSet<String>(string1set);
isect.removeAll(string2set);
if (isect.isEmpty()) {
// Save computation by breaking early
return 0;
}
double numerator = 0;
for (String fid : isect) {
double val1 = ((NumValue) item1.getFeatureValue(fid)).getNumber();
double val2 = ((NumValue) item2.getFeatureValue(fid)).getNumber();
numerator += val1 * val2;
}
double denom1 = 0;
for (String fid : string1set) {
double val1 = ((NumValue) item1.getFeatureValue(fid)).getNumber();
if (val1 == 0) {
throw new InvalidStateException("Feature value cannot be 0: " + fid + " for " + item1);
}
denom1 += val1 * val1;
}
double denom2 = 0;
for (String fid : string2set) {
double val2 = ((NumValue) item2.getFeatureValue(fid)).getNumber();
if (val2 == 0) {
throw new InvalidStateException("Feature value cannot be 0: " + fid + " for " + item2);
}
denom2 += val2 * val2;
}
double finalsim =
denom1 != 0 && denom2 != 0 ? (numerator / (Math.sqrt(denom1) * Math.sqrt(denom2))) : 0;
return finalsim;
}