public SVDRecommender(DataModel dataModel, Factorizer factorizer, CandidateItemsStrategy candidateItemsStrategy, PersistenceStrategy persistenceStrategy)
: base(dataModel, candidateItemsStrategy)
{
Action refreshRunnable = null;
this.factorizer = factorizer;
this.persistenceStrategy = persistenceStrategy;
try
{
this.factorization = persistenceStrategy.load();
}
catch (IOException exception)
{
throw new TasteException("Error loading factorization", exception);
}
if (this.factorization == null)
{
this.train();
}
if (refreshRunnable == null)
{
refreshRunnable = () => this.train();
}
this.refreshHelper = new RefreshHelper(refreshRunnable);
this.refreshHelper.addDependency(this.getDataModel());
this.refreshHelper.addDependency(factorizer);
this.refreshHelper.addDependency(candidateItemsStrategy);
}
public override bool Equals(object o)
{
if (o is Factorization)
{
Factorization factorization = (Factorization)o;
return(((this.userIDMapping.Equals(factorization.userIDMapping) && this.itemIDMapping.Equals(factorization.itemIDMapping)) && Utils.ArrayDeepEquals(this.userFeatures, factorization.userFeatures)) && Utils.ArrayDeepEquals(this.itemFeatures, factorization.itemFeatures));
}
return(false);
}
protected static void writeBinary(Factorization factorization, Stream outFile)
{
int num2;
BinaryWriter writer = new BinaryWriter(outFile);
writer.Write(factorization.numFeatures());
writer.Write(factorization.numUsers());
writer.Write(factorization.numItems());
foreach (KeyValuePair <long, int?> pair in factorization.getUserIDMappings())
{
if (pair.Value.HasValue)
{
long key = pair.Key;
writer.Write(pair.Value.Value);
writer.Write(key);
try
{
double[] numArray = factorization.getUserFeatures(key);
num2 = 0;
while (num2 < factorization.numFeatures())
{
writer.Write(numArray[num2]);
num2++;
}
}
catch (NoSuchUserException exception)
{
throw new IOException("Unable to persist factorization", exception);
}
}
}
foreach (KeyValuePair <long, int?> pair2 in factorization.getItemIDMappings())
{
if (pair2.Value.HasValue)
{
long num3 = pair2.Key;
writer.Write(pair2.Value.Value);
writer.Write(num3);
try
{
double[] numArray2 = factorization.getItemFeatures(num3);
for (num2 = 0; num2 < factorization.numFeatures(); num2++)
{
writer.Write(numArray2[num2]);
}
}
catch (NoSuchItemException exception2)
{
throw new IOException("Unable to persist factorization", exception2);
}
}
}
}
private void train()
{
this.factorization = this.factorizer.factorize();
try
{
this.persistenceStrategy.maybePersist(this.factorization);
}
catch (IOException exception)
{
throw new TasteException("Error persisting factorization", exception);
}
}
public void maybePersist(Factorization factorization)
{
Stream outFile = null;
try
{
log.info("Writing factorization to {0}...", new object[] { this.file });
outFile = new FileStream(this.file, FileMode.OpenOrCreate, FileAccess.Write);
writeBinary(factorization, outFile);
}
finally
{
outFile.Close();
}
}
