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From sro...@apache.org
Subject svn commit: r808405 - in /lucene/mahout/trunk/core/src: main/java/org/apache/mahout/cf/taste/impl/model/ test/java/org/apache/mahout/cf/taste/impl/recommender/
Date Thu, 27 Aug 2009 12:58:52 GMT
Author: srowen
Date: Thu Aug 27 12:58:52 2009
New Revision: 808405

URL: http://svn.apache.org/viewvc?rev=808405&view=rev
Log:
Added "plus anonymous user" decorators to enable anonymous user recommendations. Also snuck
in a fix to a unit test.

Added:
    lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/model/PlusAnonymousUserDataModel.java
    lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/model/PlusAnonymousUserLongPrimitiveIterator.java
Modified:
    lucene/mahout/trunk/core/src/test/java/org/apache/mahout/cf/taste/impl/recommender/GenericItemBasedRecommenderTest.java

Added: lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/model/PlusAnonymousUserDataModel.java
URL: http://svn.apache.org/viewvc/lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/model/PlusAnonymousUserDataModel.java?rev=808405&view=auto
==============================================================================
--- lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/model/PlusAnonymousUserDataModel.java
(added)
+++ lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/model/PlusAnonymousUserDataModel.java
Thu Aug 27 12:58:52 2009
@@ -0,0 +1,198 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 org.apache.mahout.cf.taste.impl.model;
+
+import org.apache.mahout.cf.taste.common.Refreshable;
+import org.apache.mahout.cf.taste.common.TasteException;
+import org.apache.mahout.cf.taste.impl.common.FastIDSet;
+import org.apache.mahout.cf.taste.impl.common.LongPrimitiveIterator;
+import org.apache.mahout.cf.taste.model.DataModel;
+import org.apache.mahout.cf.taste.model.PreferenceArray;
+
+import java.util.Collection;
+
+/**
+ * <p>This {@link DataModel} decorator class is useful in a situation where you wish
to recommend
+ * to a user that doesn't really exist yet in your actual {@link DataModel}. For example
maybe you
+ * wish to recommend DVDs to a user who has browsed a few titles on your DVD store site,
but, the
+ * user is not yet registered.</p>
+ *
+ * <p>This enables you to temporarily add a temporary user to an existing {@link DataModel}
in a way
+ * that recommenders can then produce recommendations anyway. To do so, wrap your real implementation
+ * in this class:</p>
+ *
+ * <p><pre>
+ * DataModel realModel = ...;
+ * DataModel plusModel = new PlusAnonymousUserDataModel(realModel);
+ * ...
+ * ItemSimilarity similarity = new LogLikelihoodSimilarity(realModel); // not plusModel
+ * </pre></p>
+ *
+ * <p>But, continue to use <code>realModel</code> as input to other components.
+ * To recommend, first construct and
+ * set the temporary user information on the model and then simply call the recommender.
+ * The <code>synchronized</code> block exists to remind you that this is of course
not
+ * thread-safe. Only one set of temp data can be inserted into the model and used at one
+ * time.</p>
+ *
+ * <p><pre>
+ * Recommender recommender = ...;
+ * ...
+ * synchronized(...) {
+ *   PreferenceArray tempPrefs = ...;
+ *   plusModel.setTempPrefs(tempPrefs);
+ *   recommender.recommend(PlusAnonymousUserDataModel.TEMP_USER_ID, 10);
+ * }
+ * </pre></p>
+ */
+public final class PlusAnonymousUserDataModel implements DataModel {
+
+  public static final long TEMP_USER_ID = Long.MIN_VALUE;
+
+  private final DataModel delegate;
+  private PreferenceArray tempPrefs;
+  private final FastIDSet prefItemIDs;
+
+  public PlusAnonymousUserDataModel(DataModel delegate) {
+    this.delegate = delegate;
+    this.prefItemIDs = new FastIDSet();
+  }
+
+  public void setTempPrefs(PreferenceArray prefs) {
+    this.tempPrefs = prefs;
+    this.prefItemIDs.clear();
+    for (int i = 0; i < prefs.length(); i++) {
+      this.prefItemIDs.add(prefs.getItemID(i));
+    }
+  }
+
+  @Override
+  public LongPrimitiveIterator getUserIDs() throws TasteException {
+    return new PlusAnonymousUserLongPrimitiveIterator(delegate.getUserIDs(), TEMP_USER_ID);
+  }
+
+  @Override
+  public PreferenceArray getPreferencesFromUser(long userID) throws TasteException {
+    if (userID == TEMP_USER_ID) {
+      return tempPrefs;
+    } else {
+      return delegate.getPreferencesFromUser(userID);
+    }
+  }
+
+  @Override
+  public FastIDSet getItemIDsFromUser(long userID) throws TasteException {
+    if (userID == TEMP_USER_ID) {
+      return prefItemIDs;
+    } else {
+      return delegate.getItemIDsFromUser(userID);
+    }
+  }
+
+  @Override
+  public LongPrimitiveIterator getItemIDs() throws TasteException {
+    return delegate.getItemIDs();
+    // Yeah ignoring items that only the plus-one user knows about... can't really happen
+  }
+
+  @Override
+  public PreferenceArray getPreferencesForItem(long itemID) throws TasteException {
+    PreferenceArray delegatePrefs = delegate.getPreferencesForItem(itemID);
+    for (int i = 0; i < tempPrefs.length(); i++) {
+      if (tempPrefs.getItemID(i) == itemID) {
+        int length = delegatePrefs.length();
+        PreferenceArray newPreferenceArray = new GenericItemPreferenceArray(length + 1);
+        for (int j = 0; j < length; j++) {
+          newPreferenceArray.set(j, delegatePrefs.get(j));
+        }
+        newPreferenceArray.set(length, tempPrefs.get(i));
+        newPreferenceArray.sortByUser();
+        return newPreferenceArray;
+      }
+    }
+    return delegatePrefs;
+  }
+
+  @Override
+  public Float getPreferenceValue(long userID, long itemID) throws TasteException {
+    if (userID == TEMP_USER_ID) {
+      for (int i = 0; i < tempPrefs.length(); i++) {
+        if (tempPrefs.getItemID(i) == itemID) {
+          return tempPrefs.getValue(i);
+        }
+      }
+      return null;
+    } else {
+      return delegate.getPreferenceValue(userID, itemID);
+    }
+  }
+
+  @Override
+  public int getNumItems() throws TasteException {
+    return delegate.getNumItems();
+  }
+
+  @Override
+  public int getNumUsers() throws TasteException {
+    return delegate.getNumUsers() + 1;
+  }
+
+  @Override
+  public int getNumUsersWithPreferenceFor(long... itemIDs) throws TasteException {
+    boolean hasAll = true;
+    for (long itemID : itemIDs) {
+      boolean found = false;
+      for (int i = 0; i < tempPrefs.length(); i++) {
+        if (tempPrefs.getItemID(i) == itemID) {
+          found = true;
+          break;
+        }
+      }
+      if (!found) {
+        hasAll = false;
+        break;
+      }
+    }
+    return delegate.getNumUsersWithPreferenceFor(itemIDs) + (hasAll ? 1 : 0);
+  }
+
+  @Override
+  public void setPreference(long userID, long itemID, float value) throws TasteException
{
+    if (userID == TEMP_USER_ID) {
+      throw new UnsupportedOperationException();
+    } else {
+      delegate.setPreference(userID, itemID, value);
+    }
+  }
+
+  @Override
+  public void removePreference(long userID, long itemID) throws TasteException {
+    if (userID == TEMP_USER_ID) {
+      throw new UnsupportedOperationException();
+    } else {
+      delegate.removePreference(userID, itemID);
+    }
+  }
+
+  @Override
+  public void refresh(Collection<Refreshable> alreadyRefreshed) {
+    delegate.refresh(alreadyRefreshed);
+  }
+
+}
+

Added: lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/model/PlusAnonymousUserLongPrimitiveIterator.java
URL: http://svn.apache.org/viewvc/lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/model/PlusAnonymousUserLongPrimitiveIterator.java?rev=808405&view=auto
==============================================================================
--- lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/model/PlusAnonymousUserLongPrimitiveIterator.java
(added)
+++ lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/model/PlusAnonymousUserLongPrimitiveIterator.java
Thu Aug 27 12:58:52 2009
@@ -0,0 +1,87 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 org.apache.mahout.cf.taste.impl.model;
+
+import org.apache.mahout.cf.taste.impl.common.LongPrimitiveIterator;
+
+final class PlusAnonymousUserLongPrimitiveIterator implements LongPrimitiveIterator {
+
+  private final LongPrimitiveIterator delegate;
+  private final long extraDatum;
+  private boolean datumConsumed;
+
+  PlusAnonymousUserLongPrimitiveIterator(LongPrimitiveIterator delegate, long extraDatum)
{
+    this.delegate = delegate;
+    this.extraDatum = extraDatum;
+    datumConsumed = false;
+  }
+
+  @Override
+  public long nextLong() {
+    if (datumConsumed) {
+      return delegate.nextLong();
+    } else {
+      if (delegate.hasNext()) {
+        long delegateNext = delegate.peek();
+        if (extraDatum <= delegateNext) {
+          datumConsumed = true;
+          return extraDatum;
+        } else {
+          return delegate.next();
+        }
+      } else {
+        datumConsumed = true;
+        return extraDatum;
+      }
+    }
+  }
+
+  @Override
+  public long peek() {
+    if (datumConsumed) {
+      return delegate.peek();
+    } else {
+      if (delegate.hasNext()) {
+        long delegateNext = delegate.peek();
+        if (extraDatum <= delegateNext) {
+          return extraDatum;
+        } else {
+          return delegateNext;
+        }
+      } else {
+        return extraDatum;
+      }
+    }
+  }
+
+  @Override
+  public boolean hasNext() {
+    return !datumConsumed || delegate.hasNext();
+  }
+
+  @Override
+  public Long next() {
+    return nextLong();
+  }
+
+  @Override
+  public void remove() {
+    throw new UnsupportedOperationException();
+  }
+
+}

Modified: lucene/mahout/trunk/core/src/test/java/org/apache/mahout/cf/taste/impl/recommender/GenericItemBasedRecommenderTest.java
URL: http://svn.apache.org/viewvc/lucene/mahout/trunk/core/src/test/java/org/apache/mahout/cf/taste/impl/recommender/GenericItemBasedRecommenderTest.java?rev=808405&r1=808404&r2=808405&view=diff
==============================================================================
--- lucene/mahout/trunk/core/src/test/java/org/apache/mahout/cf/taste/impl/recommender/GenericItemBasedRecommenderTest.java
(original)
+++ lucene/mahout/trunk/core/src/test/java/org/apache/mahout/cf/taste/impl/recommender/GenericItemBasedRecommenderTest.java
Thu Aug 27 12:58:52 2009
@@ -42,6 +42,7 @@
     assertEquals(0.18, firstRecommended.getValue(), EPSILON);
     recommender.refresh(null);
     recommended = recommender.recommend(1, 1);
+    firstRecommended = recommended.get(0);    
     assertEquals(2, firstRecommended.getItemID());
     assertEquals(0.18, firstRecommended.getValue(), EPSILON);
   }
@@ -116,7 +117,8 @@
   }
 
   /**
-   * Contributed test case that verifies fix for bug <a href="http://sourceforge.net/tracker/index.php?func=detail&amp;aid=1396128&amp;group_id=138771&amp;atid=741665">
+   * Contributed test case that verifies fix for bug
+   * <a href="http://sourceforge.net/tracker/index.php?func=detail&amp;aid=1396128&amp;group_id=138771&amp;atid=741665">
    * 1396128</a>.
    */
   public void testBestRating() throws Exception {



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