Author: tdunning
Date: Fri Aug 20 03:22:06 2010
New Revision: 987368
URL: http://svn.apache.org/viewvc?rev=987368&view=rev
Log:
added InteractionValueEncoder for encoding interaction of two categorical
features into feature vectors
Added:
mahout/trunk/core/src/main/java/org/apache/mahout/vectors/InteractionValueEncoder.java
Added:
mahout/trunk/core/src/main/java/org/apache/mahout/vectors/InteractionValueEncoder.java
URL:
http://svn.apache.org/viewvc/mahout/trunk/core/src/main/java/org/apache/mahout/vectors/InteractionValueEncoder.java?rev=987368&view=auto
==============================================================================
---
mahout/trunk/core/src/main/java/org/apache/mahout/vectors/InteractionValueEncoder.java
(added)
+++
mahout/trunk/core/src/main/java/org/apache/mahout/vectors/InteractionValueEncoder.java
Fri Aug 20 03:22:06 2010
@@ -0,0 +1,82 @@
+/*
+ * 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.vectors;
+
+import org.apache.mahout.math.Vector;
+
+public class InteractionValueEncoder extends FeatureVectorEncoder {
+
+ protected static final int INTERACTION_VALUE_HASH_SEED_1 = 100;
+ protected static final int INTERACTION_VALUE_HASH_SEED_2 = 200;
+
+ protected InteractionValueEncoder(String name) {
+ super(name, 2);
+ }
+
+ /**
+ * Adds a value to a vector.
+ *
+ * @param originalForm The original form of the first value as a string.
+ * @param data The vector to which the value should be added.
+ */
+ @Override
+ public void addToVector(String originalForm, double w, Vector data) {
+ }
+
+ /**
+ * Adds a value to a vector.
+ *
+ * @param originalForm1 The original form of the first value as a string.
+ * @param originalForm2 The original form of the second value as a string.
+ * @param data The vector to which the value should be added.
+ */
+ public void addInteractionToVector(String originalForm1, String
originalForm2, Vector data) {
+ int probes = getProbes();
+ String name = getName();
+ for (int i = 0; i < probes; i++) {
+ int h1 = hash1(name, originalForm1, i, data.size());
+ int h2 = hash2(name, originalForm1, i, data.size());
+ int j = hash1(name, originalForm2, i, data.size());
+ int n = (h1 + j*h2) % data.size();
+ trace(String.format("%s:%s", originalForm1, originalForm2), n);
+ data.set(n, data.get(n) + 1);
+ }
+ }
+
+ /**
+ * Converts a value into a form that would help a human understand the
internals of how the value
+ * is being interpreted. For text-like things, this is likely to be a
list of the terms found with
+ * associated weights (if any).
+ *
+ * @param originalForm The original form of the value as a string.
+ * @return A string that a human can read.
+ */
+ @Override
+ public String asString(String originalForm) {
+ return String.format("%s:%s", getName(), originalForm);
+ }
+
+ protected int hash1(String term1, String term2, int probe, int
numFeatures) {
+ return hash(term1, term2,
probe+INTERACTION_VALUE_HASH_SEED_1,numFeatures);
+ }
+
+ protected int hash2(String term1, String term2, int probe, int
numFeatures) {
+ return hash(term1, term2,
probe+INTERACTION_VALUE_HASH_SEED_2,numFeatures);
+ }
+}
+
