[GitHub] metron pull request #872: METRON-1366: Add an entropy stellar function
Github user asfgit closed the pull request at: https://github.com/apache/metron/pull/872 ---
[GitHub] metron pull request #872: METRON-1366: Add an entropy stellar function
Github user cestella commented on a diff in the pull request:
https://github.com/apache/metron/pull/872#discussion_r160532240
--- Diff:
metron-analytics/metron-statistics/src/main/java/org/apache/metron/statistics/informationtheory/InformationTheoryUtil.java
---
@@ -0,0 +1,52 @@
+/*
+ *
+ * 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.metron.statistics.informationtheory;
+
+import java.util.Map;
+
+public enum InformationTheoryUtil {
+ INSTANCE;
+ private static final double LOG2 = Math.log(2);
+
+ public double entropy(Map counts, double logOfBase) {
+double ret = 0.0;
+int n = 0;
+if(counts == null || counts.isEmpty()) {
+ return ret;
+}
+for(Integer f : counts.values()) {
+ n+=f;
+}
+
+for(Integer f : counts.values()) {
+ double p = f.doubleValue()/n;
+ ret -= p * Math.log(p) / logOfBase;
+}
+return ret;
+ }
+
--- End diff --
This is super cool, I actually looked at how this might impact performance
as a PR against your repo
[here](https://github.com/ottobackwards/stream_entropy/pull/1)
---
[GitHub] metron pull request #872: METRON-1366: Add an entropy stellar function
Github user ottobackwards commented on a diff in the pull request:
https://github.com/apache/metron/pull/872#discussion_r157332543
--- Diff:
metron-analytics/metron-statistics/src/main/java/org/apache/metron/statistics/informationtheory/InformationTheoryUtil.java
---
@@ -0,0 +1,52 @@
+/*
+ *
+ * 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.metron.statistics.informationtheory;
+
+import java.util.Map;
+
+public enum InformationTheoryUtil {
+ INSTANCE;
+ private static final double LOG2 = Math.log(2);
+
+ public double entropy(Map counts, double logOfBase) {
+double ret = 0.0;
+int n = 0;
+if(counts == null || counts.isEmpty()) {
+ return ret;
+}
+for(Integer f : counts.values()) {
+ n+=f;
+}
+
+for(Integer f : counts.values()) {
+ double p = f.doubleValue()/n;
+ ret -= p * Math.log(p) / logOfBase;
+}
+return ret;
+ }
+
--- End diff --
https://github.com/ottobackwards/stream_entropy
---
[GitHub] metron pull request #872: METRON-1366: Add an entropy stellar function
GitHub user cestella opened a pull request:
https://github.com/apache/metron/pull/872
METRON-1366: Add an entropy stellar function
## Contributor Comments
Trending entropy for various volumetric statistics (e.g. netflow data) has
been a useful metric for intrusion detection (see
http://www.cs.bu.edu/techreports/pdf/2005-002-anomaly-mining.pdf). To wit, it
makes some sense to add an entropy calculation for Stellar. Used in conjunction
with the profiler and an outlier detector, we can recreate the work of Lakhina
referenced above.
You can validate this from the REPL:
* `IT_ENTROPY({ 'a' : 10, 'b' : 5, 'c' : 5} )` should yield `1.5`
* By the definition of Entropy: `H(X) = -p(a)*log_2(p(a)) -
p(b)*log_2(p(b)) - p(c)*log_2(p(c)) = -0.5*-1 - 0.25*-2 - 0.25*-2 = 1.5`
* `IT_ENTROPY({})` should yield `0.0`
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You can merge this pull request into a Git repository by running:
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Alternatively you can review and apply these changes as the patch at:
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To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #872
commit d4494854e482e2532f707b28ef2f891d13e129f3
Author: cstella
Date: 2017-12-15T23:25:50Z
Added entropy function.
---
