Re: How to write Entropy class in java?

please help me in calling the entropy method
I don't know how to call this method inside my code, I have read a file (arff) file in my code and I am using weka package to run some classifiers over my file but I don't know how to calculate a class entropy for the classes inside my file
please help

Please don't hijack someone else's post. I have moved your post to its own thread.

Now to your problem, what have you tried? You don't give us much information, and weka is a 3rd party library that probably few of us here have experience with. I'd recommend posting an SSCCE, a link to the 3rd party API, and in specific terms describe what you are trying to accomplish.

Can Any body help me in this
I need to implement all classifiers that are defined in weka on my file
I have read the file:
// Read all the instances in the file (ARFF, CSV, XRFF, ...)

Code java:

---

 DataSource source = new DataSource("iris.arff");
   Instances instances = source.getDataSet();
 
  // Make the last attribute be the class
  instances.setClassIndex(instances.numAttributes() - 1);

---

// now I need to calculate the class entropy of the classes which is already known to the java enviroment (becuase I assigned the index as the last one of the attribute) ????

please help me as I need it for my work urgently

Please don't start new threads referring to the same question. I have merged your two threads. And please don't mention urgency - it is all relative...everyone's post is urgent to them, and saying your is more so appears selfish and does not do you any favors in receiving help

To address your question - take a look at the ContingencyTables class in weka.