title: Empty confusion matrix in Weka with test data
body: <p>I am classifying iris data using DECISION TREE (C4.5), RANDOM FOREST and  NAIVE BAYES. I am using the dataset downloaded from <a href="https://ai.arizona.edu/sites/ai/files/resources/iris-train.arff" rel="nofollow noreferrer">iris-train</a> and <a href="https://ai.arizona.edu/sites/ai/files/resources/iris-test.arff" rel="nofollow noreferrer">iris-test</a>. When I train the all networks everything is fine with proper results with 'classifier output', 'Detailed accuracy with class' and 'confusion matrix'. But, when I select the iris-test data in the Weka-explorer-classify-test options and select the iris-test file and in 'more options' select 'output prediction' as 'csv' and click start, I am getting the result as shown in the figure below. <a href="https://i.stack.imgur.com/8z5d8.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/8z5d8.jpg" alt="Weka output"></a>  The  'classifier output' is showing the classified samples correctly, but, 'Detailed accuracy with class' and 'confusion matrix' is with all values zeros. Any suggestion where I am going wrong in selecting any option. Thank you.</p>