What are the positions of the elements of the confusion matrix? How to calculate accuracy and fscore of the matrix of confusion using matlab?

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Gledson Melotti 2018-3-15

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https://ww2.mathworks.cn/matlabcentral/answers/388501-what-are-the-positions-of-the-elements-of-the-confusion-matrix-how-to-calculate-accuracy-and-fscore

回答： Morteza 2019-7-12

For example, the confusion matrix (confMat) is: confMat(1,1) = 104, confMat(1,2) = 1242, confMat(2,1) = 14 and confMat(2,2) = 14199. In matalab using accuracy = mean(diag(confMat)) provides 0.5381. However, using the relation: accuracy=(TP+TN)/(TP+TN+FP+FN)=91.92. I have two classes and unbalanced dataset.

I believe the matrix of confusion in matlab is: confMat(1,1) = TN, confMat (1,2) = FP, confMat (2,1) = FN and confMat(2,2) = TP. Whereas: Horizontal = predicted class and Vertical = real class