where is the error of following code to calculate confusionmat?

predictedLabels = predict(classifier, testFeatures);
testLabels = testSet.Labels;
confMat = confusionmat(testLabels, predictedLabels);
confMat = bsxfun(@rdivide,confMat,sum(confMat,2))

error is: G and GHAT need to have same number of rows

[Walter Roberson]

What shows up for size(testLabels), size(predictedLabels) ?

Answer 1

[Snehal]

Hi @Rafid Mustafiz,

I see you are encountering an error while using ‘confusionmat’.  

This issue arises because MATLAB’s ‘confusionmat’ function requires both input vectors - the true labels and the predicted labels to have the same length and to correspond to the same set of data samples.

Consider checking your input parameters ‘testLabels’ and ‘predictedLabels’ before passing to ‘confusionmat’

Below is a sample code on how you can use ‘confusionmat’ function:

g1 = [3 2 2 3 1 1]';	% Known groups 
g2 = [4 2 3 NaN 1 1]'; % Predicted groups 
% note that g1 and g2 have same size 
C = confusionmat(g1,g2) 

You may refer to the following documentation for more information on ‘confusionmat’:

https://www.mathworks.com/help/stats/confusionmat.html 

Hope this helps!