Shehroz Khan's answer to Is it possible to compute R-squared score in Weka for logistic regression? - Quora

R-squared score is computed for regression problems. Logistic regression, as the name suggests, is not regression but binary classification problem. Therefore, R-squared statistics cannot be computed for logistic regression. Other performance metrics, such as, accuracy, precision, recall etc are more relevant in this context. To answer your question - No R-squared score is not a valid metric for logistic regression, be it using Weka or any other ML library or even your own algorithm.