RMSE is a commonly used error metric to measure the performance of regression models, but it is also possible to use it in a classification system. The RMSE measures the standard deviation of the predictions from the ground-truth. This is the relationship between RMSE and classification.
RMSE(yhat, y, type.of = c("numeric", "text", "scalable"))A predicted value vector
A real value vector
Type of response variable, either: numeric for the numerical response variables, text for the class response variables without growing relationship or scalable for the class response variables without growing relationship.