pub trait MeanAbsoluteError {
    type Output;
    // Required method
    fn mae(&self) -> Self::Output;
}Expand description
Compute the mean absolute error (MAE) of the object; more formally, we define the MAE as the average of the absolute differences between the predicted and actual values:
$$ Err = \frac{1}{n} \sum_{i=1}^{n} |y_i - \hat{y}_i| $$