@mengxr ok ?
```
/**
       * 0 means "don't know" and positive values mean "confident that the prediction should be 1".
       * Negative values means "confident that the prediction should be 0".
       * We have in this case used some kind of weighted RMSE. The weight is the absolute value of the
       * confidence. The error is the difference between prediction and either 1 or 0, depending on
       * whether r is positive or negative.
       */
```