Method state

datafusion-examples/examples/udf/simple_udaf.rs:76–81

This function serializes our state to `ScalarValue`, which DataFusion uses to pass this state between execution stages. Note that this can be arbitrary data.

(&mut self)

    // to pass this state between execution stages.
    // Note that this can be arbitrary data.
    fn state(&mut self) -> Result<Vec<ScalarValue>> {
        Ok(vec![
            ScalarValue::from(self.prod),
            ScalarValue::from(self.n),
        ])
    }

    // DataFusion expects this function to return the final value of this aggregator.
    // in this case, this is the formula of the geometric mean