Method evaluate

datafusion/functions-aggregate/src/correlation.rs:192–223

(&mut self)

    }

    fn evaluate(&mut self) -> Result<ScalarValue> {
        let covar = self.covar.evaluate()?;
        let stddev1 = self.stddev1.evaluate()?;
        let stddev2 = self.stddev2.evaluate()?;

        // First check if we have NaN values by examining the internal state
        // This handles the case where both inputs are NaN even with count=1
        let mean1 = self.covar.get_mean1();
        let mean2 = self.covar.get_mean2();

        // If both means are NaN, then both input columns contain only NaN values
        if mean1.is_nan() && mean2.is_nan() {
            return Ok(ScalarValue::Float64(Some(f64::NAN)));
        }
        let n = self.covar.get_count();
        if mean1.is_nan() || mean2.is_nan() || n < 2 {
            return Ok(ScalarValue::Float64(None));
        }

        if let ScalarValue::Float64(Some(c)) = covar
            && let ScalarValue::Float64(Some(s1)) = stddev1
            && let ScalarValue::Float64(Some(s2)) = stddev2
        {
            if s1 == 0_f64 || s2 == 0_f64 {
                return Ok(ScalarValue::Float64(None));
            } else {
                return Ok(ScalarValue::Float64(Some(c / s1 / s2)));
            }
        }

        Ok(ScalarValue::Float64(None))
    }

    fn size(&self) -> usize {
        size_of_val(self) - size_of_val(&self.covar) + self.covar.size()