Function round_float

datafusion/spark/src/function/math/round.rs:189–205

Round a floating-point value to the given number of decimal places using HALF_UP rounding mode (ties round away from zero). This matches Spark's `RoundBase` behaviour for `FloatType` / `DoubleType`, which internally converts the value to `BigDecimal` and rounds with `RoundingMode.HALF_UP`. # Arguments `value` – the floating-point number to round `scale` – number of decimal places to keep. - `sca

(value: T, scale: i32)

/// round_float(125.0, -1) → 130.0
/// ```
fn round_float<T: num_traits::Float>(value: T, scale: i32) -> T {
    if scale >= 0 {
        let factor = T::from(10.0f64.powi(scale)).unwrap_or_else(T::infinity);
        if factor.is_infinite() {
            // Very large positive scale — value is already precise enough, return as-is
            return value;
        }
        (value * factor).round() / factor
    } else {
        let factor = T::from(10.0f64.powi(-scale)).unwrap_or_else(T::infinity);
        if factor.is_infinite() {
            // Very large negative scale — any finite value rounds to 0
            return T::zero();
        }
        (value / factor).round() * factor
    }
}

/// Round an integer value to the given scale using HALF_UP rounding mode.
///