getChan commented on code in PR #19575:
URL: https://github.com/apache/datafusion/pull/19575#discussion_r2656680519
##########
datafusion/functions/src/math/factorial.rs:
##########
@@ -92,50 +92,79 @@ impl ScalarUDFImpl for FactorialFunc {
}
}
+const FACTORIALS: [i64; 21] = [
+ 1,
+ 1,
+ 2,
+ 6,
+ 24,
+ 120,
+ 720,
+ 5040,
+ 40320,
+ 362880,
+ 3628800,
+ 39916800,
+ 479001600,
+ 6227020800,
+ 87178291200,
+ 1307674368000,
+ 20922789888000,
+ 355687428096000,
+ 6402373705728000,
+ 121645100408832000,
+ 2432902008176640000,
+];
+
/// Factorial SQL function
fn factorial(args: &[ArrayRef]) -> Result<ArrayRef> {
match args[0].data_type() {
Int64 => {
- let arg = downcast_named_arg!((&args[0]), "value", Int64Array);
- Ok(arg
- .iter()
- .map(|a| match a {
- Some(a) => (2..=a)
- .try_fold(1i64, i64::checked_mul)
- .ok_or_else(|| {
-
arrow_datafusion_err!(ArrowError::ComputeError(format!(
- "Overflow happened on FACTORIAL({a})"
- )))
- })
- .map(Some),
- _ => Ok(None),
- })
- .collect::<Result<Int64Array>>()
- .map(Arc::new)? as ArrayRef)
+ let result: Int64Array =
+ args[0].as_primitive::<Int64Type>().try_unary(|a| {
+ if a < 0 {
+ Ok(1)
+ } else if a < FACTORIALS.len() as i64 {
+ Ok(FACTORIALS[a as usize])
+ } else {
+ Err(ArrowError::ComputeError(format!(
Review Comment:
thanks! applied it
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