mgaido91 commented on code in PR #54676:
URL: https://github.com/apache/spark/pull/54676#discussion_r2935611554
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sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/mathExpressions.scala:
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@@ -418,10 +418,28 @@ case class Cosh(child: Expression) extends
UnaryMathExpression(math.cosh, "COSH"
since = "3.0.0",
group = "math_funcs")
case class Acosh(child: Expression)
- extends UnaryMathExpression((x: Double) => StrictMath.log(x + math.sqrt(x *
x - 1.0)), "ACOSH") {
+ extends UnaryMathExpression((x: Double) => x match {
+ // in case of large values, the square would lead to Infinity; also, - 1
would be ignored due
+ // to numeric precision. So log(x + sqrt(x * x - 1)) becomes log(2x) =
log(2) + log(x) for
+ // positive values.
+ case x if x >= Math.sqrt(Double.MaxValue) =>
Review Comment:
I see, thanks fot the heads-up @sarutak ! In practice I think the only
change may be the efficiency in the range `2^28` -
`Math.sqrt(Double.MaxValue)`. After `2 ^28` the +1 is ignored due to the
representational limits of the double, so the results are exaclty the same. I
can open a followup PR to align or I can also try to benchmark wihich option is
more efficient and decide based on that. Let me know how you think is best to
proceed.
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