srowen edited a comment on issue #25279: [SPARK-28519][SQL] Use StrictMath log, pow functions for platform independence URL: https://github.com/apache/spark/pull/25279#issuecomment-519726687 Yeah this is great info. I understand that java.lang.Math is allowed to return slightly different results from what some IEEE standard dictates but there is a most-correct answer in double precision, and these assembly code implementations in the x86 JVM seem to be clearly less correct for non-corner cases like log(3). That surprises me. There's a thread forwarded to dev@ with some additional info. Anyway, I think it's a good move to make the actual log() function in SQL return values that are consistent cross-platform and consistent with StrictMath, even if that doesn't mean we need to use StrictMath for every log call internally (for many usages in MLlib it won't matter at all). And because there is basically no meaningful performance change.
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