Re: Inaccurate results from numeric ln(), log(), exp() and pow() - Mailing list pgsql-hackers

On 10 December 2015 at 20:02, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> It seems to be a loss of 4 digits in every case I've seen.
>
> I wouldn't have a problem with, say, throwing in an extra DEC_DIGITS worth
> of rscale in each of these functions so that the discrepancies tend to
> favor more significant digits out, rather than fewer.  I don't know that
> it's worth trying to guarantee that the result is never fewer digits than
> before, and I certainly wouldn't want to make the rules a lot more complex
> than what's there now.  But perhaps we could cover most cases easily.
>
> Dean, do you want to recheck the patch with an eye to that?
>

OK, I'll take a look at it.

Regards,
Dean
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