Don't trust MS Excel when it comes to accuracy

[J-F Garnier]

(06-04-2023 04:42 PM)DA74254 Wrote:  Both Excel and Libreoffice Calc claims to have 15 digits accuracy. Not remotely as accurate as SM/WP calcs, of course.

Anyway, just to test the routine, I dialled in GammaLN(51) in order to calculate 50!.
While the corrct answer, confirmed with both Free/Plus42 and WP43, is about 3,041409320171338x10^64, Excel comes up with 3,0044...x10^64.
Libreoffice comes up with: 3,04140932017131x10^64.
Notice that the last digit (1, instead of 3) is incorrect. Excel cr*pped out at the second digit..

Looks like basic MS bashing...
I can't reproduce your "so bad result" on my old Excel 2010
Both GAMMALN(51) and GAMMALN.PRECISE(51) give 148.477766951773
and EXP(GAMMALN(51)) = 3.0414093201713 e+64
Where is the bug? :-(

Don't trust without checking.

J-F