random number generators for calc

[Eike Rathke]

Hi,

On Wednesday, 2012-11-28 17:41:14 -0500, Kohei Yoshida wrote:
> On Wed, Nov 28, 2012 at 5:07 PM, tino <ttk448 at gmail.com> wrote:
> > > Well, re-implementing the existing RAND and RANDBETWEEN with the new
> > > generator is no brainer.

Btw, see the pointers I added to
https://bugs.freedesktop.org/show_bug.cgi?id=33365#c13

> > Not sure I understand. My suggestion is that boost::mt19937 is the
> > only underlying generator algorithm (generating int's) which is then
> > transformed to get RAND() and RANDBETWEEN(i,j).

Isn't boost::mt19937 somewhat overkill for the simple RAND() functions?

> > Yet both are simple
> > uniform distributions but the user might need Normal distributed
> > random variables and then RAND() is of little use. So a function like
> > RANDNORMAL() which generates N(0,1) (still using boost::mt19937)
> > random numbers would be a useful addition, wouldn't it?
> >
> 
> Ah ok. I think I mis-understood. Bear with me, as I'm not that versed with
> random number generation algorithms at the moment.
> 
> Well, my position is that, since you know the subject matter very well, and
> if you think it's a useful addition then I'm with you.
> 
> My only concern is that, we try to be compliant with ODF formula
> specification, and I'm not sure how adding a custom function (that only we
> understand) would affect that compliance and interoperability with other
> ODF generators.

If we wrote such functions as, for example, ORG.LIBREOFFICE.RANDNORMAL
we would be compliant, similar to other functions listed at
http://wiki.documentfoundation.org/Development/ODF_Implementer_Notes#LibreOffice_OpenFormula_extensions

Of course interoperability depends on other ODF readers' implementation.

  Eike

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