[GNC] Decimal Precision Entering Mutual Fund Transactions

[Robin Chattopadhyay]

I have created Bug #798352 https://bugs.gnucash.org/show_bug.cgi?id=798352

Thanks,
Robin

On Sun, Oct 24, 2021 at 4:47 PM John Ralls <jralls at ceridwen.us> wrote:

>
>
> > On Oct 24, 2021, at 2:24 PM, Robin Chattopadhyay <robinraymn at gmail.com>
> wrote:
> >
> > Hi all-
> >
> > SETUP:
> > Version 4.8 (plus the commit to fix Bug 798327)
> > OS: Ubuntu 20.04 LTS
> >
> > SCENARIO:
> > My wife recently started a new job where the 401k provider maintains the
> > mutual fund positions at nine decimal places (and the price is two
> decimal
> > places precision). I set up the security with the fraction traded set to
> > 1*10^9, I set up the account's fraction traded to 'Use Commodity Value'
> >
> > When entering a transaction into the register directly with the full nine
> > decimal places, GnuCash cuts off the last digit and appears to only save
> up
> > to the 8th significant digit thus introducing a small (but annoying)
> > position difference between my books and the recordkeeper.
> >
> > However, if I import the transactions from the OFX file downloaded from
> the
> > recordkeeper's website, the full nine digits are imported and displayed
> in
> > the register.
> >
> > Another related item is that the share amount displayed changes from 9
> > digits to 8 digits back to 9 when moving between transactions. For
> example,
> > a transaction with 4.008105604 shares shows 4.0081056 as long as that
> > transaction has the focus.
> >
> > The workaround for now appears to only import transactions from the OFX
> > file, which is fine but it does seem weird to have this inconsistent
> > experience.
> >
> > I glanced through Register-related bugs but I didn't see anything that
> > jumped out at me as an open existing bug that would explain this
> behavior.
> > (I'll concede that my search may have been lacking because previous
> > discussion on this list related to precision and integer math have gone
> > over my head)
>
> I can replicate that. The truncation happens when one tabs out of the
> field, suggesting an off-by-one clamp the register somewhere.
>
> Regards,
> John Ralls
>
>