[GNC] problem setting the price of a share

Tue Sep 18 23:29:07 EDT 2018

No, GnuCash has never, ever, stored any number in floating point. Stored numbers in GnuCash have been rationals from the very beginning. It was changed in 2.6.8 to always round prices for display so that they’d always appear in decimal form to the user, but the code that did it was overwhelmed by the increased precision in GnuCash 3 so prices started displaying as rationals again. That’s fixed for 3.3, though there’s a preference to override it and display rationals if the user prefers the exact value.

Most calculations in GnuCash are in rationals. There are a couple of exceptions, the most notable being interest/time-value-of-money calculations because they require exponentiation and there isn’t yet a rational exponentiation operator in GnuCash. I’ve started writing one, but set it aside to deal with more pressing bugs.

Regards,
John Ralls

> On Sep 18, 2018, at 4:22 PM, David Carlson <david.carlson.417 at gmail.com> wrote:
> 
> There have been several discussions over the years around various aspects
> of the topics of numeric accuracy, displaying accurate values vs easily
> readable values, whether GnuCash records do or do not match brokers'
> reports or newspaper stock price listings, and even whether the GnuCash
> price database is properly configured and whether data is correctly
> extracted from it for various reports. If you want to research the topic
> further there are several threads in this user maillist going back a decade
> or more.
> 
> I just searched the bug database and found several open bug reports which
> directly involve these points.
> *Bug 787813* <https://bugs.gnucash.org/show_bug.cgi?id=787813>
> *Bug 793556* <https://bugs.gnucash.org/show_bug.cgi?id=793556>
> *Bug 638175* <https://bugs.gnucash.org/show_bug.cgi?id=638175>
> *Bug 410060* <https://bugs.gnucash.org/show_bug.cgi?id=410060>
> 
> GnuCash was changed in release 2.6.8, dated late 2015 to usually store
> prices in decimal format when they were entered in decimal format, but
> there was a regression in the 2.7.x development series leading up  to the
> 3.x releases reverting to the fractional display currently seen.  Bug
> 793556 has already been filed regarding the fractional format as related to
> CSV imports and exports, but it does not extend to use of those values in
> spreadsheets.  The fractional format is the raw display of the number
> format used internally for certain calculations requiring high accuracy,
> and a few users actually prefer to see prices displayed in that format, so
> it is not likely to be completely hidden.
> 
> John Ralls points out in his reply that release 3.3 will fix your first
> concern as well as it can in this real world.
> 
> David C
> 
> On Tue, Sep 18, 2018 at 4:22 PM Christian Pinedo Zamalloa <
> chr.pinedo at gmail.com> wrote:
> 
>> Hi David,
>> 
>> At the end I was able to get properly the price by skipping it and letting
>> to GnuCash to calculate it as you suggested. However, I think that this
>> might be a kind of bug, because if I insert the price in decimal format, it
>> shouldn't be modified and the total amount should be calculated accordingly.
>> 
>> Regarding the fractional format of prices, one more issue. Apart from
>> being more difficult to read, when transactions are exported to CSV, the
>> fractional format is maintained (i.e. "123 + 3/45") and if the CSV is
>> opened with calc/excel we need to modify all the prices to be considered
>> numbers not strings (i.e. insert "=123 + 3/45").
>> 
>> Thanks for your suggestions!!
>> 
>> 
>> 
>> El sáb., 15 sept. 2018 a las 16:26, David Carlson (<
>> david.carlson.417 at gmail.com>) escribió:
>> 
>>> As I stated in my reply, enter the number of shares and total amount,
>>> Skip the price, let GnuCash take care of that.
>>> 
>>> David C
>>> 
>>> On Sat, Sep 15, 2018 at 9:21 AM Christian Pinedo Zamalloa <
>>> chr.pinedo at gmail.com> wrote:
>>> 
>>>> Hi David,
>>>> 
>>>> I also agree with you that the fractional format is more difficult to
>>>> read than decimal and I also hope to return to decimal format or at least
>>>> to be able to choose between decimal or fractional format.
>>>> 
>>>> Regarding my problem with price, I insert the number of shares, the
>>>> prices (in decimal format) and press enter. The decimal formal is converted
>>>> to fractional format, but fractional number is not the same that I inserted
>>>> before. :-(
>>>> 
>>>> Any idea?
>>>> 
>>>> --
>>>> Christian Pinedo Zamalloa (zako)
>>>> Sent from my mobile device, please excuse brevity or typos
>>>> 
>>>> El sáb., 15 sept. 2018 14:49, David Carlson <david.carlson.417 at gmail.com>
>>>> escribió:
>>>> 
>>>>> Christian Pinedo Zamalloa
>>>>> 
>>>>> You have discovered that it is impossible to have all three values
>>>>> shares, price and total exactly as reported by your broker because he
>>>>> usually has to round off one of the numbers.  The solution is to let
>>>>> GnuCash set the price after you enter the number of shares and the total
>>>>> amount.  Actually, GnuCash is closer to being correct than your broker is.
>>>>> 
>>>>> You have also discovered that in release 3.3 GnuCash shows the number
>>>>> of shares in fractional format, which has the technical advantage of being
>>>>> very accurate, if very hard to read.  I believe that in the future GnuCash
>>>>> may be changed back to show the number of shares in decimal format to be
>>>>> easier to read, if less accurate.
>>>>> 
>>>>> David C
>>>>> 
>>>>> 
>>>>> 
>>>>> On Sat, Sep 15, 2018 at 4:16 AM Christian Pinedo Zamalloa <
>>>>> chr.pinedo at gmail.com> wrote:
>>>>> 
>>>>>> Hello,
>>>>>> 
>>>>>> I have problems to set the correct price of a share that I am selling.
>>>>>> 
>>>>>> I try to put the value "128,181208053691" which is automatically
>>>>>> converted
>>>>>> by GnuCash when i push enter key to "128 + 64/377" whose real value is
>>>>>> "128,169761". Furthermore, I checked if I insert value "1", it is
>>>>>> automatically converted by GnuCash to value "1+3/377" (1,007958).
>>>>>> 
>>>>>> I don't know how to solve this mesh. Am I doing something wrong?
>>>>>> 
>>>>>> --
>>>>>> zako
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>>>>> 
>> 
>> --
>> Christian Pinedo Zamalloa (zako)
>> PGP keyID: 0xdb577d4ee6ffbd55
>> PGP Fgprt: A895 7C11 84F6 30B4 4938  32A4 9306 DFD0 CDE4 B542
>> 
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