With those numbers payment number 2 has an error. David C
On Wed, Jan 9, 2019 at 2:23 AM David Carlson <david.carlson....@gmail.com> wrote: > I am working on a test scenario.The interest formula is ipmt( 0.03500 / > 12.00 : i : 180.00 : 172,000.00 : 0 : 0 ), the others have the same numbers > and the 71st payment contains the error. I am using these numbers because > they are exactly the same as the numbers that have already generated an > error. > i started the test loan in Jan 2000 with the first repayment in February > and I am creating one month at a time in case that makes a difference. If > the test can repeat it I will submit the bug report. > > David C > > On Tue, Jan 8, 2019 at 10:52 PM John Ralls <jra...@ceridwen.us> wrote: > >> The answer is probably in app-utils/calculation. All of that was probably >> written before Guile grew a rational number class and I think that >> GncNumerics get converted to doubles before being passed to the interest >> functions. That would pretty much guarantee rounding issues. >> >> Regards, >> John Ralls >> >> > On Jan 8, 2019, at 5:46 PM, Christopher Lam <christopher....@gmail.com> >> wrote: >> > >> > Well the SCM has numerous references to "round" and "rounding errors" >> so it's to be expected. >> > >> > Please file a bug with example numbers, and hopefully these errors may >> be fixed. >> > >> > On 9/1/19 7:35 am, David Carlson wrote: >> >> John, >> >> >> >> Thanks for the reference. Alas, I will need to do some homework to >> >> properly read SCM. There must still be some sort of rounding issue >> >> creeping in if the Scheduled Transaction SLR sometimes generates an >> >> imbalance from ppmt = pmt - ipmt. >> >> >> >> David C >> >> >> >> On Tue, Jan 8, 2019 at 3:44 PM John Ralls <jra...@ceridwen.us> wrote: >> >> >> >>> The thee functions are defined in >> >>> >> https://github.com/Gnucash/gnucash/blob/maint/libgnucash/app-utils/fin.scm >> , >> >>> prefixed with gnc: (so gnc:ipmt etc.). >> >>> >> >>> At line 41ff you'll see that ppmt = pmt - ipmt. >> >>> >> >>> Regards, >> >>> John Ralls >> >>> >> >>> >> >>>> On Jan 8, 2019, at 12:48 PM, David Carlson < >> david.carlson....@gmail.com> >> >>> wrote: >> >>>> My point is that the equations are defined by the assistant, and I >> think >> >>> that they can be expressed in a form that concentrates all the errors >> into >> >>> one line where a simple rounding would not generate a problem where >> the >> >>> parts do not add up to 100%. Granted, the errors may sometimes cause >> >>> inaccurate results, but they would not add the imbalance line to the >> >>> transaction. >> >>>> The current equations are three evaluations called pmt(numbers), >> >>> ppmt(numbers) and ipmt(numbers) with no clue how they are actually >> >>> evaluated. >> >>>> Apparently pmt is not always the sum of ppmt and ipmt. when rounding >> >>> happens. If ipmt were expressed as pmt-ppmt, there would be no >> imbalance, >> >>> but one of the other two ways to express all three may be less likely >> to >> >>> generate inaccurate results. >> >>>> David C >> >>>> >> >>>> On Mon, Jan 7, 2019 at 10:19 PM John Ralls <jra...@ceridwen.us> >> wrote: >> >>>> >> >>>> >> >>>>> On Jan 7, 2019, at 3:14 PM, David Carlson < >> david.carlson....@gmail.com> >> >>> wrote: >> >>>>> I just had a scheduled transaction that was set up by the >> loan/mortgage >> >>>>> repayment assistant appear with 0.01 Imbalance-USD. >> >>>>> >> >>>>> I would think that GnuCash should have an accuracy method that would >> >>>>> prevent this from happening. Is this a bug? >> >>>>> >> >>>>> I am using GnuCash 2.6.17 in Ubuntu 16.04 today. >> >>>> The accuracy method is what created the imbalance entry. ;-) >> >>>> >> >>>> There’s nothing in the SX system to pre-instantiate future scheduled >> >>> transactions and ensure that they’re balanced. What would you have the >> >>> check function do if it found an imbalanced case? How would you handle >> >>> variables whose values are set by the user in the SLR dialog? >> >>>> Regards, >> >>>> John Ralls >> >>>> >> >>> >> >> _______________________________________________ >> >> gnucash-user mailing list >> >> gnucash-user@gnucash.org >> >> To update your subscription preferences or to unsubscribe: >> >> https://lists.gnucash.org/mailman/listinfo/gnucash-user >> >> If you are using Nabble or Gmane, please see >> https://wiki.gnucash.org/wiki/Mailing_Lists for more information. >> >> ----- >> >> Please remember to CC this list on all your replies. >> >> You can do this by using Reply-To-List or Reply-All. >> > _______________________________________________ >> > gnucash-user mailing list >> > gnucash-user@gnucash.org >> > To update your subscription preferences or to unsubscribe: >> > https://lists.gnucash.org/mailman/listinfo/gnucash-user >> > If you are using Nabble or Gmane, please see >> https://wiki.gnucash.org/wiki/Mailing_Lists for more information. >> > ----- >> > Please remember to CC this list on all your replies. >> > You can do this by using Reply-To-List or Reply-All. >> >> _______________________________________________ >> gnucash-user mailing list >> gnucash-user@gnucash.org >> To update your subscription preferences or to unsubscribe: >> https://lists.gnucash.org/mailman/listinfo/gnucash-user >> If you are using Nabble or Gmane, please see >> https://wiki.gnucash.org/wiki/Mailing_Lists for more information. >> ----- >> Please remember to CC this list on all your replies. >> You can do this by using Reply-To-List or Reply-All. > > _______________________________________________ gnucash-user mailing list gnucash-user@gnucash.org To update your subscription preferences or to unsubscribe: https://lists.gnucash.org/mailman/listinfo/gnucash-user If you are using Nabble or Gmane, please see https://wiki.gnucash.org/wiki/Mailing_Lists for more information. ----- Please remember to CC this list on all your replies. 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