> On Feb 9, 2025, at 17:32, Bo Buckley <topherbuck...@gmail.com> wrote: > @John Ralls, would you be able to point to where in the codebase this is > handled (i.e. where the Exchange Rate from the Transfer Funds Dialog is > taken and how the Price Database entry Price is calculated?) I'd understand > a lot better seeing the code. Otherwise I'm lost on why this has to be left > as a known rounding error and cannot be handled some other way. > There is no one place. The price database is implemented in libgnucash/engine/commodity.cpp. The transfer dialog, of which the exchange rate section is a part, is in gnucash/gnome-utils/dialog-transfer.c. Transaction balancing is in libgnucash/engine, with pieces of it in Transaction.cpp, Split.cpp, and Scrub.cpp. IIRC transaction currency selection happens somewhere in gnucash/register/ledger-core/ but I don’t know offhand which file.
For the rest, you need to understand that the price database entry is a record of the last price retrieved or calculated on a particular day. (That’s not quite true, but let’s not digress into why not, it’s not important for the discussion at hand. Each split has an amount of and a value. I explained what those are in my previous letter. They don’t have an explicit price. Perhaps an example will help. You postulated an exchange rate of $0.66/100¥. Suppose you have two splits, one for 175¥ and one for 270¥. The first one is $1.155, but there’s no such thing as half-pennies in US currency so it gets rounded to $1.16. The second is 1.782 and is rounded to $1.78. The *stored numbers* for the first split are 175¥ (amount) and $1.16 (value), *implying* a price of 116/17500 or ~.006685714285714… $/¥, The second split stores an amount of 270 and a value of 1.78, *implying* a price of 178/27000 or ~.006592595…. (GnuCash uses the exact rational number internally; decimals are used only for display.) I said “implying” because while one of those prices might get stored in the price database it’s quite possible that neither will or that the price in the price database will get overwritten later. GnuCash must work this way in order for transactions, accounts, and the book to balance and stay balanced. The price database is there to calculate values for reports and the Accounts page, but reports have an option to calculate a average cost from individual splits, and that option is the only one that will allow the Trial Balance report to balance. 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 ----- Please remember to CC this list on all your replies. You can do this by using Reply-To-List or Reply-All.
