Loss of precision relating continuing fractions

[ysangkok]

If you make an expense that involves amounts of money that cannot be represented exactly with a decimal.Decimal, the expense is marked as invalid, and the NetworkX solver will complain, because the individual contribution amounts do not add up to the amount of money used anymore.

For example, create an expense of 1 unit, shared among 3 people. The expense will currently be marked as "invalid" even though it is not.

The underlying reason is that decimals.Decimal is used, and that Decimal("1")/3*3!=Decimal("1"). I believe Tykling did not prefer a pure fractions.Fraction solution, with truncation only when showing to the user, as the amounts would not add up when doing a manual check with the values from the UI.