automatic interest traction

Nikos Charonitakis nikosx at gmail.com
Thu Jul 5 11:11:08 EDT 2007


On 7/5/07, Josh Sled <jsled at asynchronous.org> wrote:
> "Nikos Charonitakis" <nikosx at gmail.com> writes:
> > i have a bond that receives money from interest once a year.
> > My bank sends me a statement monthly that calculates interest in
> > arrears, till the given date i receive the statement. These money are
> > not cash yet.
> > So any ideas how i can implement  this in gnucash?
>
> I might be misunderstanding, but I'm not sure what you'd like to model
> ... if "these money are not cash yet", then it sounds like there's no
> transaction to create, right?   You're neither receiving or sending money,
> just being informed of the value?

i m not receiving money, but these are money that i own and are
waiting to be received in a given date (once a year).
So its an asset of mine, if i understand it correctly (accounts receivable?)

>
>
> In any case, if the bond is a fixed investment with a simple interest
> schedule, and – more importantly – the transactions occur on a fixed schedule
> (monthly, as you say), then you should be able to create a scheduled
> transaction (SX) that uses a custom function to compute the correct value.
>
> All scheduled transactions – when instances are being created – get an
> 'instance number': 1, 2, 3 ... this value is bound to the variable 'i' when
> the credit and debit cells for the SX are evaluated.  These credit and debit
> cells can contain formulæ which reference this value to compute whatever they
> like; this is how the mortgage/loan druid works, for instance.  Note that the
> *date* of the instance isn't provided, so you need to frame the calculation
> in terms of a particular schedule (usually monthly), but most interest
> computations are done this way anyways.
>
> In this case, you'll need a slightly different function, however, but a
> straightforward one.  You can get an idea of how the function should be
> implemented by looking for the file 'fin.scm' in your gnucash installation.
>
> Once you've determined the function you need, you can put it in
> ~/.gnucash/config.user, or even in that same fin.scm if you want to modify
> your installed sources.  ~/.gnucash/config.user is a bit safer, though.
>
> Then, you can create a SX where the template transaction uses the formula.
> Note that the "gnc:" prefix is automagically added to whatever you enter in
> the template transaction.  If you
>
>     (define (gnc:simple_compounded_interest rate instance_num principal) ...)
>
> in your .scm file, your template transaction should simply read:
>
>     simple_compounded_interest(0.005:i:1000)
>
> (or whatever).  You might want to use the mortgage/loan druid on a
> fake/throw-away datafile just to get an idea of the types of scheduled
> transactions that it creates.
>
>
> That's not the clearest procedure in the world, so let me know if you have
> any questions.  Or maybe I should just document the procedure with
> screen shots and get it into the docs...  in any case, feedback welcome.
>
> --
> ...jsled
> http://asynchronous.org/ - a=jsled; b=asynchronous.org; echo ${a}@${b}
>

I was not clear enough :). I just wanted to do this through existing
gnucash accounts and tools and not create something new (i am not a
programmer... ).



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