Re: AccrInt

[Phillip J Shelton <shelton11 dingoblue net au>]

"John S. Dey" wrote:

> Phillip:  I went back and read the documentation for the MS Excel's
> ACCRINT function.  They refer to a concept of quasi-coupon periods
> occurring between "issue" and "settlement".

Oh.  I see I will have to find a copy of Excel that has these functions
with it.

> Further, I made the calculation of
> accrued interest from the parameters given in the example and came up
> with 16.9863; they show 16.94444.

Not good.

> I think Excel is a great product and I am sure that gnumeric is also.

I agree.

> However, I don't trust the financial calculations.

And those are what I am trying to look at.

>  With regards to
> standards, I bet that within SEC or at an industry association the
> standards for the calculation have been laid out.  With regards to the
> municipal industry, the Municipal Securities Rulemaking Board sets the
> rules (see MSRB RULES -- G33-- CALCULATION on http://msrb.org.

I will look this up.

> Its been brought up before on the gnumeric mailing list, that if, in
> fact, errors are detected in Excel, what should the gnumeric
> implementation do?  This is an issue that probably has already been
> addressed so for what its worth I would implement the error in the
> function (provided it can be replicated) and then add a feature that
> would provide the correct calculation.

I don't intend to un-Excel clone gnumeric.  If the spreadsheet functions
need errors coded in then that is what has to happen.  But I would like to
know what is meant to happen so that I can write correct code for a non-app
specifec financial library that gnucash can use.

> For me I check all calculation
> from any function that I plan on using.  If, I don't agree, I write a
> macro.  Sometimes I write a macro just for the fun of it.

Wise.

> I hope my rambling is helpful to you but realize what I am saying is
> unsettling and unfortunately does not add much clarity to the ACCRINT
> function.

Thank you for taking the time to answer the questions of someone who is new
to the ins and outs of financial math equations.

Phill