Re: financial computations

[Robert Dewar <robert_dewar@my-deja.com>]

In article <39182A7C.C1358EE2@easystreet.com>,
  Al Christians <achrist@easystreet.com> wrote:
> Robert Dewar wrote:
> >
> > What artithmetic do you use in these functions?
> > Note that the use of floating-point for many financial
> > computations, e.g. interest rate calculations for many
> > instruments, is illegal.
> >
>
> This would be way off-topic for this newsgroup, except that
> you
> are stating it as a reason to use your firm's product, so I'll
> inquire:  What do you mean?  What instruments?  Illegal where?
> According to what law or ruling?   Are you typing about the
SIA
> rules for bond calculations?  Certainly not the truth in
lending
> law?  The Cobol Programmers' Full Employment Act?

No, I'm not stating it as "a reason to use [my] firm's product."
As far as I know, almost no one is doing fiscal calculations
in Ada 95. I do know of Ada 83 fiscal calculations that use
scaled integer arithmetic.

The point is that in several contexts, including bond interest
calculations, the calculation of interest must be done precisely
in decimal arithmetic, with specified truncation or rounding
semantics. You can only approximate this in floating-point.

> Fixed-point decimal exponentiation is what ought to be
> illegal, on  the grounds that it takes to long, as anyone who
> has done this in Cobol knows too well.

COBOL has no defined semantics for exponentiation, so I do not
know what you are talking about here at all.



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