On Wed, 2010-01-06 at 13:00 -0500, wrote:
> In other words, what is the behavior when a constraint is violated? Do we
> simply say this is non conforming?
We address the issue of constraint violation in 5.2. This has nothing to
do with nonconforming since constraint violation is a result of
users/calculation. Typically these constraints act on the input, e.g.
SQRT has the constraint that its parameter is non-negative. SO if it
happens to be passed a negative number a conforming evaluator is
supposed to return an error.
My problem with ACOT is that the constraint given does not act on the
input.
> That it is implementation-dependent,
> or implementation-defined? That it returns an error? That it returns a
> specific error?
An error (see 5.2)
There are no specific errors defined, we only know that there is at
least NA().
>
> Ideally we'd want to be specific about what the constraint is and describe
> these uniformly. I imagine we have domain constraints, data type
> constraints, range constraints, ordering constaints, syntactical
> constraints, etc. Ideally we'd have a clear taxonomy of these types of
> constraints, apply them clearly, and map violation of each of these
> constraints to a unique error class: domain error, data type error, range
> error, etc.
>
> However, we're a bit hampered by the restricted and illogical error codes
> used by legacy spreadsheets. For example in Excel #NUM! conflates
> entirely different errors types including numeric overflow like in
> EXP(1000) or violation or ordering constraints like RANDBETWEEN(5,0).
> Other spreadsheets do equally strange things.
>
> Of course, it is possible to be more precise in OpenFormula, but if we did
> we'd need to allow implementations to treat these error classes
> interchangeably. This is unfortunate, but unless the vendors step up and
> agree to rationalize their error codes, we have this legacy mess.
That's why OpenFormula currently only says "some error". And the only
special error is NA.
>
Andreas
>
> "Andreas J. Guelzow" <> wrote on 01/06/2010
> 12:19:50 PM:
>
> >
> > Hi Rob,
> >
> > On Wed, 2010-01-06 at 12:04 -0500, wrote:
> > > Is the objection over the reference to PI() rather than directly using
> the
> > > Greek letter Pi?
> > >
> > > Or is the choice of convention the problem?
> > >
> > > According to http://mathworld.wolfram.com/InverseCotangent.html there
> are
> > > two conventions: (0,Pi) or (-Pi/2, Pi/2). The former is continuous,
> while
> > > that later has a discontinuity at 0.
> >
> > No, my problem is much more pedestrian:
> >
> > If a constraint is violated the function should return an error. So how
> > can a constraint talk about the function result?
> >
> > Suppose the return value is a number not in the range from 0 to PI(),
> > then by the return value must be an error, since the constraint is
> > violated. But if it is an error then it doesn't violate teh constriant
> > anymore....
> >
> > I think that should not be a constraint.
> >
> > (We might want to add to the semantics that we are returning the
> > principal value or the value derived from the branch through (1,PI()/4,
> > but that wasn't my problem.)
> >
> > Andreas
> >
> > > "Andreas J. Guelzow" <> wrote on
> 01/06/2010
> > > 11:15:44 AM:
> > >
> > > >
> > > > ACOT has the constraint "The result must be between 0 and PI()."
> This
> > > > doe snot look like a valid constraint to me.
> > > >
> > > > ANdreas
> > > > --
> > > > Andreas J. Guelzow, PhD, FTICA
> > > > Mathematical & Computing Sciences
> > > > Concordia University College of Alberta
> > > >
> > >
> > >
> > > ---------------------------------------------------------------------
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>
> > >
> >
> > --
> > Andreas J. Guelzow, PhD, FTICA
> > Mathematical & Computing Sciences
> > Concordia University College of Alberta
> >
> >
> > ---------------------------------------------------------------------
> > To unsubscribe from this mail list, you must leave the OASIS TC that
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> >
>
>
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--
Andreas J. Guelzow, PhD, FTICA
Mathematical & Computing Sciences
Concordia University College of Alberta
