Re: Surprise in array concatenation

["Dr. Adrian Wrigley" <amtw@linuxchip.demon.co.uk.uk.uk>]

On Mon, 05 Sep 2005 10:34:01 +0200, Jean-Pierre Rosen wrote:

> Jacob Sparre Andersen a �crit :
> 
>>>The values are integral multiples of small, which can be supplied by
>>>the user.  So I'd expect to be able to use fixed point types as
>>>array indices etc.  You cant :( Wouldn't fixed point be *much* more
>>>useful if it was discrete?
>> 
> That's the view of the solution space. The view of the problem space is 
> that they are a different approximation of real numbers (floating point 
> values being the other one). And you can't index an array with real 
> values, whether float or fixed.

Yes it is a solution space view.  The point that I was making was
that there were straightforward implementations available to
compilers.

The view of the problem space is that an array indexed by a real
value represents an arbitrary univariate function.  I use these
"all the time" in generating probability density estimates.
And also for lookup of complicated functions.  The example
of computing histograms from Jacob is closely related.

So I'm slightly surprised to hear you say you can't index an
array with real value (approximations).
-- 
Adrian