fabricio.olivetti@gmail.com wrote:
> [..]
> Hmm let me explain my problem further.
> I'm designin a toolbox that holds a collection of clustering
> algorithms. So let's say I'm implementing a class for algorithm A,
> another one for algorithm B and so on.
> I want the data access to be transparent for them (just use something
> like data(i,j) whenever they need a direct access of it.
>
> The data container class will have a function to read it from a file,
> to store it in the most effective way and to perform some common
> required calculations required by the algorithms.
>
> So basically I built a GUI that gives a user the option to load a data
> from a file (and the data class will be constructed), choose one
> algorithm and this algorithm will its things with the data.
>
> But, unfotunatelly, I can come accross datasets that can store either
> integer values or double values, additionally the data may be dense or
> sparse (so I may end up with a sparse matrix representation) and, even
> when sparse, the data may be so large that I MUST save memory storing
> it with "char" type instead of double!
>
> I guess declaring both types and using it internally with a variable
> that holds what type it is must be the only way to deal with it!

I am guessing you don't mind this tennis match, do you?

I take it that your data class in some cases has to store so much data,
and the data themselves are so imprecise, that storing a 'char' value
is OK and you'd like to do it because you want to save space. Well, it
smells like premature optimization, but if you want it that way, fine.

Now, it does seem that your data storage class is essentially dumb and
does not serve any other purpose except for storage and retrieval. Let
me level with you here. I don't think such class has enough reason to
exist. If your algorithm A (or B, or C) calls for some data to be
lugged around, let the class that handles the data also *store it*.

It makes no sense that the data are stored separately from where they
are processed. If your reading class knows how to read 'char' (or some
other type), fine. But let the processing class allocate the needed
buffer and pass it to the reader for populating with values from the
file.

If you let the processing object hold its own data, then you simply
declare different data types in your different processing classes.
Algorithm A would have 'double', so would Algorithm B, but Algorithm
C, for instance, would have 'char'. No need to extract this into
a separate class and torture yourself trying to squeeze two types
where even one doesn't feel comfortable.

V
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