Re: Larger matrices

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On Fri, 08 Aug 2008 13:35:04 +0200, Georg Bauhaus wrote:

> amado.alves@gmail.com schrieb:
>>>> And Ada got in the way: slicing restricted to one-dimensional arrays!
>>> Compared to other languages that have no slicing at all?
>> 
>> There are languages better than Ada at array indexing, including
>> slicing. If there aren't, there should be!
> 
> Ada is a systems programming language.  As such, it is
> targetting digital computers. In cases where Ada can be used
> for some mathematical tasks, it is still a systems programming
> language.

What?! Ada is a universal purpose language.

> Ada is about computers that have word/byte adressable
> storage cells that happen to be able to store
> bit combinations. Ada is not about cells of mathematical
> abstractions.  Overlap is accidental.

Submatrices can be handled efficiently [in-place] using interleaving
techniques.

But an efficient or hardware-close implementation was certainly not the
concern of the Ada.Numerics.Generic_Real_Arrays design. Otherwise it would
not use functions at all.

> If you do already have some theory for your graphs,
> and presuming you need a working program for large
> matrices, I'd suggest that you seriously consider prototyping
> your algorithms using one of the fine PLs that do have the
> required mathematical stuff built in.

Really? 90% of numeric libraries and applications is written in FORTRAN. Do
you think they have prototyped them in 60's? I guess that pencil and paper
is what they used. After all maths is best prototyped in math.

The major challenges numerical applications have is not math, but squeezing
most out of the hardware, in terms of memory, time, accuracy, problem size.
None of this can be "prototyped."

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de