Re: Larger matrices

[Georg Bauhaus <rm.dash-bauhaus@futureapps.de>]

Dmitry A. Kazakov schrieb:
> On Fri, 08 Aug 2008 13:35:04 +0200, Georg Bauhaus wrote:


>> Ada is a systems programming language. 

> What?! Ada is a universal purpose language.

Assembly language is universal, too, as are Lisp and Prolog with FFI,
and so on.  This notion of "purpose" is not very specific.
Let me put is this way: Ada has to be especially good at
systems programming, hence it has to be fairly low level.



> 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.

What hardware?  Assume data flow hardware, and assume a way
to put the function result in the input box of the next processing unit.
What now?


>>  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.

Only a fraction of the tabular arrays of numbers
is input to procedures of challenging numeric libraries.
I'll even guess that a larger fraction of matrices in
lots of Ada programs are 3x3, maybe 4x4.


> Do
> you think they have prototyped them in 60's?
[The libraries, or the algorithms? The latter, yes; APL is about
that old.]

I don't see how prototyping a hypertext graph algorithm
requires a maximally efficient implementation of matrix
computations.  A production system may require increased
efficiency. At that stage you have to pay attention to
the tiny bits, possibly redesigning the algorithm.
(If I could have stopped at simple recursive
functions when writing the program below it would have been
a trivial exercise. :)

Georg Bauhaus
Y A Time Drain  http://www.9toX.de