Subj : Re: largest memory block
To   : borland.public.cpp.borlandcpp
From : Ed Mulroy [TeamB]
Date : Sat Mar 26 2005 10:08 am

> ... greatly reduces the speed which is an influential
> factor in programs that analyse large scale structures
> (structural analysis).

I am familiar with the problem.  Years ago I was involved in large 
scale structural analysis on IBM mainframes  with what is now regarded 
as trivial amounts of memory.  That necessitated not only streaming 
data and constants to disks, but also 'logical transients', analagous 
to but not exactly the same as overlays.

The idea that because something is used in computation it therfore 
should always be in memory is not necessarily correct.

Computations are defined ways that separate them into phases or steps. 
What is not in this step is a candidate to be on disk.  You already 
are swapping out large portions of code and data to disk as a 
consequence of Windows' virtual memory implementation.

The net result is that you must provide enough memory in the machine 
to handle the calculations.  If you cannot then you must alter the 
architecture of your program to allow it to operate in whatever 
machine environment is realistic for its application.  Problem 
partitioning is an elemental requirement for all large array 
calculations.

At some point railing about the limitations of grabbing large hunks of 
memory with impunity becomes, at best, counterproductive.  The 
hardware and operating system you have selected have limitations. 
Accept that and configure your algorithms to best work with them.

..  Ed

> Mohsen wrote in message
> news:424576c7$1@newsgroups.borland.com...
>
> Dear Ed,
>
>  Thanks for your valuable help. At the end I guess I should
> mension some important points. First I'm not storing things in
> one array. I want to get the block of memory and devide it into
> many arrays in which many categorized data are saved. Second
> Keeping things in memory is a necessity as it is important to
> perform elaborate mathematical operations on these data and
> saving them to disk in order to load them at another time
> greatly reduces the speed which is an influential factor in
> programs that analyse large scale structures(structural
> analysis).

.