If the daase is so small that it only takes 23 Mbytes to load into memory,
it would be worth it if it took 100 Mbytes to load into memory. How many of
our machines would be constrained by this? My current machine is old and it
has 7.7 Gbytes usable. It is nothing special - a stock standard HP laptop.

The question to ask is: why has this not been done sooner?

regards to all

Hill Strong.

On Fri, Dec 8, 2023 at 1:45 AM Qian Yun <oldk1...@gmail.com> wrote:

> I did some experiments on putting daase into memory instead of disk.
>
> For the 8.5MB interp.daase, load it into memory takes 23MB:
>
> (sb-ext:gc)
> (room) ;; Dynamic space usage is:   19,602,224 bytes.
> (setq l1 '())
> (with-open-file (s "interp.daase")
>   (do ((item (read s nil 'eof) (read s nil 'eof)))
>       ((eq item 'eof))
>       (setq l1 (cons item l1))))
> (sb-ext:gc)
> (room) ;; Dynamic space usage is:   42,911,520 bytes.
>
> The number is reasonable: viewing l1 as a tree, it has 1.4 million
> leaves (which are symbol or number), and requires 1.4 million cons
> cells, and each takes a machine word -- 64 bits so:
> 1.4 million x 2 x 8 bytes = 22.4 MB
>
> Of course, if we want all of database in memory, why not put
> it directly in the various hash tables?  I have not tested how
> much memory this would require, should be much less than 23 MB.
>
> Bzip2 compress interp.daase gives 504K, that's also reasonable
> considering there's so much duplicated sub-expressions in it.
>
> So I wonder does in memory daase (then dump to disk image) have
> advantages over current external text daase?
>
> Or consider a crazier thing: load everything into memory (image)
> and distribute FriCAS as a single executable!  It actually can
> be a good idea for Windows.
>
> A rough test using fricas0 shows that loading the 1383 algebra
> fasl files (39MB) into memory takes 26MB RAM, interp/ takes 13MB.
>
> - Qian
>
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