[luatex] using (pdf)lualatex

[Yue Wang]

> no matter what speedups we are able to cook up in the future, keep in mind
> that the nature of luatex is that information is passed around in lua tables
> and this will not change; as a result luatex will always have a larger
> footprint than pdftex and xetex; for that reason it's good to have multiple
> engines: xetex is faster and uses less memory (although it has some pretty
> large usage as well) but has kind of frozen interfaces while luatex is more
> open with respect to interfaces but at the cost of speed and memory (as soon
> as one starts to do fancy things with node lists, not only memory usage but
> also procesing speed compared to the other tex engines becomes a factor);
> it's simply something that luatex users to accept
>

To be honest, the only reasons for me to use luatex is because xetex's
linebreaking is not so good, and context has better support for
luatex, so I can produce more fancy documents....

And ordinary researchers will not benefit from "open up the engines",
"lua scripting", "pass lua tables" since they just want to finish
their paper.

>> - When the font cache is not given, ConTeXt will try to dump one on
>> the first run. LuaTeX will use much more memory than expected. For
>> example, only loading the metrics from an ordinary Chinese font like
>> AdobeSongStd-Light (a 13M font) in plain TeX will use more than 700M
>> memory. I reported this problem to the ntg-context mailing list
>> yesterday.
>
> btw, the table of that font is not even that large:
>
>  7.623.626 adobesongstd-light.lua
>
> when dumped and when compiled to byte code:
>
>  3.833.022 adobesongstd-light.luc
>
> when loading this font, it takes soem 25 meg
>

Yes, 700/25=28, so fontforge use 28 times of that much memory.

>> For a normal publication, usually some 5 or 6 Chinese fonts will be
>> used. In some cases dozens of these fonts might be used. So it will
>> take very long time for luatex to parse the fonts, as well as huge
>> memory to store the metrics data. So it is suggested that users who
>> want to try luatex should have a computer with large memory and fast
>> CPU since the fontforge library is a nightmare for Asian users who
>> have old machines.
>
> by the time that luatex is mature (a couple of years down the road) machines
> have much more memory so memory is no issue then; disks might be solid state
> which also helps; processors might not be faster but caching migh be better;
> but no matter what the future brings ... luatex will never be real fast
>


Users have plenty of disk space + large memory + faster CPU, so we as
developers can waste them as we like......
The high usage of disk/memory/cpu may also boost the computer hardware
market, and finally solve the economic depression.



> (btw, cjk fonts might be large in number of glyphs, but for instance arabic
> has way more features so there processing time is more an issue)
>
> Hans
>
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