[tex4ht] problem with slow compilation of large latex file with large math content

Radhakrishnan CV cvr at river-valley.org
Sat Mar 26 07:11:36 CET 2016

On Sat, Mar 26, 2016 at 3:23 AM, Nasser M. Abbasi <nma at 12000.org> wrote:


For example, for one file, using Vbox, it took 14 hrs
> for make4ht to compile the file to html. On cygwin, it took
> little less than than. About 10 hrs. This is on windows 7, 64 bit
> 16 GB ram, fast intel i7-3930k CPU.

​That is terrible! But, it contradicts with my own experience. At work, we
do large documents (on an average 300 pages long, 800-1000 bibliographic
items, 500 to 800 equations, very complex math, large number of figures,
double column output) on a daily basis, but it takes a few seconds to
generate Elsevier XML output. Recently, another article with 350 pages, ~70
figures, four or five very long tables each spanning several pages, 350 bib
items, several hundred cross references, but very few math, took only 12
secs for three runs of TeX4ht to generate NLM XML output on a server where
at least 50 users are working simultaneously using same resources. The only
documents that take, say, 60 secs or a bit more time are documents with
atomic and nuclear data tables, each table running to 200 pages typically!
Otherwise, tex4ht run is a breeze in my experience that too on a server
shared by at least forty to fifty users at a time.


> But the issue is, pdflatex and lualatex take about 5 minutes
> on the same file to compile it to pdf !
> I can understand converting to HTML will take more time,
> since each equation is converted to svg image,

​on the fly? Why don't you write out the math in a file and process
separately to generate the svg images in one go?​


> It also seems tex4ht has more than one pass. As I see it
> generating these sequence of numbers  more than one time.

​tex4ht needs three passes for fixing cross links and multicolumns in

> I can make a zip file with typical large latex file
> with all the images it uses and my .cfg and main.mk4
> and the command I used to compile the latex file if
> any one wants to confirm this problem. Would this be ok?

​I would love to debug your problem. Please do send me. If it is too large
the archive, kindly put at some location and provide me the URL.


> Finally, is there a document that describes the passes/process
> that tex4ht uses to compile to HTML at some high level? Like block
> diagram, or such. I am not able to find such design document.

​A schematic diagram of a tex4ht run namely tex4ht.pdf is attached to this
mail. Hope this might help.​

​Best regards​

River Valley
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