on the errors from the log file i wrote it says : "unable to open image `143ebf4431f6923c64587a2965b56602_1355335161.ps': No such file or directory."

so it seems that maybe something in the script is wrong, the directory isnt right..

Every formula goes thought several formats: tex, dvi, ps and finally png. According to your first message, the process breaks at the dvi phase, so it's expected that the ps file doesn't get created.

To test further, please do the following. Edit vlatex/class_vlatex.php. Around line 411 (pretty at the end), change

To

This effectively disables the cleanup of the temp directory. Please clean it by hand (something like rm vlatex/temp/*) so we can see the results of the test.

Then, log into your forum and try to add a formula to a post. The temp folder will fill up with some files, so we can know how many of them get created ok. Please, tell me the result of ls -l after that test, or delte also vlatex/temp/index.htm so I can take a look at the directory listing at http://www.emath.co.il/forums/vlatex/temp/ (you can recreate the file after the test)

i commented the row u asked .

the ls -l gives now (while im in the temp dir) :

total 56
-rw-r--r-- 1 emath emath 49872 Dec 12 23:23 efa4c40fe23d50f46436522f01f442b1_1355350982.tex

Now, while in the temp dir, write the following:

Where Path to LaTeX is the path to latex as entered in the admincp. The default is /usr/bin/latex, so if you have the default value your line would be

This is the command the mod is issuing (Assuming that you didn't delete the file generated by the previous test; if you did, please create a new one).

See if any error happens, and see if more files are generated in the directory (i.e, check ls -l again).



If the previous command failed, try the same line but without the full path (just latex instead of /usr/bin). This should work, since we tested a different thing a while ago.

ok, the command succeeded. (with the full path)

ls -l gives :

the only error that might be is : /usr/bin/latex: /usr/local/lib/libpng12.so.0: no version information available (required by /usr/bin/latex)

That's very weird. The libpng error shouldn't matter at this point since the dvi file is generated; but it isn't when the same command is issued by the webserver.

It might be worth trying to install libpng just to see if that makes any difference; If you installed latex using a package manager (apt-get, yum, yast or whatever) then the dependence should have been installed, check your linux distribution on details why it wasn't.

Anyway, I don't think that's the problem, so let's try something else. I'm going to prepare a debug version of class_vlatex.php to gather more information and I'll get back to you when I have it.

That is unless... and I know this is a delicate question, but would you consider giving me temporary and limited ssh access to the restricted vlatex directory so I could perform tests by myself much more quickly?

I'll get back to you when I have the debug class_vlatex.php.

For the record, if it helps somebody else, it was a LaTeX install issue, latex.fmt was missing. What finally solved the problem was to run:

ive done this, and find out that the latex.fmt file is in the: /.texmf-var/web2c/

and the mod requires it to be at : /.texmf/web2c/

so ive just copied the file to that directory ( using cp command ) .

thanks to pod for the help.

one more little thing : why does the \\ command for new line doesnt work?

Not specifically this mod, but your latex installation requires it to be there.

LaTeX doesn't allow new lines in displayed equations. You can use one of amstex packages, for instance

[tex]\begin{gathered}
line 1 \\
line 2
\end{gathered}[/tex]

in mimetex it worked with no problem, and we wrote for years like this .
is there anyway to enable this command ?

Well, mimetex has some small deviations from standard latex (see here: http://www.forkosh.com/mimetexmanual.html).

I think I can adapt the mod so you can chose a different formula wrapper (instead of the current $$) so the // command works for you. But I won't be able to do so before the weekend.

ok, i think it would be great, it is necessary for everyone i guess.

any progress within this weekend?
btw i found some more commands that doesnt work : \right , \Large{} and many others from this page : http://en.wikibooks.org/wiki/LaTeX/T...atting#Spacing which i used in mimetex with no problem, why does this happenning? the code should be the same isnt ?

I just updated the mod with a functionality that will allow you to enable the \\. Update the mod (upload the files and upgrade the xml at the admincp). In vlatex options, you'll find the new setting "Equation Wrapping". Select the third option (the gather environment).

If you want the new setting to apply retroactively to old formulas, delete the pics folder and rebuild the postcache.

As I said in a previous post, mimetex defines a few non-standard commands that do not exist in stock latex, so those commands will not work out of the box. There's nothing I can do about that, since I'm neither mimetex nor latex developer. This mod just offers a interface to latex.

However, you can define the most useful commands to mimic mimetex behaviour as much as possible. You can do so in the "Preamble" option in vlatex settings page (the last one). I recommend not replacing the default content in there, just append your definitions. For instance, you can get something very similar to \Large by using

\let\Large=\large

The effect won't be the same, but at least old formulas won't be broken. Again, empty the pics folder and rebuild postcache to recreate old formulas after making changes.

great, thanks alot !

Great Job!!

Hi, I have installed the TEX live ... i have problem

the editor can't post the formulea in proper form the tag [TEX] formulea [TEX] is missing from the editor. When I'am adding tags all works fine what can be wrong?

If I'm undestanding you, you have the mod working but you have to manually type the [tex] tags? So just you're missing the "tex" button?

yes that the one I'am trying to install Ghostscript i don't know if this helps

Vbulletin 4.2.1 Web www.4-40.co.uk


I haven't got root access by ssh so finally I manage to install the TEX live on different location than usr/bin/

Is the Ghostscript realy needed for this script?

You already have everything you need installed, including ghostscript. In fact, the mod is working all right (I just checked by registering at your site; nice design btw).

The button in the editor is not installed by the mod itself, but you can install one using vb's built-in system. In the admincp, there's a section for vb codes, were you can create a tex vb code.

ok great thing this plugin thanks :)

Good job , thank you ;)

Hi. I've installed it on my forum and it works great!

I have a concern though, which becomes a suggestion/request of sorts.

My understanding is that each expression rendered results in a new PNG file in /pics. Makes sense, if so. So with that understanding...

/pics files accumulating when users iteratvely tweak TEX expressions in preview/edit?
Let's say someone is using the preview-edit-preview in a loop whilst developing a post, and tweaking the latex expression each time, hence generating however many intermediate PNG files (per latex expression tweak), only the last of which is really useful (the one they wind up posting). This results in a pile of images sitting around under /pics that are effectively wasted space. I don't think this is too unrealistic of a scenario, being that people may see a problem with their (say, nontrivial) latex in preview, so then tweak it, iteratively, until they see what the want.

Concern of "waste" /pics accumulation
Now my concern. Over time this can become a problem, lots of wasted space.

For instance, anticipating this may be a problem, I have asked the users of my forum to consider using one of the freely available online, interactive LaTeX renderers to "draft" their expressions before posting them on my forum, hoping to head off useless PNG file accumulations.

Extent suggestions/workarounds...
So. I understand that you can purge the post cache and rebuild, but that seems to be long-term unfeasible as the forum ages, and accumulates many posts, right? Just to purge unused /pic files, you have to drop and rebuild the whole post cache? Seems like hitting it with a hammer, unless I've misunderstood?

Suggestion/Question?

I'd consider making the suggestion, "Hey, can we disable the TEX tag from rendering in preview mode?", but that would just encourage people to post, then edit their post. They can iteratively tweak the TEX expressions anyhow, which does not head off the accumulation problem.

So, instead I make the suggestion (or ask for the clarification): is there a way to either prevent or periodically cleanup the long-term accumulation of effectively no-longer-used/intermediately-generated PNG files?

Such as through some "smarts" to drop any net-unused, intermediately generated /pics images during preview-edit-preview loops?

OR

Such as through a cron or somesuch? I'm not sure what the effort would be, imagining something that has to effectively sweep recent posts against the /pics folder, and weed out those which are deemed unused, etc, although I admit I can imagine it being a headache...

Perhaps my understanding is off to begin with?

Any insight here would be great. This mod is a great addition to my forum, it offers a great value to my membership!

What I do myself is to add this line in a crontab:

50 4 * * * find PATH_TO_FORUM/vlatex/pics -atime +35 -name "*_*" | xargs rm -f

This removes every morning (at 4:50) all files from the directory that were not accessed in the last 35 days. You can tune this command as you wish.

It is important that the number of days is slightly larger than the duration of your post cache (it's an option somewhere in vb's admincp), because if the post is cached, then bbcodes are not reprocessed.

If you ever empty the pics folder, then also clear or rebuild the post cache (which can be done in the admincp as well). Doing so, png's will be rebuilt the first time every post is visited by someone (I suggest doing this with the forum closed and visit yourself the posting page, 'cause the large number of formulas in the quick-menu take a while to be processed).

Pod, thanks for the quick reply. I'll play around with your suggested cron-based (and rather pragmatic) approach and see how that works.

Thanks again.

After update to latest Vbulletin 4.2.2 and php 5.4 on server this function doesn't work

\begin{align} (formula) \end{align}
\begin{gather} (formula) \end{gather}
\begin{eqnarray} (formula) \end{eqnarray}

Does anyone know what can cause this problem.

I don't think the update should affect the mod. You could try to reinstall the mod.

You should include mimetex in your install, for people who's servers don't have LaTeX installed.

mimeTeX can be easily integrated with VB using the built in bbcode editor, no need for a mod if you're going with mimeTeX ;)

Any suggestions for something like this? I'm on GoDaddy shared hosting (linux)

When I'm trying this mod with the gather environment, I get the "Convert failed" error on the snippets where I'm using "\\" "\newline".
Single line formulas do work without any error.

Is there a solution for the multiline functionality or a better workaround than using multiple tex-fields?


vb 4.2.3 PL2

might be that this command does not exist, try \\ instead.

anyway, I would use MathJax instead, there is no need for this plugin anymore. mathjax is gr8 ! (being used in mathstack as well )

I wrote \\ the first set of quotation marks (where did it go? :confused:).

As I tried to write a new formula with no line break it also went "Convert failed". So I guess, the gather doesn't work at all and it was bad luck that I had an already compiled picture of the single line equation.
I edited a post where the \\ did not do anything and changed the settings from $ formula $ to gather.

I second the opinion that MathJax works very well...we use it at MHB too. If you want to get started with that, try this product:

LaTeX By MathJax [v1.2]

First, you should use the "gathered" environment, not the "gather" one. The "gather" cannot be used inside math mode. Note that this plugin compiles your formula directly in math mode.

Also, make sure that \usepackage{amsmath} is included in the preamble (in your admin panel).

I strongly recommend KaTeX over MathJax (even tho both are great).

In fact, if I ever consider updating this plugin, I'd make it KaTeX based with server-side latex (converted to SVG instead of PNG) as fallback for full compatibility with desktop LaTeX.

I believe that server-side and client-side LaTeX have pros and cons, so both of them still have room nowadays.

I was referring to the options of this mod in the admin panel.

---

Due to security regulations I am not allowed to have things running on a server outside the university network.

You don't need any software running anywhere except where your forum is hosted.

Please find attached an example of a multi-line equation compiled with this mod. Note that I'm using the gathered environment, not simple gather. It will work if you have LaTeX correctly configured and the amsmath package is listed in the preamble (it is by default when you install the product).

Well, I have a bunch of old posts with the syntax from a 10 years old database here and [S]don't want to[/S] cannot rewrite that.

I hoped that the settings option within the mod would do the trick since you declared it as a feature.

Thanks for the image. Now I understand what you mean.

I see that you merge text and equations inside your [latex] tags. This is not how this mod is designed. This mod assumes that everything you put inside the tags is in math mode, and everything is converted to a single image.

I don't know what system you used to parse your old syntax, but I'd argue that this is not a suitable approach: in a forum, the text should be written using the editor of the forum, and use latex only for the equations.

Anyhow, the syntax of your old system is basically incompatible with this mod.

It could be easy to modify the mod so it doesn't wrap the contents of the tag in a math environment, but I'm not sure how that'd work. The system would generate a "normal" latex file that would have pretty much the width of a printed page.

If you give me more details on the system you have been using for the last 10 years, then I could try to give you some alternative. It is probably not this mod, since as I said, its design seems to differ from your syntax.