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math symbols not display correctly

math symbols not display correctly

by Siman Wong -
Number of replies: 6

Our IT staffs recently updated our virtual sever to version 2.15 (from 2.13). As I'm uploading problems I discovered several issues:

(a) repeated complains about "Provided value [a particular topic] is not in my chapter taxonomy"

(b) math symbols not display correctly

(c) cannot generate pdf files

For (a):  Several problems have the tag "probability" (subject) -> "discrete probability" (chapter).  When I go to the library browser and type "probability" for subject, indeed there is no chapter called "discrete probability".  We encounter no such error message until 2.13.  I do notice that under 2.15 there is an option for editing tags (cf first page of enclosed screenshot) that's not available in 2.13.

Is that the source of the problem, and how would I resolve this?  (I hope we don't have to manually edit them all!)  Do students see this error/warning message?

For (b,c):  The new server does not seem to be able to handle latex symbols, even for a simple problem like this (cf page 2 of enclosed screenshot for the error message):

--------------------

BEGIN_TEXT

$PAR 

Suppose that \(A)\ and \(B)\ are two events for which

\(P(A) = $a\), \(P(B) = $b\), and \(P(A\;\mathrm{and}\;B) = $banda\)  Find 

\(P(A|B)\).

$PAR

\(P(A|B) = \) \{ans_rule(15)\}

$BR

END_TEXT

-----------------------------------

I also have not been able to generate any pdf; I assume it's caused by the same underlying issue (?).  What should I go about resolving this?

The server update/maintainence was done by our IT staffs.  I believe they use the live image, but that's the extent of my understanding of their work.  How should I work with our ITs to address these problems?  

MANY THANKS for your last-minute help and guidance!

In reply to Siman Wong

Re: math symbols not display correctly

by Danny Glin -

For (a), the more recent versions of WeBWorK have the tagging tool enabled for administrators by default.  Anyone with a lower permission level (instructors, students, etc.) will not see the tagging tool, and thus will not get these errors.  To disable the tagging tool completely, comment out the following line in localOverrides.conf:

$permissionLevels{modify_tags} = "admin";

(see https://webwork.maa.org/moodle/mod/forum/discuss.php?d=4819)


For (b), this was likely caused by updating MathJax.  WeBWorK is not currently compatible with MathJax 3, so you need to revert to MathJax 2 (see https://webwork.maa.org/moodle/mod/forum/discuss.php?d=4850).  The fix is likely to run the following commands:

cd /opt/webwork/MathJax

git checkout legacy-v2


For (c), if the problem with (b) was MathJax, then it is likely unrelated to why pdf generation is not working.  My first suggestion would be to check the directory permissions.  If that doesn't work, you'll have to provide more detail on what sort of error you get with pdf generation.
In reply to Danny Glin

Re: math symbols not display correctly

by Siman Wong -
Thanks @Danny! For now I will put (a) side.

Re (b) and Mathjax: I typed

cd /opt/webwork/MathJax
git checkout legacy-v2

and the server says

Already on 'legacy-v2'
Your branch is up to date with 'origin/legacy-v2'.

but ww still does not display the math symbols correctly. I then fired up the javascript console of firefox under "developer mode" and indeed there are lots of error message (cf first block of messages of the enclosed log).

Re (c), generating pdf's: As soon as I click Homework set the js console gives the same error message (cf 2nd block); ditto if I select a specific HW set (cf 3rd block). When I click "download page or Tex hardcopy of current" I got first the same errors (cf 4th block).  Finally, when I clicked "generate hardcopy for selected sets and selected users", I got no error on the js console but instead (after a while) a "connection timed out" message.

I'm really at a lost of what to do/what to tell our IT.  Your help is most appreciative.  THANKS!
In reply to Siman Wong

Re: math symbols not display correctly

by Danny Glin -
It looks like you are serving images using lighttpd, and your apache server is set up to use SSL, whereas lighttpd is not, which is causing the browser to complain (see https://webwork.maa.org/moodle/mod/forum/discuss.php?d=4837#p14472).

In order to get this working you will probably need to follow the instructions at https://webwork.maa.org/wiki/Installation_Manual_for_2.15_on_Ubuntu_20.04_Server#Configure_lighttpd_to_use_SSL to set up SSL on lighttpd. Once everything is SSL it will hopefully fix this problem.
In reply to Danny Glin

Re: math symbols not display correctly

by Siman Wong -
Thanks! IT just applied the lighttpd/SSL fix but I still have the same error message (cf screenshot).  How might we proceed next?

(The good news I suppose is that if lighttpd is indeed the source of the problem then fixing it should solve both math symbol + pdf issues)

Thanks!

Attachment new error log.png
In reply to Siman Wong

Re: math symbols not display correctly

by Nathan Wallach -
I think the IT staff made the change to use port 8443 but not from http to https mentioned in the instructions.
In reply to Nathan Wallach

Re: math symbols not display correctly

by Danny Glin -

That appears to be correct.  Anywhere you see a url that ends with 8443 in localOverrides.conf, make sure it starts with https rather than http.