## WeBWorK Main Forum

### Getting Statistics::R::IO working

by Wesley Burr -
Number of replies: 11

Hi, folks, and happy new year. I'm finally getting around to the last thing on my WW bucket list for this school year: trying to get the integration with R (via Rserve) working.

I've got Rserve and Statistics::R::IO installed. Rserve is listening on the localhost port 6311, as default:

# netstat -tulpn
Active Internet connections (only servers)
tcp 0 0 127.0.0.1:6311 0.0.0.0:* LISTEN 1234/Rserve

# cpan Statistics::R::IO
Database was generated on Tue, 02 Jan 2018 17:17:02 GMT
Statistics::R::IO is up to date (1.0002).

I was following the guide at http://webwork.maa.org/wiki/R_in_WeBWorK#Install_the_Perl-R_bridge. However, when I check the test problem mentioned (Library/UBC/STAT/STAT300/hw07/stat300_hw07_q02.pg), I get an error caught:

ERRORS from evaluating PG file: Can't locate object method "new" via

\$pg{specialPGEnvironmentVars}{Rserve} = {host => "localhost"};

### Re: Getting Statistics::R::IO working

by Danny Glin -
First thing to check is that you have a current enough version of both webwork and pg. What version of each of these are you running (it should say at the bottom of any webwork page)?

### Re: Getting Statistics::R::IO working

by Wesley Burr -
2.12 for both:

Page generated at 01/02/2018 at 03:04pm EST

### Re: Getting Statistics::R::IO working

by Danny Glin -
The R integration was not included in version 2.12. There are two ways to fix this:

1. Upgrade to version 2.13, as it includes all of the necessary components for the R integration, as well as some other new features. Just beware that this is a full webwork update, so there may be some complications.

2. Switch to the 2.12-r version of webwork and pg. The following commands should do the trick:
cd /opt/webwork/webwork2
git fetch origin
git branch -t 2.12-r origin/2.12-r
git checkout 2.12-r
cd /opt/webwork/pg
git fetch origin
git branch -t 2.12-r origin/2.12-r
git checkout 2.12-r

The only difference between 2.12 and 2.12-r is that the latter includes the necessary code to make R work in WeBWorK, so there is little chance of breaking anything else. The only complication is that when you later want to upgrade to 2.13, you will have to switch back to the master branch.

### Re: Getting Statistics::R::IO working

by Wesley Burr -
I see the mention of 2.13 at the top of the help wiki now. My apologies for missing it before.

I checked out 2.12-r as suggested. The error message changed, which is helpful, I think. :) As above, CPAN thinks Statistics::R::IO is installed and active. Thoughts?
1. ERROR caught by Translator while processing problem file:Library/UBC/STAT/STAT300/hw07/stat300_hw07_q02.pg **************** ERRORS from evaluating PG file:
Statistics::R::IO::Rserve could not be loaded. Have you installed the module? at [PG]/lib/Rserve.pm line 12 Died within Rserve::access called at line 126 of [PG]/macros/RserveClient.pl from within main::rserve_start called at line 50 of (eval 1260) 

### Re: Getting Statistics::R::IO working

by Danny Glin -
First thing to check: have you restarted apache since the check out?

### Re: Getting Statistics::R::IO working

by Wesley Burr -
Yup. Did a httpd restart, then, when I saw the error, I did a full server reboot (it's out of semester, so I have the power. Mwhaha.) Checked after reboot to make sure Rserve was loaded automatically (check), and both Apache and WW came back up just fine. Same thing.

### Re: Getting Statistics::R::IO working

by Danny Glin -
Next thing: did you check out 2.12-r in both the webwork2 and the pg directory?

### Re: Getting Statistics::R::IO working

by Wesley Burr -
Yes, I followed your instructions to the letter.

[/opt/webwork/webwork2]# git status
# On branch 2.12-r
# Changes not staged for commit:
(some LDAP stuff)

[/opt/webwork/pg]# git status
# On branch 2.12-r

### Re: Getting Statistics::R::IO working

by Danny Glin -
Sorry, I had to ask because at least twice in recent history that has been the problem (plus that would have been an easy fix).

Are you by chance using CentOS 7? If so, then the issue described in http://webwork.maa.org/moodle/mod/forum/discuss.php?d=4161&parent=11799 may be the problem.

After that, I'm starting to run out of ideas.

### Re: Getting Statistics::R::IO working

by Wesley Burr -
Bingo. I am indeed on CentOS 7, and I did have the "special root Perl" stuff still enabled. I've disabled that, reinstalled CPAN and the R::IO package, and we're good to go. Question 23 (the test question from UBC) pops right up. Excellent!

I added a short Troubleshooting section to the Wiki page going through the stuff you mentioned with me. Hopefully it helps someone else in the future (or myself, in 6 months, when I don't remember this).

Thanks very much for all your help, Danny. I appreciate it very much.