UsingWW: Thomas Hagedorn - Error With Totals File / Multiple Sections

$inactiveTopic$ Error With Totals File / Multiple Sections

topic started 12/12/2003; 2:36:04 PM
last post 12/17/2003; 3:17:06 PM

$user$ Thomas Hagedorn - Error With Totals File / Multiple Sections $blueArrow$
12/12/2003; 2:36:04 PM (reads: 1212, responses: 8)

We're using Webwork 1.9.

A colleague with two sections (in the same course) has the
following problem. For the totals file, Webwork does
not display the scores for all his students. What it does is display
the scores for all students in the first section followed by the scores for
half of the students in the second section. The last line in the file
shows some scores for one of the students in the second section but
not all of the scores. Some students in the second section are not listed.

This error shows up whether one 1) downloads the totals file and opens it in
Excel or 2) Tries to Edit it directly using the option on the Scoring Page.

For any given assignment, looking at the student scores shows that all
students are listed with there scores. So all the info for all the students is
correctly recorded by Webwork. Unfortunately, this info isn't showing up
in the totals file.

Now I have one section with 34 students and it has worked fine before so
it doesn't seem as if this is a system wide problem.

Looking closely at my colleague's example, it seems to be the 45th student listed
that has only part of his scores listed.    Could there be a limit on the number
of students allowed in a section?

Any other suggestions would be appreciated.    I should mention that time is
a bit of an issue as our semester is ending and grades are due by next Wednesday.

Thanks,
Tom

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$user$ Arnold K. Pizer - Re: Error With Totals File / Multiple Sections $blueArrow$
12/12/2003; 3:35:17 PM (reads: 1422, responses: 0)

Hi Tom,

There is certainly no limit on the number of students allowed in a section.

One thing to try is to just rename to totals file (in order to save it especially if it contains non WeBWorK grades such as exam grades) and then just score everything again.

What does the totals file look like if you just view it in html mode?

Arnie

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$user$ Thomas Hagedorn - Re: Error With Totals File / Multiple Sections $blueArrow$
12/14/2003; 10:48:45 AM (reads: 1383, responses: 0)

Thanks Arnie,

We fixed the problem. It seems that the original totals.csv was corrupted. When I renamed it and then ran the scoring folder again, we got the correct version of the scores. Something must have happened to the system when the original totals.csv file was being created.

-Tom

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$user$ Zbigniew Fiedorowicz - Re: Error With Totals File / Multiple Sections $blueArrow$
12/16/2003; 4:39:54 PM (reads: 1350, responses: 0)

I've had a different problem with scoring in WeBWorK 1.9 this quarter. I had a large lecture class with many students. After the first and second midterms there was some attrition in the class, and I changed the status of those students to drop. Consequently subsequent WeBWorK assignments were built for decreasing sequences of subsets of the original student enrollment in the class. WeBWorK seemed to have trouble updating the totals file for these later students. While scoring the first few assignments (built for the entire superset) updated the totals file practically instantaneously, the later assignments (built for smaller subsets) took almost 10 minutes to update the totals file (with a timeout error from the web server).

This behavior recurred every time I tried it, even when I deleted all scoring files and started afresh. It also happened in a colleague's class with a similar situation.

I believe that I followed similar procedures in past years, so this seems to be a problem with version 1.9.

Zig Fiedorowicz

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$user$ Arnold K. Pizer - Re: Error With Totals File / Multiple Sections $blueArrow$
12/17/2003; 10:45:05 AM (reads: 1385, responses: 0)

Hi Zig,

I can not duplicate your problem. I tried the following example. I created a classlist with 206 students (6 standard students and students 1,2, ...,200). Then I built 5 sets for them. Next I changed the status of 50 students to drop and built 5 more sets. Finally I dropted 50 more students and built 5 additional sets. Thus I had a total of 15 sets and 343 problems. 106 students did all sets, 156 did 10 sets, and 206 did 5 sets. Except for the fact that all the scores were either 0 or blank, this seems pretty typical for a large class.

I scored all 15 sets at once and it took 38 seconds by my watch. Also I can not think of any changes between WeBWorK 1.8 and 1.9 that would slow the scoring programs down.

Arnie

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$user$ John Jones - Re: Error With Totals File / Multiple Sections $blueArrow$
12/17/2003; 12:49:00 PM (reads: 1356, responses: 0)

Hi,

I had a similar problem earlier this semester of long waits while scoring sets, and posted to this board (under the subject "use of STDERR"). We were using a mixture of 1.8 and 1.9, so I don't know if my fix will help for you. Scoring a set for a course where students have added/left was definitely one of the symptoms (it triggered the minor error reported to STDERR). This sort of problem is likely dependent on operating system, so some people may never encounter it.

John

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$user$ Arnold K. Pizer - Re: Error With Totals File / Multiple Sections $blueArrow$
12/17/2003; 2:21:38 PM (reads: 1354, responses: 0)

Thanks John. Zig, please try the following fix.

In the file .../webwork/system/scripts/pScSet6.pl comment out line 54, i.e. the line

print STDERR "$string\n";

ie, change it to

# print STDERR "$string\n";

in the subroutine scoreMessage. As John says, there is no real reason to print this message to STDERR. On my system (FreeBSD), I reran my example and it still took 38 seconds. Also this line (printing to STDERR) has been in the code since the begining. But maybe something has changed on your system to slow down printing to STDERR.

Note that if you look at the scoring log, you will see that a message is posted every time WeBWorK pads the totals file with a blank (which it will do a lot if there are a lot of people who have dropped). So if for some reason printing to STDERR is slow, it would certainly slow down the scoring process a lot.

Arnie

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$user$ Zbigniew Fiedorowicz - Re: Error With Totals File / Multiple Sections $blueArrow$
12/17/2003; 2:34:38 PM (reads: 1338, responses: 0)

Thanks, John. This was indeed the problem. Just to elaborate on your instructions: one wants to comment out the line

print STDERR "$string\n";

in scripts/pScSet6.pl

Zig

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$user$ Zbigniew Fiedorowicz - Re: Error With Totals File / Multiple Sections $blueArrow$
12/17/2003; 3:17:06 PM (reads: 1354, responses: 0)

Just a followup. This seems to have something to do with the web server setup, rather than the WeBWorK version. (WeBWorK v. 1.8 also prints these messages to STDERR.)

I wrote a simple test cgi script which prints a simple test message to a web page and also prints a varying number of lines to STDERR. I found that if this script prints 182 lines or less to STDERR, then the script runs successfully and displays the web page. If the script prints more than 182 lines to STDERR, it hangs with an internal server error message displayed after about 10 minutes.

My guess is that it has something to do with the default setup of Apache 2.0 on RedHat 9.0 (Previously we were using Apache 1.3.x on RedHat 7.x)

Zig

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