** Using WeBWorK **

I think something like this happened to me; I ended up reassigning the problem so that the images get refreshed.

Perhaps it matters if you are editing via an assigned homework problem as opposed to editing via the library browser.

Cached images for assigned problems may need to be "flushed".

hp

Arnie and Jason,

When I take out the refresh cache line in the problem's code and change the graph, it will not update the image--the file for the graph in the var/www/wwtmp/gif folder is not updated. I tried it in IE and Chrome. I edited the file from IE and looked at the problem in Chrome--it was the first time I'd logged into the course using Chrome.

--rac

Hi Robin,

Hi Robin,

Thanks, Dick,
I added the refresh cache line you mentioned to the problem's code and now it is refreshing the image. It's odd that I didn't need to do this before??
--rac

Is this behavior happening even if
        $refreshCachedImages = 1;
is used in the problem's code?

Hi everyone,

I am using WeBWorK version 2.5 on Ubuntu 10.04.3. I have a problem that asks students to find the derivative of a straight line from a graph with units, the code is below. I used this problem last semester without issue.

The problem has two answer blanks, both of which use the same answer.
A student complained to me that his first answer was being marked incorrect. I looked at his problem and WeBWorK is reporting the correct answer to the first question as -1/30 ft/min, and to the second answer as -4 ft/min (which is correct). Since both blanks use the same answer, something is amiss.

I tried giving him a new seed, but we get the same problem, just different numbers. I looked at many of the other students in the class, and he is the only one with this problem that I can find.

CODE:

loadMacros(
"PGstandard.pl",
"PGunion.pl",
"Parser.pl",
"PGcourse.pl",
"PGgraphmacros.pl",
"parserNumberWithUnits.pl",
);

TEXT(beginproblem());
BEGIN_PROBLEM();

##############################################
# Setup
$refreshCachedImages=1;
Context("Numeric");
Context()->variables->add(t=>'Real');
#
# The function to plot
#
$m = Compute(non_zero_random(-4,4));
$b = Compute(non_zero_random(-4,4));

$munits = NumberWithUnits("$m","ft/min");

$s = Formula("$m*t+$b")->reduce;
$sgraph = Formula("$m*x+$b");

#
# Graph size
#

($tm,$tM) = (-2,2);
$extreme1 = abs($s->eval(t=>"$tm"));
$extreme2 = abs($s->eval(t=>"$tM"));
if($extreme1 > $extreme2){$sM = $extreme1;}
else {$sM = $extreme2;};
$sm=-$sM;
$size = [450,450];

##############################################

#
# The plot defaults
#
@Goptions = (
$tm,$sm,$tM,$sM, # dimensions of graph
axes => [0,0], grid => [$tM-$tm,$sM-$sm], # number of grid lines
size => $size # pixel dimension
);

$plotdomain = "x in <$tm,$tM>";
$plotoptions = "using color:red and weight=2";

$graph = init_graph(@Goptions);
plot_functions($graph,"$sgraph for $plotdomain $plotoptions");



##############################################
# Main text

Context()->texStrings;
BEGIN_TEXT
$BBOLD Note: $EBOLD Your answers must include \{ helpLink('units') \}.
$BR
$BR
The position \(x\) of a car at time t is graphed below.
$BCENTER
\{ image( insertGraph($graph),width=>450, height=>450 ) \}
$ECENTER
If the position of the car is given in feet and time is measured in minutes then
\(x^\prime (t) = \) \{ans_rule\}
$BR
The velocity of the car is \{ans_rule\}
$BR

END_TEXT
Context()->normalStrings;

##################################################
# Answers

##################################################

ANS($munits->cmp() );
ANS($munits->cmp() );

END_PROBLEM();
ENDDOCUMENT(); # This should be the last executable line in the problem.

Dear Webwork,

In the process of bringing up our new Webwork server, we're trying to create a new theme. We've installed the directory, templates, and css files in the appropriate places and with the appropriate permissions. However, the drop-down list on the course configuration page doesn't give our new theme as an option, even after refreshing the page as suggested. What should we try next?

Thanks!
Randy Cone

I have created a few macros that make customization of TeX display a bit easier.  It would be nice to simplify it more.