File:  [LON-CAPA] / loncom / interface / statistics / lonstudentassessment.pm
Revision 1.71: download - view: text, annotated - select for diffs
Tue Oct 21 21:23:53 2003 UTC (20 years, 7 months ago) by matthew
Branches: MAIN
CVS tags: HEAD
Simplify user interface.  After chatting with Felicia the following
changes have been made to the 'Output Data' selection:

'Scores' has been renamed 'Scores Per Problem'
'Scores Sum and Maximum' has been renamed 'Scores'
'Scores Sum' has been removed.
'Scores Summary Table Only' has been removed.
'Tries' remains the same
'Parts Correct and Maximums' has been renamed 'Parts Correct'
'Parts Correct' has been removed.
'Parts Summary Table Only' has been removed.

Removed means access to that option has been disabled.  Can be re-enabled
without trouble in response to the inevitable outcry.

# The LearningOnline Network with CAPA
#
# $Id: lonstudentassessment.pm,v 1.71 2003/10/21 21:23:53 matthew Exp $
#
# Copyright Michigan State University Board of Trustees
#
# This file is part of the LearningOnline Network with CAPA (LON-CAPA).
# LON-CAPA is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# LON-CAPA is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with LON-CAPA; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
# /home/httpd/html/adm/gpl.txt
#
# http://www.lon-capa.org/
#
# (Navigate problems for statistical reports
#
#######################################################
#######################################################

=pod

=head1 NAME

lonstudentassessment

=head1 SYNOPSIS

Presents assessment data about a student or a group of students.

=head1 Subroutines

=over 4 

=cut

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

package Apache::lonstudentassessment;

use strict;
use Apache::lonstatistics;
use Apache::lonhtmlcommon;
use Apache::loncoursedata;
use Apache::lonnet; # for logging porpoises
use Spreadsheet::WriteExcel;

#######################################################
#######################################################
=pod

=item Package Variables

=over 4

=item $Statistics Hash ref to store student data.  Indexed by symb,
      contains hashes with keys 'score' and 'max'.

=cut

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

my $Statistics;

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

=pod

=item $show_links 'yes' or 'no' for linking to student performance data

=item $output_mode 'html', 'excel', or 'csv' for output mode

=item $show 'all', 'totals', or 'scores' determines how much data is output

=item $data  determines what performance data is shown

=item $datadescription A short description of the output data selected.

=item $base 'tries' or 'scores' determines the base of the performance shown

=item $single_student_mode evaluates to true if we are showing only one
student.

=cut

#######################################################
#######################################################
my $show_links;
my $output_mode;
my $data;
my $base;
my $datadescription;
my $single_student_mode;

#######################################################
#######################################################
# End of package variable declarations

=pod

=back

=cut

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

=pod

=item &BuildStudentAssessmentPage()

Inputs: 

=over 4

=item $r Apache Request

=item $c Apache Connection 

=back

=cut

#######################################################
#######################################################
sub BuildStudentAssessmentPage {
    my ($r,$c)=@_;

    undef($Statistics);
    undef($show_links);
    undef($output_mode);
    undef($data);
    undef($base);
    undef($datadescription);
    undef($single_student_mode);

    $single_student_mode = 0;
    $single_student_mode = 1 if ($ENV{'form.SelectedStudent'});
    if ($ENV{'form.selectstudent'}) {
        &Apache::lonstatistics::DisplayClasslist($r);
        return;
    }
    #
    # Print out the HTML headers for the interface
    #    This also parses the output mode selector
    #    This step must *always* be done.
    $r->print(&CreateInterface());
    $r->print('<input type="hidden" name="notfirstrun" value="true" />');
    $r->print('<input type="hidden" name="sort" value="'.
              $ENV{'form.sort'}.'" />');
    $r->rflush();
    #
    if (! exists($ENV{'form.notfirstrun'}) && ! $single_student_mode) {
        return;
    }
    #
    my $initialize     = \&html_initialize;
    my $output_student = \&html_outputstudent;
    my $finish         = \&html_finish;
    #
    if ($output_mode eq 'excel') {
        $initialize     = \&excel_initialize;
        $output_student = \&excel_outputstudent;
        $finish         = \&excel_finish;
    } elsif ($output_mode eq 'csv') {
        $initialize     = \&csv_initialize;
        $output_student = \&csv_outputstudent;
        $finish         = \&csv_finish;
    }
    #
    if($c->aborted()) {  return ; }
    #
    # Determine which students we want to look at
    my @Students;
    if ($single_student_mode) {
        @Students = (&Apache::lonstatistics::current_student());
        $r->print(&next_and_previous_buttons());
        $r->rflush();
    } else {
        @Students = @Apache::lonstatistics::Students;
    }
    #
    # Perform generic initialization tasks
    #       Since we use lonnet::EXT to retrieve problem weights,
    #       to ensure current data we must clear the caches out.
    #       This makes sure that parameter changes at the student level
    #       are immediately reflected in the chart.
    &Apache::lonnet::clear_EXT_cache_status();
    #
    # Clean out loncoursedata's package data, just to be safe.
    &Apache::loncoursedata::clear_internal_caches();
    #
    # Call the initialize routine selected above
    $initialize->($r);
    foreach my $student (@Students) {
        if($c->aborted()) { 
            $finish->($r);
            return ; 
        }
        # Call the output_student routine selected above
        $output_student->($r,$student);
    }
    # Call the "finish" routine selected above
    $finish->($r);
    #
    return;
}

#######################################################
#######################################################
sub next_and_previous_buttons {
    my $Str = '';
    $Str .= '<input type="hidden" name="SelectedStudent" value="'.
        $ENV{'form.SelectedStudent'}.'" />';
    #
    # Build the previous student link
    my $previous = &Apache::lonstatistics::previous_student();
    my $previousbutton = '';
    if (defined($previous)) {
        my $sname = $previous->{'username'}.':'.$previous->{'domain'};
        $previousbutton .= '<input type="button" value="'.
            'Previous Student ('.
            $previous->{'username'}.'@'.$previous->{'domain'}.')'.
            '" onclick="document.Statistics.SelectedStudent.value='.
            "'".$sname."'".';'.
            'document.Statistics.submit();" />';
    } else {
        $previousbutton .= '<input type="button" value="'.
            'Previous student (none)'.'" />';
    }
    #
    # Build the next student link
    my $next = &Apache::lonstatistics::next_student();
    my $nextbutton = '';
    if (defined($next)) {
        my $sname = $next->{'username'}.':'.$next->{'domain'};
        $nextbutton .= '<input type="button" value="'.
            'Next Student ('.
            $next->{'username'}.'@'.$next->{'domain'}.')'.
            '" onclick="document.Statistics.SelectedStudent.value='.
            "'".$sname."'".';'.
            'document.Statistics.submit();" />';
    } else {
        $nextbutton .= '<input type="button" value="'.
            'Next student (none)'.'" />';
    }
    #
    # Build the 'all students' button
    my $all = '';
    $all .= '<input type="button" value="All Students" '.
            '" onclick="document.Statistics.SelectedStudent.value='.
            "''".';'.'document.Statistics.submit();" />';
    $Str .= $previousbutton.('&nbsp;'x5).$all.('&nbsp;'x5).$nextbutton;
    return $Str;
}

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

sub get_student_fields_to_show {
    my @to_show = @Apache::lonstatistics::SelectedStudentData;
    foreach (@to_show) {
        if ($_ eq 'all') {
            @to_show = @Apache::lonstatistics::StudentDataOrder;
            last;
        }
    }
    return @to_show;
}

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

=pod

=item &CreateInterface()

Called by &BuildStudentAssessmentPage to create the top part of the
page which displays the chart.

Inputs: None

Returns:  A string containing the HTML for the headers and top table for 
the chart page.

=cut

#######################################################
#######################################################
sub CreateInterface {
    my $Str = '';
#    $Str .= &CreateLegend();
    $Str .= '<table cellspacing="5">'."\n";
    $Str .= '<tr>';
    $Str .= '<td align="center"><b>Sections</b></td>';
    $Str .= '<td align="center"><b>Student Data</b></td>';
    $Str .= '<td align="center"><b>Enrollment Status</b></td>';
    $Str .= '<td align="center"><b>Sequences and Folders</b></td>';
    $Str .= '<td align="center"><b>Output Format</b>'.
        &Apache::loncommon::help_open_topic("Chart_Output_Formats").
        '</td>';
    $Str .= '<td align="center"><b>Output Data</b>'.
        &Apache::loncommon::help_open_topic("Chart_Output_Data").
        '</td>';
    $Str .= '</tr>'."\n";
    #
    $Str .= '<tr><td align="center">'."\n";
    $Str .= &Apache::lonstatistics::SectionSelect('Section','multiple',5);
    $Str .= '</td><td align="center">';
    my $only_seq_with_assessments = sub { 
        my $s=shift;
        if ($s->{'num_assess'} < 1) { 
            return 0;
        } else { 
            return 1;
        }
    };
    $Str .= &Apache::lonstatistics::StudentDataSelect('StudentData','multiple',
                                                      5,undef);
    $Str .= '</td><td>'."\n";
    $Str .= &Apache::lonhtmlcommon::StatusOptions(undef,undef,5);
    $Str .= '</td><td>'."\n";
    $Str .= &Apache::lonstatistics::MapSelect('Maps','multiple,all',5,
                                              $only_seq_with_assessments);
    $Str .= '</td><td>'."\n";
    $Str .= &CreateAndParseOutputSelector();
    $Str .= '</td><td>'."\n";
    $Str .= &CreateAndParseOutputDataSelector();
    $Str .= '</td></tr>'."\n";
    $Str .= '</table>'."\n";
    $Str .= '<input type="submit" value="Generate Chart" />';
    $Str .= '&nbsp;'x5;
    $Str .= '<input type="submit" name="selectstudent" '.
                                  'value="Select One Student" />';
    $Str .= '&nbsp;'x5;
    $Str .= '<input type="submit" name="ClearCache" value="Clear Caches" />';
    $Str .= '&nbsp;'x5;
    $Str .= '<br />';
    return $Str;
}

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

=pod

=item &CreateAndParseOutputSelector()

=cut

#######################################################
#######################################################
my @OutputOptions = 
    ({ name  => 'HTML, with links',
       value => 'html, with links',
       description => 'Output HTML with each symbol linked to the problem '.
	   'which generated it.',
       mode => 'html',
       show_links => 'yes',
       },
     { name  => 'HTML, with all links',
       value => 'html, with all links',
       description => 'Output HTML with each symbol linked to the problem '.
	   'which generated it.  '.
           'This includes links for unattempted problems.',
       mode => 'html',
       show_links => 'all',
       },
     { name  => 'HTML, without links',
       value => 'html, without links',
       description => 'Output HTML.  By not including links, the size of the'.
	   ' web page is greatly reduced.  If your browser crashes on the '.
	   'full display, try this.',
       mode => 'html',
       show_links => 'no',
           },
     { name  => 'Excel',
       value => 'excel',
       description => 'Output an Excel file (compatable with Excel 95).',
       mode => 'excel',
       show_links => 'no',
   },
     { name  => 'CSV',
       value => 'csv',
       description => 'Output a comma seperated values file suitable for '.
           'import into a spreadsheet program.  Using this method as opposed '.
           'to Excel output allows you to organize your data before importing'.
           ' it into a spreadsheet program.',
       mode => 'csv',
       show_links => 'no',
           },
     );

sub OutputDescriptions {
    my $Str = '';
    $Str .= "<h2>Output Formats</h2>\n";
    $Str .= "<dl>\n";
    foreach my $outputmode (@OutputOptions) {
	$Str .="    <dt>".$outputmode->{'name'}."</dt>\n";
	$Str .="        <dd>".$outputmode->{'description'}."</dd>\n";
    }
    $Str .= "</dl>\n";
    return $Str;
}

sub CreateAndParseOutputSelector {
    my $Str = '';
    my $elementname = 'chartoutputmode';
    #
    # Format for output options is 'mode, restrictions';
    my $selected = 'html, without links';
    if (exists($ENV{'form.'.$elementname})) {
        if (ref($ENV{'form.'.$elementname} eq 'ARRAY')) {
            $selected = $ENV{'form.'.$elementname}->[0];
        } else {
            $selected = $ENV{'form.'.$elementname};
        }
    }
    #
    # Set package variables describing output mode
    $show_links  = 'no';
    $output_mode = 'html';
    foreach my $option (@OutputOptions) {
        next if ($option->{'value'} ne $selected);
        $output_mode = $option->{'mode'};
        $show_links  = $option->{'show_links'};
    }

    #
    # Build the form element
    $Str = qq/<select size="5" name="$elementname">/;
    foreach my $option (@OutputOptions) {
        $Str .= "\n".'    <option value="'.$option->{'value'}.'"';
        $Str .= " selected " if ($option->{'value'} eq $selected);
        $Str .= ">".$option->{'name'}."<\/option>";
    }
    $Str .= "\n</select>";
    return $Str;
}

##
## Data selector stuff
##
my @OutputDataOptions =
    (
     { name  => 'Scores',
       base  => 'scores',
       value => 'sum and total',
       shortdesc => 'Total Score and Maximum Possible for each '.
           'Sequence or Folder',
       longdesc => 'The score of each student as well as the '.
           ' maximum possible on each Sequence or Folder.',
       },
     { name  => 'Scores Per Problem',
       base  => 'scores',
       value => 'scores',
       shortdesc => 'Score on each Problem Part',
       longdesc =>'The students score on each problem part, computed as'.
           'the part weight * part awarded',
       },
#     { name  => 'Scores Sum',
#       base  => 'scores',
#       value => 'sum only',
#       shortdesc => 'Sum of Scores on each Problem Part',
#       longdesc =>'The total of the scores of the student on each problem'.
#           ' part in the sequences or folders selected.',
#       },
#     { name  => 'Scores Summary Table Only',
#       base  => 'scores',
#       value => 'final table scores',
#       shortdesc => 'Summary of Scores',
#       longdesc  => 'The average score on each sequence or folder for the '.
#           'selected students.',
#       },
     { name  =>'Tries',
       base  =>'tries',
       value => 'tries',
       shortdesc => 'Number of Tries before success on each Problem Part',
       longdesc =>'The number of tries before success on each problem part.',
       },
     { name  =>'Parts Correct',
       base  =>'tries',
       value => 'parts correct total',
       shortdesc => 'Number of Problem Parts completed successfully.',
       longdesc => 'The Number of Problem Parts completed successfully and '.
           'the maximum possible for each student',
       },
#     { name  =>'Parts Correct',
#       base  =>'tries',
#       value => 'parts correct',
#       shortdesc => 'Number of Problem Parts completed successfully.',
#       longdesc => 'The Number of Problem Parts completed successfully'.
#           ' on each sequence or folder.',
#       },
#     { name  => 'Parts Summary Table Only',
#       base  => 'tries',
#       value => 'final table parts',
#       shortdesc => 'Summary of Parts Correct',
#       longdesc  => 'A summary table of the average number of problem parts '.
#           'students were able to get correct on each sequence.',
#       },
     );

sub HTMLifyOutputDataDescriptions {
    my $Str = '';
    $Str .= "<h2>Output Data</h2>\n";
    $Str .= "<dl>\n";
    foreach my $option (@OutputDataOptions) {
        $Str .= '    <dt>'.$option->{'name'}.'</dt>';
        $Str .= '<dd>'.$option->{'longdesc'}.'</dd>'."\n";
    }
    $Str .= "</dl>\n";
    return $Str;
}

sub CreateAndParseOutputDataSelector {
    my $Str = '';
    my $elementname = 'chartoutputdata';
    #
    my $selected = 'scores';
    if (exists($ENV{'form.'.$elementname})) {
        if (ref($ENV{'form.'.$elementname} eq 'ARRAY')) {
            $selected = $ENV{'form.'.$elementname}->[0];
        } else {
            $selected = $ENV{'form.'.$elementname};
        }
    }
    #
    $data = 'scores';
    foreach my $option (@OutputDataOptions) {
        if ($option->{'value'} eq $selected) {
            $data = $option->{'value'};
            $base = $option->{'base'};
            $datadescription = $option->{'shortdesc'};
        }
    }
    #
    # Build the form element
    $Str = qq/<select size="5" name="$elementname">/;
    foreach my $option (@OutputDataOptions) {
        $Str .= "\n".'    <option value="'.$option->{'value'}.'"';
        $Str .= " selected " if ($option->{'value'} eq $data);
        $Str .= ">".$option->{'name'}."<\/option>";
    }
    $Str .= "\n</select>";
    return $Str;

}

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

=pod

=head2 HTML output routines

=item &html_initialize($r)

Create labels for the columns of student data to show.

=item &html_outputstudent($r,$student)

Return a line of the chart for a student.

=item &html_finish($r)

=cut

#######################################################
#######################################################
{
    my $padding;
    my $count;

    my $nodata_count; # The number of students for which there is no data
    my %prog_state;   # progress state used by loncommon PrgWin routines

sub html_initialize {
    my ($r) = @_;
    #
    $padding = ' 'x3;
    $count = 0;
    $nodata_count = 0;
    undef(%prog_state);
    #
    $r->print("<h3>".$ENV{'course.'.$ENV{'request.course.id'}.'.description'}.
              "&nbsp;&nbsp;".localtime(time)."</h3>");

    if ($data !~ /^final table/) {
        $r->print("<h3>".$datadescription."</h3>");        
    }
    #
    # Set up progress window for 'final table' display only
    if ($data =~ /^final table/) {
        my $studentcount = scalar(@Apache::lonstatistics::Students); 
        %prog_state=&Apache::lonhtmlcommon::Create_PrgWin
            ($r,'Summary Table Status',
             'Summary Table Compilation Progress', $studentcount);
    }
    my $Str = "<pre>\n";
    # First, the @StudentData fields need to be listed
    my @to_show = &get_student_fields_to_show();
    foreach my $field (@to_show) {
        my $title=$Apache::lonstatistics::StudentData{$field}->{'title'};
        my $base =$Apache::lonstatistics::StudentData{$field}->{'base_width'};
        my $width=$Apache::lonstatistics::StudentData{$field}->{'width'};
        $Str .= $title.' 'x($width-$base).$padding;
    }
    # Now the selected sequences need to be listed
    foreach my $sequence (&Apache::lonstatistics::Sequences_with_Assess()){
        my $title = $sequence->{'title'};
        my $base  = $sequence->{'base_width'};
        my $width = $sequence->{'width'};
        $Str .= $title.' 'x($width-$base).$padding;
    }
    $Str .= "total</pre>\n";
    $Str .= "<pre>";
    #
    # Check for suppression of output
    if ($data =~ /^final table/) {
        $Str = '';
    }
    $r->print($Str);
    $r->rflush();
    return;
}

sub html_outputstudent {
    my ($r,$student) = @_;
    my $Str = '';
    #
    if($count++ % 5 == 0 && $count > 0 && $data !~ /^final table/) {
        $r->print("</pre><pre>");
    }
    # First, the @StudentData fields need to be listed
    my @to_show = &get_student_fields_to_show();
    foreach my $field (@to_show) {
        my $title=$student->{$field};
        my $base = length($title);
        my $width=$Apache::lonstatistics::StudentData{$field}->{'width'};
        $Str .= $title.' 'x($width-$base).$padding;
    }
    # Get ALL the students data
    my %StudentsData;
    my @tmp = &Apache::loncoursedata::get_current_state
        ($student->{'username'},$student->{'domain'},undef,
         $ENV{'request.course.id'});
    if ((scalar @tmp > 0) && ($tmp[0] !~ /^error:/)) {
        %StudentsData = @tmp;
    }
    if (scalar(@tmp) < 1) {
        $nodata_count++;
        return if ($data =~ /^final table/);
        $Str .= '<font color="blue">No Course Data</font>'."\n";
        $r->print($Str);
        $r->rflush();
        return;
    }
    #
    # By sequence build up the data
    my $studentstats;
    my $PerformanceStr = '';
    foreach my $seq (&Apache::lonstatistics::Sequences_with_Assess()) {
        my ($performance,$performance_length,$score,$seq_max,$rawdata);
        if ($base eq 'tries') {
            ($performance,$performance_length,$score,$seq_max,$rawdata) =
                &StudentTriesOnSequence($student,\%StudentsData,
                                        $seq,$show_links);
        } else {
            ($performance,$performance_length,$score,$seq_max,$rawdata) =
                &StudentPerformanceOnSequence($student,\%StudentsData,
                                              $seq,$show_links);
        }
        my $ratio = sprintf("%3d",$score).'/'.sprintf("%3d",$seq_max);
        #
        if ($data eq 'sum and total' || $data eq 'parts correct total') {
            $performance  = $ratio;
            $performance .= ' 'x($seq->{'width'}-length($ratio));
        } elsif ($data eq 'sum only' || $data eq 'parts correct') {
            $performance  = $score;
            $performance .= ' 'x($seq->{'width'}-length($score));
        } else {
            # Pad with extra spaces
            $performance .= ' 'x($seq->{'width'}-$performance_length-
                                 length($ratio)
                                 ).$ratio;
        }
        #
        $Str .= $performance.$padding;
        #
        $studentstats->{$seq->{'symb'}}->{'score'}= $score;
        $studentstats->{$seq->{'symb'}}->{'max'}  = $seq_max;
    }
    #
    # Total it up and store the statistics info.
    my ($score,$max) = (0,0);
    while (my ($symb,$seq_stats) = each (%{$studentstats})) {
        $Statistics->{$symb}->{'score'} += $seq_stats->{'score'};
        if ($Statistics->{$symb}->{'max'} < $seq_stats->{'max'}) {
            $Statistics->{$symb}->{'max'} = $seq_stats->{'max'};
        }
        $score += $seq_stats->{'score'};
        $max   += $seq_stats->{'max'};
    }
    $Str .= ' '.' 'x(length($max)-length($score)).$score.'/'.$max;
    $Str .= " \n";
    #
    # Check for suppressed output and update the progress window if so...
    if ($data =~ /^final table/) {
        $Str = '';
        &Apache::lonhtmlcommon::Increment_PrgWin($r,\%prog_state,
                                                 'last student');
    }
    #
    $r->print($Str);
    #
    $r->rflush();
    return;
}    

sub html_finish {
    my ($r) = @_;
    #
    # Check for suppressed output and close the progress window if so
    if ($data =~ /^final table/) {
        &Apache::lonhtmlcommon::Close_PrgWin($r,\%prog_state);
    } else {
        $r->print("</pre>\n"); 
    }
    if ($single_student_mode) {
        $r->print(&SingleStudentTotal());
    } else {
        $r->print(&StudentAverageTotal());
    }
    $r->rflush();
    return;
}

sub StudentAverageTotal {
    my $Str = "<h3>Summary Tables</h3>\n";
    my $num_students = scalar(@Apache::lonstatistics::Students);
    my $total_ave = 0;
    my $total_max = 0;
    $Str .= '<table border=2 cellspacing="1">'."\n";
    $Str .= "<tr><th>Title</th><th>Average</th><th>Maximum</th></tr>\n";
    foreach my $seq (&Apache::lonstatistics::Sequences_with_Assess()) {
        my $ave;
        if ($num_students > $nodata_count) {
            $ave = int(100*($Statistics->{$seq->{'symb'}}->{'score'}/
                            ($num_students-$nodata_count)))/100;
        } else {
            $ave = 0;
        }
        $total_ave += $ave;
        my $max = $Statistics->{$seq->{'symb'}}->{'max'};
        $total_max += $max;
        if ($ave == 0) {
            $ave = "0.00";
        }
        $ave .= '&nbsp;';
        $max .= '&nbsp;&nbsp;&nbsp;';
        $Str .= '<tr><td>'.$seq->{'title'}.'</td>'.
            '<td align="right">'.$ave.'</td>'.
                '<td align="right">'.$max.'</td></tr>'."\n";
    }
    $total_ave = int(100*$total_ave)/100; # only two digit
    $Str .= "</table>\n";
    $Str .= '<table border=2 cellspacing="1">'."\n";
    $Str .= '<tr><th>Number of Students</th><th>Average</th>'.
        "<th>Maximum</th></tr>\n";
    $Str .= '<tr><td>'.($num_students-$nodata_count).'</td>'.
        '<td>'.$total_ave.'</td><td>'.$total_max.'</td>';
    $Str .= "</table>\n";
    return $Str;
}

sub SingleStudentTotal {
    my $student = &Apache::lonstatistics::current_student();
    my $Str = "<h3>Summary table for ".$student->{'fullname'}." ".
        $student->{'username'}.'@'.$student->{'domain'}."</h3>\n";
    $Str .= '<table border=2 cellspacing="1">'."\n";
    $Str .= 
        "<tr><th>Sequence or Folder</th><th>Score</th><th>Maximum</th></tr>\n";
    my $total = 0;
    my $total_max = 0;
    foreach my $seq (&Apache::lonstatistics::Sequences_with_Assess()) {
        my $value = $Statistics->{$seq->{'symb'}}->{'score'};
        my $max = $Statistics->{$seq->{'symb'}}->{'max'};
        $Str .= '<tr><td>'.$seq->{'title'}.'</td>'.
            '<td align="right">'.$value.'</td>'.
                '<td align="right">'.$max.'</td></tr>'."\n";
        $total += $value;
        $total_max +=$max;
    }
    $Str .= '<tr><td><b>Total</b></td>'.
        '<td align="right">'.$total.'</td>'.
        '<td align="right">'.$total_max."</td></tr>\n";
    $Str .= "</table>\n";
    return $Str;
}

}

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

=pod

=head2 EXCEL subroutines

=item &excel_initialize($r)

=item &excel_outputstudent($r,$student)

=item &excel_finish($r)

=cut

#######################################################
#######################################################
{

my $excel_sheet;
my $excel_workbook;

my $filename;
my $rows_output;
my $cols_output;

my %prog_state; # progress window state
my $request_aborted;

sub excel_initialize {
    my ($r) = @_;
    #
    undef ($excel_sheet);
    undef ($excel_workbook);
    undef ($filename);
    undef ($rows_output);
    undef ($cols_output);
    undef (%prog_state);
    undef ($request_aborted);
    #
    my $total_columns = scalar(&get_student_fields_to_show());
    foreach my $seq (&Apache::lonstatistics::Sequences_with_Assess()) {
        # Add 2 because we need a 'sum' and 'total' column for each
        $total_columns += $seq->{'num_assess_parts'}+2;
    }
    if ($data eq 'tries' && $total_columns > 255) {
        $r->print(<<END);
<h2>Unable to Complete Request</h2>
<p>
LON-CAPA is unable to produce your Excel spreadsheet because your selections
will result in more than 255 columns.  Excel allows only 255 columns in a
spreadsheet.
</p><p>
You may consider reducing the number of <b>Sequences or Folders</b> you
have selected.  
</p><p>
LON-CAPA can produce <b>CSV</b> files of this data or Excel files of the
summary data (<b>Parts Correct</b> or <b>Parts Correct & Totals</b>).
</p>
END
       $request_aborted = 1;
    }
    if ($data eq 'scores' && $total_columns > 255) {
        $r->print(<<END);
<h2>Unable to Complete Request</h2>
<p>
LON-CAPA is unable to produce your Excel spreadsheet because your selections
will result in more than 255 columns.  Excel allows only 255 columns in a
spreadsheet.
</p><p>
You may consider reducing the number of <b>Sequences or Folders</b> you
have selected.  
</p><p>
LON-CAPA can produce <b>CSV</b> files of this data or Excel files of the
summary data (<b>Scores Sum</b> or <b>Scores Sum & Totals</b>).
</p>
END
       $request_aborted = 1;
    }
    if ($data =~ /^final table/) {
        $r->print(<<END);
<h2>Unable to Complete Request</h2>
<p>
The <b>Summary Table (Scores)</b> option is not available for non-HTML output.
</p>
END
       $request_aborted = 1;
    }
    return if ($request_aborted);
    #
    $filename = '/prtspool/'.
        $ENV{'user.name'}.'_'.$ENV{'user.domain'}.'_'.
            time.'_'.rand(1000000000).'.xls';
    #
    $excel_workbook = undef;
    $excel_sheet = undef;
    #
    $rows_output = 0;
    $cols_output = 0;
    #
    # Create sheet
    $excel_workbook = Spreadsheet::WriteExcel->new('/home/httpd'.$filename);
    #
    # Check for errors
    if (! defined($excel_workbook)) {
        $r->log_error("Error creating excel spreadsheet $filename: $!");
        $r->print("Problems creating new Excel file.  ".
                  "This error has been logged.  ".
                  "Please alert your LON-CAPA administrator");
        return ;
    }
    #
    # The excel spreadsheet stores temporary data in files, then put them
    # together.  If needed we should be able to disable this (memory only).
    # The temporary directory must be specified before calling 'addworksheet'.
    # File::Temp is used to determine the temporary directory.
    $excel_workbook->set_tempdir($Apache::lonnet::tmpdir);
    #
    # Add a worksheet
    my $sheetname = $ENV{'course.'.$ENV{'request.course.id'}.'.description'};
    $sheetname = &Apache::loncommon::clean_excel_name($sheetname);
    $excel_sheet = $excel_workbook->addworksheet($sheetname);
    #
    # Put the course description in the header
    $excel_sheet->write($rows_output,$cols_output++,
                   $ENV{'course.'.$ENV{'request.course.id'}.'.description'});
    $cols_output += 3;
    #
    # Put a description of the sections listed
    my $sectionstring = '';
    my @Sections = @Apache::lonstatistics::SelectedSections;
    if (scalar(@Sections) > 1) {
        if (scalar(@Sections) > 2) {
            my $last = pop(@Sections);
            $sectionstring = "Sections ".join(', ',@Sections).', and '.$last;
        } else {
            $sectionstring = "Sections ".join(' and ',@Sections);
        }
    } else {
        if ($Sections[0] eq 'all') {
            $sectionstring = "All sections";
        } else {
            $sectionstring = "Section ".$Sections[0];
        }
    }
    $excel_sheet->write($rows_output,$cols_output++,$sectionstring);
    $cols_output += scalar(@Sections);
    #
    # Put the date in there too
    $excel_sheet->write($rows_output++,$cols_output++,
                        'Compiled on '.localtime(time));
    #
    $cols_output = 0;
    $excel_sheet->write($rows_output++,$cols_output++,$datadescription);
    #
    if ($data eq 'tries' || $data eq 'scores') {
        $rows_output++;
    }
    #
    # Add the student headers
    $cols_output = 0;
    foreach my $field (&get_student_fields_to_show()) {
        $excel_sheet->write($rows_output,$cols_output++,$field);
    }
    my $row_offset = 0;
    if ($data eq 'tries' || $data eq 'scores') {
        $row_offset = -1;
    }
    #
    # Add the remaining column headers
    foreach my $seq (&Apache::lonstatistics::Sequences_with_Assess()) {
        $excel_sheet->write($rows_output+$row_offset,
                            $cols_output,$seq->{'title'});
        if ($data eq 'tries' || $data eq 'scores') {
            foreach my $res (@{$seq->{'contents'}}) {
                next if ($res->{'type'} ne 'assessment');
                if (scalar(@{$res->{'parts'}}) > 1) {
                    foreach my $part (@{$res->{'parts'}}) {
                        $excel_sheet->write($rows_output,
                                            $cols_output++,
                                            $res->{'title'}.' part '.$part);
                    }
                } else {
                    $excel_sheet->write($rows_output,
                                        $cols_output++,
                                        $res->{'title'});
                }
            }
            $excel_sheet->write($rows_output,$cols_output++,'score');
            $excel_sheet->write($rows_output,$cols_output++,'maximum');
        } elsif ($data eq 'sum and total' || $data eq 'parts correct total') {
            $excel_sheet->write($rows_output+1,$cols_output,'score');
            $excel_sheet->write($rows_output+1,$cols_output+1,'maximum');
            $cols_output += 2;
        } else {
            $cols_output++;
        }
    }
    #
    # Bookkeeping
    if ($data eq 'sum and total' || $data eq 'parts correct total') {
        $rows_output += 2;
    } else {
        $rows_output += 1;
    }
    #
    # Output a row for MAX
    $cols_output = 0;
    foreach my $field (&get_student_fields_to_show()) {
        if ($field eq 'username' || $field eq 'fullname' || 
            $field eq 'id') {
            $excel_sheet->write($rows_output,$cols_output++,'Maximum');
        } else {
            $excel_sheet->write($rows_output,$cols_output++,'');
        }
    }
    #
    # Add the maximums for each sequence or assessment
    foreach my $seq (&Apache::lonstatistics::Sequences_with_Assess()) {
        my $weight;
        my $max = 0;
        foreach my $resource (@{$seq->{'contents'}}) {
            next if ($resource->{'type'} ne 'assessment');
            foreach my $part (@{$resource->{'parts'}}) {
                $weight = 1;
                if ($base eq 'scores') {
                    $weight = &Apache::lonnet::EXT
                        ('resource.'.$part.'.weight',$resource->{'symb'},
                         undef,undef,undef);
                    if (!defined($weight) || ($weight eq '')) { 
                        $weight=1;
                    }
                }
                if ($data eq 'scores') {
                    $excel_sheet->write($rows_output,$cols_output++,$weight);
                } elsif ($data eq 'tries') {
                    $excel_sheet->write($rows_output,$cols_output++,'');
                }
                $max += $weight;
            }
        } 
        if (! ($data eq 'sum only' || $data eq 'parts correct')) {
            $excel_sheet->write($rows_output,$cols_output++,'');
        }
        $excel_sheet->write($rows_output,$cols_output++,$max);
    }
    $rows_output++;
    #
    # Let the user know what we are doing
    my $studentcount = scalar(@Apache::lonstatistics::Students); 
    $r->print("<h1>Compiling Excel spreadsheet for ".
              $studentcount.' student');
    $r->print('s') if ($studentcount > 1);
    $r->print("</h1>\n");
    $r->rflush();
    #
    # Initialize progress window
    %prog_state=&Apache::lonhtmlcommon::Create_PrgWin
        ($r,'Excel File Compilation Status',
         'Excel File Compilation Progress', $studentcount);
    #
    &Apache::lonhtmlcommon::Update_PrgWin($r,\%prog_state,
                                          'Processing first student');
    return;
}

sub excel_outputstudent {
    my ($r,$student) = @_;
    return if ($request_aborted);
    return if (! defined($excel_sheet));
    $cols_output=0;
    #
    # Write out student data
    my @to_show = &get_student_fields_to_show();
    foreach my $field (@to_show) {
        $excel_sheet->write($rows_output,$cols_output++,$student->{$field});
    }
    #
    # Get student assessment data
    my %StudentsData;
    my @tmp = &Apache::loncoursedata::get_current_state($student->{'username'},
                                                        $student->{'domain'},
                                                        undef,
                                                   $ENV{'request.course.id'});
    if ((scalar @tmp > 0) && ($tmp[0] !~ /^error:/)) {
        %StudentsData = @tmp;
    }
    #
    # Write out sequence scores and totals data
    foreach my $seq (&Apache::lonstatistics::Sequences_with_Assess()) {
        my ($performance,$performance_length,$score,$seq_max,$rawdata);
        if ($base eq 'tries') {
            ($performance,$performance_length,$score,$seq_max,$rawdata) =
                &StudentTriesOnSequence($student,\%StudentsData,
                                        $seq,'no');
        } else {
            ($performance,$performance_length,$score,$seq_max,$rawdata) =
                &StudentPerformanceOnSequence($student,\%StudentsData,
                                              $seq,'no');
        }
        if ($data eq 'tries' || $data eq 'scores') {
            foreach my $value (@$rawdata) {
                $excel_sheet->write($rows_output,$cols_output++,$value);
            }
            $excel_sheet->write($rows_output,$cols_output++,$score);
            $excel_sheet->write($rows_output,$cols_output++,$seq_max);
        } elsif ($data eq 'sum and total' || $data eq 'sum only' || 
            $data eq 'parts correct' || $data eq 'parts correct total') {
            $excel_sheet->write($rows_output,$cols_output++,$score);
        }
        if ($data eq 'sum and total' || $data eq 'parts correct total') {
            $excel_sheet->write($rows_output,$cols_output++,$seq_max);
        }
    }
    #
    # Bookkeeping
    $rows_output++; 
    $cols_output=0;
    #
    # Update the progress window
    &Apache::lonhtmlcommon::Increment_PrgWin($r,\%prog_state,'last student');
    return;
}

sub excel_finish {
    my ($r) = @_;
    return if ($request_aborted);
    return if (! defined($excel_sheet));
    #
    # Write the excel file
    $excel_workbook->close();
    my $c = $r->connection();
    #
    return if($c->aborted());
    #
    # Close the progress window
    &Apache::lonhtmlcommon::Close_PrgWin($r,\%prog_state);
    #
    # Tell the user where to get their excel file
    $r->print('<br />'.
              '<a href="'.$filename.'">Your Excel spreadsheet.</a>'."\n");
    $r->rflush();
    return;
}

}
#######################################################
#######################################################

=pod

=head2 CSV output routines

=item &csv_initialize($r)

=item &csv_outputstudent($r,$student)

=item &csv_finish($r)

=cut

#######################################################
#######################################################
{

my $outputfile;
my $filename;
my $request_aborted;
my %prog_state; # progress window state

sub csv_initialize{
    my ($r) = @_;
    # 
    # Clean up
    undef($outputfile);
    undef($filename);
    undef($request_aborted);
    undef(%prog_state);
    #
    # Deal with unimplemented requests
    $request_aborted = undef;
    if ($data =~ /final table/) {
        $r->print(<<END);
<h2>Unable to Complete Request</h2>
<p>
The <b>Summary Table (Scores)</b> option is not available for non-HTML output.
</p>
END
       $request_aborted = 1;
    }
    return if ($request_aborted);

    #
    # Open a file
    $filename = '/prtspool/'.
        $ENV{'user.name'}.'_'.$ENV{'user.domain'}.'_'.
            time.'_'.rand(1000000000).'.csv';
    unless ($outputfile = Apache::File->new('>/home/httpd'.$filename)) {
        $r->log_error("Couldn't open $filename for output $!");
        $r->print("Problems occured in writing the csv file.  ".
                  "This error has been logged.  ".
                  "Please alert your LON-CAPA administrator.");
        $outputfile = undef;
    }
    #
    # Datestamp
    my $description = $ENV{'course.'.$ENV{'request.course.id'}.'.description'};
    print $outputfile '"'.&Apache::loncommon::csv_translate($description).'",'.
        '"'.&Apache::loncommon::csv_translate(scalar(localtime(time))).'"'.
            "\n";
    #
    # Print out the headings
    my $Str = '';
    my $Str2 = undef;
    foreach my $field (&get_student_fields_to_show()) {
        if ($data eq 'sum only') {
            $Str .= '"'.&Apache::loncommon::csv_translate($field).'",';
        } elsif ($data eq 'sum and total' || $data eq 'parts correct total') {
            $Str .= '"",'; # first row empty on the student fields
            $Str2 .= '"'.&Apache::loncommon::csv_translate($field).'",';
        } elsif ($data eq 'scores' || $data eq 'tries' || 
                 $data eq 'parts correct') {
            $Str  .= '"",';
            $Str2 .= '"'.&Apache::loncommon::csv_translate($field).'",';
        }
    }
    foreach my $seq (&Apache::lonstatistics::Sequences_with_Assess()) {
        if ($data eq 'sum only' || $data eq 'parts correct') {
            $Str .= '"'.&Apache::loncommon::csv_translate($seq->{'title'}).
                '",';
        } elsif ($data eq 'sum and total' || $data eq 'parts correct total') {
            $Str  .= '"'.&Apache::loncommon::csv_translate($seq->{'title'}).
                '","",';
            $Str2 .= '"score","total possible",';
        } elsif ($data eq 'scores' || $data eq 'tries') {
            $Str  .= '"'.&Apache::loncommon::csv_translate($seq->{'title'}).
                '",';
            $Str .= '"",'x($seq->{'num_assess_parts'}-1+2);
            foreach my $res (@{$seq->{'contents'}}) {
                next if ($res->{'type'} ne 'assessment');
                foreach my $part (@{$res->{'parts'}}) {
                    $Str2 .= '"'.&Apache::loncommon::csv_translate($res->{'title'}.', Part '.$part).'",';
                }
            }
            $Str2 .= '"score","total possible",';
        }
    }
    chop($Str);
    $Str .= "\n";
    print $outputfile $Str;
    if (defined($Str2)) {
        chop($Str2);
        $Str2 .= "\n";
        print $outputfile $Str2;
    }
    #
    # Initialize progress window
    my $studentcount = scalar(@Apache::lonstatistics::Students);
    %prog_state=&Apache::lonhtmlcommon::Create_PrgWin
        ($r,'CSV File Compilation Status',
         'CSV File Compilation Progress', $studentcount);
    return;
}

sub csv_outputstudent {
    my ($r,$student) = @_;
    return if ($request_aborted);
    return if (! defined($outputfile));
    my $Str = '';
    #
    # Output student fields
    my @to_show = &get_student_fields_to_show();
    foreach my $field (@to_show) {
        $Str .= '"'.&Apache::loncommon::csv_translate($student->{$field}).'",';
    }
    #
    # Get student assessment data
    my %StudentsData;
    my @tmp = &Apache::loncoursedata::get_current_state($student->{'username'},
                                                        $student->{'domain'},
                                                        undef,
                                                   $ENV{'request.course.id'});
    if ((scalar @tmp > 0) && ($tmp[0] !~ /^error:/)) {
        %StudentsData = @tmp;
    }
    #
    # Output performance data
    foreach my $seq (&Apache::lonstatistics::Sequences_with_Assess()) {
        my ($performance,$performance_length,$score,$seq_max,$rawdata);
        if ($base eq 'tries') {
            ($performance,$performance_length,$score,$seq_max,$rawdata) =
                &StudentTriesOnSequence($student,\%StudentsData,
                                        $seq,'no');
        } else {
            ($performance,$performance_length,$score,$seq_max,$rawdata) =
                &StudentPerformanceOnSequence($student,\%StudentsData,
                                              $seq,'no');
        }
        if ($data eq 'sum only' || $data eq 'parts correct') {
            $Str .= '"'.$score.'",';
        } elsif ($data eq 'sum and total' || $data eq 'parts correct total') {
            $Str  .= '"'.$score.'","'.$seq_max.'",';
        } elsif ($data eq 'scores' || $data eq 'tries') {
            $Str .= '"'.join('","',(@$rawdata,$score,$seq_max)).'",';
        }
    }
    chop($Str);
    $Str .= "\n";
    print $outputfile $Str;
    #
    # Update the progress window
    &Apache::lonhtmlcommon::Increment_PrgWin($r,\%prog_state,'last student');
    return;
}

sub csv_finish {
    my ($r) = @_;
    return if ($request_aborted);
    return if (! defined($outputfile));
    close($outputfile);
    #
    my $c = $r->connection();
    return if ($c->aborted());
    #
    # Close the progress window
    &Apache::lonhtmlcommon::Close_PrgWin($r,\%prog_state);
    #
    # Tell the user where to get their csv file
    $r->print('<br />'.
              '<a href="'.$filename.'">Your csv file.</a>'."\n");
    $r->rflush();
    return;
    
}

}

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

=pod

=item &StudentTriesOnSequence()

Inputs:

=over 4

=item $student

=item $studentdata Hash ref to all student data

=item $seq Hash ref, the sequence we are working on

=item $links if defined we will output links to each resource.

=back

=cut

#######################################################
#######################################################
sub StudentTriesOnSequence {
    my ($student,$studentdata,$seq,$links) = @_;
    $links = 'no' if (! defined($links));
    my $Str = '';
    my ($sum,$max) = (0,0);
    my $performance_length = 0;
    my @TriesData = ();
    my $tries;
    foreach my $resource (@{$seq->{'contents'}}) {
        next if ($resource->{'type'} ne 'assessment');
        my $resource_data = $studentdata->{$resource->{'symb'}};
        my $value = '';
        foreach my $partnum (@{$resource->{'parts'}}) {
            $tries = undef;
            $max++;
            $performance_length++;
            my $symbol = ' '; # default to space
            #
            if (exists($resource_data->{'resource.'.$partnum.'.solved'})) {
                my $status = $resource_data->{'resource.'.$partnum.'.solved'};
                if ($status eq 'correct_by_override') {
                    $symbol = '+';
                    $sum++;
                } elsif ($status eq 'incorrect_by_override') {
                    $symbol = '-';
                } elsif ($status eq 'ungraded_attempted') {
                    $symbol = '#';
                } elsif ($status eq 'incorrect_attempted')  {
                    $symbol = '.';
                } elsif ($status eq 'excused') {
                    $symbol = 'x';
                    $max--;
                } elsif (($status eq 'correct_by_scantron' ||
                          $status eq 'correct_by_student') &&
                    exists($resource_data->{'resource.'.$partnum.'.tries'})){
                    $tries = $resource_data->{'resource.'.$partnum.'.tries'};
                    if ($tries > 9) {
                        $symbol = '*';
                    } elsif ($tries > 0) {
                        $symbol = $tries;
                    } else {
                        $symbol = ' ';
                    }
                    $sum++;
                } elsif (exists($resource_data->{'resource.'.
                                                     $partnum.'.tries'})){
                    $symbol = '.';
                } else {
                    $symbol = ' ';
                }
            } else {
                # Unsolved.  Did they try?
                if (exists($resource_data->{'resource.'.$partnum.'.tries'})){
                    $symbol = '.';
                } else {
                    $symbol = ' ';
                }
            }
            #
            if (! defined($tries)) {
                $tries = $symbol;
            }
            push (@TriesData,$tries);
            #
            if ( ($links eq 'yes' && $symbol ne ' ') ||
                 ($links eq 'all')) {
                if (length($symbol) > 1) {
                    &Apache::lonnet::logthis('length of symbol "'.$symbol.'" > 1');
                }
                $symbol = '<a href="/adm/grades'.
                    '?symb='.&Apache::lonnet::escape($resource->{'symb'}).
                        '&student='.$student->{'username'}.
                            '&userdom='.$student->{'domain'}.
                                '&command=submission">'.$symbol.'</a>';
            }
            $value .= $symbol;
        }
        $Str .= $value;
    }
    if ($seq->{'randompick'}) {
        $max = $seq->{'randompick'};
    }
    return ($Str,$performance_length,$sum,$max,\@TriesData);
}

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

=pod

=item &StudentPerformanceOnSequence()

Inputs:

=over 4

=item $student

=item $studentdata Hash ref to all student data

=item $seq Hash ref, the sequence we are working on

=item $links if defined we will output links to each resource.

=back

=cut

#######################################################
#######################################################
sub StudentPerformanceOnSequence {
    my ($student,$studentdata,$seq,$links) = @_;
    $links = 'no' if (! defined($links));
    my $Str = ''; # final result string
    my ($score,$max) = (0,0);
    my $performance_length = 0;
    my $symbol;
    my @ScoreData = ();
    my $partscore;
    foreach my $resource (@{$seq->{'contents'}}) {
        next if ($resource->{'type'} ne 'assessment');
        my $resource_data = $studentdata->{$resource->{'symb'}};
        foreach my $part (@{$resource->{'parts'}}) {
            $partscore = undef;
            my $weight = &Apache::lonnet::EXT('resource.'.$part.'.weight',
                                              $resource->{'symb'},
                                              $student->{'domain'},
                                              $student->{'username'},
                                              $student->{'section'});
            if (!defined($weight) || ($weight eq '')) { 
                $weight=1;
            }
            #
            $max += $weight; # see the 'excused' branch below...
            $performance_length++; # one character per part
            $symbol = ' '; # default to space
            #
            my $awarded = 0;
            if (exists($resource_data->{'resource.'.$part.'.awarded'})) {
                $awarded = $resource_data->{'resource.'.$part.'.awarded'};
                $awarded = 0 if (! $awarded);
            }
            #
            $partscore = $weight*$awarded;
            $score += $partscore;
            $symbol = $partscore; 
            if (abs($symbol - sprintf("%.0f",$symbol)) < 0.001) {
                $symbol = sprintf("%.0f",$symbol);
            }
            if (length($symbol) > 1) {
                $symbol = '*';
            }
            if (exists($resource_data->{'resource.'.$part.'.solved'})) {
                my $status = $resource_data->{'resource.'.$part.'.solved'};
                if ($status eq 'excused') {
                    $symbol = 'x';
                    $max -= $weight; # Do not count 'excused' problems.
                }
            } else {
                # Unsolved.  Did they try?
                if (exists($resource_data->{'resource.'.$part.'.tries'})){
                    $symbol = '.';
                } else {
                    $symbol = ' ';
                }
            }
            #
            if (! defined($partscore)) {
                $partscore = $symbol;
            }
            push (@ScoreData,$partscore);
            #
            if ( ($links eq 'yes' && $symbol ne ' ') || ($links eq 'all')) {
                $symbol = '<a href="/adm/grades'.
                    '?symb='.&Apache::lonnet::escape($resource->{'symb'}).
                    '&student='.$student->{'username'}.
                    '&userdom='.$student->{'domain'}.
                    '&command=submission">'.$symbol.'</a>';
            }
            $Str .= $symbol;
        }
    }
    return ($Str,$performance_length,$score,$max,\@ScoreData);
}

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

=pod

=item &CreateLegend()

This function returns a formatted string containing the legend for the
chart.  The legend describes the symbols used to represent grades for
problems.

=cut

#######################################################
#######################################################
sub CreateLegend {
    my $Str = "<p><pre>".
              "   1  correct by student in 1 try\n".
              "   7  correct by student in 7 tries\n".
              "   *  correct by student in more than 9 tries\n".
	      "   +  correct by hand grading or override\n".
              "   -  incorrect by override\n".
	      "   .  incorrect attempted\n".
	      "   #  ungraded attempted\n".
              "      not attempted (blank field)\n".
	      "   x  excused".
              "</pre><p>";
    return $Str;
}

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

=pod 

=back

=cut

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

1;

__END__

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