File:  [LON-CAPA] / loncom / interface / lonstatistics.pm
Revision 1.27: download - view: text, annotated - select for diffs
Wed Jul 17 12:53:00 2002 UTC (21 years, 9 months ago) by stredwic
Branches: MAIN
CVS tags: HEAD
Anyone currently working on lonstatistics and relying on the global variables
like %hash, will have some intergration changes to make.  I will be happy to
help.  The key is most of the data is now stored in the cache database.  Also
look to loncoursedata.pm to see the key names.

Merged the use of loncoursedata.pm for gathering student course data.  Also
using the cache data instead of the global variables.  The process is about
75% complete.  Student Assessment and Problem Analysis pages both work the
same as before the changes.  Except for a couple of interface changes I made.
Now there is a new student and previous student buttons on the student assessment
page for cycling through the student list.  Changed all students to no student
selected because all students would not display anything anyways.  May add back
a all students which will display all students.  Removed the section selection
from only the student assessment page.  I may add this back.  The problem
analysis->analyze page was already having the problem with the broken graph.gif.
The first fix for redhat 7.3 users was to download and install the lonbarcode.
The next fix will have to fix the posting data.  Currently it is not reading
the information from ssi back correctly thus the post data is missing and
no rendering of the graph.  This problem will be further explored.

The problem statistics page is about halfway done.  The interface is up, but
you will get no data.  The will be remedied over the next few days.  I wanted
to submit because I was going to work a new scheme for downloading student
course data.

# The LearningOnline Network with CAPA
# (Publication Handler
#
# $Id: lonstatistics.pm,v 1.27 2002/07/17 12:53:00 stredwic 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
# YEAR=2001
# 5/5,7/9,7/25/1,8/11,9/13,9/26,10/5,10/9,10/22,10/26 Behrouz Minaei
# 11/1,11/4,11/16,12/14,12/16,12/18,12/20,12/31 Behrouz Minaei
# YEAR=2002
# 1/22,2/1,2/6,2/25,3/2,3/6,3/17,3/21,3/22,3/26,4/7,5/6 Behrouz Minaei
# 5/12,5/14,5/15,5/19,5/26 Behrouz Minaei
#
###

package Apache::lonstatistics; 

use strict; 
use Apache::Constants qw(:common :http);
use Apache::lonnet();
use Apache::lonhomework;
use Apache::loncommon;
use Apache::loncoursedata;
use HTML::TokeParser;
use GDBM_File;

# -------------------------------------------------------------- Module Globals
my %hash;
my %CachData;
my %GraphDat;
my %mapsort;
my $Pos;
my $r;
my $GData;
my %color;
my %foil_to_concept;
my @Concepts;
my %ConceptData;
my %Answer = ();

sub Activity {
    my $file="/home/minaeibi/activity.log";
    my $userid='adamsde1';
    $r->print("<br>Using $file");
    $r->rflush();
    open(FILEID, "<$file");
    my $line;
    my @allaccess;
    my $Count=0;
    while ($line=<FILEID>) {
	my ($time,$machine,$what)=split(':',$line);
	$what=&Apache::lonnet::unescape($what);
	my @accesses=split('&',$what);
	foreach my $access (@accesses) {
	    my ($date,$resource,$who,$domain,$post,@posts)=split(':',$access);
	    if ($who ne $userid) { next; }
	    if (!$resource) { next; }
	    my $res=&Apache::lonnet::unescape($resource);
	    if (($res =~ /\.(problem|htm|html)/)) {
		$Count++;
		$r->print("<br>$Count) ".localtime($date).": $who --> $res");
#	        if ($post) { 
#		    $Count++;
#		    $r->print("<br><b>$Count) Sent data ".join(':',
#                              &Apache::lonnet::unescape(@posts)).'</b>');
#		}
		$r->rflush();
	    }
	##    push (@allaccess,unescape($access));
	    #print $machine;
	}
    }
#    @allaccess=sort(@allaccess);
#    $Count=0;
#    foreach my $access (@allaccess) {
#	my ($date,$resource,$who,$domain,$post,@posts)=split(':',$access);
#	$Count++;
#	$r->print("<br>$Count) $date: $who --> $resource");
#	$r->rflush();
#	if ($post) { 
#	    $r->print("<br><b>Sent data ".join(':',unescape(@posts)).'</b>');
#	}
#    }
}

#---- Analyze Web Page ---------------------------------------------------

sub InitAnalysis {
    my ($uri,$part,$problem,$student,$courseID)=@_;
    my ($username,$userdomain)=split(/\:/,$student);

    # Render the student's view of the problem.  $Answ is the problem 
    # Stringafied
    my $Answ=&Apache::lonnet::ssi($uri,('grade_target'   => 'analyze',
                                        'grade_username' => $username,
                                        'grade_domain'   => $userdomain,
                                        'grade_courseid' => $courseID,
                                        'grade_symb'     => $problem));
#    my $Answ=&Apache::lonnet::ssi($uri,('grade_target' => 'analyze'));

#    (undef,$Answ)=split(/_HASH_REF__/,$Answ,2);
    %Answer=();
    %Answer=&Apache::lonnet::str2hash($Answ);

#    foreach (sort(keys(%Answer))) {
#        $r->print($_.'  '.$Answer{$_}.'<br>');
#    }

    my $parts='';
    foreach my $elm (@{$Answer{"parts"}}) {
	$parts.="$elm,";
    }
    chop($parts);
    my $conc='';
    foreach my $elm (@{$Answer{"$parts.concepts"}}) {
	$conc.="$elm@";
    }
    chop($conc);

    @Concepts=split(/\@/,$conc);
    foreach my $concept (@{$Answer{"$parts.concepts"}}) {
	foreach my $foil (@{$Answer{"$parts.concept.$concept"}}) {
	    $foil_to_concept{$foil} = $concept;
	    #$ConceptData{$foil} = $Answer{"$parts.foil.value.$foil"};
	}
    }

    return;
}

sub Interval {
    my ($part,$symb)=@_;
    my $interval=$ConceptData{"Interval"};
    my $due  = &Apache::lonnet::EXT('resource.'.$part.'.duedate',$symb)+1;
    my $open = &Apache::lonnet::EXT('resource.'.$part.'.opendate',$symb);
    my $add=int(($due-$open)/$interval);
    $ConceptData{'Interval.0'}=$open;
    for (my $i=1;$i<$interval;$i++) {
	$ConceptData{'Interval.'.$i}=$open+$i*$add;
    }
    $ConceptData{'Interval.'.$interval}=$due;     
    for (my $i=0;$i<$interval;$i++) {
	for (my $n=0; $n<=$#Concepts; $n++ ) {
	    my $tmp=$Concepts[$n];
	    $ConceptData{$tmp.'.'.$i.'.true'}=0;
	    $ConceptData{$tmp.'.'.$i.'.false'}=0;
	}
    }
}

sub ShowOpGraph {
    my ($cache, $students, $courseID)=@_;
    my $uri      = $cache->{'AnalyzeURI'};
    my $part     = $cache->{'AnalyzePart'};
    my $problem  = $cache->{'AnalyzeProblem'};
    my $title    = $cache->{'AnalyzeProblem'};
    my $interval = $cache->{'Interval'};
    $ConceptData{"Interval"} = $interval;

    #Initialize the option response true answers
    &InitAnalysis($uri, $part, $problem, $students->[0],$courseID);

    #compute the intervals
    &Interval($part,$problem);

    $title =~ s/\ /"_"/eg;
    $r->print('<br><b>'.$uri.'</b>');
    $r->rflush();
    
    #Java script Progress window
    &Create_PrgWin();
    &Update_PrgWin("Starting to analyze problem",0,0,'');
    for(my $index=0; $index<(scalar @$students); $index++) {
	&Update_PrgWin(scalar @$students, $index+1, $students->[$index]);
	&OpStatus($problem, $students->[$index], $courseID);
    }
    &Close_PrgWin();

    $r->print('<br>');
    for(my $k=0; $k<$interval; $k++ ) {
	&DrawGraph($k,$title);
    }
    for(my $k=0; $k<$interval; $k++ ) {
	&DrawTable($k);
    }
#$Apache::lonxml::debug=1;
#&Apache::lonhomework::showhash(%ConceptData);
#$Apache::lonxml::debug=0;
    my $Answ=&Apache::lonnet::ssi($uri);
    $r->print("<br><b>Here you can see the Problem:</b><br>$Answ");
}

sub DrawTable {
    my $k=shift;
    my $Max=0;
    my @data1;
    my @data2;
    my $Correct=0;
    my $Wrong=0;
    for (my $n=0; $n<=$#Concepts; $n++ ) {
	my $tmp=$Concepts[$n];
	$data1[$n]=$ConceptData{"$tmp.$k.true"};
	$Correct+=$data1[$n];
	$data2[$n]=$ConceptData{"$tmp.$k.false"};
	$Wrong+=$data2[$n];
	my $Sum=$data1[$n]+$data2[$n];
	if ( $Max<$Sum ) {$Max=$Sum;}
    }
    for (my $n=0; $n<=$#Concepts; $n++ ) {
	if ($data1[$n]+$data2[$n]<$Max) {
	    $data2[$n]+=$Max-($data1[$n]+$data2[$n]);
	}
    }
    my $P_No = $#data1+1;
#    $r->print('<br><b>From: ['.localtime($ConceptData{'Int.'.($k-1)}).
#              '] To: ['.localtime($ConceptData{"Int.$k"}).']</b>'); 
    my $Str = "\n".'<table border=2>'.
              "\n".'<tr>'.
              "\n".'<th> # </th>'.
	      "\n".'<th> Concept </th>'.
	      "\n".'<th> Correct </th>'.
	      "\n".'<th> Wrong </th>'.
	      "\n".'</tr>';

    for (my $n=0; $n<=$#Concepts; $n++ ) {
	$Str .= "\n"."<tr>".
	        "\n"."<td>".($n+1)."</td>".
                "\n".'<td bgcolor='.$color{"yellow"}.'> '.$Concepts[$n]." </td>".
                "\n".'<td bgcolor='.$color{"green"}.'> '.$data1[$n]." </td>".
                "\n".'<td bgcolor='.$color{"red"}.'> '.$data2[$n]." </td>".
                "\n"."</tr>";
    }
    $Str.='<td></td><td><b>From:['.localtime($ConceptData{'Int.'.$k}).
          '] To: ['.localtime($ConceptData{'Int.'.($k+1)}-1).
          "]</b></td><td>$Correct</td><td>$Wrong</td>";

    $Str .= "\n".'</table>';

    $r->print($Str);
#$Apache::lonxml::debug=1;
#&Apache::lonhomework::showhash(%ConceptData);
#$Apache::lonxml::debug=0;
}


sub DrawGraph {
    my ($currentInterval,$title)=@_;
    my $Max=0;
    my @data1;
    my @data2;

    # Adjust Data and find the Max 
    for(my $n=0; $n<=$#Concepts; $n++ ) {
	my $tmp=$Concepts[$n];
	$data1[$n]=$ConceptData{$tmp.'.'.$currentInterval.'.true'};
	$data2[$n]=$ConceptData{$tmp.'.'.$currentInterval.'.false'};
	my $Sum=$data1[$n]+$data2[$n];
	if($Max < $Sum) { $Max = $Sum; }
    }
    for(my $n=0; $n<=$#Concepts; $n++) {
	if($data1[$n]+$data2[$n]<$Max) {
	    $data2[$n]+=$Max-($data1[$n]+$data2[$n]);
	}
    }
    my $P_No = scalar @data1;

    if($Max > 1) { 
	$Max += (10 - $Max % 10);
	$Max = int($Max);
    } else { 
        $Max = 1;
    }

    my $Titr=($ConceptData{'Interval'}>1) ? 
        $title.'_interval_'.($currentInterval+1) : $title;
#    $GData=$Titr.'&Concepts'.'&'.'Answers'.'&'.$Max.'&'.$P_No.'&'.$data1.'&'.$data2;
    $GData  = $Titr.'&Concepts&Answers&'.$Max.'&'.$P_No.'&';
    $GData .= (join(',',@data1)).'&'.(join(',',@data2));

    $r->print('<IMG src="/cgi-bin/graph.gif?'.$GData.'" border=1/>');
}


sub Decide {
    #deciding the true or false answer belongs to each interval
    my ($type,$foil,$time)=@_; 
    my $k=0;
    while ($time>$ConceptData{'Int.'.($k+1)} && 
           $k<$ConceptData{'Interval'}) {$k++;}
    $ConceptData{"$foil_to_concept{$foil}.$k.$type"}++;
}


#restore the student submissions and finding the result
sub OpStatus {
    my ($problem, $student, $courseID)=@_;
    my ($username,$userdomain)=split(/':'/,$student);
    my $code='U';
    my %reshash=&Apache::lonnet::restore($problem, $courseID, $userdomain, 
                                         $username);
    my @True = ();
    my @False = ();
    my $flag=0;
    if ($reshash{'version'}) {
        my $tries=0;
	&Apache::lonhomework::showhash(%Answer);
	for (my $version=1;$version<=$reshash{'version'};$version++) {
	    my $time=$reshash{"$version:timestamp"};
	   
	    foreach my $key (sort(split(/\:/,$reshash{$version.':keys'}))) {
		if (($key=~/\.(\w+)\.(\w+)\.submission$/)) {
		    my $Id1 = $1; my $Id2 = $2;
		    #check if this is a repeat submission, if so skip it
          	    if ($reshash{"$version:resource.$Id1.previous"}) { next; }
		    #if no solved this wasn't a real submission, ignore it
		    if (!defined($reshash{"$version:resource.$Id1.solved"})) {
			&Apache::lonxml::debug("skipping ");
			next;
		    }
		    my $Resp = $reshash{"$version:$key"};
		    my %submission=&Apache::lonnet::str2hash($Resp);
		    foreach (keys %submission) {
			my $Ansr = $Answer{"$Id1.$Id2.foil.value.$_"};
			if ($submission{$_}) {
			    if ($submission{$_} eq $Ansr) {
				&Decide("true",$_,$time );
			    }
			    else {&Decide("false",$_,$time );}
			}
		    }
	        }	  
	    }
        }
    }
}

#---- END Analyze Web Page ----------------------------------------------

#---- Problem Statistics Web Page ---------------------------------------

#------- Processing upperlist and lowerlist according to each problem
sub ProcessDiscriminant {
    my ($List) = @_;
    my @sortedList = sort (@$List);
    my $Count = scalar @sortedList;
    my $Problem;
    my @Dis;
    my $Slvd=0;
    my $tmp;
    my $Sum1=0;
    my $Sum2=0;
    my $nIndex=0;
    my $nStudent=0;
    my %Proc=undef;
    while ($nIndex<$Count) {
	($Problem,$tmp)=split(/\=/,$sortedList[$nIndex]);
	@Dis=split(/\+/,$tmp);
	my $Temp = $Problem;
	do {
	    $nIndex++;
	    $nStudent++;
	    $Sum1 += $Dis[0];
	    $Sum2 += $Dis[1];
	    ($Problem,$tmp)=split(/\=/,$sortedList[$nIndex]);
	    @Dis=split(/\+/,$tmp);
	} while ( $Problem eq $Temp && $nIndex < $Count );
#	$Proc{$Temp}=($Sum1/$nStudent).':'.$nStudent;
	$Proc{$Temp}=($Sum1/$nStudent).':'.($Sum2/$nStudent);
#       $r->print("$nIndex) $Temp --> ($nStudent) $Proc{$Temp} <br>");
	$Sum1=0;
	$Sum2=0;
	$nStudent=0;
    }

    return %Proc;
}


#------- Creating Discimination factor   
sub Discriminant {
    my ($discriminantFactor)=@_;
    my @discriminantKeys=keys(%$discriminantFactor);
    my $Count = scalar @discriminantKeys;

    my $UpCnt = int(0.27*$Count);
    my $low=0;
    my $up=$Count-$UpCnt;
    my @UpList=();
    my @LowList=();

    $Count=0;
    foreach my $key (sort(@discriminantKeys)) { 
	$Count++;    
	if($low < $UpCnt || $Count > $up) {
            $low++;
            my $str=$discriminantFactor->{$key};
            foreach(split(/\:/,$str)){
                if($_) {
                    if($low<$UpCnt) { push(@LowList,$_); }
                    else            { push(@UpList,$_);  }
                }
            }
        }
    }
    my %DisUp =  &ProcessDiscriminant(\@UpList);
    my %DisLow = &ProcessDiscriminant(\@LowList);

    return (\%DisUp, \%DisLow);
}

sub NumericSort {          
    $a <=> $b;
}

sub CreateProblemStatisticsTableHeading {
    my ($displayFormat,$sequenceSource,$sequenceTitle,$headings)=@_;
    if($displayFormat eq 'Display CSV Format') {
        $r->print('<br>"'.$sequenceTitle.'","');
        $r->print($sequenceSource.'"');
	return;
    }

    $r->print('<br><a href="'.$sequenceSource.
              '" target="_blank">'.$sequenceTitle.'</a>');

    my $Result = "\n".'<table border=2><tr><th>P#</th>'."\n";
    for(my $nIndex=0; $nIndex < (scalar (keys %$headings)); $nIndex++) { 
	$Result .= '<th>'.'<input type="submit" name="';
        $Result .= 'ProblemStatisticsHeading" value="';
        $Result .= $headings->{$nIndex}.'" />'.'</th>'."\n";
    }
    $Result .= "\n".'</tr>'."\n";    
    $r->print($Result);
    $r->rflush();
}

sub CloseTable {
    my ($cache)=@_;
    if($cache->{'DisplayFormat'} eq 'Display CSV Format') {
	return;
    }    
    $r->print("\n".'</table>'."\n");
    $r->rflush();
}

# ------ Dump the Student's DB file and handling the data for statistics table 
sub ExtractStudentData {
    my ($cache,$name)=@_;
    my %discriminantFactor;
    my @list=();

    my $totalTries = 0;
    my $totalAwarded = 0;
    my $tempProblemOrder=0;
    foreach my $sequence (split(':', $cache->{'orderedSequences'})) {
        if($cache->{'ProblemStatisticsMap'} ne 'All Maps'  &&
           $cache->{'ProblemStatisticsMap'} ne $cache->{$sequence.':title'}) {
            next;
        }

        my $Dis = '';
        foreach my $problemID (split(':', $cache->{$sequence.':problems'})) {
            my $problem = $cache->{$problemID.':problem'};
            my $LatestVersion = $cache->{$name.':version:'.$problem};

            # Output dashes for all the parts of this problem if there
            # is no version information about the current problem.
            #if(!$LatestVersion) {
            #    foreach my $part (split(/\:/,$cache->{$sequence.':'.
            #                                          $problemID.
            #                                          ':parts'})) {
            #        $codes    .= "-,";
            #        $attempts .= "0,"; 
            #    }
            #    next;
            #}

            my %partData=undef;
            # Initialize part data, display skips correctly
            # Skip refers to when a student made no submissions on that
            # part/problem.
            foreach my $part (split(/\:/,$cache->{$sequence.':'.
                                                  $problemID.
                                                  ':parts'})) {
                $partData{$part.':tries'}=0;
                $partData{$part.':code'}='-';
            }

            # Looping through all the versions of each part, starting with the
            # oldest version.  Basically, it gets the most recent 
            # set of grade data for each part.
	    for(my $Version=1; $Version<=$LatestVersion; $Version++) {
                foreach my $part (split(/\:/,$cache->{$sequence.':'.
                                                      $problemID.
                                                      ':parts'})) {

                    if(!defined($cache->{$name.":$Version:$problem".
                                               ":resource.$part.solved"})) {
                        # No grade for this submission, so skip
                        next;
                    }

                    my $tries=0;
                    my $time=0;
                    my $awarded=0;
                    my $code='U';

                    $awarded = $cache->{$name.
                                        "$Version:$problem:resource.".
                                        "$part.awarded"};
                    $partData{$part.':awarded'} = ($awarded) ? $awarded : 0;
                    $totalAwarded += $awarded;

                    $tries = $cache->{$name.":$Version:$problem".
                                      ":resource.$part.tries"};
                    $partData{$part.':tries'} = ($tries) ? $tries : 0;
                    $partData{$part.':wrong'} = $partData{$part.':tries'};
                    $totalTries += $tries;

                    my $val = $cache->{$name.":$Version:$problem".
                                       ":resource.$part.solved"};
                    if    ($val eq 'correct_by_student')   {$code = 'C';} 
                    elsif ($val eq 'correct_by_override')  {$code = 'O';}
                    elsif ($val eq 'incorrect_attempted')  {$code = 'I';} 
                    elsif ($val eq 'incorrect_by_override'){$code = 'I';}
                    elsif ($val eq 'excused')              {$code = 'x';}
                    $partData{$part.':code'}=$code;

                    if($partData{$part.':wrong'} ne 0 && 
                       ($code eq 'C' || $code eq 'O')) {
                        $partData{$part.':wrong'}--;
                    }
                }
            }

            # Loop through all the parts for the current problem in the 
            # correct order and prepare the output
            foreach (split(/\:/,$cache->{$sequence.':'.$problemID.
                                         ':parts'})) {
                my $Yes = 0;
                if($partData{$_.':code'} eq 'C' || 
                   $partData{$_.':code'} eq 'O') {
                    $Yes=1;
                }
                #my $ptr = "$hash{'title_'.$ResId}";
                my $ptr = $tempProblemOrder.'&'.$problemID;

                if($_ > 1) {
                    $ptr .= "*(part $_)";
                    $Dis .= '&';
                }
                my $Fac = ($partData{$_.':Tries'}) ? 
                    ($partData{$_.':awarded'}/$partData{$_.':tries'}) : 0;
                my $DisF;
                if($Fac > 0 &&  $Fac < 1) { 
                    $DisF = sprintf( "%.4f", $Fac );
                } else {
                    $DisF = $Fac;
                }
                $Dis .= $tempProblemOrder.'='.$DisF.'+'.$Yes;
                $ptr .= '&'.$partData{$_.'.Tries'}.
                        '&'.$partData{$_.'.Wrongs'}.
                        '&'.$partData{$_.'.Code'};
                push (@list, $ptr);
                $tempProblemOrder++;
            }
        }
        if($totalTries) {
	    my $DisFac = ($totalAwarded/$totalTries);
	    my $DisFactor = sprintf( "%.4f", $DisFac );
	    $discriminantFactor{$DisFactor}=$Dis;
	}
    }

    return (\%discriminantFactor, \@list);
}

sub MySort {          
    if ( $Pos > 0 ) {
	if ($ENV{'form.order'} eq 'Descending') {$b <=> $a;}
	else { $a <=> $b; }
    }
    else {
	if ($ENV{'form.order'} eq 'Descending') {$b cmp $a;}
	else { $a cmp $b; }
    }
}

sub BuildStatisticsTable {
    my ($cache,$discriminantFactor,$list,$headings)=@_;

    my $p_count = 0;
    my $nIndex = 0;
    my $dummy;
    my $p_val;
    my $ResId;
    my $NoElements = scalar @$list;

    foreach my $sequence (split(':', $cache->{'orderedSequences'})) {
        if($cache->{'ProblemStatisticsMap'} ne 'All Maps'  &&
           $cache->{'ProblemStatisticsMap'} ne $cache->{$sequence.':title'}) {
            next;
        }

	&CreateProblemStatisticsTableHeading($cache->{'DisplayFormat'},
                                             $cache->{$sequence.':source'}, 
                                             $cache->{$sequence.':title'},
                                             $headings);
	my ($Hid,$pr)=split(/\:/,$mapsort{$_});
	my @lpr=split(/\&/,$pr);
	for (my $i=1; $i<=$#lpr; $i++) {
	    my %storestats=();
	    my ($PrOrd,$Prob,$Tries,$Wrongs,$Code)=split(/\&/,$list->[$nIndex]);
	    my $Temp = $Prob;
	    my $MxTries = 0;
	    my $TotalTries = 0;
	    my $YES = 0;
	    my $Incorrect = 0;
	    my $Override = 0;
	    my $StdNo = 0;
	    my @StdLst;
	    while ( $PrOrd == $lpr[$i] ) 
	    {
		$nIndex++;
		$StdNo++;
		$StdLst[ $StdNo ] = $Tries;
		$TotalTries += $Tries;
		if ( $MxTries < $Tries ) { $MxTries = $Tries; } 
		if ( $Code eq 'C' ){ $YES++; }
		elsif( $Code eq 'I' ) { $Incorrect++; }
		elsif( $Code eq 'O' ) { $Override++; }
		elsif( $Code eq 'U' ) { $StdNo--; }
		($PrOrd,$Prob,$Tries,$Wrongs,$Code)=split(/\&/,$list->[$nIndex]);
	    }	

	    $p_count++;
	    my $Dummy;
	    ($ResId,$Dummy)=split(/\*/,$Temp);

	    $Temp = '<a href="'.$hash{'src_'.$ResId}.
                '" target="_blank">'.$hash{'title_'.$ResId}.$Dummy.'</a>';

	    my $res = &Apache::lonnet::declutter($hash{'src_'.$ResId});
	    my $urlres=$res;

	    $ResId=~/(\d+)\.(\d+)/;
	    my $Map = &Apache::lonnet::declutter( $hash{'map_id_'.$1} );
	    $urlres=$Map;
 
	    $res = '<a href="'.$hash{'src_'.$ResId}.'">'.$res.'</a>';
	    #$Map = '<a href="'.$Map.'">'.$res.'</a>';

#------------------------ Compute the Average of Tries about one problem
	    my $Average = ($StdNo) ? $TotalTries/$StdNo : 0;

	    $storestats{$ENV{'request.course.id'}.'___'.$urlres.'___timestamp'}=time;       
	    $storestats{$ENV{'request.course.id'}.'___'.$urlres.'___stdno'}=$StdNo;
	    $storestats{$ENV{'request.course.id'}.'___'.$urlres.'___avetries'}=$Average;
   
#-------------------------------- Compute percentage of Wrong tries
	    my $Wrong = ( $StdNo ) ? 100 * ( $Incorrect / $StdNo ) : 0;

#-------------------------------- Compute Standard Deviation
	    my $StdDev = 0; 
	    if ( $StdNo > 1 ) {
		for ( my $n = 0; $n < $StdNo; $n++ ) {
		    my $Dif = $StdLst[ $n ]-$Average;
		    $StdDev += $Dif*$Dif;
		} 
		$StdDev /= ( $StdNo - 1 );
		$StdDev = sqrt( $StdDev );
	    }

#-------------------------------- Compute Degree of Difficulty
	    my $DoDiff = 0;
	    if( $TotalTries > 0 ) {
		$DoDiff = 1 - ( ( $YES + $Override ) / $TotalTries );
#	    $DoDiff =  ($TotalTries)/($YES + $Override+ 0.1);	    
	    }
       
	    $storestats{$ENV{'request.course.id'}.'___'.$urlres.'___difficulty'}=$DoDiff;

#-------------------------------- Compute the Skewness
	    my $Skewness = 0;
	    my $Sum = 0; 
	    if ( $StdNo > 0 && $StdDev > 0 ) {
		for ( my $n = 0; $n < $StdNo; $n++ ) {
		    my $Dif = $StdLst[ $n ]-$Average;
		    $Skewness += $Dif*$Dif*$Dif;
		} 
		$Skewness /= $StdNo;
		$Skewness /= $StdDev*$StdDev*$StdDev;
	    }

#--------------------- Compute the Discrimination Factors
            my ($Up1,$Up2)=split(/\:/,':');#jason$DisUp->{$lpr[$i]});
	    my ($Lw1,$Lw2)=split(/\:/,':');#jason$DisLow->{$lpr[$i]});
	    my $Dis1 = $Up1 - $Lw1;
	    my $Dis2 = $Up2 - $Lw2;
	    my $_D1 = sprintf("%.2f", $Dis1);
	    my $_D2 = sprintf("%.2f", $Dis2);

#-----------------  Some restition in presenting the float numbers
	    my $Avg = sprintf( "%.2f", $Average );
	    my $Wrng = sprintf( "%.1f", $Wrong );
	    my $SD = sprintf( "%.1f", $StdDev );
	    my $DoD = sprintf( "%.2f", $DoDiff );
	    my $Sk = sprintf( "%.1f", $Skewness );
	    my $join = $lpr[$i].'&'.$Temp.'&'.$StdNo.'&'.
                       $TotalTries.'&'.$MxTries.'&'.$Avg.'&'.
                       $YES.'&'.$Override.'&'.$Wrng.'&'.$DoD.'&'.
		       $SD.'&'.$Sk.'&'.$_D1.'&'.$_D2.'&'.
                       $Prob;
	    $CachData{($p_count-1)}=$join;

	    $urlres=~/^(\w+)\/(\w+)/;
	    if ($StdNo) { 
		&Apache::lonnet::put('resevaldata',\%storestats,$1,$2); 
	    }
#-------------------------------- Row of statistical table
            &TableRow($cache,$join,$i,($p_count-1));
	}
	&CloseTable($cache);
    }
    &Close_PrgWin();
}

=pod
sub Cache_Statistics {
    my ($cache)=@_;
    my @list = ();
    my $Useful;
    my $UnUseful;
#    $r->print('<input type="hidden" name="show" value="excel" />'."\n"); 
    my %myHeader = reverse( %Header );
    $Pos = $myHeader{$ENV{'form.sort'}};
    if ($Pos > 0) {$Pos++;}
    my $p_count = 0;
    foreach my $key( keys %CachData) { 
	my @Temp=split(/\&/,$CachData{$key});
	if ( $Pos == 0 ) {
	    ($UnUseful,$Useful)=split(/\>/,$Temp[$Pos]);
	}
	else {
	    $Useful = $Temp[$Pos];
	}   
	$list[$p_count]=$Useful.'@'.$CachData{$key};
        $p_count++;
    }

    @list = sort MySort (@list);

    my $nIndex=0;

    if ( $Pos == 0 ) {
	foreach (sort keys %mapsort) {
	    my ($Hid,$pr)=split(/\:/,$mapsort{$_});
	    &CreateProblemStatisticsTableHeading($cache,1,$Hid);
	    my @lpr=split(/\&/,$pr);
	    for (my $i=1; $i<=$#lpr; $i++) {
		my($Pre, $Post) = split(/\@/,$list[$nIndex]); 
		#$r->print('<br>'.$Pre.'---'.$Post);
		&TableRow($cache,$Post,$i,$nIndex);
		$nIndex++;
	    }
	    &CloseTable($cache);
	}
    }
    else {
	&CreateProblemStatisticsTableHeading($cache,0);
	for ( my $nIndex = 0; $nIndex < $p_count; $nIndex++ ) {
	    my($Pre, $Post) = split(/\@/,$list[$nIndex]); 
	    &TableRow($cache,$Post,$nIndex,$nIndex);
	} 
	&CloseTable($cache);
    }
}
=cut
sub TableRow {
    my ($cache,$Str,$Idx,$RealIdx)=@_;
    my($PrOrd,$Temp,$StdNo,$TotalTries,$MxTries,$Avg,$YES,$Override,
       $Wrng,$DoD,$SD,$Sk,$_D1,$_D2,$Prob)=split(/\&/,$Str);	
    if($cache->{'DisplayFormat'} eq 'Display CSV Format') {
        my ($ResId,$Dummy)=split(/\*/,$Prob);
        my $Ptr =  "\n".'<br>'.
               "\n".'"'.($RealIdx+1).'",'.
               "\n".'"'.$hash{'title_'.$ResId}.$Dummy.'",'.
               "\n".'"'.$hash{'src_'.$ResId}.'",'.
               "\n".'"'.$StdNo.'",'.
               "\n".'"'.$TotalTries.'",'.
               "\n".'"'.$MxTries.'",'.
               "\n".'"'.$Avg.'",'.
               "\n".'"'.$YES.'",'.
               "\n".'"'.$Override.'",'.
               "\n".'"'.$Wrng.'",'.
               "\n".'"'.$DoD.'",'.
               "\n".'"'.$SD.'",'.
               "\n".'"'.$Sk.'",'.
               "\n".'"'.$_D1.'",'.
	       "\n".'"'.$_D2.'"';
        $r->print("\n".$Ptr);
    } else {
        my $Ptr =  "\n".'<tr>'.
               "\n".'<td>'.($RealIdx+1).'</td>'.
          #     "\n".'<td>'.$PrOrd.$Temp.'</td>'.
               "\n".'<td>'.$Temp.'</td>'.
               "\n".'<td bgcolor='.$color{"yellow"}.'> '.$StdNo.'</td>'.
               "\n".'<td bgcolor='.$color{"yellow"}.'>'.$TotalTries.'</td>'.
               "\n".'<td bgcolor='.$color{"yellow"}.'>'.$MxTries.'</td>'.
               "\n".'<td bgcolor='.$color{"gb"}.'>'.$Avg.'</td>'.
               "\n".'<td bgcolor='.$color{"gb"}.'> '.$YES.'</td>'.
               "\n".'<td bgcolor='.$color{"gb"}.'> '.$Override.'</td>'.
               "\n".'<td bgcolor='.$color{"red"}.'> '.$Wrng.'</td>'.
               "\n".'<td bgcolor='.$color{"red"}.'> '.$DoD.'</td>'.
               "\n".'<td bgcolor='.$color{"green"}.'> '.$SD.'</td>'.
               "\n".'<td bgcolor='.$color{"green"}.'> '.$Sk.'</td>'.
               "\n".'<td bgcolor='.$color{"purple"}.'> '.$_D1.'</td>'.
	       "\n".'<td bgcolor='.$color{"purple"}.'> '.$_D2.'</td>';
        $r->print("\n".$Ptr.'</tr>' );
    }
    $GraphDat{$RealIdx}=$DoD.':'.$Wrng;
}

sub StatusOptions {
    my ($cache)=@_;

    my $Status = $cache->{'Status'};
    my $OpSel1 = '';
    my $OpSel2 = '';
    my $OpSel3 = '';

    if($Status eq 'Any')         { $OpSel3 = ' selected'; }
    elsif($Status eq 'Expired' ) { $OpSel2 = ' selected'; }
    else                         { $OpSel1 = ' selected'; }

    my $Ptr = '';
    $Ptr .= '<tr><td align="right"><b>Student Status:</b></td>'."\n";
    $Ptr .= '<td align="left"><select name="Status">';
    $Ptr .= '<option'.$OpSel1.'>Active</option>'."\n";
    $Ptr .= '<option'.$OpSel2.'>Expired</option>'."\n";
    $Ptr .= '<option'.$OpSel3.'>Any</option>'."\n";
    $Ptr .= '</select></td></tr>'."\n";

    return $Ptr;
}

sub AscendOrderOptions {
    my ($cache)=@_;

    my $order = $cache->{'Ascend'};
    my $OpSel1 = '';
    my $OpSel2 = '';

    if($order eq 'Ascending') {
        $OpSel1 = ' selected';
    } else {
        $OpSel2 = ' selected';
    }

    my $Ptr = '';
    $Ptr .= '<tr><td align="right"><b>Sorting Type:</b></td>'."\n";
    $Ptr .= '<td align="left"><select name="Ascend">'."\n";
    $Ptr .= '<option'.$OpSel1.'>Ascending</option>'."\n".
	    '<option'.$OpSel2.'>Descending</option>'."\n";
    $Ptr .= '</select></td></tr>'."\n";

    return $Ptr;
}

sub ProblemStatisticsButtons {
    my ($cache)=@_;

    my $Ptr = '<tr><td></td><td align="left">';
    $Ptr .= '<input type=submit name="ProblemStatisticsRecalculate" ';
    $Ptr .= 'value="Recalculate Statistics"/>'."\n";
    $Ptr .= '&nbsp;&nbsp;&nbsp;';
    $Ptr .= '<input type="submit" name="DoDiffGraph" ';
    $Ptr .= 'value="DoDiff Graph" />'."\n";
    $Ptr .= '&nbsp;&nbsp;&nbsp;';
    $Ptr .= '<input type="submit" name="PercentWrongGraph" ';
    $Ptr .= 'value="%Wrong Graph" />'."\n";
    $Ptr .= '&nbsp;&nbsp;&nbsp;';
    $Ptr .= '<input type="submit" name="DisplayCSVFormat" ';
    if($cache->{'DisplayFormat'} eq 'Display CSV Format') {
        $Ptr .= 'value="Display CSV Format" />'."\n";
    } else {
        $Ptr .= 'value="Display Table Format" />'."\n";
    }
    $Ptr .= '</td></tr>';

    return $Ptr;
}

sub ProblemStatisticsLegend {
    my $Ptr = '';
    $Ptr = '<table border="0">';
    $Ptr .= '<tr><td>';
    $Ptr .= '<b>#Stdnts</b>:</td>';
    $Ptr .= '<td>Total Number of Students opened the problem.';
    $Ptr .= '</td></tr><tr><td>';
    $Ptr .= '<b>Tries</b>:</td>';
    $Ptr .= '<td>Total Number of Tries for solving the problem.';
    $Ptr .= '</td></tr><tr><td>';
    $Ptr .= '<b>Mod</b>:</td>';
    $Ptr .= '<td>Maximunm Number of Tries for solving the problem.';
    $Ptr .= '</td></tr><tr><td>';
    $Ptr .= '<b>Mean</b>:</td>';
    $Ptr .= '<td>Average Number of the tries. [ Tries / #Stdnts ]';
    $Ptr .= '</td></tr><tr><td>';
    $Ptr .= '<b>#YES</b>:</td>';
    $Ptr .= '<td>Number of students solved the problem correctly.';
    $Ptr .= '</td></tr><tr><td>';
    $Ptr .= '<b>#yes</b>:</td>';
    $Ptr .= '<td>Number of students solved the problem by override.';
    $Ptr .= '</td></tr><tr><td>';
    $Ptr .= '<b>%Wrng</b>:</td>';
    $Ptr .= '<td>Percentage of students tried to solve the problem ';
    $Ptr .= 'but still incorrect. [ 100*((#Stdnts-(#YES+#yes))/#Stdnts) ]';
    $Ptr .= '</td></tr><tr><td>';
#    Kashy formula
#    '<b>  DoDiff </b>: Degree of Difficulty of the problem.<br>'.
#    '[ Tries/(#YES+#yes+0.1) ]<br>'.
    #Gerd formula
    $Ptr .= '<b>DoDiff</b>:</td>';
    $Ptr .= '<td>Degree of Difficulty of the problem.  ';
    $Ptr .= '[ 1 - ((#YES+#yes) / Tries) ]';
    $Ptr .= '</td></tr><tr><td>';
    $Ptr .= '<b>S.D.</b>:</td>';
    $Ptr .= '<td>Standard Deviation of the tries.  ';
    $Ptr .= '[ sqrt(sum((Xi - Mean)^2)) / (#Stdnts-1) ';
    $Ptr .= 'where Xi denotes every student\'s tries ]';
    $Ptr .= '</td></tr><tr><td>';
    $Ptr .= '<b>Skew.</b>:</td>';
    $Ptr .= '<td>Skewness of the students tries.';
    $Ptr .= '[(sqrt( sum((Xi - Mean)^3) / #Stdnts)) / (S.D.^3)]';
    $Ptr .= '</td></tr><tr><td>';
    $Ptr .= '<b>Dis.F.</b>:</td>';
    $Ptr .= '<td>Discrimination Factor: A Standard for evaluating the ';
    $Ptr .= 'problem according to a Criterion<br>';
    $Ptr .= '<b>[Applied Criterion in %27 Upper Students - ';
    $Ptr .= 'Applied the same Criterion in %27 Lower Students]</b><br>';
    $Ptr .= '<b>1st Criterion</b> for Sorting the Students: ';
    $Ptr .= '<b>Sum of Partial Credit Awarded / Total Number of Tries</b><br>';
    $Ptr .= '<b>2nd Criterion</b> for Sorting the Students: ';
    $Ptr .= '<b>Total number of Correct Answers / Total Number of Tries</b>';
    $Ptr .= '</td></tr></table>';

    return $Ptr;
}

#---- END Problem Statistics Web Page ----------------------------------------

#---- Problem Statistics Graph Web Page --------------------------------------

sub GetGraphData {
    my ($whichGraph, $courseID)=@_;
    my $Col=0;
    my $graphTitle='';
    my $data='';
    my $count = 0;
    my $Max = 0;
    my $graphData='Graph data does not exist.';
    my $GraphDB = "/home/httpd/perl/tmp/$ENV{'user.name'}".
                  "_$ENV{'user.domain'}_$courseID\_graph.db";
    if(-e $GraphDB) {
	if(tie(%GraphDat,'GDBM_File',"$GraphDB",&GDBM_READER,0640)) {
	    if($whichGraph eq 'DiffGraph') {
		$graphTitle = 'Degree-of-Difficulty';
		$Col = 0;
	    } else {
		$graphTitle = 'Wrong-Percentage';
		$Col = 1;
	    }
	    foreach (sort NumericSort keys %GraphDat) { 
		my @Temp=split(/\:/,$GraphDat{$_});
                my $inf = $Temp[$Col]; 
		if($Max < $inf) {
                    $Max = $inf;
                }
		$data .= $inf.',';
		$count++;
	    }
	    if($Max > 1) { 
		$Max += (10 - $Max % 10);
		$Max = int($Max);
	    } else { 
                $Max = 1;
            }
            untie(%GraphDat);
	    my $Course = $ENV{'course.'.$courseID.'.description'};
	    $Course =~ s/\ /"_"/eg;
	    $graphData  = $Course.'&'.'Problems'.'&'.$graphTitle.'&'.$Max.'&';
            $graphData .= $count.'&'.$data;
	} else {
	    $graphData = "Unable to tie hash to db file";
	}
    }

    return $graphData;
}

#---- END Problem Statistics Graph Web Page ----------------------------------

#---- Problem Analysis Web Page ----------------------------------------------

sub IntervalOptions {
    my ($cache)=@_;

    my $interval = 1;
    for(my $n=1; $n<=7; $n++) {
        if($cache->{'Interval'} == $n) {
            $interval = $n;
        }
    }

    my $Ptr = '<br><b>Select number of intervals</b>'."\n".
       	      '<select name="Interval">'."\n";
    for(my $n=1; $n<=7;$ n++) {
	$Ptr .= '<option';
        if($interval == $n) {
            $Ptr .= ' selected';
        }
	$Ptr .= '>'.$n."</option>"."\n";
    }
    $Ptr .= '</select>'."\n";

    return $Ptr;
}

sub OptionResponseTable {
    my ($cache)=@_;
    my $Str = '';
    $Str .= '<br><b> Option Response Problems in this course:</b>'."\n";
    $Str .= '<br><br>'."\n";
    $Str .= "<table border=2><tr><th> \# </th><th> Problem Title </th>";
    $Str .= '<th> Resource </th><th> Analysis  </th></tr>'."\n";

    my $number=1;
    foreach (split(':::',$cache->{'OptionResponses'})) {
        my ($uri,$title,$part,$problem)=split('::',$_);
        my $Temp = '<a href="'.$uri.'" target="_blank">'.$title.'</a>';
        $Str .= '<tr>';
        $Str .= '<td> '.$number.' </td>';
        $Str .= '<td bgcolor="'.$color{"green"}.'"> '.$Temp.' </td>';
        $Str .= '<td bgcolor="'.$color{"yellow"}.'"> '.$uri.' </td>';
        $Str .= '<td><input type="submit" name="Analyze:::'.$uri.':::';
        $Str .= $title.':::'.$part.':::'.$problem.'" value="';
        $Str .= 'Analyze" /></td></tr>'."\n";
        $number++;
    }
    $Str .= '</table>'."\n";

    return $Str;
}

#---- END Problem Analysis Web Page ------------------------------------------

#---- Student Assessment Web Page --------------------------------------------

sub MapOptions {
    my ($cache, $page)=@_;
    my $Ptr = '<tr>';
    $Ptr .= '<td align="right"><b>Select Map</b></td>'."\n";
    $Ptr .= '<td align="left"><select name="Maps">'."\n";

    my $selected = 0;
    foreach my $sequence (split(':',$cache->{'orderedSequences'})) {
	$Ptr .= '<option';
        if($cache->{$page.'Map'} eq $cache->{$sequence.':title'}) {
            $Ptr .= ' selected';
            $selected = 1;
        }
	$Ptr .= '>'.$cache->{$sequence.':title'}.'</option>'."\n";	     
    }
    $Ptr .= '<option';
    if(!$selected) {
        $Ptr .= ' selected';
    }
    $Ptr .= '>All Maps</option>'."\n";

    $Ptr .= '</select></td></tr>'."\n";

    return $Ptr;
}

sub StudentOptions {
    my ($students, $selectedName)=@_;

    my $Ptr ='<tr>';
    $Ptr .= '<td align="right"><b>Select Student</b></td>'."\n";
    $Ptr .= '<td align="left"><select name="Students">'."\n";

    my $selected=0;
    foreach (@$students) {
        my ($name) = split(':',$_);
	$Ptr .= '<option';
	if($selectedName eq $name) {
            $Ptr .= ' selected';
            $selected = 1;
        }
        $Ptr .= '>'.$name.'</option>'."\n";	     
    }

    $Ptr .= '<option';
    if(!$selected) {
        $Ptr .= ' selected';
    }
    $Ptr .= '>No Student Selected</option>'."\n";

    $Ptr .= '</select></td></tr>'."\n";

    return $Ptr;
}

# ------ Create different Student Report 
sub StudentReport {
    my ($cache, $name)=@_;

    my $Str = '';
    if($cache->{$name.':error'} =~ /course/) {
        my ($username)=split(':',$name);
        $Str .= '<b><font color="blue">No course data for student </font>';
        $Str .= '<font color="red">'.$username.'.</font></b><br>';
        return $Str;
    }

    $Str .= "<table border=2><tr><th> \# </th><th> Set Title </th>";
    $Str .= '<th> Results </th><th> Tries </th></tr>'."\n";

    my $codes;
    my $attempts;
    foreach my $sequence (split(':', $cache->{'orderedSequences'})) {
        if($cache->{'StudentAssessmentMap'} ne 'All Maps'  &&
           $cache->{'StudentAssessmentMap'} ne $cache->{$sequence.':title'}) {
            next;
        }

        $Str .= '<tr><td>'.$sequence.'</td>';
        $Str .= '<td>'.$cache->{$sequence.':title'}.'</td>';

        $codes = '';
        $attempts = '';
        foreach my $problemID (split(':', $cache->{$sequence.':problems'})) {
            my $problem = $cache->{$problemID.':problem'};
            my $LatestVersion = $cache->{$name.':version:'.$problem};

            # Output dashes for all the parts of this problem if there
            # is no version information about the current problem.
            if(!$LatestVersion) {
                foreach my $part (split(/\:/,$cache->{$sequence.':'.
                                                      $problemID.
                                                      ':parts'})) {
		    $codes    .= "-,";
                    $attempts .= "0,"; 
                }
                next;
            }

            my %partData=undef;
            # Initialize part data, display skips correctly
            # Skip refers to when a student made no submissions on that
            # part/problem.
            foreach my $part (split(/\:/,$cache->{$sequence.':'.
                                                  $problemID.
                                                  ':parts'})) {
                $partData{$part.':tries'}=0;
                $partData{$part.':code'}='-';
            }

            # Looping through all the versions of each part, starting with the
            # oldest version.  Basically, it gets the most recent 
            # set of grade data for each part.
	    for(my $Version=1; $Version<=$LatestVersion; $Version++) {
                foreach my $part (split(/\:/,$cache->{$sequence.':'.
                                                      $problemID.
                                                      ':parts'})) {

                    if(!defined($cache->{$name.":$Version:$problem".
                                               ":resource.$part.solved"})) {
                        # No grade for this submission, so skip
                        next;
                    }

                    my $tries=0;
                    my $code='U';

                    $tries = $cache->{$name.":$Version:$problem".
                                      ":resource.$part.tries"};
                    $partData{$part.':tries'}=($tries) ? $tries : 0;

                    my $val = $cache->{$name.":$Version:$problem".
                                       ":resource.$part.solved"};
                    if    ($val eq 'correct_by_student')   {$code = 'Y';} 
                    elsif ($val eq 'correct_by_override')  {$code = 'y';}
                    elsif ($val eq 'incorrect_attempted')  {$code = 'N';} 
                    elsif ($val eq 'incorrect_by_override'){$code = 'N';}
                    elsif ($val eq 'excused')              {$code = 'x';}
                    $partData{$part.':code'}=$code;
                }
            }

            # Loop through all the parts for the current problem in the 
            # correct order and prepare the output
            foreach (split(/\:/,$cache->{$sequence.':'.$problemID.
                                         ':parts'})) {
                $codes    .= $partData{$_.':code'}.',';
                $attempts .= $partData{$_.':tries'}.','; 
            }
        }
        $codes    =~ s/,$//;
        $attempts =~ s/,$//;
        $Str .= '<td>'.$codes.'</td>';
        $Str .= '<td>'.$attempts.'</td>';
        $Str .= '</tr>'."\n";
    }

    $Str .= '</table>'."\n";

    return $Str;
}

#---- END Student Assessment Web Page ----------------------------------------

#---- Menu Web Page ----------------------------------------------------------

sub Title {
    my ($downloadTime)=@_;

    my $Ptr = '';

    $Ptr .= '<html><head><title>LON-CAPA Statistics</title></head>'."\n";
    $Ptr .= '<body bgcolor="#FFFFFF">'."\n";
    $Ptr .= '<script>window.focus(); window.width=500;window.height=500;';
    $Ptr .= '</script>'."\n";
    $Ptr .= '<img align=right src=/adm/lonIcons/lonlogos.gif>'."\n";
    $Ptr .= '<h1> Course : "';
    $Ptr .= $ENV{'course.'.$ENV{'request.course.id'}.'.description'};
    $Ptr .= '"</h1>'."\n";
    $Ptr .= '<h3>'.$downloadTime.'</h3>';

    return $Ptr;
}

sub CreateMenuForm {
    my ($cache)=@_;
    my $Ptr = '<table border="0">';
    $Ptr .= '<tr><td><input type="submit" name="ProblemStatistics" ';
    $Ptr .= 'value="Problem Stats"/>';
    $Ptr .= '</td></tr>'."\n";

    if(defined($cache->{'OptionResponses'})) {
        $Ptr .= '<tr><td><input type="submit" name="ProblemAnalysis" ';
        $Ptr .= 'value="Problem Analysis"/>';
        $Ptr .= '</td></tr>'."\n";
    }

    $Ptr .= '<tr><td><input type="submit" name="StudentAssessment" ';
    $Ptr .= 'value="Student Assessment"/>';
    $Ptr .= '</td></tr>'."\n";
    #$Ptr .= '<input type="submit" name="ActivityLog" value="Activity Log"/>';

    $Ptr .= '</table>'."\n";

    return $Ptr;
}

#---- END Menu Web Page ------------------------------------------------------

#---- HELPER FUNCTIONS -------------------------------------------------------

sub CheckFormElement {
    my ($cache, $ENVName, $cacheName, $default)=@_;

    if(defined($ENV{'form.'.$ENVName})) {
        $cache->{$cacheName} = $ENV{'form.'.$ENVName};
    } elsif(!defined($cache->{$cacheName})) {
        $cache->{$cacheName} = $default;
    }

    return;
}

sub ProcessFormData{
    my ($cacheDB, $isCached)=@_;
    my %cache;

    if(tie(%cache,'GDBM_File',$cacheDB,&GDBM_WRCREAT,0640)) {
        # Select page to display
        if(defined($ENV{'form.ProblemStatistics'}) ||
           defined($ENV{'form.ProblemStatisticsRecalculate'}) || 
           defined($ENV{'form.DisplayCSVFormat'})) {
            $cache{'GoToPage'} = 'ProblemStatistics';
            &CheckFormElement(\%cache, 'DisplayCSVFormat',
                              'DisplayFormat', 'Display Table Format');
            &CheckFormElement(\%cache, 'Ascend','ProblemStatisticsAscend',
                              'Ascending');
            &CheckFormElement(\%cache, 'Maps', 'ProblemStatisticsMap', 
                              'All Maps');
        } elsif(defined($ENV{'form.ProblemAnalysis'})) {
            $cache{'GoToPage'} = 'ProblemAnalysis';
            &CheckFormElement(\%cache, 'Interval', 'Interval', '1');
        } elsif(defined($ENV{'form.StudentAssessment'}) ||
                defined($ENV{'form.CreateStudentAssessment'}) ||
                defined($ENV{'form.NextStudent'}) ||
                defined($ENV{'form.PreviousStudent'})) {
            $cache{'GoToPage'} = 'StudentAssessment';
            if(defined($ENV{'form.NextStudent'})) {
                $cache{'StudentAssessmentMove'} = 'next';
            } elsif(defined($ENV{'form.PreviousStudent'})) {
                $cache{'StudentAssessmentMove'} = 'previous';
            } else {
                $cache{'StudentAssessmentMove'} = 'selected';
            }
            &CheckFormElement(\%cache, 'Maps', 'StudentAssessmentMap', 
                              'All Maps');

            &CheckFormElement(\%cache, 'Students', 'StudentAssessmentStudent', 
                              'No Student Selected');
        } elsif(defined($ENV{'form.DoDiffGraph'})) {
            $cache{'GoToPage'} = 'DoDiffGraph';
        } elsif(defined($ENV{'form.PercentWrongGraph'})) {
            $cache{'GoToPage'} = 'PercentWrongGraph';
        } elsif(defined($ENV{'form.ActivityLog'})) {
            $cache{'GoToPage'} = 'ActivityLog';
        } else {
            $cache{'GoToPage'} = 'Menu';
        }

        &CheckFormElement(\%cache, 'Status', 'Status', 'Active');

        foreach (keys(%ENV)) {
            if(/form\.Analyze:::/) {
                $cache{'GoToPage'} = 'Analyze';
                my ($uri, $title, $part, $problem);
                (undef, $uri, $title, $part, $problem)=split(':::', $_);
                $cache{'AnalyzeURI'}     = $uri;
                $cache{'AnalyzeTitle'}   = $title;
                $cache{'AnalyzePart'}    = $part;
                $cache{'AnalyzeProblem'} = $problem;

                &CheckFormElement(\%cache, 'Interval', 'Interval', '1');
            }
        }
    }

    return;
}

=pod

=item &SortStudents()

Determines which students to display and in which order.  Which are 
displayed are determined by their status(active/expired).  The order
is determined by the sort button pressed (default to username).  The
type of sorting is username, lastname, or section.

=over 4

Input: $students, $CacheData

$students: A array pointer to a list of students (username:domain)

$CacheData: A pointer to the hash tied to the cached data

Output: \@order

@order: An ordered list of students (username:domain)

=back

=cut

sub SortStudents {
    my ($students,$cache)=@_;

    my @sorted1Students=();
    foreach (@$students) {
        push(@sorted1Students, $_);
    }
#        my ($end,$start)=split(/\:/,$cache->{$_.':date'});
#        my $active=1;
#        my $now=time;
#        my $Status=$cache->{'form.Status'};
#        $Status = ($Status) ? $Status : 'Active';
#        if((($end) && $now > $end) && (($Status eq 'Active'))) { 
#            $active=0; 
#        }
#        if(($Status eq 'Expired') && ($end == 0 || $now < $end)) {
#            $active=0;
#        }
#        if($active) {
#            push(@sorted1Students, $_);
#        }
#    }

    my $Pos = $cache->{'form.ChartSort'};
    my %sortData;
    if($Pos eq 'Last Name') {
	for(my $index=0; $index<scalar @sorted1Students; $index++) {
	    $sortData{$cache->{$sorted1Students[$index].':fullname'}}=
		$sorted1Students[$index];
	}
    } elsif($Pos eq 'Section') {
	for(my $index=0; $index<scalar @sorted1Students; $index++) {
	    $sortData{$cache->{$sorted1Students[$index].':section'}.
		      $sorted1Students[$index]}=$sorted1Students[$index];
	}
    } else {
	# Sort by user name
	for(my $index=0; $index<scalar @sorted1Students; $index++) {
	    $sortData{$sorted1Students[$index]}=$sorted1Students[$index];
	}
    }

    my @order = ();
    foreach my $key (sort(keys(%sortData))) {
	push (@order,$sortData{$key});
    }

    return \@order;
}

sub PrepareData {
    my ($c, $cacheDB)=@_;

    # Test for access to the cache data
    my $isCached=0;
    my $courseID=$ENV{'request.course.id'};
    my $isRecalculate=0;
    if(defined($ENV{'form.ProblemStatisticsRecalculate'}) ||
       defined($ENV{'form.ChartRecalculate'})) {
        $isRecalculate=1;
    }

    $isRecalculate=1;

    $isCached=&Apache::loncoursedata::TestCacheData($cacheDB, $isRecalculate);
    if($isCached < 0) {
        return "Unable to tie hash to db file.";
    }
    &ProcessFormData($cacheDB, $isCached);

    # Download class list information if not using cached data
    my %cache;
    my @students=();
    if(!$isCached) {
        unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_WRCREAT,0640)) {
            return "Unable to tie hash to db file.";
        }

        my $processTopResourceMapReturn=
            &Apache::loncoursedata::ProcessTopResourceMap(\%cache, $c);
        if($processTopResourceMapReturn ne 'OK') {
            untie(%cache);
            return $processTopResourceMapReturn;
        }

        if($c->aborted()) {
            untie(%cache);
            return 'aborted'; 
        }

        my $classlist=&Apache::loncoursedata::DownloadStudentNamePIDSection(
                                                                   $courseID, 
                                                                   $c);
        my ($checkForError)=keys(%$classlist);
        if($checkForError =~ /^(con_lost|error|no_such_host)/i ||
           defined($classlist->{'error'})) {
            untie(%cache);
            return "Error getting student data.";
        }

        if($c->aborted()) {
            untie(%cache);
            return 'aborted'; 
        }

        # Active is a temporary solution, remember to change
        @students=&Apache::loncoursedata::ProcessClassList(\%cache, 
                                                           $classlist, 
                                                           $courseID, 
                                                           'Active', $c);

        if($c->aborted()) {
            untie(%cache);
            return 'aborted'; 
        }

        untie(%cache);
    } else {
        if(!$c->aborted() && tie(%cache,'GDBM_File',$cacheDB,
                                 &GDBM_READER,0640)) {
            @students=split(/:::/,$cache{'NamesOfStudents'});
        } else {
            return 'aborted';
        }
    }

    return ('OK', $isCached, \@students);
}

# Create progress
sub Create_PrgWin {
    $r->print(<<ENDPOP);
    <script>
    popwin=open('','popwin','width=400,height=100');
    popwin.document.writeln('<html><body bgcolor="#88DDFF">'+
      '<title>LON-CAPA Statistics</title>'+
      '<h4>Computation Progress</h4>'+
      '<form name=popremain>'+
      '<input type=text size=35 name=remaining value=Starting></form>'+
      '</body></html>');
    popwin.document.close();
    </script>
ENDPOP

    $r->rflush();
}

# update progress
sub Update_PrgWin {
    my ($totalStudents,$index,$name)=@_;
    $r->print('<script>popwin.document.popremain.remaining.value="'.
              'Computing '.$index.'/'.$totalStudents.': '.
              $name.'";</script>');
    $r->rflush();
}

# close Progress Line
sub Close_PrgWin {
    $r->print('<script>popwin.close()</script>');
    $r->rflush(); 
}

# For loading the colored table for display or un-colored for print
sub setbgcolor {
    my $PrintTable=shift;
    undef %color;
    if ($PrintTable){
	$color{"gb"}="#FFFFFF";
	$color{"red"}="#FFFFFF";
	$color{"yellow"}="#FFFFFF";
	$color{"green"}="#FFFFFF";
	$color{"purple"}="#FFFFFF";
    } else {
	$color{"gb"}="#DDFFFF";
	$color{"red"}="#FFDDDD";
	$color{"yellow"}="#EEFFCC";
	$color{"green"}="#DDFFDD";
	$color{"purple"}="#FFDDFF";
    }

    return;
}

sub initial {
    undef %hash;
    undef %CachData;
    undef %GraphDat;
    undef %ConceptData;
    undef $Pos;
    undef $GData;
}

#---- END HELPER FUNCTIONS ---------------------------------------------------

sub BuildProblemStatisticsPage {
    my ($cacheDB, $students)=@_;

    my %cache;
    unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_READER,0640)) {
        $r->print('<html><body>Unable to tie database.</body></html>');
        return;
    }

    my $Ptr = '';
    $Ptr .= '<form name="ProblemStatisticsPage" method="post" ';
    $Ptr .= 'action="/adm/statistics">'."\n";
    $Ptr .= '<table border="0"><tbody>';
    $Ptr .= '<tr><td></td><td align="left"><input type="submit" name="Menu" ';
    $Ptr .= 'value="Return to Menu" /></td></tr>'."\n";
    $r->print($Ptr);

    $r->print(&MapOptions(\%cache, 'ProblemStatistics'));
    $r->print(&StatusOptions());
    $r->print(&AscendOrderOptions());
    $r->print(&ProblemStatisticsButtons(\%cache));
    $r->print('</table>');

    $r->print(&ProblemStatisticsLegend());

#    my $discriminantFactor;
#    my $list;
#    foreach (@$students) {
#        ($discriminantFactor, $list) = &ExtractStudentData($_);
#    }

#    my ($upper, $lower) = &Discriminant($discriminantFactor);
#    my %Header = (0,"Homework Sets Order",1,"#Stdnts",2,"Tries",3,"Mod",
#                  4,"Mean",5,"#YES",6,"#yes",7,"%Wrng",8,"DoDiff",
#                  9,"S.D.",10,"Skew.",11,"D.F.1st",12,"D.F.2nd");
#    &BuildStatisticsTable(\%cache, $discriminantFactor, $list, \%Header);

    $r->print('</form>');

    untie(%cache);

    return;
}

sub BuildDiffGraph {
    my ($courseID)=@_;

    my $graphData = &GetGraphData('DiffGraph', $courseID);
    $r->print('<IMG src="/cgi-bin/graph.gif?'.$graphData.'" />');

    return;
}

sub BuildWrongGraph {
    my ($courseID)=@_;

    my $graphData = &GetGraphData('WrongGraph', $courseID);
    $r->print('<IMG src="/cgi-bin/graph.gif?'.$graphData.'" />');

    return;
}

sub BuildAnalyzePage {
    my ($cacheDB, $students, $courseID)=@_;

    my %cache;
    unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_READER,0640)) {
        $r->print('<html><body>Unable to tie database.</body></html>');
        return;
    }

    &ShowOpGraph(\%cache, $students, $courseID);

    untie(%cache);

    return;
}

sub BuildProblemAnalysisPage {
    my ($cacheDB)=@_;

    my %cache;
    unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_READER,0640)) {
        $r->print('<html><body>Unable to tie database.</body></html>');
        return;
    }

    $r->print('<form name="ProblemAnalysisPage" method="post" ');
    $r->print('action="/adm/statistics">'."\n");
    $r->print('<tr><td></td><td align="left"><input type="submit" ');
    $r->print('name="Menu" value="Return to Menu" /></td></tr>'."\n");
    $r->print(&IntervalOptions());
    $r->print(&OptionResponseTable(\%cache));
    $r->print('</form>'."\n");

    untie(%cache);

    return;
}

sub BuildStudentAssessmentPage {
    my ($cacheDB, $students, $courseID)=@_;

    my %cache;

    my $Ptr = '';
    $Ptr .= '<form name="StudentAssessmentPage" method="post" ';
    $Ptr .= 'action="/adm/statistics">'."\n";
    $Ptr .= '<table border="0"><tbody>';
    $Ptr .= '<tr><td></td><td align="left"><input type="submit" name="Menu" ';
    $Ptr .= 'value="Return to Menu" /></td></tr>'."\n";
    $r->print($Ptr);

    unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_READER,0640)) {
        $r->print('<html><body>Unable to tie database.</body></html>');
        return;
    }

    my $selectedName = $cache{'StudentAssessmentStudent'};
    for(my $index=0; $index<(scalar @$students); $index++) {
        my ($username) = split(':', $students->[$index]);
        if($username eq $selectedName) {
            if($cache{'StudentAssessmentMove'} eq 'next') {
                if($index == ((scalar @$students) - 1)) {
                    ($selectedName) = split(':',$students->[0]);
                } else {
                    ($selectedName) = split(':',$students->[$index+1]);
                }
            } elsif($cache{'StudentAssessmentMove'} eq 'previous') {
                if($index == 0) {
                    ($selectedName) = split(':',
                                           $students->[(scalar @$students)-1]);
                } else {
                    ($selectedName)=split(':',$students->[$index-1]);
                }
            }
            last;
        }
    }

    $r->print(&MapOptions(\%cache, 'StudentAssessment'));
    $r->print(&StudentOptions($students, $selectedName));

    $Ptr  = '<tr><td></td><td align="left">';
    $Ptr .= '<input type="submit" name="CreateStudentAssessment" ';
    $Ptr .= 'value="Create Student Report" />';
    $Ptr .= '&nbsp&nbsp&nbsp';
    $Ptr .= '<input type="submit" name="PreviousStudent" ';
    $Ptr .= 'value="Previous Student" />';
    $Ptr .= '&nbsp&nbsp&nbsp';
    $Ptr .= '<input type="submit" name="NextStudent" ';
    $Ptr .= 'value="Next Student" />';
    $Ptr .= '&nbsp&nbsp&nbsp';
    $Ptr .= '</td></tr></tbody></table></form>'."\n";
    $r->print($Ptr);

    untie(%cache);

    if($selectedName eq 'No Student Selected') {
	$r->print('<h3><font color=blue>WARNING: ');
        $r->print('Please select a student</font></h3>');
        return;
    }

    my $name = '';
    foreach (@$students) {
        my ($currentName) = split(':',$_);
        if($currentName eq $selectedName) {
            $name = $_;
            last;
        }
    }
    if($name eq '') {
        $r->print('<h3><font color=blue>ERROR: Unknown student selected.');
        $r->print('</font></h3>');
        return;
    }

    my $courseData = 
        &Apache::loncoursedata::DownloadStudentCourseInformation($name, 
                                                                 $courseID);
    if(tie(%cache,'GDBM_File',$cacheDB,&GDBM_WRCREAT,0640)) {
        &Apache::loncoursedata::ProcessStudentData(\%cache, 
                                                   $courseData, $name);
        untie(%cache);
    }

    unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_READER,0640)) {
        $Ptr .= 'Could not tie database.';
        return $Ptr;
    }
    $r->print(&StudentReport(\%cache, $name));
    untie(%cache);

    return;
}

sub BuildMenu {
    my ($cacheDB)=@_;

    my %cache;
    unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_READER,0640)) {
        $r->print('<html><body>Unable to tie database.</body></html>');
        return;
    }

    $r->print('<form name="Menu" method="post" action="/adm/statistics" >');
    $r->print(&CreateMenuForm(\%cache));
    $r->print('</form>'."\n");

    untie(%cache);

    return;
}

# ================================================================ Main Handler

sub handler {
    $r=shift;
    &initial();

    unless(&Apache::lonnet::allowed('vgr',$ENV{'request.course.id'})) {
        $ENV{'user.error.msg'}=
        $r->uri.":vgr:0:0:Cannot view grades for complete course";
        return HTTP_NOT_ACCEPTABLE; 
    }

    # Set document type for header only
    if($r->header_only) {
        if ($ENV{'browser.mathml'}) {
            $r->content_type('text/xml');
        } else {
            $r->content_type('text/html');
        }
        &Apache::loncommon::no_cache($r);
        $r->send_http_header;
        return OK;
    }

    unless($ENV{'request.course.fn'}) {
	my $requrl=$r->uri;
        $ENV{'user.error.msg'}="$requrl:bre:0:0:Course not initialized";
        return HTTP_NOT_ACCEPTABLE; 
    }

    $r->content_type('text/html');
    $r->send_http_header;

    my %cache;
    my $courseID=$ENV{'request.course.id'};
    my $cacheDB = "/home/httpd/perl/tmp/$ENV{'user.name'}".
                  "_$ENV{'user.domain'}_$courseID\_statistics.db";
    my $c = $r->connection;

    my ($returnValue, $isCached, $students) = &PrepareData($c, $cacheDB);
    if($returnValue ne 'OK') {
        $r->print('<html><body>'.$returnValue."\n".'</body></html>');
        return OK;
    }

    my $downloadTime=0;
    my $GoToPage;
    if(tie(%cache,'GDBM_File',$cacheDB,&GDBM_READER,0640)) {
        $students = &SortStudents($students, \%cache);
        if(defined($cache{'time'})) {
            $downloadTime=$cache{'time'};
        } else {
            $downloadTime=localtime();
        }
        if(!defined($cache{'GoToPage'})) {
            $GoToPage = 'Menu';
        } else {
            $GoToPage = $cache{'GoToPage'};
        }
        untie(%cache);
    } else {
        $r->print('<html><body>Unable to tie database.</body></html>');
        return OK;
    }

    &setbgcolor(0);
    $r->print(&Title());

    if($GoToPage eq 'ActivityLog') {
        &Activity();
    } elsif($GoToPage eq 'ProblemStatistics') {
        &BuildProblemStatisticsPage($cacheDB, $students);
    } elsif($GoToPage eq 'ProblemAnalysis') {
        &BuildProblemAnalysisPage($cacheDB);
    } elsif($GoToPage eq 'StudentAssessment') {
        &BuildStudentAssessmentPage($cacheDB, $students, $courseID);
    } elsif($GoToPage eq 'Analyze') {
        &BuildAnalyzePage($cacheDB, $students, $courseID);
    } elsif($GoToPage eq 'DoDiffGraph') {
        &BuildDiffGraph($courseID);
    } elsif($GoToPage eq 'PercentWrongGraph') {
        &BuildWrongGraph($courseID);
    } else {
        &BuildMenu($cacheDB);
    }

    $r->print("\n".'</body>'."\n".'</html>');
    $r->rflush();

    return OK;
}
1;
__END__

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