--- loncom/interface/lonstatistics.pm	2002/03/06 18:42:01	1.7
+++ loncom/interface/lonstatistics.pm	2002/08/13 12:21:46	1.42
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # (Publication Handler
 #
-# $Id: lonstatistics.pm,v 1.7 2002/03/06 18:42:01 minaeibi Exp $
+# $Id: lonstatistics.pm,v 1.42 2002/08/13 12:21:46 stredwic Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -27,10 +27,12 @@
 #
 # (Navigate problems for statistical reports
 # YEAR=2001
-# 5/05,7/09,7/25/01,8/11,9/13,9/26,10/5,10/9,10/22,10/26 Behrouz Minaei
-# 11/1, 11/4, 11/16, 12/14, 12/16, 12/18,12/20,12/31 Behrouz Minaei
+# 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 Behrouz Minaei
+# 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
+# 5/12,5/14,5/15,5/19,5/26,7/16,25/7,29/7  Behrouz Minaei
+#
 ###
 
 package Apache::lonstatistics; 
@@ -39,1244 +41,593 @@ use strict;
 use Apache::Constants qw(:common :http);
 use Apache::lonnet();
 use Apache::lonhomework;
+use Apache::loncommon;
+use Apache::loncoursedata;
+use Apache::lonhtmlcommon;
+use Apache::lonproblemanalysis;
+use Apache::lonproblemstatistics;
+use Apache::lonstudentassessment;
 use HTML::TokeParser;
 use GDBM_File;
 
-# -------------------------------------------------------------- Module Globals
-my %hash;
-my %CachData;
-my %GraphDat;
-my %maps;
-my %mapsort;
-my %section;
-my %StuBox;
-my %DiscFac;
-my %DisUp;
-my %DisLow;
-my $UpCnt;
-my $CurMap;
-my $CurSec;
-my $CurStu;
-my @cols;
-my @list;
-my @students;
-my $p_count;
-my $Pos;
-my $r;
-my $OpSel1;
-my $OpSel2;
-my $OpSelDis1;
-my $OpSelDis2;
-my $CurDis=0;
-my $OpSel3;
-my $OpSel4;
-my $GData;
-my $cid;
-my $firstres;
-my $lastres;
-my $DiscFlag;
-my $HWN;
-my $P_Order;
-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.",12,"U.A.",13,"L.A.",14,"U.R.",15,"L.R.");
-
-#------- Processing upperlist and lowerlist according to each problem
-sub ProcessDisc {
-    my @List = @_;
-    @List = sort (@List);
-    my $Count = $#List+1;
-    my $Prb;
-    my @Dis;
-    my $Slvd=0;
-    my $tmp;
-    my $Sum=0;
-    my $nIdx=0;
-    my $nStud=0;
-    my %Proc;
-    undef %Proc;
-    while ($nIdx<$Count) {
-	($Prb,$tmp)=split(/\=/,$List[$nIdx]);
-	@Dis=split(/\+/,$tmp);
-	my $Temp = $Prb;
-	do {
-	    $nIdx++;
-	    $nStud++;
-	    $Sum += $Dis[$CurDis];
-	    ($Prb,$tmp)=split(/\=/,$List[$nIdx]);
-	    @Dis=split(/\+/,$tmp);
-	} while ( $Prb eq $Temp && $nIdx < $Count );
-	$Proc{$Temp}=$Sum.':'.$nStud;
-	$Proc{$Temp}=($Sum/$nStud).':'.$nStud;
-#        $r->print("$nIdx) $Temp --> ($nStud) $Proc{$Temp} <br>");
-	$Sum=0;
-	$nStud=0;
+
+sub CheckFormElement {
+    my ($cache, $ENVName, $cacheName, $default)=@_;
+
+    if(defined($ENV{'form.'.$ENVName})) {
+        $cache->{$cacheName} = $ENV{'form.'.$ENVName};
+    } elsif(!defined($cache->{$cacheName})) {
+        $cache->{$cacheName} = $default;
+    }
+
+    return;
+}
+
+sub ProcessFormData{
+    my ($cache)=@_;
+
+    $cache->{'reportKey'} = 'false';
+
+    &Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},
+                                            ['sort','download',
+                                             'reportSelected',
+                                             'StudentAssessmentStudent',
+                                             'ProblemStatisticsSort']);
+    &CheckFormElement($cache, 'Status', 'Status', 'Active');
+    &CheckFormElement($cache, 'postdata', 'reportSelected', 'Class list');
+    &CheckFormElement($cache, 'reportSelected', 'reportSelected', 
+                      'Class list');
+    $cache->{'reportSelected'} = 
+        &Apache::lonnet::unescape($cache->{'reportSelected'});
+    &CheckFormElement($cache, 'DownloadAll', 'DownloadAll', 'false');
+    &CheckFormElement($cache, 'sort', 'sort', 'fullname');
+    &CheckFormElement($cache, 'download', 'download', 'false');
+
+    # student assessment
+    if(defined($ENV{'form.CreateStudentAssessment'}) ||
+       defined($ENV{'form.NextStudent'}) ||
+       defined($ENV{'form.PreviousStudent'})) {
+        $cache->{'reportSelected'} = 'Student Assessment';
+    }
+    if(defined($ENV{'form.NextStudent'})) {
+        $cache->{'StudentAssessmentMove'} = 'next';
+    } elsif(defined($ENV{'form.PreviousStudent'})) {
+        $cache->{'StudentAssessmentMove'} = 'previous';
+    } else {
+        $cache->{'StudentAssessmentMove'} = 'selected';
+    }
+    &CheckFormElement($cache, 'StudentAssessmentStudent', 
+                      'StudentAssessmentStudent', 'All Students');
+    $cache->{'StudentAssessmentStudent'} = 
+        &Apache::lonnet::unescape($cache->{'StudentAssessmentStudent'});
+    &CheckFormElement($cache, 'DefaultColumns', 'DefaultColumns', 'false');
+
+    if(defined($ENV{'form.Section'})) {
+        my @sectionsSelected = (ref($ENV{'form.Section'}) ?
+                               @{$ENV{'form.Section'}} :
+                                ($ENV{'form.Section'}));
+        $cache->{'sectionsSelected'} = join(':', @sectionsSelected);
+    } elsif(!defined($cache->{'sectionsSelected'})) {
+        $cache->{'sectionsSelected'} = $cache->{'sectionList'};
+    }
+
+    # Problem analysis
+    &CheckFormElement($cache, 'Interval', 'Interval', '1');
+
+    # ProblemStatistcs
+    &CheckFormElement($cache, 'DisplayCSVFormat',
+                      'DisplayFormat', 'Display Table Format');
+    &CheckFormElement($cache, 'ProblemStatisticsAscend',
+                      'ProblemStatisticsAscend', 'Ascending');
+    &CheckFormElement($cache, 'ProblemStatisticsMaps', 
+                      'ProblemStatisticsMaps', 'All Maps');
+    &CheckFormElement($cache, 'ProblemStatisticsSort',
+                      'ProblemStatisticsSort', 'Homework Sets Order');
+    &CheckFormElement($cache, 'DisplayLegend', 'DisplayLegend', 'Hide Legend');
+
+    # Search only form elements
+    my @headingColumns=();
+    my @sequenceColumns=();
+    my $foundColumn = 0;
+    if(defined($ENV{'form.ReselectColumns'})) {
+        my @reselected = (ref($ENV{'form.ReselectColumns'}) ? 
+                          @{$ENV{'form.ReselectColumns'}}
+                          : ($ENV{'form.ReselectColumns'}));
+        foreach (@reselected) {
+            if(/HeadingColumn/) {
+                push(@headingColumns, $_);
+                $foundColumn = 1;
+            } elsif(/SequenceColumn/) {
+                push(@sequenceColumns, $_);
+                $foundColumn = 1;
+            }
+        }
     }
-    return %Proc;
-}
 
+    $cache->{'reportKey'} = 'false';
+    if($cache->{'reportSelected'} eq 'Analyze') {
+        $cache->{'reportKey'} = 'Analyze';
+    } elsif($cache->{'reportSelected'} eq 'DoDiffGraph') {
+        $cache->{'reportKey'} = 'DoDiffGraph';
+    } elsif($cache->{'reportSelected'} eq 'PercentWrongGraph') {
+        $cache->{'reportKey'} = 'PercentWrongGraph';
+    }
+
+    if(defined($ENV{'form.DoDiffGraph'})) {
+        $cache->{'reportSelected'} = 'DoDiffGraph';
+        $cache->{'reportKey'} = 'DoDiffGraph';
+    } elsif(defined($ENV{'form.PercentWrongGraph'})) {
+        $cache->{'reportSelected'} = 'PercentWrongGraph';
+        $cache->{'reportKey'} = 'PercentWrongGraph';
+    }
+
+    foreach (keys(%ENV)) {
+        if(/form\.Analyze/) {
+            $cache->{'reportSelected'} = 'Analyze';
+            $cache->{'reportKey'} = 'Analyze';
+            my $data;
+            (undef, $data)=split(':::', $_);
+            $cache->{'AnalyzeInfo'}=$data;
+        } elsif(/form\.HeadingColumn/) {
+            my $value = $_;
+            $value =~ s/form\.//;
+            push(@headingColumns, $value);
+            $foundColumn=1;
+        } elsif(/form\.SequenceColumn/) {
+            my $value = $_;
+            $value =~ s/form\.//;
+            push(@sequenceColumns, $value);
+            $foundColumn=1;
+        }
+    }
 
-#------- Creating Discimination factor   
-sub Discriminant {
-    my $Count=0;
-    foreach (keys(%DiscFac)){ 
-	$Count++;
-    }
-    $UpCnt = int(0.27*$Count);
-    my $low=0;
-    my $up=$Count-$UpCnt;
-    my @UpList=();
-    my @LowList=();
-    $Count=0;
-    foreach my $key (sort(keys(%DiscFac))){ 
-	$Count++;    
-        #$r->print("<br>$Count) $key = $DiscFac{$key}");
-	if ($low < $UpCnt || $Count > $up) {
-	    $low++;
-	    my $str=$DiscFac{$key};
-	    foreach(split(/\:/,$str)){
-		if ($_) {
-		    if ($low<$UpCnt){push(@LowList,$_);}
-		    else {push(@UpList,$_);}
-		}
-	    }
-	}
+    if($foundColumn) {
+        $cache->{'HeadingsFound'} = join(':', @headingColumns);
+        $cache->{'SequencesFound'} = join(':', @sequenceColumns);;
     }
-    %DisUp=&ProcessDisc(@UpList);
-    %DisLow=&ProcessDisc(@LowList);
-}
+    if(!defined($cache->{'HeadingsFound'}) || 
+       $cache->{'DefaultColumns'} ne 'false') {
+        $cache->{'HeadingsFound'}='HeadingColumnFull Name';
+    }
+    if(!defined($cache->{'SequencesFound'}) ||
+       $cache->{'DefaultColumns'} ne 'false') {
+        $cache->{'SequencesFound'}='All Sequences';
+    }
+    $cache->{'DefaultColumns'} = 'false';
 
-   
-sub NumericSort {          
-    $a <=> $b;
+    return;
 }
 
-# ------ Create different Student Report 
-sub StudentReport {
+=pod
 
-    my ($sname,$sdom)=@_;
+=item &SortStudents()
 
-    if ( $sname eq 'All Students' ) {
-	$r->print( '<h3><font color=blue>WARNING: 
-                    Please select a student</font></h3>' );
-	return;
-    }
-    my $shome=&Apache::lonnet::homeserver($sname,$sdom);          
-    my $reply=&Apache::lonnet::reply('dump:'.$sdom.':'.$sname.':'.$cid,$shome );
-    my %result = ();
-    my $ResId;
-    my $PrOrd;
-    my $Code;
-    my $Tries;
-    my $TotalTries = 0;
-    my $ParCr = 0;
-    my $Wrongs;
-    my %TempHash;
-    my $Version;
-    my $LatestVersion;
-    my $PtrTry='';
-    my $PtrCod='';
-    my $SetNo=0;
-    my $Str = "\n".'<table border=2>'.
-              "\n".'<tr>'.
-              "\n".'<th> # </th>'.
-	      "\n".'<th> Set Title </th>'.
-	      "\n".'<th> Results </th>'.
-	      "\n".'<th> Tries </th>'.
-	      "\n".'</tr>';
-    unless ($reply=~/^error\:/) {
-        foreach (split(/\&/,$reply)){
-            my ($name,$value)=split(/\=/,&Apache::lonnet::unescape($_));
-            $result{$name}=$value;
-        }
-        foreach my $CurCol (@cols) {
-	    if (!$CurCol){
-		my $Set=&Apache::lonnet::declutter($hash{'map_id_'.$1});
-		if ( $Set ) {
-		    $SetNo++;
-		    $Str .= "\n"."<tr>".
-			    "\n"."<td> $SetNo </td>".
-                            "\n"."<td> $Set </td>".
-                            "\n"."<td> $PtrCod </td>".
-                            "\n"."<td> $PtrTry</td>".
-                            "\n"."</tr>";
-		}
-		$PtrTry='';
-		$PtrCod='';
-		next; 
-	    }
-	    ($PrOrd,$ResId)=split(/\:/,$CurCol);
-            $ResId=~/(\d+)\.(\d+)/;
-            my $Map = &Apache::lonnet::declutter( $hash{'map_id_'.$1} );
-            if ( $CurMap ne 'All Maps' ) {
-		my ( $ResMap, $NameMap ) = split(/\=/,$CurMap);
-		if ( $Map ne $ResMap ) { next; }
-	    }
-	    my $meta=$hash{'src_'.$ResId};
-	    my $PartNo = 0;
-	    undef %TempHash;
-	    foreach (split(/\,/,&Apache::lonnet::metadata($meta,'keys'))){
-		if ($_=~/^stores\_(\d+)\_tries$/) {
-                    my $Part=&Apache::lonnet::metadata($meta,$_.'.part');
-		    if ( $TempHash{"$Part"} eq '' ) { 
-			$TempHash{"$Part"} = $Part;
-			$TempHash{$PartNo}=$Part;
-			$TempHash{"$Part.Code"} = '-';  
-			$TempHash{"$Part.PrOrd"} = $PrOrd+$PartNo;  
-			$PartNo++;
-		    }
-		}
-            }
+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.
 
-            my $Prob = $Map.'___'.$2.'___'.
-                       &Apache::lonnet::declutter( $hash{'src_'.$ResId} );
-            $Code='U';
-            $Tries = 0;
-            $Wrongs = 0;
-  	    $LatestVersion = $result{"version:$Prob"};
-	    if ( $LatestVersion ) {
-		for ( my $Version=1; $Version<=$LatestVersion; $Version++ ) {
-		    my $vkeys = $result{"$Version:keys:$Prob"};
-		    my @keys = split(/\:/,$vkeys);		
-  
-		    foreach my $Key (@keys) {		  
-			if (($Key=~/\.(\w+)\.solved$/) && ($Key!~/^\d+\:/)) {
-			    my $Part = $1;
-			    $Tries = $result{"$Version:$Prob:resource.$Part.tries"};
-			    $TempHash{"$Part.Tries"} = ($Tries) ? $Tries : 0; 
-			    $TotalTries += $Tries;
-			    my $Val = $result{"$Version:$Prob:resource.$Part.solved"};
-			    if ( $Val eq 'correct_by_student' )
-                                { $Wrongs = $Tries - 1; $Code = 'Y'; } 
-			    elsif ( $Val eq 'correct_by_override' )
-                                { $Wrongs = $Tries - 1; $Code = 'y'; }                        
-			    elsif ( $Val eq 'incorrect_attempted' || 
-                                $Val eq 'incorrect_by_override' )
-		                { $Wrongs = $Tries; $Code = 'N'; }
-			    $TempHash{"$Part.Code"} = $Code;
-			    $TempHash{"$Part.Wrongs"} = $Wrongs;
-			}
-     		    }
-                }
-		for ( my $n = 0; $n < $PartNo; $n++ ) {		  
-		    my $part = $TempHash{$n};
-		    if ($PtrTry ne '') {$PtrTry .= ',';}
-		    $PtrTry .= "$TempHash{$part.'.Tries'}";
-                    $PtrCod .= "$TempHash{$part.'.Code'}";    
-		}
-            }
-	    else { 
-		for(my $n=0; $n<$PartNo; $n++) { 
-		    if ($PtrTry ne '') {$PtrTry .= ',';}
-		    $PtrTry .= "0";
-                    $PtrCod .= "-"; 
-		}
-	    }
-        }
-    }
-    $Str .= "\n".'</table>';
-    $r->print($Str);
-    $r->rflush();
-}
+=over 4
 
-sub CreateTable {
-    my $ColNo=0;
-    foreach (keys(%Header)){ 
-	$ColNo++;
-    } 
-    my ($Hd, $Hid)=@_;
-    if ( $Hd == 1 ) {
-	$r->print('<br><a href="'.$hash{'src_'.$Hid}.
-                  '" target="_blank">'.$hash{'title_'.$Hid}.'</a>');
-    }
-    my $Result = "\n".'<table border=2>';
-    $Result .= '<tr><th>P#</th>'."\n";
-    for ( my $nIdx=0; $nIdx < $ColNo; $nIdx++ ) { 
-	$Result .= '<th>'.'<input type="submit" name="sort" value="'.
-                   $Header{$nIdx}.'" />'.'</th>'."\n";
-    }
-    $Result .= "\n".'</tr>'."\n";    
-    $r->print( $Result );
-    $r->rflush();
-}
+Input: $students, $CacheData
 
-sub CloseTable {
-    $r->print("\n".'</table>'."\n");
-    $r->rflush();
-}
- 
-# ------------------------------------------- Prepare Statistics Table
-sub PreStatTable {
-    my $CacheDB = "/home/httpd/perl/tmp/$ENV{'user.name'}".
-                  "_$ENV{'user.domain'}_$cid\_statistics.db";
-    my $GraphDB = "/home/httpd/perl/tmp/$ENV{'user.name'}".
-                  "_$ENV{'user.domain'}_$cid\_graph.db";
-    my $CachDisFac = "/home/httpd/perl/tmp/$ENV{'user.name'}".
-		     "_$ENV{'user.domain'}_$cid\_DiscFactor.db";
-    my $OpSel11='';
-    my $OpSel12='';
-    my $OpSel13='';
-    my $Status = $ENV{'form.status'};
-    if ( $Status eq 'Any' ) { $OpSel13='selected'; }
-    elsif ($Status eq 'Expired' ) { $OpSel12 = 'selected'; }
-    else { $OpSel11 = 'selected'; }
-
-    my $Ptr = '';
-    $Ptr .= '<br><b> Student Status: &nbsp; </b>'."\n".
-            '<select name="status">'. 
-            '<option '.$OpSel11.' >Active</option>'."\n".
-            '<option '.$OpSel12.' >Expired</option>'."\n".
-	    '<option '.$OpSel13.' >Any</option> </select> '."\n";
-    $Ptr .= '&nbsp;&nbsp;&nbsp;';
-    $Ptr .= '<input type=submit name=sort value="Recalculate Statistics"/>'."\n";
-
-    $Ptr .= '<br><b> Sorting Type: &nbsp; </b>'."\n".
-            '<select name="order"> <option '.$OpSel1.' >Ascending</option>'."\n".
-	    '<option '.$OpSel2.'>Descending</option> </select> '."\n";
-    $Ptr .= '&nbsp;&nbsp;&nbsp;';
-    $Ptr .= '<input type="submit" name="sort" value="DoDiff Graph" />'."\n";
-    $Ptr .= '&nbsp;&nbsp;&nbsp;';
-    $Ptr .= '<input type="submit" name="sort" value="%Wrong Graph" />'."\n";
-
-    $Ptr .= '<pre>'.
-    '<b>  #Stdnts</b>: Total Number of Students opened the problem.<br>'. 
-    '<b>  Tries  </b>: Total Number of Tries for solving the problem.<br>'. 
-    '<b>  Mod   </b> : Maximunm Number of Tries for solving the problem.<br>'. 
-    '<b>  Mean   </b>: Average Number of the tries. [ Tries / #Stdnts ]<br>'.
-    '<b>  #YES   </b>: Number of students solved the problem correctly.<br>'. 
-    '<b>  #yes   </b>: Number of students solved the problem by override.<br>'.
-    '<b>  %Wrng  </b>: Percentage of students tried to solve the problem but'.
-    ' still incorrect. [ 100*((#Stdnts-(#YES+#yes))/#Stdnts) ]<br>'.
-#    '  DoDiff : Degree of Difficulty of the problem. [ Tries/(#YES+#yes+0.1) ]<br>'.
-    '<b>  DoDiff </b>: Degree of Difficulty of the problem. [ 1 - ((#YES+#yes) / Tries) ]<br>'.
-    '<b>  S.D.  </b> : Standard Deviation of the tries.'.
-    '[ sqrt(sum((Xi - Mean)^2)) / (#Stdnts-1)'.
-    ' where Xi denotes every student\'s tries ]<br>'.
-    '<b>  Skew.  </b>: Skewness of the students tries.'.
-    ' [ (sqrt( sum((Xi - Mean)^3) / #Stdnts)) / (S.D.^3) ]<br>'.
-
-    '<b>  Dis.F. </b>: Discrimination Factor. [ Sum of Partial Credits'.
-    ' Awarded / Total Number of Tries in %27 upper and lower students]<br>'.	
-    '<b>  U.A.   </b>: Upper %27 Award<br>'.	
-    '<b>  L.A.   </b>: Lower %27 Award<br>'.	
-    '<b>  U.R.   </b>: Upper %27 Records<br>'.	
-    '<b>  L.R.   </b>: Lower %27 Records'.	
-
-#    "<br>The <b>Upper 27%</b> has <b>$UpCnt</b> records.".
-#    "&nbsp;&nbsp;The <b>Lower 27%</b> has <b>$UpCnt</b> records <br>".
-#    "The Criterion of sorting the students: ". 
-#    "<b>( Sum of Partial Credits Awarded / ".
-#    "Total Number of Tries )</b>".
-
-            '</pre>';
-
-    $r->print($Ptr);
-    $r->rflush();	
-
-    if ((-e "$CacheDB")&&($ENV{'form.sort'} ne 'Recalculate Statistics')) {
-	if (tie(%CachData,'GDBM_File',"$CacheDB",&GDBM_READER,0640)) {
-	    tie(%DiscFac,'GDBM_File',$CachDisFac,&GDBM_READER,0640);
-	    tie(%GraphDat,'GDBM_File',$GraphDB,&GDBM_WRCREAT,0640);
-	    &Cache_Statistics();
-        }
-        else {
-	    $r->print("Unable to tie hash to db file");
+$students: A array pointer to a list of students (username:domain)
+
+$CacheData: A pointer to the hash tied to the cached data
+
+Output: \@order
+
+@order: An ordered list of students (username:domain)
+
+=back
+
+=cut
+
+sub SortStudents {
+    my ($cache)=@_;
+
+    my @students = split(':::',$cache->{'NamesOfStudents'});
+    my @sorted1Students=();
+    foreach (@students) {
+        if($cache->{'Status'} eq 'Any' || 
+           $cache->{$_.':Status'} eq $cache->{'Status'}) {
+            push(@sorted1Students, $_);
         }
     }
-    else {
-	if (tie(%CachData,'GDBM_File',$CacheDB,&GDBM_WRCREAT,0640)) {
-	    tie(%DiscFac,'GDBM_File',$CachDisFac,&GDBM_WRCREAT,0640);
-	    tie(%GraphDat,'GDBM_File',$GraphDB,&GDBM_WRCREAT,0640);
-	    foreach (keys %DiscFac) {delete $CachData{$_};}
-	    foreach (keys %CachData) {delete $CachData{$_};}
-	    $DiscFlag=0;
-	    &Build_Statistics();
-	}
-        else {
-	    $r->print("Unable to tie hash to db file");
-        }
+
+    my $sortBy = '';
+    if(defined($cache->{'sort'})) {
+        $sortBy = ':'.$cache->{'sort'};
     }
-    #$r->print('Total instances of the problems : '.($p_count*($#students+1)));
+    my @order = sort { $cache->{$a.$sortBy} cmp $cache->{$b.$sortBy} ||
+                       $cache->{$a.':fullname'} cmp $cache->{$b.':fullname'} } 
+                @sorted1Students;
 
-    untie(%CachData);
-    untie(%GraphDat);
-    untie(%DiscFac);       
+    return \@order;
 }
 
+=pod
 
-# ------------------------------------- Find the section of student in a course
+=item &SpaceColumns()
 
-sub usection {
-    my ($udom,$unam,$courseid,$ActiveFlag)=@_;
-    $courseid=~s/\_/\//g;
-    $courseid=~s/^(\w)/\/$1/;
-    foreach (split(/\&/,&Apache::lonnet::reply('dump:'.
-             $udom.':'.$unam.':roles',
-             &Apache::lonnet::homeserver($unam,$udom)))){
-        my ($key,$value)=split(/\=/,$_);
-        $key=&Apache::lonnet::unescape($key);
-        if ($key=~/^$courseid(?:\/)*(\w+)*\_st$/) {
-            my $section=$1;
-            if ($key eq $courseid.'_st') { $section=''; }
-	    my ($dummy,$end,$start)=split(/\_/,&Apache::lonnet::unescape($value));
-	    if ( $ActiveFlag ne 'Any' ) {
-		my $now=time;
-		my $notactive=0;
-		if ($start) {
-		    if ($now<$start) { $notactive=1; }
-		}
-		if ($end) {
-		    if ($now>$end) { $notactive=1; }
-		}
-		if ((($ActiveFlag eq 'Expired') && $notactive == 1) || 
-                    (($ActiveFlag eq 'Active') && $notactive == 0 ) ) {
-		    return $section;
-		}
-		else { return '-1'; } 
-	    }
-	    return $section;
-        }
-    }
-    return '-1';
-}
+Determines the width of all the columns in the chart.  It is based on
+the max of the data for that column and its header.
 
+=over 4
 
-# ------ Dump the Student's DB file and handling the data for statistics table 
+Input: $students, $studentInformation, $headings, $ChartDB
 
-sub ExtractStudentData {
-    my ($student,$coid)=@_;
-    my ($sname,$sdom) = split( /\:/, $student );
-    my $shome=&Apache::lonnet::homeserver( $sname,$sdom );          
-    my $reply=&Apache::lonnet::reply('dump:'.$sdom.':'.$sname.':'.$coid,$shome );
-    my %result = ();
-    my $ResId;
-    my $PrOrd;
-    my $Dis = '';
-    my $Code;
-    my $Tries;
-    my $ParCr;
-    my $TotalTries = 0;
-    my $TotalOpend = 0;
-    my $ProbSolved = 0;
-    my $ProbTot = 0;
-    my $TimeTot = 0;
-    my $TotParCr = 0;
-    my $Wrongs;
-    my %TempHash;
-    my $Version;
-    my $LatestVersion;
-    my $SecLimit;
-    my $MapLimit;
-    unless ($reply=~/^error\:/) {
-        foreach (split(/\&/,$reply)) {
-            my ($name,$value)=split(/\=/,&Apache::lonnet::unescape($_));
-            $result{$name}=$value;
-        }
-        foreach my $CurCol(@cols) {
-	    ($PrOrd,$ResId)=split(/\:/,$CurCol);
-	    if ( !$CurCol ) { next; }
-            $ResId=~/(\d+)\.(\d+)/;
-	    my $MapId=$1;
-	    my $PrbId=$2;
-            my $Map = &Apache::lonnet::declutter( $hash{'map_id_'.$MapId} );
-            if ( $CurMap ne 'All Maps' ) {
-		my ( $ResMap, $NameMap ) = split(/\=/,$CurMap);
-		if ( $Map ne $ResMap ) { next; }
-	    }
-	    my $meta=$hash{'src_'.$ResId};
-	    my $PartNo = 0;
-	    $Dis .= ':';
-	    undef %TempHash;
-	    foreach (split(/\,/,&Apache::lonnet::metadata($meta,'keys'))) {
-		if ($_=~/^stores\_(\d+)\_tries$/) {
-                    my $Part=&Apache::lonnet::metadata($meta,$_.'.part');
-		    if ( $TempHash{"$Part"} eq '' ) { 
-			$TempHash{"$Part"} = $Part;
-			$TempHash{$PartNo}=$Part;
-			$TempHash{"$Part.Code"} = 'U';  
-			$TempHash{"$Part.PrOrd"} = $PrOrd+$PartNo;
-			$PartNo++;
-		    }
-		}
-            }
+$students: An array pointer to a list of students (username:domain)
 
-            my $Prob = $Map.'___'.$PrbId.'___'.
-                       &Apache::lonnet::declutter( $hash{'src_'.$ResId} );
-            $Code='U';
-            $Tries = 0;
-	    $ParCr = 0;
-            $Wrongs = 0;
-  	    $LatestVersion = $result{"version:$Prob"};       
-
-	    if ( $LatestVersion ) {
-		for ( my $Version=1; $Version<=$LatestVersion; $Version++ ) {
-		    my $vkeys = $result{"$Version:keys:$Prob"};
-		    my @keys = split(/\:/,$vkeys);		
-  
-		    foreach my $Key (@keys) {		  
-			if (($Key=~/\.(\w+)\.solved$/) && ($Key!~/^\d+\:/)) {
-			    my $Part = $1;
-			    $Tries = $result{"$Version:$Prob:resource.$Part.tries"};
-			    $ParCr = $result{"$Version:$Prob:resource.$Part.awarded"};
-			    my $Time = $result{"$Version:$Prob:timestamp"};
-			    $TempHash{"$Part.Time"} = ($Time) ? $Time : 0;
-			    $TempHash{"$Part.Tries"} = ($Tries) ? $Tries : 0;
-			    $TempHash{"$Part.ParCr"} = ($ParCr) ? $ParCr : 0;        
-			    $TotalTries += $TempHash{"$Part.Tries"};
-			    $TotParCr += $TempHash{"$Part.ParCr"};
-#$r->print($Version.'---'.$Prob.'==='.$Time.'<br>');
-			    my $Val = $result{"$Version:$Prob:resource.$Part.solved"};
-			    if ( $Val eq 'correct_by_student' )
-                               { $Wrongs = $Tries - 1; $Code = 'C'; } 
-			    elsif ( $Val eq 'correct_by_override' )
-                               { $Wrongs = $Tries - 1; $Code = 'O'; }                        
-			    elsif ( $Val eq 'incorrect_attempted' || 
-                                $Val eq 'incorrect_by_override' )
-		               { $Wrongs = $Tries; $Code = 'I'; }
-			    $TempHash{"$Part.Code"} = $Code;
-			    $TempHash{"$Part.Wrongs"} = $Wrongs;
-			}
-     		    }
-                } 
-		for ( my $n = 0; $n < $PartNo; $n++ ) {		  
-		    my $part = $TempHash{$n};
-		    my $Yes = 0;
-                    if ( $TempHash{$part.'.Code'} eq 'C' ||
-                         $TempHash{$part.'.Code'} eq 'O'  ) 
-		       {$ProbSolved++;$Yes=1;}		
-
- #		    my $ptr = "$hash{'title_'.$ResId}";
-		    my $ptr = $TempHash{$part.'.PrOrd'}.':'.$ResId;
-
-		    if ( $PartNo > 1 ) {                
-			$ptr .= "*(part $part)";
-			$Dis .= ':';
-		    }
-		    my $Fac = ($TempHash{"$part.Tries"}) ? 
-                              ($TempHash{"$part.ParCr"}/$TempHash{"$part.Tries"}) : 0;
-		    my $DisF;
-		    if ( $Fac > 0 &&  $Fac < 1 ) { 
-			$DisF = sprintf( "%.4f", $Fac );
-		    }
-		    else {$DisF = $Fac;}
-#		    $DisF .= '+'.$TempHash{"$part.Time"};
-		    $TimeTot += $TempHash{"$part.Time"};
-		    $Dis .= $TempHash{$part.'.PrOrd'}.'='.$DisF.'+'.$Yes;
-
-            #$r->print('<br>'.$DisFactor,'###',$DiscFac{$DisFactor});
-		    $ptr .= ":$TempHash{$part.'.Tries'}".
-		            ":$TempHash{$part.'.Wrongs'}".
-                            ":$TempHash{$part.'.Code'}";
-		    push (@list, $ptr);
-		    $TotalOpend++;
-		    $ProbTot++;
-		}
+$studentInformatin: The type of data for the student information.  It is
+used as part of the key in $CacheData.
+
+$headings: The name of the student information columns.
+
+$ChartDB: The name of the cache database which is opened for read/write.
+
+Output: None - All data stored in cache.
+
+=back
+
+=cut
+
+sub SpaceColumns {
+    my ($students,$studentInformation,$headings,$cache)=@_;
+
+    # Initialize Lengths
+    for(my $index=0; $index<(scalar @$headings); $index++) {
+        my @titleLength=split(//,$headings->[$index]);
+        $cache->{$studentInformation->[$index].':columnWidth'}=
+            scalar @titleLength;
+    }
+
+    foreach my $name (@$students) {
+        foreach (@$studentInformation) {
+            my @dataLength=split(//,$cache->{$name.':'.$_});
+            my $length=(scalar @dataLength);
+            if($length > $cache->{$_.':columnWidth'}) {
+                $cache->{$_.':columnWidth'}=$length;
             }
-	    #else { 
-		#for(my $n=0; $n<$PartNo; $n++) {
-		#    push (@list, "$hash{'title_'.$ResId}*$ResId:0:0:U");
-		#    $ProbTot++; 
-		#}
-	    #}
         }
-	if ( $TotalTries ) {
-	    my $DisFac = ( $TotalTries ) ? ($TotParCr/$TotalTries) : 0;
-	    my $DisFactor = sprintf( "%.4f", $DisFac );
-	    $DiscFac{$DisFactor}=$Dis;
-            #$r->print('<br>'.$DisFactor,'###',$DiscFac{$DisFactor});
-	    #my $time;
-	    #if ($ProbSolved){
-		#$time = int(($TimeTot/$ProbSolved)-10000000);
-	    #}
-	    #$DiscFac{($DisFactor.':'.$sname.':'.$ProbTot.':'.$TotalOpend.':'.
-            #          $TotalTries.':'.$ProbSolved.':'.$time)}=$Dis;
-	}
     }
-    #$r->print($sname.' PrCr= '.$TotParCr.' Slvd= '.$ProbSolved.' Tries='.$TotalTries.'<br>');
+
+    return;
 }
 
+sub PrepareData {
+    my ($c, $cacheDB, $studentInformation, $headings,$r)=@_;
 
-# ------------------------------------------------------------ Build page table
-sub tracetable {
-    my ($rid,$beenhere)=@_;
-    $rid=~/(\d+)\.(\d+)/;
-    $maps{&Apache::lonnet::declutter($hash{'map_id_'.$1})}='';#$hash{'title_'.$rid}; 
-    #$maps{$HWN}=$hash{'title_'.$rid}; 
-    unless ($beenhere=~/\&$rid\&/) {
-       $beenhere.=$rid.'&'; 
-       if (defined($hash{'is_map_'.$rid})) {
-	   my $cmap=$hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$rid}}};
-           if ( $cmap eq 'sequence' || $cmap eq 'page' ) { 
-               $cols[$#cols+1]=0;
-	       $P_Order++;
-	       $HWN=$P_Order;
-               $mapsort{$HWN} = $rid.':'; 
-               #$maps{&Apache::lonnet::declutter($hash{'src_'.$rid})}= 
-               #      $hash{'title_'.$rid}; 
-           }
-           if ((defined($hash{'map_start_'.$hash{'src_'.$rid}})) &&
-               (defined($hash{'map_finish_'.$hash{'src_'.$rid}}))) {
-	       my $frid=$hash{'map_finish_'.$hash{'src_'.$rid}};
-
-               &tracetable($hash{'map_start_'.$hash{'src_'.$rid}},
-			   '&'.$frid.'&');
-
-	       $cols[$#cols+1]=($P_Order+1).':'.$frid;
-      
-	       my $meta=$hash{'src_'.$frid};
-	       my $PartNo = 0;
-               if ($meta) {
-		   if ($meta=~/\.(problem|exam|quiz|assess|survey|form)$/) {
-		       foreach (split(/\,/,&Apache::lonnet::metadata($meta,'keys'))) {
-			   if ($_=~/^stores\_(\d+)\_tries$/) {
-			       &Apache::lonnet::metadata($meta,$_.'.part');
-			       $P_Order++;
-			       $mapsort{$HWN} .= '&'.$P_Order;
-			       $PartNo++;
-			       $r->print('<br>'.$PartNo.'---'.$P_Order);
-			   }
-		       }
-		   }
-               }
-	   }
-       } else {
-	   $cols[$#cols+1]=($P_Order+1).':'.$rid;
-	   my $meta=$hash{'src_'.$rid};
-	   my $PartNo = 0;
-           if ($meta) {
-	       if ($meta=~/\.(problem|exam|quiz|assess|survey|form)$/) {
-		   foreach (split(/\,/,&Apache::lonnet::metadata($meta,'keys'))) {
-		       if ($_=~/^stores\_(\d+)\_tries$/) {
-			   &Apache::lonnet::metadata($meta,$_.'.part');
-			   $P_Order++;
-			   $mapsort{$HWN} .= '&'.$P_Order;
-			   $PartNo++;
-		       }
-		   }
-	       }
-	   }
-       }
-       if (defined($hash{'to_'.$rid})) {
-          foreach (split(/\,/,$hash{'to_'.$rid})){
-              &tracetable($hash{'goesto_'.$_},$beenhere);
-          }
-       }
+    # Test for access to the cache data
+    my $courseID=$ENV{'request.course.id'};
+    my $isRecalculate=0;
+    if(defined($ENV{'form.Recalculate'})) {
+        $isRecalculate=1;
     }
-}
 
-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; }
+    my $isCached = &Apache::loncoursedata::TestCacheData($cacheDB, 
+                                                         $isRecalculate);
+    if($isCached < 0) {
+        return "Unable to tie hash to db file.";
     }
-}
 
-sub Build_Statistics {
-    $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();
-# ---------------------------- Gathering the Data of students' tries
-    my $index;
-    for ($index=0;$index<=$#students;$index++) {
-#----------- update progress
-        $r->print('<script>popwin.document.popremain.remaining.value="'.
-                  'Computing '.($index+1).'/'.($#students+1).': '.
-                  $students[$index].'";</script>');
-        $r->rflush();
-
-        &ExtractStudentData($students[$index],$cid);
+    # Download class list information if not using cached data
+    my %cache;
+    unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_WRCREAT(),0640)) {
+        return "Unable to tie hash to db file.";
     }
 
-# -------------------- sorting the Data
-    $r->print('<script>popwin.document.popremain.remaining.value="'.
-              'Calculating Discrimination Factors...";</script>');
-
-    @list = sort (@list);
-
-
-    &Discriminant();
-
-    $OpSel2='';
-    $OpSel1='selected';
- 		   
-    $p_count = 0; 
-    my $nIdx = 0;
-    my $dummy; 
-    my $p_val;
-    my $ResId;
-    my $NoElements = $#list + 1;
-#-------------------------------- loop for data representation
-    foreach (sort keys %mapsort) {
-	my ($Hid,$pr)=split(/\:/,$mapsort{$_});
-	my @lpr=split(/\&/,$pr);
-	&CreateTable(1,$Hid);
-	for (my $i=1; $i<=$#lpr; $i++) {
-	    my %storestats=();
-	    my ($PrOrd,$Prob,$Tries,$Wrongs,$Code)=split(/\:/,$list[$nIdx]);
-	    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] ) 
-	    {
-		$nIdx++;
-		$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(/\:/,$list[$nIdx]);
-	    }	
-
-	    $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*$StdDev;
-	    }
-
-#--------------------- Compute the Discrimination Factors
-	    my ($UpD,$UpNo)=split(/\:/,$DisUp{$lpr[$i]});
-	    my ($LwD,$LwNo)=split(/\:/,$DisLow{$lpr[$i]});
-	    $UpNo = ($UpNo) ? $UpNo : 0;
-	    $LwNo = ($LwNo) ? $LwNo : 0;
-	    my $U_D = sprintf("%.2f", $UpD);
-	    my $L_D = sprintf("%.2f", $LwD);
-	    my $DisFac = $UpD - $LwD;
-	    my $_Dis = sprintf("%.2f", $DisFac);
-
-#-----------------  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 = $PrOrd.':'.$Temp.':'.$StdNo.':'.
-                       $TotalTries.':'.$MxTries.':'.$Avg.':'.
-                       $YES.':'.$Override.':'.$Wrng.':'.$DoD.':'.
-		       $SD.':'.$Sk.':'.$_Dis.':'.$U_D.':'.
-                       $L_D.':'.$UpNo.':'.$LwNo.':'.$Prob;
-	    $CachData{($p_count-1)}=$join;
-
-	    $urlres=~/^(\w+)\/(\w+)/;
-	    if ($StdNo) { 
-		&Apache::lonnet::put('resevaldata',\%storestats,$1,$2); 
-	    }
-#-------------------------------- Row of statistical table
-	    if ( $DiscFlag == 0 ) {
-		&TableRow($join,$i,($p_count-1));
-	    } 
-	}
-	&CloseTable();
-    }
-#--------------------- close Progress Line
-    $r->print('<script>popwin.close()</script>');
-    $r->rflush(); 
-}
+    if(!$isCached) {
+        my $processTopResourceMapReturn=
+            &Apache::loncoursedata::ProcessTopResourceMap(\%cache, $c, $r);
+        if($processTopResourceMapReturn ne 'OK') {
+            untie(%cache);
+            return $processTopResourceMapReturn;
+        }
+    }
 
-sub Cache_Statistics {
-    my @list = ();
-    my $Useful;
-    my $UnUseful;
-    my %myHeader = reverse( %Header );
-    $Pos = $myHeader{$ENV{'form.sort'}};
-    if ($Pos > 0) {$Pos++;}
-    $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 $nIdx=0;
-
-    if ( $Pos == 0 ) {
-	foreach (sort keys %mapsort) {
-	    my ($Hid,$pr)=split(/\:/,$mapsort{$_});
-	    &CreateTable(1,$Hid);
-	    my @lpr=split(/\&/,$pr);
-	    for (my $i=1; $i<=$#lpr; $i++) {
-		my($Pre, $Post) = split(/\&/,$list[$nIdx]); 
-		&TableRow($Post,$i,$nIdx);
-		$nIdx++;
-	    }
-	    &CloseTable();
-	}
-    }
-    else {
-	&CreateTable(0);
-	for ( my $nIdx = 0; $nIdx < $p_count; $nIdx++ ) {
-	    my($Pre, $Post) = split(/\&/,$list[$nIdx]); 
-	    &TableRow($Post,$nIdx,$nIdx);
-	} 
-	&CloseTable();
+    if($c->aborted()) {
+        untie(%cache);
+        return 'aborted'; 
     }
-}
 
-sub TableRow {
-    my ($Str,$Idx,$RealIdx)=@_;
-    my($PrOrd,$Temp,$StdNo,$TotalTries,$MxTries,$Avg,$YES,
-       $Override,$Wrng,$DoD,$SD,$Sk,$_Dis,$U_D,$L_D,$UpNo,$LwNo,
-       $Prob)=split(/\:/,$Str);	
-    $r->print( "\n".'<tr>'.
-               "\n".'<td>'.($RealIdx+1).'</td>'.
-               "\n".'<td bgcolor="#FFFFFF">'.$Temp.'</td>'.
-               "\n".'<td bgcolor="#EEFFCC"> '.$StdNo.'</td>'.
-               "\n".'<td bgcolor="#EEFFCC">'.$TotalTries.'</td>'.
-               "\n".'<td bgcolor="#EEFFCC">'.$MxTries.'</td>'.
-               "\n".'<td bgcolor="#DDFFFF">'.$Avg.'</td>'.
-               "\n".'<td bgcolor="#DDFFFF"> '.$YES.'</td>'.
-               "\n".'<td bgcolor="#DDFFFF"> '.$Override.'</td>'.
-               "\n".'<td bgcolor="#FFDDDD"> '.$Wrng.'</td>'.
-               "\n".'<td bgcolor="#FFDDDD">'.$DoD.'</td>'.
-               "\n".'<td bgcolor="#DDFFDD"> '.$SD.'</td>'.
-               "\n".'<td bgcolor="#DDFFDD"> '.$Sk.'</td>'.
-               "\n".'<td bgcolor="#FFDDCC"> '.$_Dis.'</td>'.
-               "\n".'<td bgcolor="#FFFFDD"> '.$U_D.'</td>'.
-               "\n".'<td bgcolor="#FFFFDD"> '.$L_D.'</td>'.
-               "\n".'<td bgcolor="#FFFFDD"> '.$UpNo.'</td>'.
-               "\n".'<td bgcolor="#FFFFDD"> '.$LwNo.'</td>'.
-               "\n".'</tr>' );
-    $GraphDat{$RealIdx}=$DoD.':'.$Wrng;
-}
+    my $classlist=&Apache::loncoursedata::DownloadClasslist($courseID,
+                                                $cache{'ClasslistTimestamp'},
+                                                $c);
+    foreach (keys(%$classlist)) {
+        if(/^(con_lost|error|no_such_host)/i) {
+            untie(%cache);
+            return "Error getting student data.";
+        }
+    }
 
-# ------------------------------------------- Prepare data for Graphical chart
+    if($c->aborted()) {
+        untie(%cache);
+        return 'aborted'; 
+    }
+
+    # Active is a temporary solution, remember to change
+    Apache::loncoursedata::ProcessClasslist(\%cache,$classlist,$courseID,$c);
+    if($c->aborted()) {
+        untie(%cache);
+        return 'aborted'; 
+    }
+
+    &ProcessFormData(\%cache);
+    my $students = &SortStudents(\%cache);
+    &SpaceColumns($students, $studentInformation, $headings, \%cache);
+    $cache{'updateTime:columnWidth'}=24;
+
+    if($cache{'download'} ne 'false') {
+        my @who = ($cache{'download'});
+        $cache{'download'} = 'false';
+        if(&Apache::loncoursedata::DownloadStudentCourseData(\@who, 'false', 
+                                                             $cacheDB, 'true', 
+                                                             'false', $courseID,
+                                                             $r, $c) ne 'OK') {
+            untie(%cache);
+            return 'Stop at download individual';
+        }
+    } elsif($cache{'DownloadAll'} ne 'false') {
+        $cache{'DownloadAll'} = 'false';
+        my @allStudents;
+        if($cache{'DownloadAll'} eq 'sorted') {
+            @allStudents = @$students;
+        } else {
+            @allStudents = split(':::', $cache{'NamesOfStudents'});
+        }
+        if(&Apache::loncoursedata::DownloadStudentCourseData(\@allStudents, 
+                                                             'false', 
+                                                             $cacheDB, 'true', 
+                                                             'true', $courseID,
+                                                             $r, $c) ne 'OK') {
+            untie(%cache);
+            return 'Stop at download all';
+        }
+    }
 
-sub GetGraphData {
-    my $Tag = shift;
-    my $Col;
-    my $data='';
-    my $count = 0;
-    my $Max = 0;
-    my $cid=$ENV{'request.course.id'};
-    my $GraphDB = "/home/httpd/perl/tmp/$ENV{'user.name'}".
-                  "_$ENV{'user.domain'}_$cid\_graph.db";
-    foreach (keys %GraphDat) {delete $GraphDat{$_};}
-    if (-e "$GraphDB") {
-	if (tie(%GraphDat,'GDBM_File',"$GraphDB",&GDBM_READER,0640)) {
-	    if ( $Tag eq 'DoDiff Graph' ) {
-		$Tag = 'Degree-of-Difficulty';
-		$Col = 0;
-	    }
-	    else {
-		$Tag = '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++;
-	    }
-            untie(%GraphDat);
-	    my $Course = $ENV{'course.'.$cid.'.description'};
-	    $Course =~ s/\ /"_"/eg;
-	    $GData=$Course.'&'.$Tag.'&'.$Max.'&'.$count.'&'.$data;
-
-	}
-	else {
-	    $r->print("Unable to tie hash to db file");
-	}
+    if($c->aborted()) {
+        untie(%cache);
+        return 'aborted'; 
     }
-}
 
+    untie(%cache);
 
-sub initial {
-# --------------------------------- Initialize the global varaibles
-  undef @students;
-  undef @cols;
-  undef %maps;
-  undef %section;
-  undef %StuBox;
-  undef @list;
-  undef %CachData;
-  undef %GraphDat;
-  undef %DiscFac;
-  undef $CurMap;
-  undef $CurSec;
-  undef $CurStu;
-  undef $p_count;
-  undef $Pos;
-  undef $GData;
-  $DiscFlag=0; 
-  $P_Order=100000;
-  $HWN=$P_Order;
+    return ('OK', $students);
 }
 
+sub BuildClasslist {
+    my ($cacheDB,$students,$studentInformation,$headings,$r)=@_;
 
-sub ClassList {
-
-    &GetStatus();
+    my %cache;
+    unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_READER(),0640)) {
+        return '<html><body>Unable to tie database.</body></html>';
+    }
 
-    $cid=$ENV{'request.course.id'};
-    my $chome=$ENV{'course.'.$cid.'.home'};
-    my ($cdom,$cnum)=split(/\_/,$cid);
-# ----------------------- Get first and last resource, see if there is anything
-    $firstres=$hash{'map_start_/res/'.$ENV{'request.course.uri'}};
-    $lastres=$hash{'map_finish_/res/'.$ENV{'request.course.uri'}};
-    if (($firstres) && ($lastres)) {
-# ----------------------------------------------------------------- Render page
-	my $classlst=&Apache::lonnet::reply
-                 ('dump:'.$cdom.':'.$cnum.':classlist',$chome);
-	my $StudNo = 0;
-	my $now=time;
-	unless ($classlst=~/^error\:/) {
-	    foreach (sort split(/\&/,$classlst)) {
-		my ($name,$value)=split(/\=/,$_);
-		my ($end,$start)=split(/\:/,&Apache::lonnet::unescape($value));
-		$name=&Apache::lonnet::unescape($name);
-		my ($sname,$sdom)=split(/\:/,$name);
-		my $active=1;
-		my $Status=$ENV{'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) {
-		    my $thisindex=$#students+1;
-		    $name=&Apache::lonnet::unescape($name);
-		    $students[$thisindex]=$name;
-		    my ($sname,$sdom)=split(/\:/,$name);
-
-		    #my %reply=&Apache::lonnet::idrget($sdom,$sname);
-		    #my $reply=&Apache::lonnet::reply('get:'.$sdom.':'.$sname.
-		    #         ':environment:lastname&generation&firstname&middlename',
-		    #         &Apache::lonnet::homeserver($sname,$sdom));
-		    my $ssec=&usection($sdom,$sname,$cid,$Status);
-		    if ($ssec==-1) {next;}
-		    $ssec=($ssec) ? $ssec : '(none)';
-		    #$ssec=(int($ssec)) ? int($ssec) : $ssec;
-		    #$r->print($sname.'...'.$ssec.'<br>');
-		    $section{$ssec}=$ssec;
-		    if ($CurSec eq 'All Sections' || $ssec eq $CurSec) {
-			$students[$StudNo]=$name;
-			$StuBox{$sname}=$sdom;
-		    }
-		    $StudNo++;
-	        }
-	    }
-	}
-	else {
-	    $r->print('<h1>Could not access course data</h1>');
-	} 
-        $r->print("Total number of students : ".($#students+1));
-        $r->rflush();
-# --------------- Find all assessments and put them into some linear-like order
-	&tracetable($firstres,'&'.$lastres.'&');
+    my $Str='';
+    $Str .= '<table border="0"><tr><td bgcolor="#777777">'."\n";
+    $Str .= '<table border="0" cellpadding="3"><tr bgcolor="#e6ffff">'."\n";
 
-#    my $c=0;
-#    foreach (sort keys %mapsort) {
-#	$r->print('<br>'.$c.')'.$_.' ... '.$mapsort{$_});
-#	$c++;
-#    }
-#foreach(@cols) {
-#    $c++;
-#    $r->print('<br>'.$cols[$c]);
-#}
-#$r->print('<br> Count = '.$c);
+    my $displayString = '<td align="left"><a href="/adm/statistics?';
+    $displayString .= 'sort=LINKDATA">DISPLAYDATA&nbsp</a></td>'."\n";
+    $Str .= &Apache::lonhtmlcommon::CreateHeadings(\%cache, 
+                                                   $studentInformation,
+                                                   $headings, $displayString);
+    $Str .= '</tr>'."\n";
 
-    }
+    my $alternate=0;
+    foreach (@$students) {
+        my ($username, $domain) = split(':', $_);
+        if($alternate) {
+            $Str .= '<tr bgcolor="#ffffe6">';
+        } else {
+            $Str .= '<tr bgcolor="#ffffc6">';
+        }
+        $alternate = ($alternate + 1) % 2;
+        foreach my $data (@$studentInformation) {
+            $Str .= '<td>';
+            if($data eq 'fullname') {
+                $Str .= '<a href="/adm/statistics?reportSelected=';
+                $Str .= &Apache::lonnet::escape('Student Assessment');
+                $Str .= '&StudentAssessmentStudent=';
+                $Str .= &Apache::lonnet::escape($cache{$_.':'.$data}).'">';
+                $Str .= $cache{$_.':'.$data}.'&nbsp';
+                $Str .= '</a>';
+            } elsif($data eq 'updateTime') {
+                $Str .= '<a href="/adm/statistics?reportSelected=';
+                $Str .= &Apache::lonnet::escape('Class list');
+                $Str .= '&download='.$_.'">';
+                $Str .= $cache{$_.':'.$data}.'&nbsp';
+                $Str .= '&nbsp</a>';
+            } else {
+                $Str .= $cache{$_.':'.$data}.'&nbsp';
+            }
 
-# ------------------------------------------------------------- End render page 
-    else {
-	$r->print('<h3>Undefined course sequence</h3>');
+            $Str .= '</td>'."\n";
+        }
     }
-    &MapSecOptions();
-}
 
+    $Str .= '</tr>'."\n";
+    $Str .= '</table></td></tr></table>'."\n";
+    $r->print($Str);
+    $r->rflush();
 
-sub Menu {
-    my $InpStr = $ENV{'form.sort'};
-    if ( $InpStr eq 'DoDiff Graph' || $InpStr eq '%Wrong Graph' ) {      
-	&GetGraphData($InpStr);
-    	$r->print('<IMG src="/cgi-bin/graph.gif?'.$GData.'" />');
-    }
-    else {
-	$r->print('<html><head><title>LON-CAPA Statistics</title></head>');
-
-
-        $r->print('<body bgcolor="#FFFFFF">'.
-                  '<script>window.focus(); window.width=500;window.height=500; </script>'.
-                  '<img align=right src=/adm/lonIcons/lonlogos.gif>');
-# ---------------------------------------------------------------- Course title
-        $r->print('<h1> Course : "'.
-                  $ENV{'course.'.$ENV{'request.course.id'}.
-                  '.description'}.'"</h1><h2>'.localtime().'</h2>');
-# ------------------------------- This is going to take a while, produce output
-        $r->rflush();	
-
-	$r->print("\n".'<form name=stat method=post action="/adm/statistics" >');
-
-	my $content = $ENV{'form.sort'};
-	if ($content eq '' || $content eq 'Return to Menu') {
-	    my $Ptr = '<h3>';
-	    $Ptr .= '<input type=submit name=sort value="Problem Evaluation"/>';
-	    $Ptr .= '<br><br>';
-	    $Ptr .= '<input type=submit name=sort value="Student Assessment"/>';
-	    $Ptr .= '</h3>';
-	    $r->print( $Ptr );
-      	}
-	else {
-	    &initial();
-	    &ClassList();
-	    if ( $content eq 'Discrimination' || #'Problem Evaluation' ||
-                 $content eq 'Recalculate Discrimintion Factor' ) {
-		&CreateDiscFac();
-	    }
-	    elsif ( $content eq 'Student Assessment' || 
-                    $content eq 'Create Student Report' ) {
-		&StudentOptions();
-		&StudentReport($CurStu,$StuBox{"$CurStu"});
-	    }
-	    else {
-		&PreStatTable();
-	    }
-	}
-	$r->print("\n".'</form>'.
-                  "\n".'</body>'.
-                  "\n".'</html>');
-	$r->rflush();
-    }
-}
+    untie(%cache);
 
-sub StudentOptions {
-    my $OpSel5='';
-    $CurStu = $ENV{'form.student'};
-    if ( $CurStu eq '' ) { 
-        $CurStu = 'All Students';
-        $OpSel5 = 'selected';
-    }
-    my $Ptr ='';
-# ----------------------------------- Loading the Students Combobox
-    $Ptr .= '<br><b>Select Student</b>'."\n".
-       	    '<select name="student">'."\n". 
-	    '<option '.$OpSel5.'>All Students</option>';                     	     	     
-    foreach my $key ( sort keys %StuBox ) {	          
-	$Ptr .= '<option';
-	if ($CurStu eq $key) {$Ptr .= ' selected';}     
-        $Ptr .= '>'.$key."</option>\n";	     
-    }
-    $Ptr .= '</select>';
-    $Ptr .= '<br><input type="submit" name="sort" value="Create Student Report" />';
-    $r->print( $Ptr );
-    $r->rflush();	
+    return;
 }
 
-sub GetStatus {
+sub CreateMainMenu {
+    my ($status, $reports)=@_;
 
-#    $OpSelDis1='';
-#    $OpSelDis2='';
-    $OpSel1='';
-    $OpSel2='';
-    $OpSel3='';
-    $OpSel4='';
-
-#    if ( $ENV{'form.DisType'} eq 'Total Number of Correct Answers' ) { 
-#	$OpSelDis1='selected'; 
-#	$CurDis=0;
-#    }
-#    else { $OpSel2 = 'selected'; $CurDis = 1;}
-
-    if ( $ENV{'form.order'} eq 'Descending' ) { $OpSel2='selected'; }
-    else { $OpSel1 = 'selected'; }
-
-    my %myHeader = reverse( %Header );
-    $Pos = $myHeader{$ENV{'form.sort'}};
-    if ($Pos == 0) {
-	$OpSel1 = 'selected';
-	$ENV{'form.order'}='Ascendig';
-    }
-
-    $CurMap = $ENV{'form.maps'};
-    if ( $CurMap eq '' ) { 
-	$CurMap = 'All Maps';
-	$OpSel3 = 'selected';
-    }
-    $CurSec = $ENV{'form.section'};
-    if ( $CurSec eq '' ) { 
-	$CurSec = 'All Sections';
-        $OpSel4 = 'selected';
+    my $Str = '';
+
+    $Str .= '<table border="0"><tbody><tr>'."\n";
+    $Str .= '<td></td><td></td>'."\n";
+    $Str .= '<td align="center"><b>Analysis Reports:</b></td>'."\n";
+    $Str .= '<td align="center"><b>Student Status:</b></td></tr>'."\n";
+    $Str .= '<tr>'."\n";
+    $Str .= '<td align="center"><input type="submit" name="Refresh" ';
+    $Str .= 'value="Refresh" /></td>'."\n";
+    $Str .= '<td align="center"><input type="submit" name="DownloadAll" ';
+    $Str .= 'value="Update All Student Data" /></td>'."\n";
+    $Str .= '<td align="center">';
+    $Str .= '<select name="reportSelected" onchange="document.';
+    $Str .= 'Statistics.submit()">'."\n";
+
+    foreach (sort(keys(%$reports))) {
+        next if($_ eq 'reportSelected');
+        $Str .= '<option name="'.$_.'"';
+        if($reports->{'reportSelected'} eq $reports->{$_}) {
+            $Str .= ' selected=""';
+        }
+        $Str .= '>'.$reports->{$_}.'</option>'."\n";
     }
-}
+    $Str .= '</select></td>'."\n";
 
+    $Str .= '<td align="center">';
+    $Str .= &Apache::lonhtmlcommon::StatusOptions($status, 'Statistics');
+    $Str .= '</td>'."\n";
+
+    $Str .= '</tr></tbody></table>'."\n";
+    $Str .= '<hr>'."\n";
+
+    return $Str;
+}
+
+sub BuildStatistics {
+    my ($r)=@_;
+
+    my $c = $r->connection;
+    my @studentInformation=('fullname','section','id','domain','username',
+                            'updateTime');
+    my @headings=('Full Name', 'Section', 'PID', 'Domain', 'User Name',
+                  'Last Updated');
+    my $spacing = '   ';
+    my %reports = ('classlist'          => 'Class list',
+                   'problem_statistics' => 'Problem Statistics',
+                   'student_assessment' => 'Student Assessment',
+#                   'activitylog'        => 'Activity Log',
+                   'reportSelected'     => 'Class list');
+
+    my %cache;
+    my $courseID=$ENV{'request.course.id'};
+    my $cacheDB = "/home/httpd/perl/tmp/$ENV{'user.name'}".
+                  "_$ENV{'user.domain'}_$courseID\_statistics.db";
+
+    $r->print(&Apache::lonhtmlcommon::Title('LON-CAPA Statistics'));
+
+    my ($returnValue, $students) = &PrepareData($c, $cacheDB, 
+                                                \@studentInformation, 
+                                                \@headings,$r);
+    if($returnValue ne 'OK') {
+        $r->print($returnValue."\n".'</body></html>');
+        return OK;
+    }
+    if(!$c->aborted()) {
+        &Apache::loncoursedata::CheckForResidualDownload($cacheDB, 
+                                                         'true', 'true',
+                                                         $courseID,
+                                                         $r, $c);
+    }
+
+    my $GoToPage;
+    if(tie(%cache,'GDBM_File',$cacheDB,&GDBM_READER(),0640)) {
+        $GoToPage = $cache{'reportSelected'};
+        $reports{'reportSelected'} = $cache{'reportSelected'};
+        if(defined($cache{'reportKey'}) && 
+           !exists($reports{$cache{'reportKey'}}) && 
+           $cache{'reportKey'} ne 'false') {
+            $reports{$cache{'reportKey'}} = $cache{'reportSelected'};
+        }
 
-sub MapSecOptions {
-# ----------------------------------- Loading the Maps Combobox
-    my $Ptr = '<br>';
-    $Ptr .= '<br><input type="submit" name="sort" value="Return to Menu" />';
-    $Ptr .= '<br><b> Select &nbsp; Map &nbsp; &nbsp; </b>'."\n".
-       	    '<select name="maps">'."\n". 
-	    '<option '.$OpSel3.'>All Maps</option>';                     	     	     
-    foreach my $key ( sort keys %maps ) {	          
-	$Ptr .= '<option';
-        if ($CurMap eq $key) {$Ptr .= ' selected';}	     
-	$Ptr .= '>'.$key."</option>\n";	     
-    }
-    $Ptr .= '</select>';
-    $Ptr .= '&nbsp;&nbsp;&nbsp;';
-
-# ----------------------------------- Loading the Sections Combobox
-    $Ptr .= '<br><b>Select Section</b>'."\n".
-       	    '<select name="section">'."\n". 
-	    '<option '.$OpSel4.'>All Sections</option>';                     	     	     
-    foreach my $key ( sort keys %section ) {	          
-	$Ptr .= '<option';
-        if ($CurSec eq $key) {$Ptr .= ' selected';}     
-	$Ptr .= '>'.$key."</option>"."\n";	     
+        if(defined($cache{'OptionResponses'})) {
+            $reports{'problem_analysis'} = 'Problem Analysis';
+        }
+
+        $r->print('<form name="Statistics" ');
+        $r->print('method="post" action="/adm/statistics">');
+        $r->print(&CreateMainMenu($cache{'Status'}, \%reports));
+        $r->rflush();
+        untie(%cache);
+    } else {
+        $r->print('<html><body>Unable to tie database.</body></html>');
+        return OK;
+    }
+
+    if($GoToPage eq 'Activity Log') {
+        &Apache::lonproblemstatistics::Activity();
+    } elsif($GoToPage eq 'Problem Statistics') {
+        &Apache::lonproblemstatistics::BuildProblemStatisticsPage($cacheDB, 
+                                                                  $students, 
+                                                                  $courseID, 
+                                                                  $c,$r);
+    } elsif($GoToPage eq 'Problem Analysis') {
+        &Apache::lonproblemanalysis::BuildProblemAnalysisPage($cacheDB, $r);
+    } elsif($GoToPage eq 'Student Assessment') {
+        &Apache::lonstudentassessment::BuildStudentAssessmentPage($cacheDB,
+                                                          $students,
+                                                          $courseID,
+                                                          'Statistics',
+                                                          \@headings,
+                                                          $spacing,
+                                                          \@studentInformation,
+                                                          $r, $c);
+    } elsif($GoToPage eq 'Analyze') {
+        &Apache::lonproblemanalysis::BuildAnalyzePage($cacheDB, $students, 
+                                                      $courseID, $r);
+    } elsif($GoToPage eq 'DoDiffGraph' || $GoToPage eq 'PercentWrongGraph') {
+        &Apache::lonproblemstatistics::BuildGraphicChart($GoToPage,$r,$cacheDB);
+    } elsif($GoToPage eq 'Class list') {
+        &BuildClasslist($cacheDB, $students, \@studentInformation,
+                        \@headings, $r);
     }
-    $Ptr .= '</select>'."\n";
 
-    $r->print( $Ptr );
+    $r->print('</form>'."\n");
+    $r->print("\n".'</body>'."\n".'</html>');
     $r->rflush();
-}
 
+    return OK;
+}
 
 # ================================================================ Main Handler
 
 sub handler {
-    $r=shift;
-
-    if (&Apache::lonnet::allowed('vgr',$ENV{'request.course.id'})) {
-# ------------------------------------------- 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');
-	    }
-	    $r->send_http_header;
-	    return OK;
-	}    
-	my $requrl=$r->uri;
-# ----------------------------------------------------------------- Tie db file
+    my $r=shift;
 
-	undef %hash;
+#    $jr = $r;
 
-	if ($ENV{'request.course.fn'}) {
-	    my $fn=$ENV{'request.course.fn'};
-	    if (-e "$fn.db") {
-		if (tie(%hash,'GDBM_File',"$fn.db",&GDBM_READER,0640)) {
-# ------------------------------------------------------------------- Hash tied
-		    $r->content_type('text/html');
-		    $r->send_http_header;
-		    &Menu();
-		}
-		else {
-		    $r->content_type('text/html');
-		    $r->send_http_header;
-		    $r->print('<html><body>Coursemap undefined.</body></html>');
-		}
-# ------------------------------------------------------------------ Untie hash
-		unless (untie(%hash)) {
-		    &Apache::lonnet::logthis("<font color=blue>WARNING: ".
-                            "Could not untie coursemap $fn (browse).</font>"); 
-		}
-
-# -------------------------------------------------------------------- All done
-		return OK;
-# ----------------------------------------------- Errors, hash could no be tied
-	    }
-	} 
-	else {
-	    $ENV{'user.error.msg'}="$requrl:bre:0:0:Course not initialized";
-	    return HTTP_NOT_ACCEPTABLE; 
-	}
-    }
-    else {
+    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');
+    $r->send_http_header;
+
+    &BuildStatistics($r);
+
+    return OK;
 }
 1;
 __END__
 
-
-