--- loncom/interface/statistics/lonproblemstatistics.pm	2002/07/29 22:01:11	1.6
+++ loncom/interface/statistics/lonproblemstatistics.pm	2002/08/13 00:37:18	1.19
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # (Publication Handler
 #
-# $Id: lonproblemstatistics.pm,v 1.6 2002/07/29 22:01:11 minaeibi Exp $
+# $Id: lonproblemstatistics.pm,v 1.19 2002/08/13 00:37:18 stredwic Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -31,7 +31,7 @@
 # 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
-# 5/12,5/14,5/15,5/19,5/26,7/16,7/25,7/29  Behrouz Minaei
+# 5/12,5/14,5/15,5/19,5/26,7/16,7/25,7/29,8/5  Behrouz Minaei
 #
 ###
 
@@ -43,12 +43,15 @@ use Apache::lonhtmlcommon;
 use Apache::loncoursedata;
 use GDBM_File;
 
+my $jr;
 
 sub BuildProblemStatisticsPage {
     my ($cacheDB, $students, $courseID, $c, $r)=@_;
     my %cache;
-    #my %DoDiff;
-    unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_READER,0640)) {
+
+    $jr = $r;
+
+    unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_READER(),0640)) {
         return '<html><body>Unable to tie database.</body></html>';
     }
 
@@ -56,308 +59,86 @@ sub BuildProblemStatisticsPage {
     $Ptr .= '<table border="0"><tbody>';
     $Ptr .= '<tr><td align="right"><b>Select Map</b></td>'."\n";
     $Ptr .= '<td align="left">';
-    $Ptr .= &Apache::lonhtmlcommon::MapOptions(\%cache, 'ProblemStatistics');
+    $Ptr .= &Apache::lonhtmlcommon::MapOptions(\%cache, 'ProblemStatistics',
+                                               'Statistics');
+    $Ptr .= '</td></tr>'."\n";
+    $Ptr .= '<tr><td align="right"><b>Sorting Type:</b></td>'."\n";
+    $Ptr .= '<td align="left">'."\n";
+    $Ptr .= &Apache::lonhtmlcommon::AscendOrderOptions(
+                                            $cache{'ProblemStatisticsAscend'}, 
+                                            'ProblemStatistics',
+                                            'Statistics');
     $Ptr .= '</td></tr>'."\n";
-    $Ptr .= &AscendOrderOptions($cache{'Ascend'});
     $Ptr .= &ProblemStatisticsButtons($cache{'DisplayFormat'});
     $Ptr .= '</table>';
     $Ptr .= &ProblemStatisticsLegend();
     $r->print($Ptr);
+    $r->rflush();
 
     untie(%cache);
-    foreach (@$students) {
-        my $courseData = 
-            &Apache::loncoursedata::DownloadCourseInformation($_, $courseID);
-        last if ($c->aborted());
-        if(tie(%cache,'GDBM_File',$cacheDB,&GDBM_WRCREAT,0640)) {
-            &Apache::loncoursedata::ProcessStudentData(\%cache, 
-                                                       $courseData, $_);
-            untie(%cache);
-        }
-    }
+
+    &Apache::loncoursedata::DownloadStudentCourseDataSeparate($students,'true',
+                                                              $cacheDB,'true', 
+                                                              'true',$courseID,
+                                                              $r, $c);
     if($c->aborted()) { return; }
 
-    unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_READER,0640)) {
+    unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_READER(),0640)) {
         return '<html><body>Unable to tie database.</body></html>';
     }
-    my %discriminant=();
-    my @list=();
-    my %Discuss=&Apache::loncoursedata::LoadDiscussion($courseID);
-    my $index=0;
-    foreach (@$students) {
-	$index++;
-	#&Apache::lonstatistics::Update_PrgWin(++$index,$r);
-        &ExtractStudentData(\%cache, $_, \@list,\%Discuss, $r, \%discriminant);
-    }
-    #&Apache::lonstatistics::Close_PrgWin($r);
- 
-    my ($upper, $lower) = &Discriminant(\%discriminant);
-    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", 13, "Disc.");
-    my $color=&setbgcolor(0);
-    my %GraphDat= &BuildStatisticsTable(\%cache, \%discriminant, \@list, 
-                                        \%Header, $students, $r, $color);
-    untie(%cache);
-}
-
-
-#---- Problem Statistics Web Page ---------------------------------------
-
-
-sub NumericSort {          
-    $a <=> $b;
-}
-
-
-sub CreateProblemStatisticsTableHeading {
-    my ($displayFormat,$sequenceSource,$sequenceTitle,$headings,$r)=@_;
-    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,$r)=@_;
-    if($cache->{'DisplayFormat'} eq 'Display CSV Format') {
-	return;
-    }    
-    $r->print("\n".'</table>'."\n");
-    $r->rflush();
-}
 
+    my @Header = ("Homework Sets Order","#Stdnts","Tries","Mod",
+                  "Mean","#YES","#yes","%Wrng","DoDiff",
+                  "S.D.","Skew.","D.F.1st","D.F.2nd","Disc.");
+    my $color=&setbgcolor(0);
 
- 
-# ------ Dump the Student's DB file and handling the data for statistics table 
-sub ExtractStudentData {
-    my ($cache,$name,$list,$Discuss,$r,$discriminant)=@_;
-    my $totalTries = 0;
-    my $totalAwarded = 0;
-    my $spent=0;
-    my $spent_yes=0;
-    my $TotDiscuss=0;
-    my $TotalOpend = 0;
-    my $ProbSolved = 0;
-    my $ProbTot = 0;
-    my $TotFirst = 0;
-    my $TimeTot = 0;
-    my $Discussed=0;
-    my $tempSequenceOrder=100;
-
-#$Apache::lonxml::debug=1;
-#&Apache::lonhomework::showhash(%$cache);
-#$Apache::lonxml::debug=0;
+#    my %Discuss=&Apache::loncoursedata::LoadDiscussion($courseID);
+#    my ($upper, $lower) = &Discriminant(\%discriminant,$r);
+    my ($problemData) = &ExtractStudentData(\%cache, $students);
+    &CalculateStatistics($problemData);
+    &SortProblems($problemData, $cache{'ProblemStatisticsSort'},
+                  $cache{'ProblemStatisticsAscend'});
+    #$TempCache=
+    &BuildStatisticsTable(\%cache, $cache{'DisplayFormat'},
+                          $problemData, \@Header, $r, $color);
+    untie(%cache);
 
-    foreach my $sequence (split(':', $cache->{'orderedSequences'})) {
-	my $tempProblemOrder=100;
-	$tempSequenceOrder++;
-#        if($cache->{'ProblemStatisticsMap'} ne 'All Maps'  &&
-#           $cache->{'ProblemStatisticsMap'} ne $cache->{$sequence.':title'}) {
-#	    $r->print("<br>sequences=$cache->{'orderedSequences'}");
-#	    $r->print("<br>".$cache->{$sequence.':title'});
-#            next;
+#    foreach (keys %$TempCache) {
+#        last if ($c->aborted());
+#        if(tie(%cache,'GDBM_File',$cacheDB,&GDBM_WRCREAT(),0640)) {
+#	    $cache{$_}=$TempCache->{$_};
+#            untie(%cache);
 #        }
+#    }
 
-        my $Dis = '';
-        foreach my $problemID (split(':', $cache->{$sequence.':problems'})) {
-#	    $r->print("<br>problems=$cache->{$sequence.':problems'}");
-            my $problem = $cache->{$problemID.':problem'};
-#	    $r->print("<br>$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'})) {
-		$tempProblemOrder++;
-#		$r->print("<br>parts=$cache->{$sequence.':'.$problemID.':parts'}");
-                $partData{$part.':order'}=$tempProblemOrder;
-                $partData{$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;
-		    $Discussed=0;
-                    my $code='-';
-
-                    $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'}--;
-                    }
-                }
-            }
-
-#$Apache::lonxml::debug=1;
-#&Apache::lonhomework::showhash(%partData);
-#$Apache::lonxml::debug=0;
+#    if($c->aborted()) { return; }
+#    untie(%cache);
 
-            # Loop through all the parts for the current problem in the 
-            # correct order and prepare the output
-            foreach (split(/\:/,$cache->{$sequence.':'.$problemID.
-                                         ':parts'})) {
-	    #$r->print("<br>".$cache->{$sequence.':title'});
-
-                my $Yes = 0;
-                if($partData{$_.':code'} eq 'C' || 
-                   $partData{$_.':code'} eq 'O') {
-                    $Yes=1;
-                }
-                my $pOrder=$partData{$_.':order'};
-                my $ptr = $tempSequenceOrder.':'.$pOrder.':'.$problemID;
-
-                if($_ > 1) {
-                    $ptr .= "*(part $_)";
-                    $Dis .= '&';
-                }
-
-		my ($pr_no,$dod)=split('&',$ptr);
-#		my $DoDiff=$DoDiff->{$dod};
-#               $r->print('<br>'.$name.'---'.$ptr.'==='.$DoDiff);
-
-                my $Fac = ($partData{$_.':tries'}) ? 
-                    ($partData{$_.':awarded'}/$partData{$_.':tries'}) : 0;
-                my $DisF;
-                if($Fac > 0 &&  $Fac < 1) { 
-                    $DisF = sprintf( "%.4f", $Fac );
-                } else {
-                    $DisF = $Fac;
-                }
+    return;
+}
 
-                if ($Discuss->{"$name:$problem"}) {
-		    $TotDiscuss++;
-                    $Discussed=1;
-                }
-                my $time = $cache->{"$name:$LatestVersion:$problem:timestamp"};
-                $Dis .= $tempSequenceOrder.'@'.$pOrder.'='.$DisF.'+'.$Yes;
-                $ptr .= '&'.$partData{$_.':tries'}.
-                        '&'.$partData{$_.':wrong'}.
-                        '&'.$partData{$_.':code'};
-                push (@$list, $ptr."&$Discussed");
-#                $r->print('<br>'.$_.$name.'---'.$ptr);
-		
-####		if ($DoDiff>0.85) {
 
-                $TimeTot += $time;
+#---- Problem Statistics Web Page ---------------------------------------
 
-                if ($Yes==1 && $partData{$_.':tries'}==1) {
-		    $TotFirst++;
-                }
-#		my $Acts= $Activity->{$name.':'.$problem};
-#		if ($Acts) {
-#		    my $Pt=&ProcAct( $Acts, $time );
-		    #my ($spe,$beg) = split(/\+/,$Pt);
-#                    my $spe= $Pt;
-#		    if ($Yes==1) {$spent_yes += $spe;}
-#		    $spent += $spe;
-		    #$Beg += $beg;
-#                   $r->print('<br>'.$name.'---'.$problem.'---'.$spe);
-#		}
-		$TotalOpend++;
-		$ProbTot++;
+sub CreateProblemStatisticsTableHeading {
+    my ($headings,$r)=@_;
 
-                $tempProblemOrder++;
-            }
-        }
-	my $pstr;
-        if($totalTries) {
-	    my $DisFac = ($totalAwarded/$totalTries);
-	    my $DisFactor = sprintf( "%.4f", $DisFac );
-            my $TS = sprintf( "%.2f", $spent );
-            my $TS_yes = sprintf( "%.2f", $spent_yes );
-	   # $DiscFac{$DisFactor}=$Dis;
-	    $pstr=$DisFactor.':'.$name.':'.$ProbTot.':'.$TotalOpend.':'.
-                  $totalTries.':'.$ProbSolved.':'.$TotFirst.':'.
-                  $TS_yes.':'.$TS.':'.$TotDiscuss;
-	    (%$discriminant)->{$pstr}=$Dis;
-	}
+    my $Str='';
+    $Str .= '<tr>'."\n";
+    $Str .= '<th bgcolor="#ffffe6">P#</th>'."\n";
+    foreach(@$headings) {
+	$Str .= '<th bgcolor="#ffffe6">'.'<a href="/adm/statistics?reportSelected=';
+        $Str .= &Apache::lonnet::escape('Problem Statistics');
+        $Str .= '&ProblemStatisticsSort=';
+        $Str .= &Apache::lonnet::escape($_).'">'.$_.'</a>&nbsp</th>'."\n";
     }
-}
+    $Str .= "\n".'</tr>'."\n";    
 
-
-=pod
-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; }
-    }
+    return $Str;
 }
-=cut
-
 
 sub BuildStatisticsTable {
-    my ($cache,$discriminantFactor,$list,$headings,$students,$r,$color)=@_;
-
-    my $NoElements = scalar @$list;
-    my @List=sort(@$list);
+    my ($cache,$displayFormat,$data,$headings,$r,$color)=@_;
 
 #6666666
 #    my $file="/home/httpd/perl/tmp/183d.txt";
@@ -373,256 +154,185 @@ sub BuildStatisticsTable {
 ##777777
 ##    $Str .= &Classify($discriminantFactor, $students);
 
-    my $p_count = 0;
-    my $dummy;
-    my $p_val;
-    my $ResId;
-    my %GraphDat;
-    my $cIdx=0;
-
-    foreach my $sequence (split(':', $cache->{'orderedSequences'})) {
-
-        &CreateProblemStatisticsTableHeading(1,$cache->{$sequence.':source'},
-                                             $cache->{$sequence.':title'}, 
-                                             $headings,$r);
-
-	my ($tar,$Tries,$Wrongs,$Code,$Disc)=split(/\&/,
-                                                   $List[$cIdx]);
-
-        my ($SqOrd,$PrOrd,$Prob)=split(/\:/,$tar);
-	$sequence+=100;
-	while ($SqOrd==$sequence && $cIdx<$NoElements) {
-	    my %storestats=();
-	    my $pOrd=$PrOrd;
-	    my $Temp = $Prob;
-	    my $MxTries = 0;
-	    my $TotalTries = 0;
-	    my $YES = 0;
-	    my $Incorrect = 0;
-	    my $Override = 0;
-	    my $StdNo = 0;
-	    my $DiscNo=0;
-	    my @StdLst;
-	    while ($pOrd==$PrOrd && $cIdx<$NoElements)
-	    {
-		$cIdx++;
-		$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 '-' ) { $StdNo--; }
-		($tar,$Tries,$Wrongs,$Code,$Disc)=split(/\&/,
-                                                     $List[$cIdx]);
-	        ($SqOrd,$PrOrd,$Prob)=split(/\:/,$tar);
-	    }
-
-	    $p_count++;
-	    my $Dummy;
-	    ($ResId,$Dummy)=split(/\*/,$Temp);
-
-######################
-	    $Temp = '<a href="'.$cache->{$ResId.':source'}.
-                '" target="_blank">'.$cache->{$ResId.':title'}.$Dummy.'</a>';
-
-	    my $res = &Apache::lonnet::declutter($cache->{'src_'.$ResId});
-	    my $urlres=$res;
-
-	    $ResId=~/(\d+)\.(\d+)/;
-	    my $Map = &Apache::lonnet::declutter( $cache->{'map_id_'.$1} );
-	    $urlres=$Map;
-#######################
-
-#	    $res = '<a href="'.$cache->{'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;
-	    }
+    my %TempCache;
+    my $problems = $data->{'problemList'};
+    if($displayFormat ne 'Display CSV Format') {
+        $r->print('<table border="0"><tr><td bgcolor="#777777">'."\n");
+        $r->print('<table border="0" cellpadding="3">'."\n");
+        $r->print(&CreateProblemStatisticsTableHeading($headings, $r));
+    } else {
+        $r->print('<br>');
+    }
 
-#--------------------- 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 = $Prob.'&'.$Temp.'&'.$StdNo.'&'.
-                       $TotalTries.'&'.$MxTries.'&'.$Avg.'&'.
-                       $YES.'&'.$Override.'&'.$Wrng.'&'.$DoD.'&'.
-		       $SD.'&'.$Sk.'&'.$_D1.'&'.$_D2.'&'.
-                       $DiscNo.'&'.$Prob;
-##8888	    $CachData{($p_count-1)}=$join;
+    my $count = 1;
+    foreach(@$problems) {
+        my ($sequence,$problem,$part)=split(':', $_);
+#        my $problemRef = '<a href="'.$cache->{$problem.':source'}.
+#                '" target="_blank">'.$cache->{$problem.':title'}.'</a>';
+
+        my $ref = $cache->{$problem.':title'};
+        my $title = $cache->{$problem.':title'};
+        my $source = 'source';
+        my $tableData = join('&', $ref, $title, $source,
+                         $data->{$_.':studentCount'},
+                         $data->{$_.':totalTries'},
+                         $data->{$_.':maxTries'},
+                         sprintf("%.2f", $data->{$_.':mean'}),
+                         $data->{$_.':correct'},
+                         $data->{$_.':correctByOverride'},
+                         sprintf("%.1f", $data->{$_.':percentWrong'}),
+                         sprintf("%.2f", $data->{$_.':degreeOfDifficulty'}),
+                         sprintf("%.1f", $data->{$_.':standardDeviation'}),
+                         sprintf("%.1f", $data->{$_.':skewness'}),
+                         sprintf("%.2f", $data->{$_.':discriminationFactor1'}),
+                         sprintf("%.2f", $data->{$_.':discriminationFactor2'}),
+                         0); # 0 is for discussion, need to figure out
+#        $TempCache{'CacheTable:'.$_}=$join;
 
 #6666666
 #	    $r->print('<br>'.$out.'&'.$DoD);
 #            print (OUT $out.'@'.$DoD.'&');
 #6666666
 
-	    $urlres=~/^(\w+)\/(\w+)/;
-	    if ($StdNo) { 
-		&Apache::lonnet::put('resevaldata',\%storestats,$1,$2); 
-	    }
+#check with Gerd
+#        $urlres=~/^(\w+)\/(\w+)/;
+#        if ($StdNo) {
+#            &Apache::lonnet::put('nohist_resevaldata',\%storestats,
+#                                 $1,$2);
+#        }
 #-------------------------------- Row of statistical table
-            &TableRow($cache,$join,$cIdx,($p_count-1),$r,$color,\%GraphDat);
-	}
-	&CloseTable($cache,$r);
+        &TableRow($displayFormat,$tableData,$count,$r,$color);
+#        $GraphDat->{'GraphGif:'.($count-1)}=$DoD.':'.$Wrng;
+        $count++;
+    }
+#    $TempCache{'ProblemCount'}=$count;
+    if($cache->{'DisplayFormat'} ne 'Display CSV Format') {
+        $r->print('</table>'."\n");
     }
-###    &Close_PrgWin();
-#666666
+    $r->print('</td></tr></table>');
+#6666666
 #    close( OUT );
 #666666
+    return \%TempCache;
 }
 
 =pod
-sub Cache_Statistics {
-    my ($cache,$color)=@_;
-    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};
-        $p_count++;
+sub CacheStatisticsTable {
+    my ($state,$cache,$headings,$r,$color)=@_;
+    my @list = (); 
+    my %TempCache;
+    my %myHeader = reverse( %$headings );
+    my $pos = $myHeader{$state};
+    if ($pos > 0) {$pos++;}
+    my $p_count = $cache->{'ProblemCount'};
+
+    for ( my $k=0; $k<$p_count;$k++) {
+	my $key=$cache->{'CacheTable:'.$k};
+	my @Temp=split(/\&/,$key);
+	$list[$k]=$Temp[$pos].'+'.$key;
+    }
+    
+    if ($pos>0) {
+        @list = sort OrderedSort (@list);
+    } else {
+        @list = sort (@list);
     }
+    my $cIdx=0;
 
-    @list = sort MySort (@list);
-
-    my $nIndex=0;
+    if ( $pos == 0 ) {
+	foreach my $sequence (split(':', $cache->{'orderedSequences'})) {
+	    if($cache->{'ProblemStatisticsMaps'} ne 'All Maps'  &&
+	       $cache->{'ProblemStatisticsMaps'} ne $cache->{$sequence.':title'}) {
+		next;
+	    }
+	    if ($cIdx==$p_count) {
+		return \%TempCache;
+	    }
+	    $r->print(&CreateProblemStatisticsTableHeading(
+                                             $cache->{'DisplayFormat'}, 
+                                             $cache->{$sequence.':source'},
+                                             $cache->{$sequence.':title'}, 
+                                             $headings,$r));
 
-    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,$color,\%GraphDat);
-		$nIndex++;
+	    my ($tar)=split(/\&/,$list[$cIdx]);
+	    $tar=~s/\+//eg;
+	    my ($SqOrd)=split(/\@/,$tar);
+	    $sequence+=100;
+	    while ($SqOrd==$sequence && $cIdx<$p_count) {
+		my($Pre, $Post) = split(/\+/,$list[$cIdx]); 
+		&TableRow($cache,$Post,$cIdx,$cIdx,$r,$color,\%TempCache);
+		$cIdx++;
+		my ($tar)=split(/\&/,$list[$cIdx]);
+		$tar=~s/\+//eg;
+		($SqOrd)=split(/\@/,$tar);
 	    }
-	    &CloseTable($cache);
+	    &CloseTable($cache,$r);
 	}
     }
     else {
-	&CreateProblemStatisticsTableHeading($cache,0);
+        $r->print(&CreateProblemStatisticsTableHeading(
+                                             $cache->{'DisplayFormat'}, 
+                                             'Sorted by: ',
+					     $headings->{$pos-1},
+                                             $headings,$r));
 	for ( my $nIndex = 0; $nIndex < $p_count; $nIndex++ ) {
-	    my($Pre, $Post) = split(/\@/,$list[$nIndex]); 
-	    &TableRow($cache,$Post,$nIndex,$nIndex,$color,\%GraphDat);
+	    my($Pre, $Post) = split(/\+/,$list[$nIndex]);
+	    &TableRow($cache,$Post,$nIndex,$nIndex,$r,$color,\%TempCache);
 	} 
-	&CloseTable($cache);
+	&CloseTable($cache,$r);
     }
+
+    return \%TempCache;
 }
-=cut 
+=cut
 
 sub TableRow {
-    my ($cache,$Str,$Idx,$RealIdx,$r,$color,$GraphDat)=@_;
-    my($PrOrd,$Temp,$StdNo,$TotalTries,$MxTries,$Avg,$YES,$Override,
+    my ($displayFormat,$Str,$RealIdx,$r,$color)=@_;
+    my($ref,$title,$source,$StdNo,$TotalTries,$MxTries,$Avg,$YES,$Override,
        $Wrng,$DoD,$SD,$Sk,$_D1,$_D2,$DiscNo,$Prob)=split(/\&/,$Str);	
-#    $r->print('<br>'.$Str);
-    if ($ENV{'form.showcsv'}) {
-        my ($ResId,$Dummy)=split(/\*/,$Prob);
-        my $Ptr =  "\n".'<br>'.
-               "\n".'"'.($RealIdx+1).'",'.
-               "\n".'"'.$cache->{'title_'.$ResId}.$Dummy.'",'.
-               "\n".'"'.$cache->{'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".'"'.$_D2.'"'.
-	       "\n".'"'.$DiscNo.'"';
+    my $Ptr;
+    if($displayFormat eq 'Display CSV Format') {
+        $Ptr="\n".'<br>'.
+             "\n".'"'.$RealIdx.'",'.
+             "\n".'"'.$title.'",'.
+             "\n".'"'.$source.'",'.
+             "\n".'"'.$StdNo.'",'.
+             "\n".'"'.$TotalTries.'",'.
+             "\n".'"'.$MxTries.'",'.
+             "\n".'"'.$Avg.'",'.
+             "\n".'"'.$YES.'",'.
+             "\n".'"'.$Override.'",'.
+             "\n".'"'.$Wrng.'",'.
+             "\n".'"'.$DoD.'",'.
+             "\n".'"'.$SD.'",'.
+             "\n".'"'.$Sk.'",'.
+             "\n".'"'.$_D1.'",'.
+	     "\n".'"'.$_D2.'"'.
+	     "\n".'"'.$DiscNo.'"';
 
         $r->print("\n".$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"}.'> '.$_D2.'</td>'.
-               "\n".'<td bgcolor='.$color->{"yellow"}.'> '.$DiscNo.'</td>';
+    } else {
+        $Ptr="\n".'<tr>'.
+             "\n".'<td bgcolor="#ffffe6">'.$RealIdx.'</td>'.
+             "\n".'<td bgcolor="#ffffe6">'.$ref.'</td>'.
+             "\n".'<td bgcolor='.$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"}.'> '.$_D2.'</td>'.
+             "\n".'<td bgcolor='.$color->{"yellow"}.'> '.$DiscNo.'</td>';
         $r->print("\n".$Ptr.'</tr>' );
     }
-#    $GraphDat->{$RealIdx}=$DoD.':'.$Wrng;
-}
 
+    return;
+}
 
 # For loading the colored table for display or un-colored for print
 sub setbgcolor {
@@ -645,59 +355,10 @@ sub setbgcolor {
     return \%color;
 }
 
-
-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 $Ptr;
-}
-
-sub AscendOrderOptions {
-    my ($order)=@_;
-
-    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 $Ptr;
-}
-
 sub ProblemStatisticsButtons {
     my ($displayFormat)=@_;
 
     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;';
@@ -706,9 +367,9 @@ sub ProblemStatisticsButtons {
     $Ptr .= '&nbsp;&nbsp;&nbsp;';
     $Ptr .= '<input type="submit" name="DisplayCSVFormat" ';
     if($displayFormat eq 'Display CSV Format') {
-        $Ptr .= 'value="Display CSV Format" />'."\n";
-    } else {
         $Ptr .= 'value="Display Table Format" />'."\n";
+    } else {
+        $Ptr .= 'value="Display CSV Format" />'."\n";
     }
     $Ptr .= '</td></tr>';
 
@@ -720,16 +381,16 @@ sub ProblemStatisticsLegend {
     $Ptr = '<table border="0">';
     $Ptr .= '<tr><td>';
     $Ptr .= '<b>#Stdnts</b></td>';
-    $Ptr .= '<td>Total Number of Students opened the problem.';
+    $Ptr .= '<td>Total number of students attempted the problem.';
     $Ptr .= '</td></tr><tr><td>';
     $Ptr .= '<b>Tries</b></td>';
-    $Ptr .= '<td>Total Number of Tries for solving the problem.';
+    $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>Largest number of tries for solving the problem by a student.';
     $Ptr .= '</td></tr><tr><td>';
     $Ptr .= '<b>Mean</b></td>';
-    $Ptr .= '<td>Average Number of the tries. [ Tries / #Stdnts ]';
+    $Ptr .= '<td>Average number of tries. [ Tries / #Stdnts ]';
     $Ptr .= '</td></tr><tr><td>';
     $Ptr .= '<b>#YES</b></td>';
     $Ptr .= '<td>Number of students solved the problem correctly.';
@@ -737,9 +398,9 @@ sub ProblemStatisticsLegend {
     $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 .= '<b>%Wrong</b></td>';
+    $Ptr .= '<td>Percentage of students who tried to solve the problem ';
+    $Ptr .= 'but is still incorrect. [ 100*((#Stdnts-(#YES+#yes))/#Stdnts) ]';
     $Ptr .= '</td></tr><tr><td>';
     $Ptr .= '<b>DoDiff</b></td>';
     $Ptr .= '<td>Degree of Difficulty of the problem.  ';
@@ -772,6 +433,182 @@ sub ProblemStatisticsLegend {
 }
 
 #------- Processing upperlist and lowerlist according to each problem
+
+sub ExtractStudentData {
+    my ($cache, $students)=@_;
+
+#$Apache::lonxml::debug=1;
+#&Apache::lonhomework::showhash(%$cache);
+#$Apache::lonxml::debug=0;
+
+    my @problemList=();
+    my %problemData;
+    foreach my $sequence (split(':', $cache->{'orderedSequences'})) {
+        if($cache->{'ProblemStatisticsMaps'} ne 'All Maps'  &&
+           $cache->{'ProblemStatisticsMaps'} ne $cache->{$sequence.':title'}) {
+            next;
+        }
+
+        foreach my $problemID (split(':', $cache->{$sequence.':problems'})) {
+            foreach my $part (split(/\:/,$cache->{$sequence.':'.
+                                                  $problemID.
+                                                  ':parts'})) {
+                my $id = $sequence.':'.$problemID.':'.$part;
+                push(@problemList, $id);
+                my $totalTries = 0;
+                my $totalAwarded = 0;
+                my $correct = 0;
+                my $correctByOverride = 0;
+                my $studentCount = 0;
+                my $maxTries = 0;
+                my $totalFirst = 0;
+                my @studentTries=();
+                foreach(@$students) {
+                    my $code = $cache->{"$_:$problemID:$part:code"};
+
+                    if(defined($cache->{$_.':error'}) || $code eq ' ' ||
+                       $cache->{"$_:$problemID:NoVersion"} eq 'true') {
+                        next;
+                    }
+
+                    $studentCount++;
+                    my $tries =  $cache->{"$_:$problemID:$part:tries"};
+                    if($maxTries < $tries) {
+                        $maxTries = $tries;
+                    }
+                    $totalTries += $tries;
+                    push(@studentTries, $tries);
+
+                    my $awarded = $cache->{"$_:$problemID:$part:awarded"};
+                    $totalAwarded += $awarded;
+
+                    if($code eq '*') {
+                        $correct++;
+                        if($tries == 1) {
+                            $totalFirst++;
+                        }
+                    } elsif($code eq '+') {
+                        $correctByOverride++;
+                    }
+                }
+
+                $problemData{$id.':sequenceTitle'} = 
+                    $cache->{$sequence.':title'};
+                $problemData{$id.':studentCount'} = $studentCount;
+                $problemData{$id.':totalTries'} = $totalTries;
+                $problemData{$id.':studentTries'} = \@studentTries;
+                $problemData{$id.':totalAwarded'} = $totalAwarded;
+                $problemData{$id.':correct'} = $correct;
+                $problemData{$id.':correctByOverride'} = $correctByOverride;
+                $problemData{$id.':wrong'} = $studentCount - 
+                                             ($correct + $correctByOverride);
+                $problemData{$id.':maxTries'} = $maxTries;
+                $problemData{$id.':totalFirst'} = $totalFirst;
+            }
+        }
+    }
+
+    $problemData{'problemList'} = \@problemList;
+#                $Discussed=0;
+#                if($Discuss->{"$name:$problem"}) {
+#		    $TotDiscuss++;
+#                    $Discussed=1;
+#                }
+
+    return \%problemData;
+}
+
+sub SortProblems {
+    my ($problemData,$sortBy,$ascend)=@_;
+
+    if($sortBy eq "Homework Sets Order") {
+        return;
+    }
+
+    my $data;
+
+    if   ($sortBy eq "#Stdnts") { $data = ':studentCount'; }
+    elsif($sortBy eq "Tries")   { $data = ':totalTries'; }
+    elsif($sortBy eq "Mod")     { $data = ':maxTries'; }
+    elsif($sortBy eq "Mean")    { $data = ':mean'; }
+    elsif($sortBy eq "#YES")    { $data = ':correct'; }
+    elsif($sortBy eq "#yes")    { $data = ':correctByOverride'; }
+    elsif($sortBy eq "%Wrng")   { $data = ':percentWrong'; }
+    elsif($sortBy eq "DoDiff")  { $data = ':degreeOfDifficulty'; }
+    elsif($sortBy eq "S.D.")    { $data = ':standardDeviation'; }
+    elsif($sortBy eq "Skew.")   { $data = ':skewness'; }
+    elsif($sortBy eq "D.F.1st") { $data = ':discriminantFactor1'; }
+    elsif($sortBy eq "D.F.2nd") { $data = ':discriminantFactor2'; }
+    elsif($sortBy eq "Disc.")   { $data = ''; }
+    else                        { return; }
+
+    my $problems = $problemData->{'problemList'};
+    my @orderedProblems = 
+        sort { $problemData->{$a.$data} <=> $problemData->{$b.$data} }
+             @$problems;
+    if($ascend eq 'Descending') {
+        @orderedProblems = reverse(@orderedProblems);
+    }
+
+    $problemData->{'problemList'} = \@orderedProblems;
+
+    return;
+}
+
+sub CalculateStatistics {
+    my ($data)=@_;
+
+    my $problems = $data->{'problemList'};
+    foreach(@$problems) {
+        # Mean
+        $data->{$_.':mean'} = ($data->{$_.':studentCount'}) ? 
+            ($data->{$_.':totalTries'} / $data->{$_.':studentCount'}) : 0;
+
+        # %Wrong
+        $data->{$_.':percentWrong'} = ($data->{$_.':studentCount'}) ?
+            (($data->{$_.':wrong'} / $data->{$_.':studentCount'}) * 100.0) : 
+            100.0;
+
+        # Degree of Difficulty
+        $data->{$_.':degreeOfDifficulty'} = ($data->{$_.':totalTries'}) ?
+            (1 - (($data->{$_.':correct'} + $data->{$_.':correctByOverride'}) /
+                  $data->{$_.':totalTries'})) : 0;
+
+        # Factor in mean
+        my $studentTries = $data->{$_.':studentTries'};
+        foreach(my $index=0; $index < scalar(@$studentTries); $index++) {
+            $studentTries->[$index] -= $data->{$_.':mean'};
+        }
+        my $sumSquared = 0;
+        my $sumCubed = 0;
+        foreach(@$studentTries) {
+            my $squared = ($_ * $_);
+            my $cubed = ($squared * $_);
+            $sumSquared += $squared;
+            $sumCubed += $cubed;
+        }
+
+        # Standard deviation
+        $data->{$_.':standardDeviation'} = ($data->{$_.':studentCount'} - 1) ?
+            ((sqrt($sumSquared)) / ($data->{$_.':studentCount'} - 1)) : 0;
+
+        # Skewness
+        my $standardDeviation = $data->{$_.':standardDeviation'};
+        $data->{$_.':skewness'} = ($data->{$_.':standardDeviation'}) ?
+            (((sqrt($sumSquared)) / $data->{$_.':studentCount'}) / 
+             ($standardDeviation * $standardDeviation * $standardDeviation)) :
+             0;
+
+        # Discrimination Factor 1
+        $data->{$_.':discriminationFactor1'} = 0;
+
+        # Discrimination Factor 2
+        $data->{$_.':discriminationFactor2'} = 0;
+    }
+
+    return;
+}
+
 sub ProcessDiscriminant {
     my ($List) = @_;
     my @sortedList = sort (@$List);
@@ -786,6 +623,7 @@ sub ProcessDiscriminant {
     my $nStudent=0;
     my %Proc=undef;
     while ($nIndex<$Count) {
+#        $jr->print("<br> $nIndex) $sortedList[$nIndex]");
 	($Problem,$tmp)=split(/\=/,$sortedList[$nIndex]);
 	@Dis=split(/\+/,$tmp);
 	my $Temp = $Problem;
@@ -797,9 +635,8 @@ sub ProcessDiscriminant {
 	    ($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>");
+#        $jr->print("<br> $nIndex) $Temp --> ($nStudent) $Proc{$Temp}");
 	$Sum1=0;
 	$Sum2=0;
 	$nStudent=0;
@@ -810,8 +647,8 @@ sub ProcessDiscriminant {
 
 #------- Creating Discimination factor   
 sub Discriminant {
-    my ($discriminantFactor)=@_;
-    my @discriminantKeys=keys(%$discriminantFactor);
+    my ($discriminant)=@_;
+    my @discriminantKeys=keys(%$discriminant);
     my $Count = scalar @discriminantKeys;
 
     my $UpCnt = int(0.27*$Count);
@@ -825,8 +662,8 @@ sub Discriminant {
 	$Count++;    
 	if($low < $UpCnt || $Count > $up) {
             $low++;
-            my $str=$discriminantFactor->{$key};
-            foreach(split(/\:/,$str)){
+            my $str=$discriminant->{$key};
+            foreach(split(/\&/,$str)){
                 if($_) {
                     if($low<$UpCnt) { push(@LowList,$_); }
                     else            { push(@UpList,$_);  }
@@ -838,9 +675,7 @@ sub Discriminant {
     my %DisLow = &ProcessDiscriminant(\@LowList);
 
     return (\%DisUp, \%DisLow);
-}
-
-   
+}   
 
 #---- END Problem Statistics Web Page ----------------------------------------
 
@@ -848,65 +683,53 @@ sub Discriminant {
 
 # ------------------------------------------- Prepare data for Graphical chart
 
-sub BuildDiffGraph {
-    my ($r)=@_;
-
-    my $graphData = &GetGraphData('DiffGraph', $r);
-    return '<IMG src="/cgi-bin/graph.gif?'.$graphData.'" />';
-}
-
-sub BuildWrongGraph {
-    my ($r)=@_;
-
-    my $graphData = &GetGraphData('WrongGraph', $r);
-    return '<IMG src="/cgi-bin/graph.gif?'.$graphData.'" />';
-}
-
-
-sub GetGraphData {
-    my ($ylab,$r,%GraphDat)=@_;
+sub BuildGraphicChart {
+    my ($ylab,$r,$cacheDB)=@_;
+    my %cache;
     my $Col;
     my $data='';
     my $count = 0;
     my $Max = 0;
+
+    unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_READER(),0640)) {
+        return '<html><body>Unable to tie database.</body></html>';
+    }
+   
+    my $p_count = $cache{'ProblemCount'};
+
+    for ( my $k=0; $k<$p_count;$k++) {
+        my @Temp=split(/\:/,$cache{'GraphGif:'.$k});
+        my $inf = $Temp[$Col]; 
+	if ( $Max < $inf ) {$Max = $inf;}
+      	$data .= $inf.',';
+       	$count++;
+    }
+    untie(%cache);
+#    $r->print("<br>count=$p_count >>data= $data");
+
+    if ( $Max > 1 ) { 
+	$Max += (10 - $Max % 10);
+      	$Max = int($Max);
+    } else { $Max = 1; }
+
     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 ( $ylab eq 'DoDiff Graph' ) {
-		$ylab = 'Degree-of-Difficulty';
-		$Col = 0;
-	    }
-	    else {
-		$ylab = '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 = $ENV{'course.'.$cid.'.description'};
-	    $Course =~ s/\ /"_"/eg;
-	    my $GData=$Course.'&'.'Problems'.'&'.$ylab.'&'.
-		      $Max.'&'.$count.'&'.$data;
-	}
-	else {
-	    $r->print("Unable to tie hash to db file");
-	}
+
+    if ( $ylab eq 'DoDiff Graph' ) {
+	$ylab = 'Degree-of-Difficulty';
+	$Col = 0;
+    } else {
+	$ylab = 'Wrong-Percentage';
+	$Col = 1;
     }
-}
+    my $Course = $ENV{'course.'.$cid.'.description'};
+    $Course =~ s/\ /"_"/eg;
+    my $GData=$Course.'&'.'Problems#'.'&'.$ylab.'&'.
+	      $Max.'&'.$count.'&'.$data;
+
+    $r->print('<IMG src="/cgi-bin/graph.gif?'.$GData.'" />');
 
+    return;
+}
 
 1;
 __END__