--- loncom/homework/grades.pm	2011/12/01 00:36:59	1.596.2.12
+++ loncom/homework/grades.pm	2012/08/09 23:25:48	1.596.2.13
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # The LON-CAPA Grading handler
 #
-# $Id: grades.pm,v 1.596.2.12 2011/12/01 00:36:59 raeburn Exp $
+# $Id: grades.pm,v 1.596.2.13 2012/08/09 23:25:48 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -52,6 +52,7 @@ use POSIX qw(floor);
 
 
 my %perm=();
+my %old_essays=();
 
 #  These variables are used to recover from ssi errors
 
@@ -260,6 +261,7 @@ sub showResourceInfo {
 sub reset_caches {
     &reset_analyze_cache();
     &reset_perm();
+    &reset_old_essays();
 }
 
 {
@@ -738,7 +740,11 @@ sub compute_points {
 #
 
 sub most_similar {
-    my ($uname,$udom,$uessay,$old_essays)=@_;
+    my ($uname,$udom,$symb,$uessay)=@_;
+
+    unless ($symb) { return ''; }
+
+    unless (ref($old_essays{$symb}) eq 'HASH') { return ''; }
 
 # ignore spaces and punctuation
 
@@ -755,11 +761,11 @@ sub most_similar {
     my $scrsid='';
     my $sessay='';
 # go through all essays ...
-    foreach my $tkey (keys(%$old_essays)) {
+    foreach my $tkey (keys(%{$old_essays{$symb}})) {
 	my ($tname,$tdom,$tcrsid)=map {&unescape($_)} (split(/\./,$tkey));
 # ... except the same student
         next if (($tname eq $uname) && ($tdom eq $udom));
-	my $tessay=$old_essays->{$tkey};
+	my $tessay=$old_essays{$symb}{$tkey};
 	$tessay=~s/\W+/ /gs;
 # String similarity gives up if not even limit
 	my $tsimilar=&String::Similarity::similarity($uessay,$tessay,$limit);
@@ -769,7 +775,7 @@ sub most_similar {
 	    $sname=$tname;
 	    $sdom=$tdom;
 	    $scrsid=$tcrsid;
-	    $sessay=$old_essays->{$tkey};
+	    $sessay=$old_essays{$symb}{$tkey};
 	}
     }
     if ($limit>0.6) {
@@ -2009,7 +2015,6 @@ sub submission {
 	'" src="'.$request->dir_config('lonIconsURL').
 	'/check.gif" height="16" border="0" />';
 
-    my %old_essays;
     # header info
     if ($counter == 0) {
 	&sub_page_js($request);
@@ -2125,7 +2130,7 @@ KEYWORDS
 	    my ($adom,$aname,$apath)=($essayurl=~/^($LONCAPA::domain_re)\/($LONCAPA::username_re)\/(.*)$/);
 	    $apath=&escape($apath);
 	    $apath=~s/\W/\_/gs;
-	    %old_essays=&Apache::lonnet::dump('nohist_essay_'.$apath,$adom,$aname);
+	    &init_old_essays($symb,$apath,$adom,$aname);
         }
     }
 
@@ -2262,7 +2267,7 @@ KEYWORDS
                     }
 		    if($env{'form.checkPlag'}){
 			my ($oname,$odom,$ocrsid,$oessay,$osim)=
-			    &most_similar($uname,$udom,$subval,\%old_essays);
+			    &most_similar($uname,$udom,$symb,$subval);
 			if ($osim) {
 			    $osim=int($osim*100.0);
 			    my %old_course_desc = 
@@ -8964,6 +8969,21 @@ sub init_perm {
     }
 }
 
+sub init_old_essays {
+    my ($symb,$apath,$adom,$aname) = @_;
+    if ($symb ne '') {
+        my %essays = &Apache::lonnet::dump('nohist_essay_'.$apath,$adom,$aname);
+        if (keys(%essays) > 0) {
+            $old_essays{$symb} = \%essays;
+        }
+    }
+    return;
+}
+
+sub reset_old_essays {
+    undef(%old_essays);
+}
+
 sub gather_clicker_ids {
     my %clicker_ids;