--- loncom/interface/lonfeedback.pm	2012/01/06 01:59:53	1.323
+++ loncom/interface/lonfeedback.pm	2012/01/06 19:18:11	1.325
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # Feedback
 #
-# $Id: lonfeedback.pm,v 1.323 2012/01/06 01:59:53 www Exp $
+# $Id: lonfeedback.pm,v 1.325 2012/01/06 19:18:11 www Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -941,6 +941,8 @@ sub build_posting_display {
                           $env{'course.'.$env{'request.course.id'}.'.num'},
                           '^'.$symb.':');
     my $thisuser=$env{'user.name'}.':'.$env{'user.domain'};
+# Array with likes to figure out averages, etc.
+    my @theselikes=();
 # Is the user allowed to see the real name behind anonymous postings?
     my $see_anonymous = 
 	&Apache::lonnet::allowed('rin',$env{'request.course.id'}.($env{'request.course.sec'}?'/'.$env{'request.course.sec'}:''));
@@ -962,7 +964,7 @@ sub build_posting_display {
        $hidden =~ s/\.$//;
        %hiddens = map { $_ => 1 } (split(/\.\./,$hidden));
     }
-# Versions ...
+# Versions if store/restore are used to actually store the messages. 
     if ($contrib{'version'}) {
         my $oldest = $contrib{'1:timestamp'};
         if ($prevread eq '0') {
@@ -973,11 +975,43 @@ sub build_posting_display {
             ($skiptest,$roleregexp,$secregexp,$statusregexp) = 
                      &filter_regexp($rolefilter,$sectionpick,$statusfilter);
             $rolematch = $roleregexp.':'.$secregexp.':'.$statusregexp;
-        } 
+        }
+# We need to go through this twice, first to get the likes/dislikes, then to actually build the display
+        for (my $id=1;$id<=$contrib{'version'};$id++) {
+            my $idx=$id;
+            next if ($contrib{$idx.':deleted'});
+            next if ($contrib{$idx.':hidden'});
+            unless ((($hiddens{$idx}) && (!$seeid)) || ($deletions{$idx}) || (!$contrib{$idx.':message'})) {
+                push(@theselikes,$likes{$symb.':'.$idx.':likes'});
+            }
+        }
+# Figure out average likes and standard deviation if there are enough discussions to warrant that
+        my $ave=0;
+        my $stddev=10000;
+        if ($#theselikes>1) {
+            my $sum=0;
+            my $num=$#theselikes+1;
+            foreach my $thislike (@theselikes) {
+                $sum+=$thislike;
+            }
+            $ave=$sum/$num;
+            my $sumsq=0;
+            foreach my $thislike (@theselikes) {
+                $sumsq+=($thislike-$ave)*($thislike-$ave);
+            }
+            $stddev=sqrt($sumsq/$num);
+        }
+# Now we know the average likes $ave and the standard deviation $stddev
+#            &Apache::lonnet::logthis(join(',',@theselikes)." Ave $ave StdDev $stddev");
+#
+# This is now the real loop. Go through all entries, pick up what we need
+# 
 	for (my $id=1;$id<=$contrib{'version'};$id++) {
 	    my $idx=$id;
             next if ($contrib{$idx.':deleted'});
             next if ($contrib{$idx.':hidden'});
+# If we get here, we are actually going to display the message - we don't know where and we don't know if we display
+# previous edits, but it counts as one entry
             my $posttime = $contrib{$idx.':timestamp'};
             if ($prevread <= $posttime) {
                 $$newpostsflag = 1;
@@ -1319,12 +1353,19 @@ sub build_posting_display {
                                     $$discussionitems[$idx] .= '<b>'.$version.'.</b> - '.&Apache::lonlocal::locallocaltime($postversions[$i]).'  ';
                                 }
                             }
+# end of unless ($$notshown ...)
                         }
+# end of if ($message) ...
                     }
+# end of the else-branch of target being export
                 }
+# end of unless hidden or deleted
             }
+# end of the loop over all discussion entries
 	}
+# end of "if there actually are any discussions
     }
+# end of subroutine "build_posting_display" 
 }
 
 sub filter_regexp {