--- loncom/interface/statistics/lonproblemanalysis.pm	2005/04/19 13:59:34	1.121
+++ loncom/interface/statistics/lonproblemanalysis.pm	2006/05/01 19:29:13	1.125
@@ -1,6 +1,6 @@
 # The LearningOnline Network with CAPA
 #
-# $Id: lonproblemanalysis.pm,v 1.121 2005/04/19 13:59:34 matthew Exp $
+# $Id: lonproblemanalysis.pm,v 1.125 2006/05/01 19:29:13 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -97,8 +97,11 @@ sub BuildProblemAnalysisPage {
             $r->print($html.(' 'x5));
         }
         #
-        $r->print(&Apache::lonstathelpers::submission_report_form
-                                                      ('problem_analysis'));
+
+        # This is commented out pending actual implementation of 
+        # CSV and Excel output.
+        #$r->print(&Apache::lonstathelpers::submission_report_form
+        #                                              ('problem_analysis'));
         #
         $r->print('<hr />');
         $r->rflush();
@@ -341,7 +344,9 @@ sub numerical_plot_percent {
     while (my ($ans,$submissions) = each(%$responses)) {
         while (my ($submission,$counts) = each(%$submissions)) {
             my ($correct_count,$incorrect_count) = @$counts;
-            my $scaled_value = 100*($submission-$ans)/abs($ans);
+	    my $scaled_value = 
+		($ans) ? 100*($submission-$ans)/abs($ans)
+		       : 0;
             if ($scaled_value < $bins[0]) {
                 $bins[0]=$scaled_value -1;
             }
@@ -396,7 +401,8 @@ sub numerical_plot_differences {
     } elsif ($low_bin < 0 && $high_bin < -$low_bin) {
         $high_bin = -$low_bin;
     }
-    if (($high_bin -$low_bin)/$min_bin_size * 2 > $max_bins) {
+    if (!$min_bin_size ||
+        ($high_bin -$low_bin)/$min_bin_size * 2 > $max_bins) {
         $min_bin_size = abs($high_bin - $low_bin) / $max_bins * 2;
     }
     my @bins;
@@ -1817,8 +1823,7 @@ sub CreateInterface {
     ##
     ## Build the menu
     my $Str = '';
-    $Str .= &Apache::lonhtmlcommon::breadcrumbs
-        (undef,'Detailed Problem Analysis');
+    $Str .= &Apache::lonhtmlcommon::breadcrumbs('Detailed Problem Analysis');
     $Str .= '<table cellspacing="5">'."\n";
     $Str .= '<tr>';
     $Str .= '<td align="center"><b>'.&mt('Sections').'</b></td>';