--- loncom/homework/functionplotresponse.pm	2010/11/12 02:16:20	1.35
+++ loncom/homework/functionplotresponse.pm	2010/11/12 22:23:40	1.36
@@ -1,7 +1,7 @@
 # LearningOnline Network with CAPA
 # option list style responses
 #
-# $Id: functionplotresponse.pm,v 1.35 2010/11/12 02:16:20 www Exp $
+# $Id: functionplotresponse.pm,v 1.36 2010/11/12 22:23:40 www Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -31,7 +31,7 @@ use strict;
 use Apache::response();
 use Apache::lonlocal;
 use Apache::lonnet;
-
+ 
 BEGIN {
   &Apache::lonxml::register('Apache::functionplotresponse',('functionplotresponse','backgroundplot','spline','functionplotrule'));
 }
@@ -396,8 +396,8 @@ sub start_functionplotrule {
           )));
    } elsif ($target eq 'edit') {
         $result=&Apache::edit::tag_start($target,$token,'Function Plot Evaluation Rule').
-             &Apache::edit::text_arg('Index:','index',
-                                     $token,'4').' '.
+             &Apache::edit::text_arg('Index/Name:','index',
+                                     $token,'10').' '.
              &Apache::edit::select_arg(&mt('Function:'),'derivativeorder',
                                   [['0','Function itself'],
                                    ['1','First derivative'],
@@ -784,8 +784,9 @@ sub start_functionplotresponse {
 
 sub compare_rel {
    my ($relationship,$value,$realval,$tol)=@_;
-# is the real value defined?
+# is the real value undefined?
    unless (defined($realval)) {
+# the real value is not defined
       if ($relationship eq 'eq') {
          if ($value eq 'undef') {
             return 1;
@@ -803,7 +804,13 @@ sub compare_rel {
       }
    }
 
-# it is defined.
+# is the expected value undefined?
+   if ($value eq 'undef') {
+# but by now we know that the real value is defined
+      return 0;
+   }
+
+# both are defined.
    if ($relationship eq 'gt') {
       return ($realval>$value);
    } elsif ($relationship eq 'ge') {
@@ -905,9 +912,9 @@ sub functionplotrulecheck {
         } else {
            $val=$Apache::functionplotresponse::func[$i];
         }
+        &addlog("Actual value ".(defined($val)?$val:'undef').", expected $value, tolerance $tol");
         unless (&compare_rel($relationship,$value,$val,$tol)) { 
            &addlog("Condition not fulfilled at x=".&actualval($i,$xmin,$xmax)." (".$Apache::functionplotresponse::actualxval[$i]."; index $i)");
-           &addlog("Actual value ".(defined($val)?$val:'undef').", expected $value, tolerance $tol");
            if (($findupper) && ($i>$li)) {
 # check for minimum and maximum lengths
               my $length=&actualval($i,$xmin,$xmax)-&actualval($li,$xmin,$xmax);
@@ -945,6 +952,7 @@ sub end_functionplotresponse {
   my $partid=$Apache::inputtags::part;
   my $internalid = $partid.'_'.$id;
 
+
     if ($target eq 'edit') { $result=&Apache::edit::end_table(); }
     if ($target eq 'grade'
          && &Apache::response::submitted()