--- loncom/homework/functionplotresponse.pm	2011/11/21 19:48:52	1.81
+++ loncom/homework/functionplotresponse.pm	2011/11/21 20:20:48	1.82
@@ -1,7 +1,7 @@
 # LearningOnline Network with CAPA
 # Functionplot responses
 #
-# $Id: functionplotresponse.pm,v 1.81 2011/11/21 19:48:52 www Exp $
+# $Id: functionplotresponse.pm,v 1.82 2011/11/21 20:20:48 www Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -894,14 +894,12 @@ sub start_functionplotvectorsumrule {
       my $id=$Apache::inputtags::response[-1];
       my $partid=$Apache::inputtags::part;
       my $internalid = $partid.'_'.$id;
-      my $object=&Apache::lonxml::get_param('object',$parstack,$safeeval);
-      $object=~s/\W//gs;
-      $object=ucfirst($object);
+      my $vectors=&Apache::lonxml::get_param('vectors',$parstack,$safeeval);
       push(@Apache::functionplotresponse::functionplotvectorrules,join(':',(
            $label,
            'sum',
            $internalid,
-           $object,
+           $vectors,
            &Apache::lonxml::get_param('length',$parstack,$safeeval),
            &Apache::lonxml::get_param('angle',$parstack,$safeeval),
            &Apache::lonxml::get_param('lengtherror',$parstack,$safeeval),
@@ -911,8 +909,8 @@ sub start_functionplotvectorsumrule {
         $result=&Apache::edit::tag_start($target,$token,'Function Plot Vector Sum Rule').
              &Apache::edit::text_arg('Index/Name:','index',
                                      $token,'10').' '.
-             &Apache::edit::text_arg('Vectors attached to object:','object',
-                                      $token,'16').'<br />'.
+             &Apache::edit::text_arg('Comma-separated list of vectors:','vectors',
+                                      $token,'30').'<br />'.
              &Apache::edit::text_arg('Sum vector length:','length',
                                      $token,'16').
              &Apache::edit::text_arg('Sum vector angle:','angle',
@@ -925,7 +923,7 @@ sub start_functionplotvectorsumrule {
   } elsif ($target eq 'modified') {
     $env{'form.'.&Apache::edit::html_element_name('object')}=ucfirst($env{'form.'.&Apache::edit::html_element_name('object')});
     my $constructtag=&Apache::edit::get_new_args($token,$parstack,
-                                                 $safeeval,'index','object',
+                                                 $safeeval,'index','vectors',
                                                            'length','angle',
                                                            ,'lengtherror','angleerror');
     if ($constructtag) { $result=&Apache::edit::rebuild_tag($token); }
@@ -1520,9 +1518,16 @@ sub vectorcheck {
 
 sub sumcheck {
    my ($rule,$xmin,$xmax,$ymin,$ymax,$safeeval)=@_;
-   my ($label,$type,$id,$object,$length,$angle,$lengtherror,$angleerror)=split(/\:/,$rule);
-   &addlog("Vector Sum Rule $label for vectors attached to ".$object);
-
+   my ($label,$type,$id,$vectors,$length,$angle,$lengtherror,$angleerror)=split(/\:/,$rule);
+   &addlog("Vector Sum Rule $label for vectors ".$vectors);
+   my $sumx=0;
+   my $sumy=0;
+   foreach my $sv (split(/\s*\,\s*/,$vectors)) {
+      my ($rx,$ry)=&relvector(&vectorcoords($id,$sv));
+      $sumx+=$rx;
+      $sumy+=$ry;
+   }
+   &addlog("Sum vector ($sumx,$sumy)");
    &addlog("Rule $label passed.");
    return 1;
 }