--- loncom/homework/functionplotresponse.pm	2011/11/21 19:48:52	1.81
+++ loncom/homework/functionplotresponse.pm	2011/11/21 21:45:32	1.84
@@ -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 1.84 2011/11/21 21:45:32 www Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -837,11 +837,11 @@ sub start_functionplotvectorrule {
              &Apache::edit::text_arg('Tip not attached to object:','nottippoint',
                                       $token,'16').'<br />'.
              &Apache::edit::text_arg('Length:','length',
-                                     $token,'16').
-             &Apache::edit::text_arg('Angle:','angle',
-                                     $token,'16').
+                                     $token,'30').
              &Apache::edit::text_arg('Absolute error length:','lengtherror',
-                                     $token,'8').
+                                     $token,'8').'<br />'.
+             &Apache::edit::text_arg('Angle:','angle',
+                                     $token,'30').
              &Apache::edit::text_arg('Absolute error angle:','angleerror',
                                      $token,'8').
              &Apache::edit::end_row();
@@ -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),
@@ -911,21 +909,21 @@ sub start_functionplotvectorsumrule {
         $result=&Apache::edit::tag_start($target,$token,'Function Plot Vector Sum Rule').
              &Apache::edit::text_arg('Index/Name:','index',
                                      $token,'10').'&nbsp;'.
-             &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').
+                                     $token,'30').
+             &Apache::edit::text_arg('Absolute error length:','lengtherror',
+                                     $token,'8').'<br />'.
              &Apache::edit::text_arg('Sum vector angle:','angle',
-                                     $token,'16').
-             &Apache::edit::text_arg('Error length:','lengtherror',
-                                     $token,'8').
-             &Apache::edit::text_arg('Error angle:','angleerror',
+                                     $token,'30').
+             &Apache::edit::text_arg('Absolute error angle:','angleerror',
                                      $token,'8').
              &Apache::edit::end_row();
   } elsif ($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); }
@@ -1358,6 +1356,43 @@ sub fpr_d2fdx2 {
                                                                 $arg)];
 }
 
+sub fpr_vectorcoords {
+   my ($arg)=@_;
+   $arg=~s/\W//gs;
+   $arg=ucfirst($arg);
+   my $id=$Apache::inputtags::response[-1];
+   my $partid=$Apache::inputtags::part;
+   my $internalid = $partid.'_'.$id;
+   return ($env{'form.HWVAL_'.$internalid.'_'.$arg.'Start_x'},
+           $env{'form.HWVAL_'.$internalid.'_'.$arg.'End_x'},
+           $env{'form.HWVAL_'.$internalid.'_'.$arg.'Start_y'},
+           $env{'form.HWVAL_'.$internalid.'_'.$arg.'End_y'});
+}
+
+sub fpr_objectcoords {
+   my ($arg)=@_;
+   $arg=~s/\W//gs;
+   $arg=ucfirst($arg);
+   my $id=$Apache::inputtags::response[-1];
+   my $partid=$Apache::inputtags::part;
+   my $internalid = $partid.'_'.$id;
+   return ($env{'form.HWVAL_'.$internalid.'_'.$arg.'_x'},
+           $env{'form.HWVAL_'.$internalid.'_'.$arg.'_y'});
+}
+
+sub fpr_vectorlength {
+   my ($arg)=@_;
+   my ($xs,$xe,$ys,$ye)=&fpr_vectorcoords($arg);
+   return sqrt(($xe-$xs)*($xe-$xs)+($ye-$ys)*($ye-$ys));
+}
+
+sub fpr_vectorangle {
+   my ($arg)=@_;
+   my ($xs,$xe,$ys,$ye)=&fpr_vectorcoords($arg);
+   my $angle=57.2957795*atan2(($ye-$ys),($xe-$xs));
+   if ($angle<0) { $angle=360+$angle; }
+   return $angle;
+}
 
 sub vectorcoords {
    my ($id,$label)=@_;
@@ -1520,9 +1555,44 @@ 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)");
+   if ($length ne '') {
+      &addlog("Checking length $length with error $lengtherror");
+      $length=&Apache::run::run($length,$safeeval);
+      &addlog("Evaluated to $length");
+      my $thislength=&vectorlength($sumx,$sumy);
+      &addlog("Actual length $thislength");
+      if (abs($length-$thislength)>$lengtherror) {
+                  &setfailed($label);
+         return 0;
+      }
+   }
+   if ($angle ne '') {
+      &addlog("Checking angle $angle with error $angleerror");
+      $angle=&Apache::run::run($angle,$safeeval);
+      &addlog("Evaluated to $angle");
+      my $thisangle=&vectorangle($sumx,$sumy);
+      &addlog("Actual angle $thisangle");
+      my $anglediff=abs($thisangle-$angle);
+      &addlog("Angle difference: $anglediff");
+      if ($anglediff>360.-$anglediff) {
+         $anglediff=360.-$anglediff;
+      }
+      &addlog("Smallest angle difference: $anglediff");
+      if ($anglediff>$angleerror) {
+         &setfailed($label);
+         return 0;
+      }
+   }
    &addlog("Rule $label passed.");
    return 1;
 }