--- loncom/homework/functionplotresponse.pm	2011/11/18 16:39:22	1.70
+++ loncom/homework/functionplotresponse.pm	2011/11/21 20:48:50	1.83
@@ -1,7 +1,7 @@
 # LearningOnline Network with CAPA
 # Functionplot responses
 #
-# $Id: functionplotresponse.pm,v 1.70 2011/11/18 16:39:22 www Exp $
+# $Id: functionplotresponse.pm,v 1.83 2011/11/21 20:48:50 www Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -35,7 +35,7 @@ use Apache::run;
  
 BEGIN {
   &Apache::lonxml::register('Apache::functionplotresponse',('functionplotresponse','backgroundplot','spline',
-                                                            'plotobject','plotvector',
+                                                            'plotobject','plotvector','functionplotvectorrule','functionplotvectorsumrule',
                                                             'functionplotrule','functionplotruleset',
                                                             'functionplotelements'));
 }
@@ -389,6 +389,7 @@ sub plotobject_script {
       $Apache::functionplotresponse::counter++;
       $label='O'.$Apache::functionplotresponse::counter;
    }
+   &generate_input_field($id,$label,$x,$y);
    return "document.ggbApplet_$id.evalCommand('a=1');\n".
           "document.ggbApplet_$id.setVisible('a', false);\n".
           "document.ggbApplet_$id.setLabelVisible('a', false);\n".
@@ -402,29 +403,27 @@ sub plotobject_script {
 #
 
 sub plotvector_script {
-   my ($id,$label,$xs,$ys,$xe,$ye)=@_;
+   my ($id,$label,$xs,$ys,$xe,$ye,$xmin,$xmax)=@_;
    unless ($label) {
       $Apache::functionplotresponse::counter++;
       $label='V'.$Apache::functionplotresponse::counter;
    }
-   return(<<ENDVECTOR);
-document.ggbApplet1.evalCommand("Gravitystart=(20,0)");
-document.ggbApplet1.setVisible("Gravitystart",false);
-document.ggbApplet1.setLabelVisible("Gravitystart",false);
-document.ggbApplet1.evalCommand("Gravityend=(20,-5)");
-document.ggbApplet1.setLabelVisible("Gravityend",false);
-document.ggbApplet1.evalCommand("Gravity=Vector[Gravitystart, Gravityend]");
-document.ggbApplet1.setLabelVisible("Gravity",true);
-document.ggbApplet1.setLineThickness("Gravity",8);
-// Displays the Angle
-document.ggbApplet1.evalCommand("Gravitypoint=(110,y(Gravitystart))"); //The x-value for this should be 2*(xmax-xmin)+xmax;
-document.ggbApplet1.evalCommand("GravityAngle=Angle[Gravitypoint,Gravitystart,Gravityend]");
-document.ggbApplet1.setLabelVisible("GravityAngle",true);
-document.ggbApplet1.setLabelStyle("GravityAngle",VALUE=2);
-// Keeps track of points we care about (This should use the same listener function we use in graph problems)
-//document.ggbApplet1.registerObjectUpdateListener('Gravitystart','updatePointCoordinates');
-//document.ggbApplet1.registerObjectUpdateListener('Gravityend','updatePointCoordinates');
-//document.ggbApplet1.registerObjectUpdateListener('GravityAngle','updatePointCoordinates');
+   my $startlabel=$label.'Start';
+   my $endlabel=$label.'End';
+   my $pointlabel=$label.'Point';
+   my $pointx=2.*($xmax-$xmin)+$xmax;
+   my $anglelabel=$label.'Angle';
+   return 
+       &new_point_coordinate($id,$startlabel,$xs,$ys,0).
+       &new_point_coordinate($id,$endlabel,$xe,$ye,0).
+       (<<ENDVECTOR);
+document.ggbApplet_$id.evalCommand("$label=Vector[$startlabel,$endlabel]");
+document.ggbApplet_$id.setLabelVisible("$label",true);
+document.ggbApplet_$id.setLineThickness("$label",8);
+document.ggbApplet_$id.evalCommand("$pointlabel=($pointx,y($startlabel))");
+document.ggbApplet_$id.evalCommand("$anglelabel=Angle[$pointlabel,$startlabel,$endlabel]");
+document.ggbApplet_$id.setLabelVisible("$anglelabel",true);
+document.ggbApplet_$id.setLabelStyle("$anglelabel",VALUE=2);
 ENDVECTOR
 }
 
@@ -511,6 +510,7 @@ sub start_plotobject {
                                      $token,'8').
              &Apache::edit::end_row();
   } elsif ($target eq 'modified') {
+    $env{'form.'.&Apache::edit::html_element_name('label')}=ucfirst($env{'form.'.&Apache::edit::html_element_name('label')});
     my $constructtag=&Apache::edit::get_new_args($token,$parstack,$safeeval,'label','x','y');
     if ($constructtag) { $result=&Apache::edit::rebuild_tag($token); }
   }
@@ -526,6 +526,62 @@ sub end_plotobject {
    return $result;
 }
 
+#
+# Vector
+#
+
+sub start_plotvector {
+   my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
+   my $result='';
+   my $internalid = $Apache::inputtags::part.'_'.$Apache::inputtags::response[-1];
+   my $tailx=&Apache::lonxml::get_param('tailx',$parstack,$safeeval);
+   my $taily=&Apache::lonxml::get_param('taily',$parstack,$safeeval);
+   my $tipx=&Apache::lonxml::get_param('tipx',$parstack,$safeeval);
+   my $tipy=&Apache::lonxml::get_param('tipy',$parstack,$safeeval);
+
+   my $label=&Apache::lonxml::get_param('label',$parstack,$safeeval);
+   $label=~s/\W//gs;
+   $label=ucfirst($label);
+   unless ($label) { $label="NewVector"; }
+   if ($target eq 'web') {
+      my ($xmin,$xmax,$ymin,$ymax)=&boundaries($parstack,$safeeval,-3);
+      unless (defined($tailx)) { $tailx=$xmin; }
+      unless (defined($taily)) { $taily=$ymin; }
+      unless (defined($tipx)) { $tipx=$xmin; }
+      unless (defined($tipy)) { $tipy=$ymin; }
+      $result.=&plotvector_script($internalid,$label,$tailx,$taily,$tipx,$tipy,$xmin,$xmax);
+   } elsif ($target eq 'edit') {
+        $result=&Apache::edit::tag_start($target,$token,'Plot Vector').
+             &Apache::edit::text_arg('Label on Plot:','label',
+                                     $token,'16').
+             &Apache::edit::text_arg('Tail x:','tailx',
+                                     $token,'8').
+             &Apache::edit::text_arg('Tail y:','taily',
+                                     $token,'8').
+             &Apache::edit::text_arg('Tip x:','tipx',
+                                     $token,'8').
+             &Apache::edit::text_arg('Tip y:','tipy',
+                                     $token,'8').
+
+             &Apache::edit::end_row();
+  } elsif ($target eq 'modified') {
+    $env{'form.'.&Apache::edit::html_element_name('label')}=ucfirst($env{'form.'.&Apache::edit::html_element_name('label')});
+    my $constructtag=&Apache::edit::get_new_args($token,$parstack,$safeeval,'label','tailx','taily','tipx','tipy');
+    if ($constructtag) { $result=&Apache::edit::rebuild_tag($token); }
+  }
+  return $result;
+}
+
+sub end_plotvector {
+   my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
+   my $result='';
+   if ($target eq 'edit') {
+       $result=&Apache::edit::end_table();
+   }
+   return $result;
+}
+
+
 
 #
 # <backgroundplot function="..." fixed="yes/no" />
@@ -598,10 +654,6 @@ sub start_functionplotrule {
    } else {
       $label='R'.$label;
    }
-   if ($Apache::functionplotresponse::splineorder{$label}) {
-       &Apache::lonxml::error(&mt('Rule indices must be unique.'));
-   }
-
 
    if ($target eq 'grade') {
 # Simply remember - in order - for later
@@ -638,7 +690,7 @@ sub start_functionplotrule {
            &Apache::lonxml::get_param('percenterror',$parstack,$safeeval)
           )));
    } elsif ($target eq 'edit') {
-        $result=&Apache::edit::tag_start($target,$token,'Function Plot Evaluation Rule').
+        $result=&Apache::edit::tag_start($target,$token,'Function Plot Graph Rule').
              &Apache::edit::text_arg('Index/Name:','index',
                                      $token,'10').'&nbsp;'.
              &Apache::edit::select_arg(&mt('Function:'),'derivativeorder',
@@ -700,6 +752,195 @@ sub end_functionplotrule {
 
 
 #
+# <functionplotvectorrule ... />
+#
+sub start_functionplotvectorrule {
+   my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
+   my $result='';
+   my $label=&Apache::lonxml::get_param('index',$parstack,$safeeval);
+   $Apache::functionplotresponse::counter++;
+   if ($label=~/\W/) {
+      &Apache::lonxml::warning(&mt('Rule indices should only contain alphanumeric characters.'));
+   }
+   $label=~s/\W//gs;
+   unless ($label) {
+      $label='R'.$Apache::functionplotresponse::counter;
+   } else {
+      $label='R'.$label;
+   }
+
+   if ($target eq 'grade') {
+# Simply remember - in order - for later
+
+      my $id=$Apache::inputtags::response[-1];
+      my $partid=$Apache::inputtags::part;
+      my $internalid = $partid.'_'.$id;
+
+      my $vector=&Apache::lonxml::get_param('vector',$parstack,$safeeval);
+      $vector=~s/\W//gs;
+      $vector=ucfirst($vector);
+
+      my $attachpoint=&Apache::lonxml::get_param('attachpoint',$parstack,$safeeval);
+      $attachpoint=~s/\W//gs;
+      $attachpoint=ucfirst($attachpoint);
+
+      my $notattachpoint=&Apache::lonxml::get_param('notattachpoint',$parstack,$safeeval);
+      $notattachpoint=~s/\W//gs;
+      $notattachpoint=ucfirst($notattachpoint);
+
+      my $tailpoint=&Apache::lonxml::get_param('tailpoint',$parstack,$safeeval);
+      $tailpoint=~s/\W//gs;
+      $tailpoint=ucfirst($tailpoint);
+      my $tippoint=&Apache::lonxml::get_param('tippoint',$parstack,$safeeval);
+      $tippoint=~s/\W//gs;
+      $tippoint=ucfirst($tippoint);
+
+      my $nottailpoint=&Apache::lonxml::get_param('nottailpoint',$parstack,$safeeval);
+      $nottailpoint=~s/\W//gs;
+      $nottailpoint=ucfirst($nottailpoint);
+      my $nottippoint=&Apache::lonxml::get_param('nottippoint',$parstack,$safeeval);
+      $nottippoint=~s/\W//gs;
+      $nottippoint=ucfirst($nottippoint);
+
+      push(@Apache::functionplotresponse::functionplotvectorrules,join(':',(
+           $label,
+           'vector',
+           $internalid,
+           $vector,
+           $attachpoint,
+           $notattachpoint,
+           $tailpoint,
+           $tippoint,
+           $nottailpoint,
+           $nottippoint,
+           &Apache::lonxml::get_param('length',$parstack,$safeeval),
+           &Apache::lonxml::get_param('angle',$parstack,$safeeval),
+           &Apache::lonxml::get_param('lengtherror',$parstack,$safeeval),
+           &Apache::lonxml::get_param('angleerror',$parstack,$safeeval),
+          )));
+   } elsif ($target eq 'edit') {
+        $result=&Apache::edit::tag_start($target,$token,'Function Plot Vector Rule').
+             &Apache::edit::text_arg('Index/Name:','index',
+                                     $token,'10').'&nbsp;'.
+             &Apache::edit::text_arg('Vector:','vector',
+                                      $token,'16').'<br />'.
+             &Apache::edit::text_arg('Attached to object:','attachpoint',
+                                      $token,'16').
+             &Apache::edit::text_arg('Not attached to object:','notattachpoint',
+                                      $token,'16').'<br />'.
+             &Apache::edit::text_arg('Tail attached to object:','tailpoint',
+                                      $token,'16').
+             &Apache::edit::text_arg('Tip attached to object:','tippoint',
+                                      $token,'16').
+             &Apache::edit::text_arg('Tail not attached to object:','nottailpoint',
+                                      $token,'16').
+             &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').
+             &Apache::edit::text_arg('Absolute error length:','lengtherror',
+                                     $token,'8').
+             &Apache::edit::text_arg('Absolute error angle:','angleerror',
+                                     $token,'8').
+             &Apache::edit::end_row();
+  } elsif ($target eq 'modified') {
+    $env{'form.'.&Apache::edit::html_element_name('vector')}=ucfirst($env{'form.'.&Apache::edit::html_element_name('vector')});
+    $env{'form.'.&Apache::edit::html_element_name('attachpoint')}=ucfirst($env{'form.'.&Apache::edit::html_element_name('attachpoint')});
+    $env{'form.'.&Apache::edit::html_element_name('notattachpoint')}=ucfirst($env{'form.'.&Apache::edit::html_element_name('notattachpoint')});
+    $env{'form.'.&Apache::edit::html_element_name('tailpoint')}=ucfirst($env{'form.'.&Apache::edit::html_element_name('tailpoint')});
+    $env{'form.'.&Apache::edit::html_element_name('tippoint')}=ucfirst($env{'form.'.&Apache::edit::html_element_name('tippoint')});
+    $env{'form.'.&Apache::edit::html_element_name('nottailpoint')}=ucfirst($env{'form.'.&Apache::edit::html_element_name('nottailpoint')});
+    $env{'form.'.&Apache::edit::html_element_name('nottippoint')}=ucfirst($env{'form.'.&Apache::edit::html_element_name('nottippoint')});
+    my $constructtag=&Apache::edit::get_new_args($token,$parstack,
+                                                 $safeeval,'index','vector','attachpoint','notattachpoint',
+                                                           'tailpoint','tippoint','nottailpoint','nottipoint',
+                                                           'length','angle',
+                                                           'lengtherror','angleerror');
+    if ($constructtag) { $result=&Apache::edit::rebuild_tag($token); }
+   }
+   return $result;
+}
+
+sub end_functionplotvectorrule {
+   my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
+   my $result='';
+   if ($target eq 'edit') {
+       $result=&Apache::edit::end_table();
+   }
+   return $result;
+}
+
+#
+# <functionplotvectorsumrule ... />
+#
+sub start_functionplotvectorsumrule {
+   my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
+   my $result='';
+   my $label=&Apache::lonxml::get_param('index',$parstack,$safeeval);
+   $Apache::functionplotresponse::counter++;
+   if ($label=~/\W/) {
+      &Apache::lonxml::warning(&mt('Rule indices should only contain alphanumeric characters.'));
+   }
+   $label=~s/\W//gs;
+   unless ($label) {
+      $label='R'.$Apache::functionplotresponse::counter;
+   } else {
+      $label='R'.$label;
+   }
+   if ($target eq 'grade') {
+# Simply remember - in order - for later
+      my $id=$Apache::inputtags::response[-1];
+      my $partid=$Apache::inputtags::part;
+      my $internalid = $partid.'_'.$id;
+      my $vectors=&Apache::lonxml::get_param('vectors',$parstack,$safeeval);
+      push(@Apache::functionplotresponse::functionplotvectorrules,join(':',(
+           $label,
+           'sum',
+           $internalid,
+           $vectors,
+           &Apache::lonxml::get_param('length',$parstack,$safeeval),
+           &Apache::lonxml::get_param('angle',$parstack,$safeeval),
+           &Apache::lonxml::get_param('lengtherror',$parstack,$safeeval),
+           &Apache::lonxml::get_param('angleerror',$parstack,$safeeval),
+          )));
+   } elsif ($target eq 'edit') {
+        $result=&Apache::edit::tag_start($target,$token,'Function Plot Vector Sum Rule').
+             &Apache::edit::text_arg('Index/Name:','index',
+                                     $token,'10').'&nbsp;'.
+             &Apache::edit::text_arg('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',
+                                     $token,'16').
+             &Apache::edit::text_arg('Error length:','lengtherror',
+                                     $token,'8').
+             &Apache::edit::text_arg('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,
+                                                 $safeeval,'index','vectors',
+                                                           'length','angle',
+                                                           ,'lengtherror','angleerror');
+    if ($constructtag) { $result=&Apache::edit::rebuild_tag($token); }
+   }
+   return $result;
+}
+
+sub end_functionplotvectorsumrule {
+   my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
+   my $result='';
+   if ($target eq 'edit') {
+       $result=&Apache::edit::end_table();
+   }
+   return $result;
+}
+
+#
 # <spline index="..." order="1,2,3,4" initx="..." inity="..." scalex="..." scaley="..." />
 #
 # Unfortunately, GeoGebra seems to want all splines after everything else, so we need to store them
@@ -940,6 +1181,7 @@ sub start_functionplotresponse {
   $Apache::functionplotresponse::counter=0;
 # Remember rules
   undef @Apache::functionplotresponse::functionplotrules;
+  undef @Apache::functionplotresponse::functionplotvectorrules;
 # Remember failed rules
   if ($target eq 'grade') {
      undef @Apache::functionplotresponse::failedrules;
@@ -1113,6 +1355,214 @@ sub fpr_d2fdx2 {
                                                                 $Apache::functionplotresponse::fpr_xmax,
                                                                 $arg)];
 }
+
+
+sub vectorcoords {
+   my ($id,$label)=@_;
+   return ($env{'form.HWVAL_'.$id.'_'.$label.'Start_x'},
+           $env{'form.HWVAL_'.$id.'_'.$label.'End_x'},
+           $env{'form.HWVAL_'.$id.'_'.$label.'Start_y'},
+           $env{'form.HWVAL_'.$id.'_'.$label.'End_y'});
+}
+
+sub objectcoords {
+   my ($id,$label)=@_;
+   return ($env{'form.HWVAL_'.$id.'_'.$label.'_x'},
+           $env{'form.HWVAL_'.$id.'_'.$label.'_y'});
+}
+
+sub attached {
+   my ($id,$vector,$object,$xmin,$xmax,$ymin,$ymax)=@_;
+   my ($xs,$xe,$ys,$ye)=&vectorcoords($id,$vector);
+   my ($xo,$yo)=&objectcoords($id,$object);
+   my $tolx=($xmax-$xmin)/100.;
+   my $toly=($ymax-$ymin)/100.;
+   my $tail=0;
+   my $tip=0;
+   &addlog("Proximity $vector ($xs,$xe,$ys,$ye) to $object ($xo,$yo)");
+   if ((abs($xs-$xo)<$tolx) && (abs($ys-$yo)<$toly)) { $tail=1; }
+   if ((abs($xe-$xo)<$tolx) && (abs($ye-$yo)<$toly)) { $tip=1; }
+   &addlog("Result tail:$tail tip:$tip");
+   return($tail,$tip);
+}
+
+ 
+sub vectorangle {
+   my ($x,$y)=@_;
+   my $angle=57.2957795*atan2($y,$x);
+   if ($angle<0) { $angle=360+$angle; }
+   return $angle;
+}
+
+sub vectorlength {
+   my ($x,$y)=@_;
+   return sqrt($x*$x+$y*$y);
+}
+
+sub relvector {
+   my ($xs,$xe,$ys,$ye)=@_;
+   return ($xe-$xs,$ye-$ys);
+}
+
+sub plotvectorlength {
+   return &vectorlength(&relvector(&vectorcoords(@_)));
+}
+
+sub plotvectorangle {
+   return &vectorangle(&relvector(&vectorcoords(@_)));
+}
+
+
+#
+# Evaluate a functionplotvectorrule
+#
+
+sub functionplotvectorrulecheck {
+   my ($rule,$xmin,$xmax,$ymin,$ymax,$safeeval)=@_;
+   &addlog("=================");
+   my ($label,$type)=split(/\:/,$rule);
+   if ($type eq 'vector') {
+      return &vectorcheck($rule,$xmin,$xmax,$ymin,$ymax,$safeeval);
+   } elsif ($type eq 'sum') {
+      return &sumcheck($rule,$xmin,$xmax,$ymin,$ymax,$safeeval);
+   }
+}
+
+sub vectorcheck {
+   my ($rule,$xmin,$xmax,$ymin,$ymax,$safeeval)=@_;
+   my ($label,$type,$id,$vector,
+       $attachpoint,$notattachpoint,
+       $tailpoint,$tippoint,$nottailpoint,$nottippoint,
+       $length,$angle,$lengtherror,$angleerror)=split(/\:/,$rule);
+   &addlog("Vector Rule $label for vector ".$vector);
+   if ($length ne '') {
+      &addlog("Checking for length $length with error $lengtherror");
+      $length=&Apache::run::run($length,$safeeval);
+      &addlog("Length evaluated to $length");
+      my $thislength=&plotvectorlength($id,$vector);
+      &addlog("Found length $thislength");
+      if (abs($thislength-$length)>$lengtherror) {
+         &setfailed($label);
+         return 0;
+      }
+   }
+   if ($angle ne '') {
+      &addlog("Checking for angle $angle with error $angleerror");
+      $angle=&Apache::run::run($angle,$safeeval);
+      &addlog("Angle evaluated to $angle");
+      my $thisangle=&plotvectorangle($id,$vector);
+      &addlog("Found 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;
+      }
+   }
+   if ($attachpoint ne '') {
+      &addlog("Checking attached: ".$attachpoint);
+      my ($tail,$tip)=&attached($id,$vector,$attachpoint,$xmin,$xmax,$ymin,$ymax);
+      unless ($tail || $tip) {
+         &setfailed($label);
+         return 0;
+      }
+   }
+   if ($notattachpoint ne '') {
+      &addlog("Checking not attached: ".$notattachpoint);
+      my ($tail,$tip)=&attached($id,$vector,$notattachpoint,$xmin,$xmax,$ymin,$ymax);
+      if ($tail || $tip) {
+         &setfailed($label);
+         return 0;
+      }
+   }
+   if ($tailpoint ne '') {
+      &addlog("Checking tail: ".$tailpoint);
+      my ($tail,$tip)=&attached($id,$vector,$tailpoint,$xmin,$xmax,$ymin,$ymax);
+      unless ($tail) {
+         &setfailed($label);
+         return 0;
+      }
+   }
+   if ($nottailpoint ne '') {
+      &addlog("Checking not tail: ".$nottailpoint);
+      my ($tail,$tip)=&attached($id,$vector,$nottailpoint,$xmin,$xmax,$ymin,$ymax);
+      if ($tail) {
+         &setfailed($label);
+         return 0;
+      }
+   }
+   if ($tippoint ne '') {
+      &addlog("Checking tip: ".$tippoint);
+      my ($tail,$tip)=&attached($id,$vector,$tippoint,$xmin,$xmax,$ymin,$ymax);
+      unless ($tip) {
+         &setfailed($label);
+         return 0;
+      }
+   }
+   if ($nottippoint ne '') {
+      &addlog("Checking not tip: ".$nottippoint);
+      my ($tail,$tip)=&attached($id,$vector,$nottippoint,$xmin,$xmax,$ymin,$ymax);
+      if ($tip) {
+         &setfailed($label);
+         return 0;
+      }
+   }
+
+   &addlog("Rule $label passed.");
+   return 1;
+}
+
+sub sumcheck {
+   my ($rule,$xmin,$xmax,$ymin,$ymax,$safeeval)=@_;
+   my ($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;
+}
+
+#
+# Evaluate a functionplotrule
+#
  
 sub functionplotrulecheck {
    my ($rule,$xmin,$xmax,$ymin,$ymax,$safeeval)=@_;
@@ -1209,10 +1659,7 @@ sub functionplotrulecheck {
      unless (&compare_rel($relationship,$value,$integral,$tol)) {
         &addlog("Actual integral ".(defined($integral)?$integral:'undef').", expected $value, tolerance $tol");
         &addlog("Rule $label failed.");
-        my $hintlabel=$label;
-        $hintlabel=~s/^R//;
-        push(@Apache::functionplotresponse::failedrules,$hintlabel);
-        &addlog("Set hint condition $hintlabel");
+        &setfailed($label);
         return 0;
      } 
    } else {
@@ -1278,8 +1725,7 @@ sub checklength {
 }
 
 sub setfailed {
-   my ($label)=@_;
-   my $hintlabel=$label;
+   my ($hintlabel)=@_;
    $hintlabel=~s/^R//;
    push(@Apache::functionplotresponse::failedrules,$hintlabel);
    &addlog("Set hint condition $hintlabel");
@@ -1337,6 +1783,13 @@ sub end_functionplotruleset {
                  $ad='INCORRECT';
                  last;
               }
+           }
+# And now go through the vector rules
+           foreach my $rule (@Apache::functionplotresponse::functionplotvectorrules) {
+              unless (&functionplotvectorrulecheck($rule,$xmin,$xmax,$ymin,$ymax,$safeeval)) {
+                 $ad='INCORRECT';
+                 last;
+              }
            }
 # If it's not wrong, it's correct 
            unless ($ad) { $ad='EXACT_ANS' };