--- loncom/homework/functionplotresponse.pm	2010/10/30 02:31:27	1.18
+++ loncom/homework/functionplotresponse.pm	2010/11/19 17:20:44	1.40
@@ -1,7 +1,7 @@
 # LearningOnline Network with CAPA
 # option list style responses
 #
-# $Id: functionplotresponse.pm,v 1.18 2010/10/30 02:31:27 www Exp $
+# $Id: functionplotresponse.pm,v 1.40 2010/11/19 17:20:44 www Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -31,9 +31,11 @@ use strict;
 use Apache::response();
 use Apache::lonlocal;
 use Apache::lonnet;
-
+ 
 BEGIN {
-  &Apache::lonxml::register('Apache::functionplotresponse',('functionplotresponse','backgroundplot','spline','splinerule'));
+  &Apache::lonxml::register('Apache::functionplotresponse',('functionplotresponse','backgroundplot','spline',
+                                                            'functionplotrule','functionplotruleset',
+                                                            'functionplotelements'));
 }
 
 #
@@ -45,7 +47,7 @@ sub geogebra_startcode {
     my ($id)=@_;
     return (<<ENDSTARTCODE);
 <applet name="ggbApplet_$id" code="geogebra.GeoGebraApplet" archive="geogebra.jar"
-         codebase="/adm/geogebra/"  width="714" height="447" MAYSCRIPT>
+         codebase="/adm/geogebra/"  width="722" height="447" MAYSCRIPT>
        <param name="java_arguments" value="-Xmx512m -Djnlp.packEnabled=true"/>
 ENDSTARTCODE
 }
@@ -72,9 +74,8 @@ sub geogebra_default_parameters {
         <param name="image" value="/adm/lonIcons/lonanim.gif"  />
         <param name="boxborder" value="false"  />
         <param name="centerimage" value="true"  />
-        <param name="java_arguments" value="-Xmx512m" />
-        <param name="cache_archive" value="geogebra.jar, geogebra_main.jar, geogebra_gui.jar, geogebra_cas.jar, geogebra_export.jar, geogebra_properties.jar" />
-        <param name="cache_version" value="3.2.44.0, 3.2.44.0, 3.2.44.0, 3.2.44.0, 3.2.44.0, 3.2.44.0" />
+	<param name="cache_archive" value="geogebra.jar, geogebra_main.jar, geogebra_gui.jar, geogebra_cas.jar, geogebra_algos.jar, geogebra_export.jar, geogebra_javascript.jar, jlatexmath.jar, jlm_greek.jar, jlm_cyrillic.jar, geogebra_properties.jar" />
+	<param name="cache_version" value="3.9.115.0, 3.9.115.0, 3.9.115.0, 3.9.115.0, 3.9.115.0, 3.9.115.0, 3.9.115.0, 3.9.115.0, 3.9.115.0, 3.9.115.0, 3.9.115.0" />
         <param name="framePossible" value="false" />
 
         <param name="showResetIcon" value="false" />
@@ -157,16 +158,40 @@ sub update_register {
 }
 
 #
-# Set a coordinate variable
+# Set a point coordinate variable
 #
-sub set_coordinate {
+sub set_point_coordinate {
    my ($id,$variable,$x,$y)=@_;
    return (<<ENDSETVARIABLE);
 document.ggbApplet_$id.evalCommand("$variable=($x,$y)");
+document.ggbApplet_$id.setLabelVisible("$variable",false);
 ENDSETVARIABLE
 }
 
 #
+# Set a slope coordinate variable
+#
+sub set_slope_coordinate {
+   my ($id,$variable,$xrel,$yrel,$xmin,$xmax,$ymin,$ymax,$pointname)=@_;
+   my $xvariable=$variable.'x';
+   my $yvariable=$variable.'y';
+   my $domain=$xmax-$xmin;
+   my $range=$ymax-$ymin;
+   my $xinterval=$domain/100.;
+   my $yinterval=$range/200.;
+   return (<<ENDSETSVARIABLE);
+document.ggbApplet_$id.evalCommand("$xvariable=Slider[0,$domain,$xinterval]");
+document.ggbApplet_$id.setVisible("$xvariable", false);
+document.ggbApplet_$id.evalCommand("$xvariable=$xrel");
+document.ggbApplet_$id.evalCommand("$yvariable=Slider[-$range,$range,$yinterval]");
+document.ggbApplet_$id.setVisible("$yvariable", false);
+document.ggbApplet_$id.evalCommand("$yvariable=$yrel");
+document.ggbApplet_$id.evalCommand("$variable=($xvariable+x($pointname),$yvariable+y($pointname))");
+document.ggbApplet_$id.setLabelVisible("$variable", false);
+ENDSETSVARIABLE
+}
+
+#
 # Input field name for a coordinate variable
 #
 
@@ -187,9 +212,9 @@ sub generate_input_field {
 }
 
 #
-# Initialize a new coordinate variable at set a listener on it
+# Initialize a new point coordinate variable at set a listener on it
 #
-sub new_coordinate {
+sub new_point_coordinate {
     my ($id,$variable,$x,$y)=@_;
     if (defined($Apache::functionplotresponse::previous{&field_name($id,$variable,'x')})) {
        $x=$Apache::functionplotresponse::previous{&field_name($id,$variable,'x')};
@@ -198,7 +223,37 @@ sub new_coordinate {
        $y=$Apache::functionplotresponse::previous{&field_name($id,$variable,'y')};
     }
     &generate_input_field($id,$variable,$x,$y);
-    return &set_coordinate($id,$variable,$x,$y).&update_register($id,$variable);
+    return &set_point_coordinate($id,$variable,$x,$y).&update_register($id,$variable);
+}
+
+#
+# Initialize a new slope coordinate variable at set a listener on it
+#
+sub new_slope_coordinate {
+    my ($id,$variable,$x,$y,$pointname,$xp,$yp,$xmin,$xmax,$ymin,$ymax)=@_;
+#
+# $variable: name of the slope point
+# $x, $y: coordinates of the slope point
+# $pointname: name of the associated point point
+# $xp $yp: coordinates of the point point
+#
+    if (defined($Apache::functionplotresponse::previous{&field_name($id,$variable,'x')})) {
+       $x=$Apache::functionplotresponse::previous{&field_name($id,$variable,'x')};
+    }
+    if (defined($Apache::functionplotresponse::previous{&field_name($id,$variable,'y')})) {
+       $y=$Apache::functionplotresponse::previous{&field_name($id,$variable,'y')};
+    }
+    if (defined($Apache::functionplotresponse::previous{&field_name($id,$pointname,'x')})) {
+       $xp=$Apache::functionplotresponse::previous{&field_name($id,$pointname,'x')};
+    }
+    if (defined($Apache::functionplotresponse::previous{&field_name($id,$pointname,'y')})) {
+       $yp=$Apache::functionplotresponse::previous{&field_name($id,$pointname,'y')};
+    }
+
+    &generate_input_field($id,$variable,$x,$y);
+    my $xrel=$x-$xp;
+    my $yrel=$y-$yp;
+    return &set_slope_coordinate($id,$variable,$xrel,$yrel,$xmin,$xmax,$ymin,$ymax,$pointname).&update_register($id,$variable);
 }
 
 #
@@ -282,7 +337,7 @@ ENDPLOTSCRIPT
 #
 
 sub generate_spline {
-   my ($id,$label)=@_;
+   my ($id,$label,$xmin,$xmax,$ymin,$ymax)=@_;
    my $result='';
    my $order=$Apache::functionplotresponse::splineorder{$label};
    my $x=$Apache::functionplotresponse::splineinitx{$label};
@@ -291,10 +346,11 @@ sub generate_spline {
    my $sy=$Apache::functionplotresponse::splinescaley{$label};
    my @coords=();
    foreach my $i (1..$order) {
-       $result.=&new_coordinate($id,$label.'P'.$i,$x,$y);
+       $result.=&new_point_coordinate($id,$label.'P'.$i,$x,$y);
+       my $xp=$x;
        $x+=$sx/(2.*($order-1));
        push(@coords,$label.'P'.$i);
-       $result.=&new_coordinate($id,$label.'S'.$i,$x,$y+$sy);
+       $result.=&new_slope_coordinate($id,$label.'S'.$i,$x,$y+$sy,$label.'P'.$i,$xp,$y,$xmin,$xmax,$ymin,$ymax);
        $x+=$sx/(2.*($order-1));
        push(@coords,$label.'S'.$i);
    }
@@ -339,20 +395,106 @@ sub end_backgroundplot {
 }
 
 #
-# <splinerule ... />
+# <functionplotrule ... />
 #
-sub start_splinerule {
+sub start_functionplotrule {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
    my $result='';
-   my $internalid = $Apache::inputtags::part.'_'.$Apache::inputtags::response[-1];
-   if ($target eq 'edit') {
-        $result=&Apache::edit::tag_start($target,$token,'Spline Evaluation Rule').
-                &Apache::edit::end_row();
+   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 ($Apache::functionplotresponse::splineorder{$label}) {
+       &Apache::lonxml::error(&mt('Rule indices must be unique.'));
+   }
+
+
+   if ($target eq 'grade') {
+# Simply remember - in order - for later
+      my $beginninglabel=&Apache::lonxml::get_param('xinitiallabel',$parstack,$safeeval);
+      my $endinglabel=&Apache::lonxml::get_param('xfinallabel',$parstack,$safeeval);
+      if (($beginninglabel=~/\W/) || ($endinglabel=~/W/)) {
+          &Apache::lonxml::warning(&mt('Rule labels must be alphanumeric.'));
+      }
+      $beginninglabel=~s/\W//gs;
+      $endinglabel=~s/\W//gs;
+      my $relationship=&Apache::lonxml::get_param('relationship',$parstack,$safeeval);
+      $relationship=~s/\W//gs;
+      $relationship=lc($relationship);
+      unless ($relationship=~/^(eq|ge|gt|le|lt|ne)$/) {
+          &Apache::lonxml::warning(&mt('Rule relationship not defined.'));
+          $relationship='eq';
+      }
+      my $derivative=&Apache::lonxml::get_param('derivativeorder',$parstack,$safeeval);
+      unless (($derivative==0) || ($derivative==1) || ($derivative==2)) {
+         &Apache::lonxml::warning(&mt('Rule derivative not defined.'));
+         $derivative=0;
+      }
+      push(@Apache::functionplotresponse::functionplotrules,join(':',(
+           $label,
+           $derivative,
+           &Apache::lonxml::get_param('xinitial',$parstack,$safeeval),
+           $beginninglabel,
+           &Apache::lonxml::get_param('xfinal',$parstack,$safeeval),
+           $endinglabel,
+           &Apache::lonxml::get_param('minimumlength',$parstack,$safeeval),
+           &Apache::lonxml::get_param('maximumlength',$parstack,$safeeval),
+           $relationship,
+           &Apache::lonxml::get_param('value',$parstack,$safeeval),
+           &Apache::lonxml::get_param('percenterror',$parstack,$safeeval)
+          )));
+   } elsif ($target eq 'edit') {
+        $result=&Apache::edit::tag_start($target,$token,'Function Plot Evaluation Rule').
+             &Apache::edit::text_arg('Index/Name:','index',
+                                     $token,'10').'&nbsp;'.
+             &Apache::edit::select_arg(&mt('Function:'),'derivativeorder',
+                                  [['0','Function itself'],
+                                   ['1','First derivative'],
+                                   ['2','Second derivative']],$token).'<br />'.
+             &Apache::edit::text_arg('(Initial) x-value:','xinitial',
+                                      $token,'8').
+             &Apache::edit::select_or_text_arg('(Initial) x-value label:','xinitiallabel',
+                                               [['start','Start of Plot']],$token,'8').'<br />'.
+
+             &Apache::edit::text_arg('Optional final x-value for ranges:','xfinal',
+                                      $token,'8').
+             &Apache::edit::select_or_text_arg('Optional final x-value label:','xfinallabel',
+                                               [['end','End of Plot']],$token,'8').'<br />'.
+             &Apache::edit::text_arg('Optional minimum length for range:','minimumlength',
+                                     $token,'8').
+             &Apache::edit::text_arg('Optional maximum length for range:','maximumlength',
+                                     $token,'8').'<br />'.
+             &Apache::edit::select_or_text_arg(&mt('Relationship:'),'relationship',
+                                  [['eq','equal'],
+                                   ['ne','not equal'],
+                                   ['ge','greater than or equal'],
+                                   ['gt','greater than'],
+                                   ['lt','less than'],
+                                   ['le','less than or equal']],$token).
+             $result.= &Apache::edit::select_or_text_arg('Value:','value',
+                                               [['undef','not defined']],$token,'8').
+             &Apache::edit::text_arg('Percent error:','percenterror',
+                                     $token,'8').
+             &Apache::edit::end_row();
+  } elsif ($target eq 'modified') {
+    my $constructtag=&Apache::edit::get_new_args($token,$parstack,
+                                                 $safeeval,'index','derivativeorder',
+                                                           'xinitial','xinitiallabel','xfinal','xfinallabel',
+                                                           'minimumlength','maximumlength',
+                                                           'relationship','value','percenterror');
+    if ($constructtag) { $result=&Apache::edit::rebuild_tag($token); }
    }
    return $result;
 }
 
-sub end_splinerule {
+sub end_functionplotrule {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
    my $result='';
    if ($target eq 'edit') {
@@ -363,7 +505,7 @@ sub end_splinerule {
 
 
 #
-# <spline label="..." order="1,2,3,4" initx="..." inity="..." scalex="..." scaley="..." />
+# <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
 #
@@ -371,15 +513,19 @@ sub start_spline {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
    my $result='';
    if ($target eq 'web') {
-      my $label=&Apache::lonxml::get_param('label',$parstack,$safeeval);
+      my $label=&Apache::lonxml::get_param('index',$parstack,$safeeval);
       $Apache::functionplotresponse::counter++;
       if ($label=~/\W/) {
-         &Apache::lonxml::warning(&mt('Spline labels should only contain alphanumeric characters.'));
+         &Apache::lonxml::warning(&mt('Spline indices should only contain alphanumeric characters.'));
       }
       $label=~s/\W//gs;
-      unless ($label) { $label='S'.$Apache::functionplotresponse::counter; }
+      unless ($label) { 
+         $label='S'.$Apache::functionplotresponse::counter; 
+      } else {
+         $label='S'.$label;
+      }
       if ($Apache::functionplotresponse::splineorder{$label}) {
-         &Apache::lonxml::error(&mt('Spline labels must be unique.'));
+         &Apache::lonxml::error(&mt('Spline indices must be unique.'));
       }
 
       my $order=&Apache::lonxml::get_param('order',$parstack,$safeeval);
@@ -404,7 +550,7 @@ sub start_spline {
       $Apache::functionplotresponse::splinescaley{$label}=$sy;
    } elsif ($target eq 'edit') {
         $result=&Apache::edit::tag_start($target,$token,'Spline').
-             &Apache::edit::text_arg('Label:','label',
+             &Apache::edit::text_arg('Index:','index',
                                      $token,'4').'&nbsp;'.
              &Apache::edit::select_arg('Order:','order',
                                   ['2','3','4','5','6','7','8','9'],$token).'&nbsp;'.
@@ -419,7 +565,7 @@ sub start_spline {
              &Apache::edit::end_row();
   } elsif ($target eq 'modified') {
     my $constructtag=&Apache::edit::get_new_args($token,$parstack,
-                                                 $safeeval,'label','order','initx','inity',
+                                                 $safeeval,'index','order','initx','inity',
                                                            'scalex','scaley');
     if ($constructtag) { $result=&Apache::edit::rebuild_tag($token); }
   }
@@ -503,8 +649,11 @@ sub d2dt2_cubic_hermite {
 #
 sub array_index {
    my ($xmin,$xmax,$x)=@_;
-   my $index=int(($x-$xmin)/($xmax-$xmin)*200.+0.5);
-   return $index;
+   if ($x ne '') {
+      return int(($x-$xmin)/($xmax-$xmin)*400.+0.5);
+   } else {
+      return undef;
+   }
 }
 
 #
@@ -513,17 +662,18 @@ sub array_index {
 
 sub populate_arrays {
     my ($id,$xmin,$xmax)=@_;
-    for (my $i=0; $i<=200; $i++) {
-       undef $Apache::functionplotresponse::func[$i];
-       undef $Apache::functionplotresponse::dfunddx[$i];
-       undef $Apache::functionplotresponse::d2funcd2x[$i];
+    for (my $i=0; $i<=400; $i++) {
+       $Apache::functionplotresponse::actualxval[$i]=undef;
+       $Apache::functionplotresponse::func[$i]=undef;
+       $Apache::functionplotresponse::dfuncdx[$i]=undef;
+       $Apache::functionplotresponse::d2funcd2x[$i]=undef;
     }
-    unless ($xmax>$xmin) { return; }
+    unless ($xmax>$xmin) { return 'no_func'; }
 # Run over all splines in response
     foreach my $label (split(/\,/,$env{"form.HWVAL_AllSplines_$id"})) {
+        my $xiold=-1;
 # Run over all points in spline
-        for (my $i=0; $i<$env{"form.HWVAL_SplineOrder_".$id."_".$label}; $i++) {
-            my $xiold=-1;
+        for (my $i=1; $i<$env{"form.HWVAL_SplineOrder_".$id."_".$label}; $i++) {
             my $ni=$i+1;
             my @xparms=($env{'form.HWVAL_'.$id.'_'.$label.'P'.$i.'_x'},
                         $env{'form.HWVAL_'.$id.'_'.$label.'S'.$i.'_x'},
@@ -533,14 +683,36 @@ sub populate_arrays {
                         $env{'form.HWVAL_'.$id.'_'.$label.'S'.$i.'_y'},
                         $env{'form.HWVAL_'.$id.'_'.$label.'P'.$ni.'_y'},
                         $env{'form.HWVAL_'.$id.'_'.$label.'S'.$ni.'_y'});
-
 # Run in small steps over spline parameter
-            for (my $t=0; $t<=1; $t+=0.00025) {
-                my $xi=&array_index($xmin,$xmax,&cubic_hermite($t,@xparms));
-                if ($xi<$xiold-5) { return 'no_func'; }
-                if ($xi>$xiold) {
+            for (my $t=0; $t<=1; $t+=0.0001) {
+                my $xreal=&cubic_hermite($t,@xparms);
+                my $xi=&array_index($xmin,$xmax,$xreal);
+                if ($xi<$xiold) { return 'no_func'; }
+                if (($xi>$xiold) && ($xi>=0) && ($xi<=400)) {
+                   if (defined($Apache::functionplotresponse::func[$xi])) { return 'no_func'; }
                    $xiold=$xi;
-                   $Apache::functionplotresponse::func[$xi]=&cubic_hermite($t,@yparms);
+                   $Apache::functionplotresponse::actualxval[$xi]=$xreal;
+# Function value
+                   my $funcval=&cubic_hermite($t,@yparms);
+                   $Apache::functionplotresponse::func[$xi]=$funcval;
+                   if (defined($funcval)) {
+                      if ($xi<$Apache::functionplotresponse::functionplotrulelabels{'start'}) {
+                         $Apache::functionplotresponse::functionplotrulelabels{'start'}=$xi;
+                      }
+                      if ($xi>$Apache::functionplotresponse::functionplotrulelabels{'end'}) {
+                         $Apache::functionplotresponse::functionplotrulelabels{'end'}=$xi;
+                      }
+                   }
+# Chain rule
+# dy/dx=dy/dt/(dx/dt)
+                   my $dxdt=&ddt_cubic_hermite($t,@xparms);
+                   if ($dxdt) {
+                      $Apache::functionplotresponse::dfuncdx[$xi]=&ddt_cubic_hermite($t,@yparms)/$dxdt;
+# Second derivative
+                      $Apache::functionplotresponse::d2funcdx2[$xi]=
+                         ($dxdt*&d2dt2_cubic_hermite($t,@yparms)-&ddt_cubic_hermite($t,@yparms)*&d2dt2_cubic_hermite($t,@xparms))/
+                         ($dxdt*$dxdt*$dxdt);
+                   }
                 }
             }
         }
@@ -548,7 +720,7 @@ sub populate_arrays {
 }
 
 #
-# Implentation of <functionplotresponse>
+# Implementation of <functionplotresponse>
 #
 
 sub start_functionplotresponse {
@@ -564,6 +736,14 @@ sub start_functionplotresponse {
   undef %Apache::functionplotresponse::previous;
   $Apache::functionplotresponse::inputfields='';
   $Apache::functionplotresponse::counter=0;
+# Remember rules
+  undef @Apache::functionplotresponse::functionplotrules;
+# Remember failed rules
+  if ($target eq 'grade') {
+     undef @Apache::functionplotresponse::failedrules;
+  }
+# Delete previous awards
+  undef $Apache::functionplotresponse::awarddetail;
 # Part and ID
   my $partid=$Apache::inputtags::part;
   my $id=&Apache::response::start_response($parstack,$safeeval);
@@ -581,6 +761,14 @@ sub start_functionplotresponse {
   $ymin=(defined($ymin)?$ymin:-10);
   my $ymax=&Apache::lonxml::get_param('ymax',$parstack,$safeeval);
   $ymax=(defined($ymax)?$ymax:10);
+  if ($xmax<=$xmin) {
+     &Apache::lonxml::warning('Maximum x-value needs to be larger than minimum value.');
+     $xmax=$xmin+20;
+  }
+  if ($ymax<=$ymin) {
+     &Apache::lonxml::warning('Maximum y-value needs to be larger than minimum value.');
+     $ymax=$ymin+20;
+  }
   my $xaxisvisible=(&Apache::lonxml::get_param('xaxisvisible',$parstack,$safeeval)=~/on|true|yes|1/i?'true':'false');
   my $yaxisvisible=(&Apache::lonxml::get_param('yaxisvisible',$parstack,$safeeval)=~/on|true|yes|1/i?'true':'false');
   my $gridvisible=(&Apache::lonxml::get_param('gridvisible',$parstack,$safeeval)=~/on|true|yes|1/i?'true':'false');
@@ -590,7 +778,8 @@ sub start_functionplotresponse {
     $result.=&Apache::edit::start_table($token)
        .'<tr><td><span class="LC_nobreak">'.&mt('Function Plot Question').'</span></td>'
        .'<td><span class="LC_nobreak">'.&mt('Delete?').' '
-       .&Apache::edit::deletelist($target,$token)
+       .&Apache::edit::deletelist($target,$token).'&nbsp;&nbsp;&nbsp;'
+       .&Apache::edit::insertlist($target,$token)
        .'</span></td>'
        ."<td>&nbsp;"
        .&Apache::edit::end_row()
@@ -603,7 +792,7 @@ sub start_functionplotresponse {
              &Apache::edit::text_arg('Maximum x-value:','xmax',
                                      $token,'4').'&nbsp;'.
              &Apache::edit::select_arg('x-axis visible:','xaxisvisible',
-                                  ['yes','no'],$token).'&nbsp;&nbsp;'.
+                                  ['yes','no'],$token).'<br />'.
              &Apache::edit::text_arg('Label y-axis:','ylabel',
                                      $token,'6').'&nbsp;'.
              &Apache::edit::text_arg('Minimum y-value:','ymin',
@@ -611,7 +800,7 @@ sub start_functionplotresponse {
              &Apache::edit::text_arg('Maximum y-value:','ymax',
                                      $token,'4').'&nbsp;'.
              &Apache::edit::select_arg('y-axis visible:','yaxisvisible',
-                                  ['yes','no'],$token).'&nbsp;&nbsp;'.
+                                  ['yes','no'],$token).'<br />'.
              &Apache::edit::select_arg('Grid visible:','gridvisible',
                                   ['yes','no'],$token).
              &Apache::edit::end_row().&Apache::edit::start_spanning_row();
@@ -623,19 +812,269 @@ sub start_functionplotresponse {
 
   } elsif ($target eq 'meta') {
        $result=&Apache::response::meta_package_write('functionplotresponse');
-  } elsif ($target eq 'web') {
-# paste in the update routine to receive stuff back from the applet
-     $result.=&update_script($internalid);
-# start the initscript for this applet
-     $result.=&start_init_script($internalid);
-# put the axis commands inside
-     $result.=&axes_script($internalid,$xmin,$xmax,$ymin,$ymax,$xaxisvisible,$yaxisvisible,$gridvisible);
-     $result.=&axes_label($internalid,$xlabel,$ylabel);
-# init script is left open
-  }
+  } elsif (($target eq 'answer') &&
+            ($env{'form.answer_output_mode'} ne 'tex') &&
+            ($Apache::lonhomework::viewgrades == 'F')) {
+      my (undef,undef,$udom,$uname)=&Apache::lonnet::whichuser();
+      my $windowopen=&Apache::lonhtmlcommon::javascript_docopen();
+      my $start_page = &Apache::loncommon::start_page('Rules Log', undef,
+                                               {'only_body' => 1,
+                                                'bgcolor'   => '#FFFFFF',
+                                                'js_ready'  => 1,});
+      my $end_page = &Apache::loncommon::end_page({'js_ready' => 1,});
+      $uname =~s/\W//g;
+      $udom  =~s/\W//g;
+      my $function_name =
+                join('_','LONCAPA_scriptvars',$uname,$udom,
+                     $env{'form.counter'},$Apache::lonxml::curdepth);
+      my $rules_var ="<script type=\"text/javascript\">
+// <![CDATA[
+    function $function_name() {newWindow=open('','new_W','width=500,height=500,scrollbars=1,resizable=yes');newWindow.$windowopen;newWindow.document.writeln('$start_page<pre>".
+    $Apache::functionplotresponse::ruleslog.
+    "<\\/pre>$end_page');newWindow.document.close();newWindow.focus()}
+// ]]>
+</script><a href=\"javascript:$function_name();void(0);\">".&mt('Rules Log')."</a><br />";
+            &Apache::lonxml::add_script_result($rules_var);
+        }
+
   return $result;
 }
 
+sub compare_rel {
+   my ($relationship,$value,$realval,$tol)=@_;
+# is the real value undefined?
+   unless (defined($realval)) {
+# the real value is not defined
+      if ($relationship eq 'eq') {
+         if ($value eq 'undef') {
+            return 1;
+         } else {
+            return 0;
+         }
+      } elsif ($relationship eq 'ne') {
+         if ($value eq 'undef') {
+            return 0;
+         } else {
+            return 1;
+         }
+      } else {
+         return 0;
+      }
+   }
+
+# is the expected value undefined?
+   if ($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') {
+      return ($realval>$value-$tol);
+   } elsif ($relationship eq 'lt') {
+      return ($realval<$value);
+   } elsif ($relationship eq 'le') {
+      return ($realval<$value+$tol);
+   } elsif ($relationship eq 'ne') {
+      return (abs($value-$realval)>$tol);
+   } else {
+      return (abs($value-$realval)<$tol);
+   }
+   return 0;
+}
+
+sub addlog {
+   my ($text)=@_;
+   $Apache::functionplotresponse::ruleslog.=$text.'<br />';
+}
+
+sub actualval {
+   my ($i,$xmin,$xmax)=@_;
+   return $xmin+$i/400.*($xmax-$xmin);
+}
+ 
+sub functionplotrulecheck {
+   my ($rule,$xmin,$xmax,$ymin,$ymax)=@_;
+
+   my ($label,$derivative,$xinitial,$xinitiallabel,$xfinal,$xfinallabel,$minimumlength,$maximumlength,$relationship,$value,$percent)
+      =split(/\:/,$rule);
+   $percent=($percent>0?$percent:5);
+   &addlog("=================");
+   &addlog("Rule $label for ".('function itself','first derivative','second derivative')[$derivative]." $relationship $value");
+   my $li=0;
+   my $lh=400;
+
+# Special case: the upper boundary was not defined
+# and needs to be set to the value where
+# the condition is not true anymore => set flag
+
+   my $findupper=0;
+   if (($xfinal eq '')
+    && (!defined($Apache::functionplotresponse::functionplotrulelabels{$xfinallabel}))
+    && ($xfinallabel)) {
+       $findupper=1;
+   }
+
+# if a hard value is set for the boundaries, it overrides the label
+   if (($xinitial ne '') && ($xinitiallabel ne '') && ($xinitiallabel ne 'start')) {
+      $li=&array_index($xmin,$xmax,$xinitial);
+      $Apache::functionplotresponse::functionplotrulelabels{$xinitiallabel}=$li;
+   }
+   if (($xfinal ne '') && ($xfinallabel ne '') && ($xfinallabel ne 'end')) {
+      $lh=&array_index($xmin,$xmax,$xfinal);
+      $Apache::functionplotresponse::functionplotrulelabels{$xfinallabel}=$lh;
+   }
+# if the label is defined, use it
+   if (defined($Apache::functionplotresponse::functionplotrulelabels{$xinitiallabel})) {
+      &addlog("Using lower label $xinitiallabel");
+      $li=$Apache::functionplotresponse::functionplotrulelabels{$xinitiallabel};
+   } else {
+      $li=&array_index($xmin,$xmax,$xinitial);
+   }
+   unless ($findupper) {
+      if (defined($Apache::functionplotresponse::functionplotrulelabels{$xfinallabel})) {
+         &addlog("Using upper label $xfinallabel");
+         $lh=$Apache::functionplotresponse::functionplotrulelabels{$xfinallabel}-1;
+      } else {
+         $lh=&array_index($xmin,$xmax,$xfinal);
+      }
+   }
+# Basic sanity checks
+   if ($li<0) { $li=0; }
+   if ($lh>400) { $lh=400; }
+   if (($li>$lh) || (!defined($lh))) {
+       $lh=$li;
+   }
+
+   &addlog("Boundaries: x=".&actualval($li,$xmin,$xmax)." (".$Apache::functionplotresponse::actualxval[$li]."; index $li)) to x=".
+                            &actualval($lh,$xmin,$xmax)." (".$Apache::functionplotresponse::actualxval[$lh]."; index $lh))");
+   if ($findupper) {
+      &addlog("Looking for label $xfinallabel");
+   }
+   my $tol=$percent*($ymax-$ymin)/100;
+   if ($xmax>$xmin) {
+      if ($derivative==2) {
+         $tol=4.*$tol/($xmax-$xmin);
+      } elsif ($derivative==1) {
+         $tol=2.*$tol/($xmax-$xmin);
+      }
+   }
+   for (my $i=$li; $i<=$lh; $i++) {
+        my $val;
+        if ($derivative==2) {
+           $val=$Apache::functionplotresponse::d2funcdx2[$i];
+        } elsif ($derivative==1) {
+           $val=$Apache::functionplotresponse::dfuncdx[$i];
+        } else {
+           $val=$Apache::functionplotresponse::func[$i];
+        }
+        unless (&compare_rel($relationship,$value,$val,$tol)) { 
+           &addlog("Actual value ".(defined($val)?$val:'undef').", expected $value, tolerance $tol");
+           &addlog("Condition not fulfilled at x=".&actualval($i,$xmin,$xmax)." (".$Apache::functionplotresponse::actualxval[$i]."; index $i)");
+           if (($findupper) && ($i>$li)) {
+# check for minimum and maximum lengths
+              my $length=&actualval($i,$xmin,$xmax)-&actualval($li,$xmin,$xmax);
+              if ($minimumlength) {
+                 if ($length<$minimumlength) {
+                    &addlog("Rule $label failed, actual length $length, minimum length $minimumlength");
+                    return 0;
+                 }
+              }
+              if ($maximumlength) {
+                 if ($length>$maximumlength) {
+                    &addlog("Rule $label failed, actual length $length, maximum length $maximumlength");
+                    return 0;
+                 }
+              }
+              $Apache::functionplotresponse::functionplotrulelabels{$xfinallabel}=$i;
+              &addlog("Rule $label passed, setting label $xfinallabel");
+              return 1;
+           } else {
+              &addlog("Rule $label failed.");
+              my $hintlabel=$label;
+              $hintlabel=~s/^R//;
+              push(@Apache::functionplotresponse::failedrules,$hintlabel);
+              &addlog("Set hint condition $hintlabel");
+              return 0; 
+           }
+        }
+   }
+   &addlog("Rule $label passed.");
+   return 1;
+}
+
+sub start_functionplotruleset {
+   my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
+   if ($target eq 'edit') {
+      return &Apache::edit::start_table($token).
+        '<tr><td><span class="LC_nobreak">'.&mt('Function Plot Rule Set').'</span></td>'
+       .'<td><span class="LC_nobreak">'.&mt('Delete?').' '
+       .&Apache::edit::deletelist($target,$token).'&nbsp;&nbsp;&nbsp;'.
+        &Apache::edit::insertlist($target,$token)
+       .'</span></td>'
+       ."<td>&nbsp;"
+       .&Apache::edit::end_row()
+       .&Apache::edit::start_spanning_row()
+       ."\n";
+   }
+}
+
+sub end_functionplotruleset {
+    my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
+    my $id=$Apache::inputtags::response[-1];
+    my $partid=$Apache::inputtags::part;
+    my $internalid = $partid.'_'.$id;
+
+    if ($target eq 'edit' ) {
+        return &Apache::edit::end_table();
+    }  elsif ($target eq 'grade'
+         && &Apache::response::submitted()
+         && $Apache::lonhomework::type ne 'exam') {
+#
+# Actually grade
+#
+        my $xmin=&Apache::lonxml::get_param('xmin',$parstack,$safeeval,-2);
+        $xmin=(defined($xmin)?$xmin:-10);
+        my $xmax=&Apache::lonxml::get_param('xmax',$parstack,$safeeval,-2);
+        $xmax=(defined($xmax)?$xmax:10);
+        my $ymin=&Apache::lonxml::get_param('ymin',$parstack,$safeeval,-2);
+        $ymin=(defined($ymin)?$ymin:-10);
+        my $ymax=&Apache::lonxml::get_param('ymax',$parstack,$safeeval,-2);
+        $ymax=(defined($ymax)?$ymax:10);
+
+        my $ad='';
+        undef  %Apache::functionplotresponse::functionplotrulelabels;
+        $Apache::functionplotresponse::ruleslog='';
+        $Apache::functionplotresponse::functionplotrulelabels{'start'}=400;
+        $Apache::functionplotresponse::functionplotrulelabels{'end'}=0;
+        if (&populate_arrays($internalid,$xmin,$xmax) eq 'no_func') {
+           $ad='NOT_FUNCTION';
+        } else {
+           &addlog("Start of function ".&actualval($Apache::functionplotresponse::functionplotrulelabels{'start'},$xmin,$xmax)." (index ".
+                                        $Apache::functionplotresponse::functionplotrulelabels{'start'}.")");
+           &addlog("End of function ".&actualval($Apache::functionplotresponse::functionplotrulelabels{'end'},$xmin,$xmax)." (index ".
+                                        $Apache::functionplotresponse::functionplotrulelabels{'end'}.")");
+
+# We have a function that we can actually grade, go through the spline rules.
+           foreach my $rule (@Apache::functionplotresponse::functionplotrules) {
+              unless (&functionplotrulecheck($rule,$xmin,$xmax,$ymin,$ymax)) {
+                 $ad='INCORRECT';
+                 last;
+              }
+           }
+# If it's not wrong, it's correct 
+           unless ($ad) { $ad='EXACT_ANS' };
+        }
+        &addlog("Set hint conditions: ".join(",",@Apache::functionplotresponse::failedrules));
+        &addlog("Assigned award detail: $ad");
+# Store for later to be assigned at end_functionplotresponse
+        $Apache::functionplotresponse::awarddetail=$ad;
+     }
+}
+
+
 sub end_functionplotresponse {
   my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
   &Apache::response::end_response;
@@ -650,7 +1089,7 @@ sub end_functionplotresponse {
          && &Apache::response::submitted()
          && $Apache::lonhomework::type eq 'exam') {
 
-        #&Apache::response::scored_response($partid,$id);
+        &Apache::response::scored_response($partid,$id);
 
     } elsif ($target eq 'grade'
          && &Apache::response::submitted()
@@ -659,27 +1098,46 @@ sub end_functionplotresponse {
         $Apache::lonhomework::results{"resource.$partid.$id.submission"}=$response;
         my %previous=&Apache::response::check_for_previous($response,$partid,$id);
 #
-# Actually grade
+# Assign grade
 #
-        my $xmin=&Apache::lonxml::get_param('xmin',$parstack,$safeeval);
-        $xmin=(defined($xmin)?$xmin:-10);
-        my $xmax=&Apache::lonxml::get_param('xmax',$parstack,$safeeval);
-        $xmax=(defined($xmax)?$xmax:10);
-        my $ad;
-        if (&populate_arrays($internalid,$xmin,$xmax) eq 'no_func') {
-           $ad='BAD_FORMULA';
-        } else {
-           $ad='INCORRECT';
-        }
+        my $ad=$Apache::functionplotresponse::awarddetail;
 #
 # Store grading info
 #
         $Apache::lonhomework::results{"resource.$partid.$id.awarddetail"}=$ad;
         &Apache::response::handle_previous(\%previous,$ad);
    } elsif ($target eq 'web') {
+        undef @Apache::functionplotresponse::failedrules;
+   }
+   return $result;
+}
+
+sub end_functionplotelements {
+  my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
+  my $result='';
+  my $id=$Apache::inputtags::response[-1];
+  my $partid=$Apache::inputtags::part;
+  my $internalid = $partid.'_'.$id;
+  if ($target eq 'edit' ) {
+     $result=&Apache::edit::end_table();
+  } elsif ($target eq 'web') {
 # Now is the time to render all of the stored splines
+      my $xmin=&Apache::lonxml::get_param('xmin',$parstack,$safeeval,-2);
+      $xmin=(defined($xmin)?$xmin:-10);
+      my $xmax=&Apache::lonxml::get_param('xmax',$parstack,$safeeval,-2);
+      $xmax=(defined($xmax)?$xmax:10);
+      my $ymin=&Apache::lonxml::get_param('ymin',$parstack,$safeeval,-2);
+      $ymin=(defined($ymin)?$ymin:-10);
+      my $ymax=&Apache::lonxml::get_param('ymax',$parstack,$safeeval,-2);
+      $ymax=(defined($ymax)?$ymax:10);
+      if ($xmax<=$xmin) {
+        $xmax=$xmin+20;
+      }
+      if ($ymax<=$ymin) {
+         $ymax=$ymin+20;
+      }
      foreach my $label (keys(%Apache::functionplotresponse::splineorder)) {
-        $result.=&generate_spline($internalid,$label);
+        $result.=&generate_spline($internalid,$label,$xmin,$xmax,$ymin,$ymax);
      }
 # close the init script
      $result.=&end_init_script();
@@ -703,6 +1161,58 @@ sub end_functionplotresponse {
   }
   return $result;
 }
+
+sub start_functionplotelements {
+   my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
+   my $result='';
+   my $id=$Apache::inputtags::response[-1];
+   my $partid=$Apache::inputtags::part;
+   my $internalid = $partid.'_'.$id;
+
+   if ($target eq 'edit') {
+      return &Apache::edit::start_table($token).
+        '<tr><td><span class="LC_nobreak">'.&mt('Function Plot Elements').'</span></td>'
+       .'<td><span class="LC_nobreak">'.&mt('Delete?').' '
+       .&Apache::edit::deletelist($target,$token).'&nbsp;&nbsp;&nbsp;'.
+        &Apache::edit::insertlist($target,$token)
+       .'</span></td>'
+       ."<td>&nbsp;"
+       .&Apache::edit::end_row()
+       .&Apache::edit::start_spanning_row()
+       ."\n";
+   } elsif ($target eq 'web') {
+      my $xmin=&Apache::lonxml::get_param('xmin',$parstack,$safeeval,-2);
+      $xmin=(defined($xmin)?$xmin:-10);
+      my $xmax=&Apache::lonxml::get_param('xmax',$parstack,$safeeval,-2);
+      $xmax=(defined($xmax)?$xmax:10);
+      my $ymin=&Apache::lonxml::get_param('ymin',$parstack,$safeeval,-2);
+      $ymin=(defined($ymin)?$ymin:-10);
+      my $ymax=&Apache::lonxml::get_param('ymax',$parstack,$safeeval,-2);
+      $ymax=(defined($ymax)?$ymax:10);
+      if ($xmax<=$xmin) {
+        $xmax=$xmin+20;
+      }
+      if ($ymax<=$ymin) {
+         $ymax=$ymin+20;
+      }
+      my $xaxisvisible=(&Apache::lonxml::get_param('xaxisvisible',$parstack,$safeeval,-2)=~/on|true|yes|1/i?'true':'false');
+      my $yaxisvisible=(&Apache::lonxml::get_param('yaxisvisible',$parstack,$safeeval,-2)=~/on|true|yes|1/i?'true':'false');
+      my $gridvisible=(&Apache::lonxml::get_param('gridvisible',$parstack,$safeeval,-2)=~/on|true|yes|1/i?'true':'false');
+      my $xlabel=&Apache::lonxml::get_param('xlabel',$parstack,$safeeval,-2);
+      my $ylabel=&Apache::lonxml::get_param('ylabel',$parstack,$safeeval,-2);
+
+
+# paste in the update routine to receive stuff back from the applet
+     $result.=&update_script($internalid);
+# start the initscript for this applet
+     $result.=&start_init_script($internalid);
+# put the axis commands inside
+     $result.=&axes_script($internalid,$xmin,$xmax,$ymin,$ymax,$xaxisvisible,$yaxisvisible,$gridvisible);
+     $result.=&axes_label($internalid,$xlabel,$ylabel);
+# init script is left open
+  }
+  return $result;
+}
 
 1;