--- loncom/homework/functionplotresponse.pm	2010/10/17 22:32:19	1.14
+++ loncom/homework/functionplotresponse.pm	2010/11/01 00:04:09	1.22
@@ -1,7 +1,7 @@
 # LearningOnline Network with CAPA
 # option list style responses
 #
-# $Id: functionplotresponse.pm,v 1.14 2010/10/17 22:32:19 www Exp $
+# $Id: functionplotresponse.pm,v 1.22 2010/11/01 00:04:09 www Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -101,12 +101,25 @@ ENDDEFAULTPARAMETERS
 #
 
 sub init_script {
-   if ($Apache::functionplotresponse::callscripts) {
+   if ($#Apache::functionplotresponse::callscripts>=0) {
+      my $script='';
+      foreach my $id (@Apache::functionplotresponse::callscripts) {
+          $script.="if (param=='applet_$id') { loaded_$id=true; }\n";
+      }
+      $script.="if (".join(' && ',map { "loaded_$_" } (@Apache::functionplotresponse::callscripts)).
+               ") { setTimeout('ggbInitAll()',20) }";
+      my $calls=join("\n",map { "ggbInit_$_();" } (@Apache::functionplotresponse::callscripts)); 
       return (<<ENDGGBINIT);
 <script type="text/javascript">
 // <![CDATA[
+// Function that each applet will call when loaded
+// It will pass "its" parameter
+// Set flags for when an applet is loaded, wait till all are loaded, and then some
 function ggbOnInit(param) {
-$Apache::functionplotresponse::callscripts
+$script
+}
+function ggbInitAll() {
+$calls
 }
 // ]]>
 </script>
@@ -194,14 +207,16 @@ sub new_coordinate {
 #
 sub start_init_script {
     my ($id)=@_;
-# Add a line to ggbOnInit-function which calls the right function based on parameter passed from GeoGebra
-    $Apache::functionplotresponse::callscripts.="if (param=='applet_$id') { ggbInit_$id(); }\n";
+# Add id to the list of ggbInit_$id functions that need to be called
+    push(@Apache::functionplotresponse::callscripts,$id);
 # ... and open this function
     return (<<ENDSTARTINIT);
 <script type="text/javascript">
 // <![CDATA[
 // variable that will eventually be passed back to the server
 var coordinateMap_$id = [];
+// flag for not loaded yet
+var loaded_$id=false;
 // Init-function for applet
 function ggbInit_$id() {
 ENDSTARTINIT
@@ -453,6 +468,178 @@ sub get_answer_from_form_fields {
    return ($answer,%coords);
 }
 
+#
+# The following functions calculate the cubic-hermite splines server-side
+#
+
+sub cubic_hermite {
+   my ($t,$p1,$s1,$p2,$s2)=@_;
+   return (2.*$t*$t*$t-3.*$t*$t+1.)*$p1 + 5.*($t*$t*$t-2.*$t*$t+$t)*($s1-$p1)+
+          (-2.*$t*$t*$t+3.*$t*$t)  *$p2 + 5.*($t*$t*$t-$t*$t)      *($s2-$p2);
+}
+
+#
+# d/dt(...)
+# 
+
+sub ddt_cubic_hermite {
+   my ($t,$p1,$s1,$p2,$s2)=@_;
+   return (6.*$t*$t-6.*$t) *$p1 + 5.*(3.*$t*$t-4.*$t+1.)*($s1-$p1)+
+          (-6.*$t*$t+6.*$t)*$p2 + 5.*(3.*$t*$t-2.*$t)   *($s2-$p2);
+}
+
+#
+# d^2/dt^2(...)
+#
+
+sub d2dt2_cubic_hermite {
+   my ($t,$p1,$s1,$p2,$s2)=@_;
+   return (12.*$t-6.) *$p1 + 5.*(6.*$t-4.)*($s1-$p1)+
+          (-12.*$t+6.)*$p2 + 5.*(6.*$t-2.)*($s2-$p2);
+}
+
+#
+# Array index calculation
+#
+sub array_index {
+   my ($xmin,$xmax,$x)=@_;
+   return int(($x-$xmin)/($xmax-$xmin)*200.+0.5);
+}
+
+#
+# Actual x-value of array index
+#
+
+sub index_x {
+   my ($xmin,$xmax,$i)=@_;
+   return $i*($xmax-$xmin)/200.+$xmin;
+}
+
+#
+# Assume function to be linear between array points
+# Return the two indices and the scale factor
+#
+
+sub indices_scale {
+   my ($xmin,$xmax,$x)=@_;
+   my $i=&array_index($xmin,$xmax,$x);
+   my $xr=&index_x($xmin,$xmax,$i);
+   if ($xr<$x) {
+# Desired x is right of array index
+      if ($i>=200) { return (200,200,0); }
+      return($i,$i+1,200.*($x-$xr)/($xmax-$xmin));
+   } elsif ($xr>$x) {
+# Desired x is left of array index
+      if ($i<=0) { return (0,0,0); }
+      return($i-1,$i,1.-200.*($xr-$x)/($xmax-$xmin));
+   } else {
+# Desired x is at array index (unlikely, but ...)
+      if ($i>=200) { return (200,200,0); }
+      if ($i<=0) { return (0,0,0); }
+      return ($i,$i,0);
+   }
+}
+
+#
+# Function value
+#
+
+sub func_val {
+   my ($xmin,$xmax,$x)=@_;
+   my ($il,$ih,$factor)=&indices_scale($xmin,$xmax,$x);
+   my $fl=$Apache::functionplotresponse::func[$il];
+   my $fh=$Apache::functionplotresponse::func[$ih];
+   unless (defined($fl) || defined($fh)) { return undef; }
+   unless (defined($fl)) { return $fh; }
+   unless (defined($fh)) { return $fl; }
+   return $fl+$factor*($fh-$fl);
+}
+
+#
+# First derivative
+#
+
+sub dfuncdx_val {
+   my ($xmin,$xmax,$x)=@_;
+   my ($il,$ih,$factor)=&indices_scale($xmin,$xmax,$x);
+   my $fl=$Apache::functionplotresponse::dfuncdx[$il];
+   my $fh=$Apache::functionplotresponse::dfuncdx[$ih];
+   unless (defined($fl) || defined($fh)) { return undef; }
+   unless (defined($fl)) { return $fh; }
+   unless (defined($fh)) { return $fl; }
+   return $fl+$factor*($fh-$fl);
+}
+
+#
+# Second derivative
+#
+
+sub d2funcdx2_val {
+   my ($xmin,$xmax,$x)=@_;
+   my ($il,$ih,$factor)=&indices_scale($xmin,$xmax,$x);
+   my $fl=$Apache::functionplotresponse::d2funcdx2[$il];
+   my $fh=$Apache::functionplotresponse::d2funcdx2[$ih];
+   unless (defined($fl) || defined($fh)) { return undef; }
+   unless (defined($fl)) { return $fh; }
+   unless (defined($fh)) { return $fl; }
+   return $fl+$factor*($fh-$fl);
+}
+
+#
+# Populate the arrays
+#
+
+sub populate_arrays {
+    my ($id,$xmin,$xmax)=@_;
+    for (my $i=0; $i<=200; $i++) {
+       $Apache::functionplotresponse::func[$i]=undef;
+       $Apache::functionplotresponse::dfuncdx[$i]=undef;
+       $Apache::functionplotresponse::d2funcd2x[$i]=undef;
+    }
+    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=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'},
+                        $env{'form.HWVAL_'.$id.'_'.$label.'P'.$ni.'_x'},
+                        $env{'form.HWVAL_'.$id.'_'.$label.'S'.$ni.'_x'});
+            my @yparms=($env{'form.HWVAL_'.$id.'_'.$label.'P'.$i.'_y'},
+                        $env{'form.HWVAL_'.$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) { return 'no_func'; }
+                if (($xi>$xiold) && ($xi>=0) && ($xi<=200)) {
+                   if (defined($Apache::functionplotresponse::func[$xi])) { return 'no_func'; }
+                   $xiold=$xi;
+# Function value
+                   $Apache::functionplotresponse::func[$xi]=&cubic_hermite($t,@yparms);
+# 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;
+                   }
+# d^2y/dx^2
+                   my $d2xdt2=&d2dt2_cubic_hermite($t,@xparms);
+                   if ($d2xdt2) {
+                      $Apache::functionplotresponse::d2funcd2x[$xi]=&d2dt2_cubic_hermite($t,@yparms)/$d2xdt2;
+                   }
+                }
+            }
+        }
+    }
+}
+
+#
+# Implentation of <functionplotresponse>
+#
+
 sub start_functionplotresponse {
   my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
   my $result='';
@@ -476,13 +663,13 @@ sub start_functionplotresponse {
 
 # Parameters of <functionplotresponse>
   my $xmin=&Apache::lonxml::get_param('xmin',$parstack,$safeeval);
-  $xmin=($xmin?$xmin:-10);
+  $xmin=(defined($xmin)?$xmin:-10);
   my $xmax=&Apache::lonxml::get_param('xmax',$parstack,$safeeval);
-  $xmax=($xmax?$xmax:10);
+  $xmax=(defined($xmax)?$xmax:10);
   my $ymin=&Apache::lonxml::get_param('ymin',$parstack,$safeeval);
-  $ymin=($ymin?$ymin:-10);
+  $ymin=(defined($ymin)?$ymin:-10);
   my $ymax=&Apache::lonxml::get_param('ymax',$parstack,$safeeval);
-  $ymax=($ymax?$ymax:10);
+  $ymax=(defined($ymax)?$ymax:10);
   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');
@@ -563,7 +750,17 @@ sub end_functionplotresponse {
 #
 # Actually grade
 #
-        my $ad='INCORRECT';
+        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='NOT_FUNCTION';
+        } else {
+           $ad='INCORRECT';
+        }
+
 #
 # Store grading info
 #
@@ -576,6 +773,13 @@ sub end_functionplotresponse {
      }
 # close the init script
      $result.=&end_init_script();
+# register all splines in this response 
+     $result.='<input type="hidden" name="HWVAL_AllSplines_'.$internalid.'" value="'.
+                 join(',',keys(%Apache::functionplotresponse::splineorder)).'" />'."\n";
+     foreach my $label (keys(%Apache::functionplotresponse::splineorder)) {
+        $result.='<input type="hidden" name="HWVAL_SplineOrder_'.$internalid.'_'.$label.'" value="'.
+                 $Apache::functionplotresponse::splineorder{$label}.'" />'."\n";
+     }
 # generate the input fields
      $result.=$Apache::functionplotresponse::inputfields;
 # actually start the <applet>-tag