--- loncom/homework/functionplotresponse.pm	2010/11/10 22:41:29	1.31
+++ loncom/homework/functionplotresponse.pm	2010/11/11 15:57:49	1.34
@@ -1,7 +1,7 @@
 # LearningOnline Network with CAPA
 # option list style responses
 #
-# $Id: functionplotresponse.pm,v 1.31 2010/11/10 22:41:29 www Exp $
+# $Id: functionplotresponse.pm,v 1.34 2010/11/11 15:57:49 www Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -389,7 +389,8 @@ sub start_functionplotrule {
            &Apache::lonxml::get_param('xfinal',$parstack,$safeeval),
            $endinglabel,
            $relationship,
-           &Apache::lonxml::get_param('value',$parstack,$safeeval)
+           &Apache::lonxml::get_param('value',$parstack,$safeeval),
+           &Apache::lonxml::get_param('percenterror',$parstack,$safeeval)
           )));
    } elsif ($target eq 'edit') {
         $result=&Apache::edit::tag_start($target,$token,'Function Plot Evaluation Rule').
@@ -398,17 +399,17 @@ sub start_functionplotrule {
              &Apache::edit::select_arg(&mt('Function:'),'derivative',
                                   [['0','Function itself'],
                                    ['1','First derivative'],
-                                   ['2','Second derivative']],$token).' '.
+                                   ['2','Second derivative']],$token).'<br />'.
 
              &Apache::edit::text_arg('(Initial) x-value:','xinitial',
                                       $token,'4').
              &Apache::edit::select_or_text_arg('(Initial) x-value label:','xinitiallabel',
-                                               [['start','Start of Plot']],$token,'8').'&nbsp;'.
+                                               [['start','Start of Plot']],$token,'8').'<br />'.
 
              &Apache::edit::text_arg('Optional final x-value for ranges:','xfinal',
                                       $token,'4').
              &Apache::edit::select_or_text_arg('Optional final x-value label:','xfinallabel',
-                                               [['end','End of Plot']],$token,'8').'&nbsp;'.
+                                               [['end','End of Plot']],$token,'8').'<br />'.
 
              &Apache::edit::select_arg(&mt('Relationship:'),'relationship',
                                   [['eq','equal'],
@@ -638,14 +639,10 @@ sub populate_arrays {
                    my $dxdt=&ddt_cubic_hermite($t,@xparms);
                    if ($dxdt) {
                       $Apache::functionplotresponse::dfuncdx[$xi]=&ddt_cubic_hermite($t,@yparms)/$dxdt;
-                   }
-# Faa di Bruno
-# d^2y/dx^2=(d^2y/dt^2)/(dx/dt)^2+(dy/dt)/(d^2x/dt^2)
-                   my $d2xdt2=&d2dt2_cubic_hermite($t,@xparms);
-                   if (($dxdt) && ($d2xdt2)) {
+# Second derivative
                       $Apache::functionplotresponse::d2funcdx2[$xi]=
-                         &d2dt2_cubic_hermite($t,@yparms)/($dxdt*$dxdt)
-                        +&ddt_cubic_hermite($t,@yparms)/$d2xdt2;
+                         ($dxdt*&d2dt2_cubic_hermite($t,@yparms)-&ddt_cubic_hermite($t,@yparms)*&d2dt2_cubic_hermite($t,@xparms))/
+                         ($dxdt*$dxdt*$dxdt);
                    }
                 }
             }
@@ -719,7 +716,7 @@ 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',
@@ -727,7 +724,7 @@ 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();
@@ -791,10 +788,13 @@ sub compare_rel {
 }
 
 sub functionplotrulecheck {
-   my ($rule,$xmin,$xmax,$tolfunc,$toldfdx,$told2fdx2)=@_;
-   &Apache::lonnet::logthis("Rule $rule TolFunc $tolfunc TolDfDx $toldfdx TolD2fDx2 $told2fdx2");
-   my ($label,$derivative,$xinitial,$xinitiallabel,$xfinal,$xfinallabel,$relationship,$value)
+   my ($rule,$xmin,$xmax,$ymin,$ymax)=@_;
+
+#   &Apache::lonnet::logthis("Rule $rule $xmin $xmax $ymin $ymax");
+
+   my ($label,$derivative,$xinitial,$xinitiallabel,$xfinal,$xfinallabel,$relationship,$value,$percent)
       =split(/\:/,$rule);
+   $percent=($percent>0?$percent:5);
 
    my $li=0;
    my $lh=400;
@@ -827,7 +827,7 @@ sub functionplotrulecheck {
    }
    unless ($findupper) {
       if (defined($Apache::functionplotresponse::functionplotrulelabels{$xfinallabel})) {
-         $lh=$Apache::functionplotresponse::functionplotrulelabels{$xfinallabel};
+         $lh=$Apache::functionplotresponse::functionplotrulelabels{$xfinallabel}-1;
       } else {
          $lh=&array_index($xmin,$xmax,$xfinal);
       }
@@ -839,12 +839,14 @@ sub functionplotrulecheck {
        $lh=$li;
    }
 
-   &Apache::lonnet::logthis("Init $xinitial=$li Final $xfinal=$lh Findupper: $findupper");
-   my $tol=$tolfunc;
-   if ($derivative==2) {
-      $tol=$told2fdx2;
-   } elsif ($derivative==1) {
-      $tol=$toldfdx;
+#   &Apache::lonnet::logthis("Init $xinitial=$li Final $xfinal=$lh Findupper: $findupper");
+   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;
@@ -856,10 +858,10 @@ sub functionplotrulecheck {
            $val=$Apache::functionplotresponse::func[$i];
         }
         unless (&compare_rel($relationship,$value,$val,$tol)) { 
-           &Apache::lonnet::logthis("Condition false $findupper at $i with $val");
+#           &Apache::lonnet::logthis("Condition false $findupper at $i with $val tol:$tol from $value");
            if (($findupper) && ($i>$li)) {
               $Apache::functionplotresponse::functionplotrulelabels{$xfinallabel}=$i;
-              &Apache::lonnet::logthis("Setting $xfinallabel to $i");
+#              &Apache::lonnet::logthis("Setting $xfinallabel to $i");
               return 1;
            } else {
               return 0; 
@@ -903,17 +905,6 @@ sub end_functionplotresponse {
         my $ymax=&Apache::lonxml::get_param('ymax',$parstack,$safeeval);
         $ymax=(defined($ymax)?$ymax:10);
 
-        my $percent=&Apache::lonxml::get_param('percenterror',$parstack,$safeeval);
-        $percent=(defined($percent)?$percent:5);
-
-        my $tolfunc=$percent*($ymax-$ymin)/100.;
-        my $toldfdx=1;
-        my $told2fdx2=1;
-        if ($xmax>$xmin) {
-           $toldfdx=$tolfunc/($xmax-$xmin);
-           $told2fdx2=$toldfdx/($xmax-$xmin);
-        }
-
         my $ad='';
         undef  %Apache::functionplotresponse::functionplotrulelabels;
         $Apache::functionplotresponse::functionplotrulelabels{'start'}=400;
@@ -923,7 +914,7 @@ sub end_functionplotresponse {
         } else {
 # 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,$tolfunc,$toldfdx,$told2fdx2)) {
+              unless (&functionplotrulecheck($rule,$xmin,$xmax,$ymin,$ymax)) {
                  $ad='INCORRECT';
                  last;
               }