--- loncom/homework/functionplotresponse.pm	2011/05/11 21:17:59	1.62
+++ loncom/homework/functionplotresponse.pm	2011/10/14 00:40:24	1.66
@@ -1,7 +1,7 @@
 # LearningOnline Network with CAPA
 # option list style responses
 #
-# $Id: functionplotresponse.pm,v 1.62 2011/05/11 21:17:59 www Exp $
+# $Id: functionplotresponse.pm,v 1.66 2011/10/14 00:40:24 www Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -31,6 +31,7 @@ use strict;
 use Apache::response();
 use Apache::lonlocal;
 use Apache::lonnet;
+use Apache::run;
  
 BEGIN {
   &Apache::lonxml::register('Apache::functionplotresponse',('functionplotresponse','backgroundplot','spline',
@@ -563,7 +564,7 @@ sub start_functionplotrule {
                                    ['lt','less than'],
                                    ['le','less than or equal']],$token).
              $result.= &Apache::edit::select_or_text_arg('Value:','value',
-                                               [['undef','not defined']],$token,'8').
+                                               [['undef','not defined']],$token,'30').
              &Apache::edit::text_arg('Percent error:','percenterror',
                                      $token,'8').
              &Apache::edit::end_row();
@@ -751,7 +752,7 @@ sub array_index {
 #
 
 sub populate_arrays {
-    my ($id,$xmin,$xmax)=@_;
+    my ($id,$xmin,$xmax,$ymin,$ymax)=@_;
     for (my $i=0; $i<=400; $i++) {
        $Apache::functionplotresponse::actualxval[$i]=undef;
        $Apache::functionplotresponse::func[$i]=undef;
@@ -779,12 +780,19 @@ sub populate_arrays {
                 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;
                    $Apache::functionplotresponse::actualxval[$xi]=$xreal;
 # Function value
                    my $funcval=&cubic_hermite($t,@yparms);
+
+# Do we already have a value for this point, and is it different from the new one?
+                   if ((defined($Apache::functionplotresponse::func[$xi])) &&
+                       (abs($Apache::functionplotresponse::func[$xi]-$funcval)>($ymax-$ymin)/100.)) { 
+                       return 'no_func'; 
+                   }
+# Okay, remember the new point
                    $Apache::functionplotresponse::func[$xi]=$funcval;
+
                    if (defined($funcval)) {
                       if ($xi<$Apache::functionplotresponse::functionplotrulelabels{'start'}) {
                          $Apache::functionplotresponse::functionplotrulelabels{'start'}=$xi;
@@ -880,8 +888,7 @@ sub start_functionplotresponse {
              &Apache::edit::select_arg('Grid visible:','gridvisible',
                                   ['yes','no'],$token).'<br />'.
              &Apache::edit::text_arg('Background plot(s) for answer (function(x):xmin:xmax,function(x):xmin:xmax,x1:y1:sx1:sy1:x2:y2:sx2:sy2,...):',
-                                         'answerdisplay',$token,'50');
-
+                                         'answerdisplay',$token,'50').
              &Apache::edit::end_row().&Apache::edit::start_spanning_row();
   } elsif ($target eq 'modified') {
     my $constructtag=&Apache::edit::get_new_args($token,$parstack,
@@ -973,15 +980,56 @@ sub actualval {
    my ($i,$xmin,$xmax)=@_;
    return $xmin+$i/400.*($xmax-$xmin);
 }
+
+sub fpr_val {
+   my ($arg)=@_;
+   return &actualval($Apache::functionplotresponse::functionplotrulelabels{$arg},
+                     $Apache::functionplotresponse::fpr_xmin,
+                     $Apache::functionplotresponse::fpr_xmax);
+}
+
+sub fpr_f {
+   my ($arg)=@_;
+   return $Apache::functionplotresponse::func[&array_index($Apache::functionplotresponse::fpr_xmin,
+                                                           $Apache::functionplotresponse::fpr_xmax,
+                                                           $arg)];
+}
+
+sub fpr_dfdx {
+   my ($arg)=@_;
+   return $Apache::functionplotresponse::dfuncdx[&array_index($Apache::functionplotresponse::fpr_xmin,
+                                                              $Apache::functionplotresponse::fpr_xmax,
+                                                              $arg)];
+}
+
+sub fpr_d2fdx2 {
+   my ($arg)=@_;
+   return $Apache::functionplotresponse::d2funcdx2[&array_index($Apache::functionplotresponse::fpr_xmin,
+                                                                $Apache::functionplotresponse::fpr_xmax,
+                                                                $arg)];
+}
  
 sub functionplotrulecheck {
-   my ($rule,$xmin,$xmax,$ymin,$ymax)=@_;
+   my ($rule,$xmin,$xmax,$ymin,$ymax,$safeeval)=@_;
 
    my ($label,$derivative,$xinitial,$xinitiallabel,$xfinal,$xfinallabel,$minimumlength,$maximumlength,$relationship,$value,$percent)
       =split(/\:/,$rule);
    $percent=($percent>0?$percent:5);
    &addlog("=================");
    &addlog("Rule $label for ".($derivative<0?'integral':('function itself','first derivative','second derivative')[$derivative])." $relationship $value");
+#
+# Evaluate the value
+#
+   if ($value=~/\D/) {
+      $Apache::functionplotresponse::fpr_xmin=$xmin;
+      $Apache::functionplotresponse::fpr_xmax=$xmax;
+      $value=&Apache::run::run($value,$safeeval);
+      &addlog("Value evaluated to $value");
+   }
+
+#
+# Minimum and maximum lengths of the interval
+#
    if ((defined($minimumlength)) || (defined($maximumlength))) {
       &addlog("Minimumlength $minimumlength Maximumlength $maximumlength");
    }
@@ -1170,7 +1218,7 @@ sub end_functionplotruleset {
         $Apache::functionplotresponse::ruleslog='';
         $Apache::functionplotresponse::functionplotrulelabels{'start'}=400;
         $Apache::functionplotresponse::functionplotrulelabels{'end'}=0;
-        if (&populate_arrays($internalid,$xmin,$xmax) eq 'no_func') {
+        if (&populate_arrays($internalid,$xmin,$xmax,$ymin,$ymax) eq 'no_func') {
            $ad='NOT_FUNCTION';
         } else {
            &addlog("Start of function ".&actualval($Apache::functionplotresponse::functionplotrulelabels{'start'},$xmin,$xmax)." (index ".
@@ -1180,7 +1228,7 @@ sub end_functionplotruleset {
 
 # 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)) {
+              unless (&functionplotrulecheck($rule,$xmin,$xmax,$ymin,$ymax,$safeeval)) {
                  $ad='INCORRECT';
                  last;
               }