[system] / trunk / pg / lib / Value / AnswerChecker.pm Repository:
ViewVC logotype

View of /trunk/pg/lib/Value/AnswerChecker.pm

Parent Directory Parent Directory | Revision Log Revision Log


Revision 5826 - (download) (as text) (annotate)
Sat Jun 28 19:27:31 2008 UTC (4 years, 10 months ago) by dpvc
File size: 69923 byte(s)
Fixed problem with Union answer checker where incorrect error messages
could be given when intervals needed to be checked for syntax
errors.  Also fixed some comments.

    1 
    2 =head1 DESCRIPTION
    3 
    4  #############################################################
    5  #
    6  #  Implements the ->cmp method for Value objects.
    7  #  Otherwise known as MathObjects.  This produces
    8  #  an answer checker appropriate for the type of object.
    9  #  Additional options can be passed to the cmp method to
   10  #  modify its action.
   11  #
   12  #   Usage:  $num = Real(3.45); # Real can be replaced by any other MathObject
   13  #       ANS($num->cmp(compareOptionName => compareOptionValue, ... ))
   14  #
   15  #  The individual Value packages are modified below to add the
   16  #  needed methods.
   17  #
   18  #############################################################
   19 
   20 =cut
   21 
   22 package Value;
   23 
   24 #
   25 #  Context can add default values to the answer checkers by class;
   26 #
   27 $Value::defaultContext->{cmpDefaults} = {};
   28 
   29 =head5 $mathObject->cmp_defaults()
   30 
   31 #  Internal use.
   32 #  Set default flags for the answer checker in this object
   33 #   showTypeWarnings => 1
   34 #       showEqualErrors  => 1
   35 #       ignoreStrings    => 1
   36 #       studentsMustReduceUnions => 1
   37 #       showUnionReduceWarnings  => 1
   38 #
   39 
   40 =cut
   41 
   42 sub cmp_defaults {(
   43   showTypeWarnings => 1,
   44   showEqualErrors  => 1,
   45   ignoreStrings    => 1,
   46   studentsMustReduceUnions => 1,
   47   showUnionReduceWarnings => 1,
   48 )}
   49 
   50 
   51 #
   52 #  Special Context flags to be set for the student answer
   53 #
   54 
   55 sub cmp_contextFlags {
   56   my $self = shift; my $ans = shift;
   57   return (
   58     StringifyAsTeX => 0,                 # reset this, just in case.
   59     no_parameters => 1,                  # don't let students enter parameters
   60     showExtraParens => 2,                # make student answer painfully unambiguous
   61     reduceConstants => 0,                # don't combine student constants
   62     reduceConstantFunctions => 0,        # don't reduce constant functions
   63     ($ans->{studentsMustReduceUnions} ?
   64       (reduceUnions => 0, reduceSets => 0,
   65        reduceUnionsForComparison => $ans->{showUnionReduceWarnings},
   66        reduceSetsForComparison => $ans->{showUnionReduceWarnings}) :
   67       (reduceUnions => 1, reduceSets => 1,
   68        reduceUnionsForComparison => 1, reduceSetsForComparison => 1)),
   69     ($ans->{requireParenMatch}? (): ignoreEndpointTypes => 1),  # for Intervals
   70   );
   71 }
   72 
   73 
   74 #
   75 #  Create an answer checker for the given type of object
   76 #
   77 
   78 sub cmp {
   79   my $self = shift;
   80   my $ans = new AnswerEvaluator;
   81   my $correct = preformat($self->{correct_ans});
   82   $correct = $self->correct_ans unless defined($correct);
   83   $self->{context} = Value->context unless defined($self->{context});
   84   $ans->ans_hash(
   85     type => "Value (".$self->class.")",
   86     correct_ans => $correct,
   87     correct_value => $self,
   88     $self->cmp_defaults(@_),
   89     %{$self->{context}{cmpDefaults}{$self->class} || {}},  # context-specified defaults
   90     @_,
   91   );
   92   $ans->{debug} = $ans->{rh_ans}{debug};
   93   $ans->install_evaluator(sub {
   94      my $ans = shift;
   95      $ans->{_filter_name} = "MathObjects answer checker";
   96      $ans->{correct_value}->cmp_parse($ans);
   97   });
   98   $ans->install_pre_filter('erase') if $self->{ans_name}; # don't do blank check if answer_array
   99   $self->cmp_diagnostics($ans);
  100   return $ans;
  101 }
  102 
  103 sub correct_ans {preformat(shift->string)}
  104 sub cmp_diagnostics {}
  105 
  106 #
  107 #  Parse the student answer and compute its value,
  108 #    produce the preview strings, and then compare the
  109 #    student and professor's answers for equality.
  110 #
  111 sub cmp_parse {
  112   my $self = shift; my $ans = shift;
  113   #
  114   #  Do some setup
  115   #
  116   my $current = Value->context; # save it for later
  117   my $context = $ans->{correct_value}{context} || $current;
  118   Parser::Context->current(undef,$context); # change to correct answser's context
  119   my $flags = contextSet($context,$self->cmp_contextFlags($ans)); # save old context flags
  120   my $inputs = $self->getPG('$inputs_ref');
  121   $ans->{isPreview} = $inputs->{previewAnswers} || ($inputs->{action} =~ m/^Preview/);
  122   $ans->{cmp_class} = $self->cmp_class($ans) unless $ans->{cmp_class};
  123   $ans->{error_message} = $ans->{ans_message} = ''; # clear any old messages
  124   $ans->{preview_latex_string} = $ans->{preview_text_string} = '';
  125   $context->clearError();
  126   $context->{answerHash} = $ans; # values here can override context flags
  127 
  128   #
  129   #  Parse and evaluate the student answer
  130   #
  131   $ans->score(0);  # assume failure
  132   $ans->{student_value} = $ans->{student_formula} = Parser::Formula($ans->{student_ans});
  133   $ans->{student_value} = Parser::Evaluate($ans->{student_formula})
  134     if defined($ans->{student_formula}) && $ans->{student_formula}->isConstant;
  135 
  136   #
  137   #  If it parsed OK, save the output forms and check if it is correct
  138   #   otherwise report an error
  139   #
  140   if (defined $ans->{student_value}) {
  141     $ans->{student_value} = $self->Package("Formula")->new($ans->{student_value})
  142        unless Value::isValue($ans->{student_value});
  143     $ans->{student_value}{isStudent} = 1;
  144     $ans->{preview_latex_string} = $ans->{student_formula}->TeX;
  145     $ans->{preview_text_string}  = preformat($ans->{student_formula}->string);
  146     #
  147     #  Get the string for the student answer
  148     #
  149     for ($self->getFlag('formatStudentAnswer')) {
  150       /evaluated/i  and do {$ans->{student_ans} = preformat($ans->{student_value}->string); last};
  151       /parsed/i     and do {$ans->{student_ans} = $ans->{preview_text_string}; last};
  152       /reduced/i    and do {
  153   my $oldFlags = contextSet($context,reduceConstants=>1,reduceConstantFunctions=>0);
  154   $ans->{student_ans} = preformat($ans->{student_formula}->substitute()->string);
  155   contextSet($context,%{$oldFags}); last;
  156       };
  157       warn "Unkown student answer format |$ans->{formatStudentAnswer}|";
  158     }
  159     if ($self->cmp_collect($ans)) {
  160       $self->cmp_preprocess($ans);
  161       $self->cmp_equal($ans);
  162       $self->cmp_postprocess($ans) if !$ans->{error_message} && !$ans->{typeError};
  163       $self->cmp_diagnostics($ans);
  164     }
  165   } else {
  166     $self->cmp_collect($ans);
  167     $self->cmp_error($ans);
  168   }
  169   $context->{answerHash} = undef;
  170   contextSet($context,%{$flags});            # restore context values
  171   Parser::Context->current(undef,$current);  # put back the old context
  172   return $ans;
  173 }
  174 
  175 #
  176 #  Check if the object has an answer array and collect the results
  177 #  Build the combined student answer and set the preview values
  178 #
  179 sub cmp_collect {
  180   my $self = shift; my $ans = shift;
  181   return 1 unless $self->{ans_name};
  182   $ans->{preview_latex_string} = $ans->{preview_text_string} = "";
  183   my $OK = $self->ans_collect($ans);
  184   $ans->{student_ans} = $self->format_matrix($ans->{student_formula},@{$self->{format_options}},tth_delims=>1);
  185   return 0 unless $OK;
  186   my $array = $ans->{student_formula};
  187   if ($self->{ColumnVector}) {
  188     my @V = (); foreach my $x (@{$array}) {push(@V,$x->[0])}
  189     $array = [@V];
  190   } elsif (scalar(@{$array}) == 1) {$array = $array->[0]}
  191   my $type = $self;
  192   $type = $self->Package($self->{tree}->type) if $self->isFormula;
  193   $ans->{student_formula} = eval {$type->new($array)->with(ColumnVector=>$self->{ColumnVector})};
  194   if (!defined($ans->{student_formula}) || $self->context->{error}{flag})
  195     {Parser::reportEvalError($@); $self->cmp_error($ans); return 0}
  196   $ans->{student_value} = $ans->{student_formula};
  197   $ans->{preview_text_string} = $ans->{student_ans};
  198   $ans->{preview_latex_string} = $ans->{student_formula}->TeX;
  199   if (Value::isFormula($ans->{student_formula}) && $ans->{student_formula}->isConstant) {
  200     $ans->{student_value} = Parser::Evaluate($ans->{student_formula});
  201     return 0 unless $ans->{student_value};
  202   }
  203   return 1;
  204 }
  205 
  206 #
  207 #  Check if the parsed student answer equals the professor's answer
  208 #
  209 sub cmp_equal {
  210   my $self = shift; my $ans = shift;
  211   my $correct = $ans->{correct_value};
  212   my $student = $ans->{student_value};
  213   if ($correct->typeMatch($student,$ans)) {
  214     $self->context->clearError();
  215     my $equal = $correct->cmp_compare($student,$ans);
  216     if ($self->context->{error}{flag} != $CMP_MESSAGE &&
  217         (defined($equal) || !$ans->{showEqualErrors})) {$ans->score(1) if $equal; return}
  218     $self->cmp_error($ans);
  219   } else {
  220     return if $ans->{ignoreStrings} && (!Value::isValue($student) || $student->type eq 'String');
  221     $ans->{typeError} = 1;
  222     $ans->{ans_message} = $ans->{error_message} =
  223       "Your answer isn't ".lc($ans->{cmp_class})."\n".
  224         "(it looks like ".lc($student->showClass).")"
  225      if !$ans->{isPreview} && $ans->{showTypeWarnings} && !$ans->{error_message};
  226   }
  227 }
  228 
  229 #
  230 #  Perform the comparison, either using the checker supplied
  231 #  by the answer evaluator, or the overloaded == operator.
  232 #
  233 
  234 our $CMP_ERROR = 2;   # a fatal error was detected
  235 our $CMP_WARNING = 3; # a warning was produced
  236 our $CMP_MESSAGE = 4; # an message should be reported for this check
  237 
  238 sub cmp_compare {
  239   my $self = shift; my $other = shift; my $ans = shift; my $nth = shift || '';
  240   my $context = (Value::isValue($self) ? $self->context : Value->context);
  241   return eval {$self == $other} unless ref($ans->{checker}) eq 'CODE';
  242   my @equal = eval {&{$ans->{checker}}($self,$other,$ans,$nth,@_)};
  243   if (!defined($equal) && $@ ne '' && (!$context->{error}{flag} || $ans->{showAllErrors})) {
  244     $context->setError(["<I>An error occurred while checking your$nth answer:</I>\n".
  245       '<DIV STYLE="margin-left:1em">%s</DIV>',$@],'',undef,undef,$CMP_ERROR);
  246     warn "Please inform your instructor that an error occurred while checking your answer";
  247   }
  248   return (wantarray ? @equal : $equal[0]);
  249 }
  250 
  251 sub cmp_list_compare {Value::List::cmp_list_compare(@_)}
  252 
  253 #
  254 #  Check if types are compatible for equality check
  255 #
  256 sub typeMatch {
  257   my $self = shift;  my $other = shift;
  258   return 1 unless ref($other);
  259   $self->type eq $other->type && !$other->isFormula;
  260 }
  261 
  262 #
  263 #  Class name for cmp error messages
  264 #
  265 sub cmp_class {
  266   my $self = shift; my $ans = shift;
  267   my $class = $self->showClass; $class =~ s/Real //;
  268   return $class if $class =~ m/Formula/;
  269   return "an Interval, Set or Union" if $self->isSetOfReals;
  270   return $class;
  271 }
  272 
  273 #
  274 #  Student answer evaluation failed.
  275 #  Report the error, with formatting, if possible.
  276 #
  277 sub cmp_error {
  278   my $self = shift; my $ans = shift;
  279   my $error = $self->context->{error};
  280   my $message = $error->{message};
  281   if ($error->{pos}) {
  282     my $string = $error->{string};
  283     my ($s,$e) = @{$error->{pos}};
  284     $message =~ s/; see.*//;  # remove the position from the message
  285     $ans->{student_ans} =
  286        protectHTML(substr($string,0,$s)) .
  287        '<SPAN CLASS="parsehilight">' .
  288          protectHTML(substr($string,$s,$e-$s)) .
  289        '</SPAN>' .
  290        protectHTML(substr($string,$e));
  291   }
  292   $self->cmp_Error($ans,$message);
  293 }
  294 
  295 #
  296 #  Set the error message
  297 #
  298 sub cmp_Error {
  299   my $self = shift; my $ans = shift;
  300   return unless scalar(@_) > 0;
  301   $ans->score(0);
  302   $ans->{ans_message} = $ans->{error_message} = join("\n",@_);
  303 }
  304 
  305 #
  306 #  Force a message into the results message column and die
  307 #  (To be used when overriding Parser classes that need
  308 #  to report errors to the student but can't do it in
  309 #  the overridden == since errors are trapped.)
  310 #
  311 sub cmp_Message {
  312   my $message = shift; my $context = Value->context;
  313   $message = [$message,@_] if scalar(@_) > 0;
  314   $context->setError($message,'',undef,undef,$CMP_MESSAGE);
  315   $message = $context->{error}{message};
  316   die $message . traceback() if $context->flags('showTraceback');
  317   die $message . getCaller();
  318 }
  319 
  320 #
  321 #  filled in by sub-classes
  322 #
  323 sub cmp_preprocess {}
  324 sub cmp_postprocess {}
  325 
  326 #
  327 #  Check for unreduced reduced Unions and Sets
  328 #
  329 sub cmp_checkUnionReduce {
  330   my $self = shift; my $student = shift; my $ans = shift; my $nth = shift || '';
  331   return unless $ans->{studentsMustReduceUnions} &&
  332                 $ans->{showUnionReduceWarnings} &&
  333                 !$ans->{isPreview} && !Value::isFormula($student);
  334   return unless $student->isSetOfReals;
  335   my ($result,$error) = $student->isReduced;
  336   return unless $error;
  337   return {
  338     "overlaps" => "Your$nth union contains overlapping intervals",
  339     "overlaps in sets" => "Your$nth union contains sets and intervals that overlap",
  340     "uncombined intervals" => "Your$nth union can be simplified by combining intervals",
  341     "uncombined sets" => "Your$nth union can be simplified by combining some sets",
  342     "repeated elements in set" => "Your$nth union contains sets with repeated elements",
  343     "repeated elements" => "Your$nth set should have no repeated elements",
  344   }->{$error};
  345 }
  346 
  347 #
  348 #  create answer rules of various types
  349 #
  350 sub ans_rule {shift; pgCall('ans_rule',@_)}
  351 sub named_ans_rule {shift; pgCall('NAMED_ANS_RULE',@_)}
  352 sub named_ans_rule_extension {shift; pgCall('NAMED_ANS_RULE_EXTENSION',@_)}
  353 sub ans_array {shift->ans_rule(@_)};
  354 sub named_ans_array {shift->named_ans_rule(@_)};
  355 sub named_ans_array_extension {shift->named_ans_rule_extension(@_)};
  356 
  357 sub pgCall {my $call = shift; &{WeBWorK::PG::Translator::PG_restricted_eval('\&'.$call)}(@_)}
  358 sub pgRef {WeBWorK::PG::Translator::PG_restricted_eval('\&'.shift)}
  359 
  360 our $answerPrefix = "MaTrIx";
  361 
  362 #
  363 #  Lay out a matrix of answer rules
  364 #
  365 sub ans_matrix {
  366   my $self = shift;
  367   my ($extend,$name,$rows,$cols,$size,$open,$close,$sep) = @_;
  368   my $named_extension = pgRef('NAMED_ANS_RULE_EXTENSION');
  369   my $new_name = pgRef('RECORD_FORM_LABEL');
  370   my $HTML = ""; my $ename = $name;
  371   if ($name eq '') {
  372     my $n = pgCall('inc_ans_rule_count');
  373     $name = pgCall('NEW_ANS_NAME',$n);
  374     $ename = $answerPrefix.$n;
  375   }
  376   $self->{ans_name} = $ename;
  377   $self->{ans_rows} = $rows;
  378   $self->{ans_cols} = $cols;
  379   my @array = ();
  380   foreach my $i (0..$rows-1) {
  381     my @row = ();
  382     foreach my $j (0..$cols-1) {
  383       if ($i == 0 && $j == 0) {
  384   if ($extend) {push(@row,&$named_extension(&$new_name($name),$size))}
  385           else {push(@row,pgCall('NAMED_ANS_RULE',$name,$size))}
  386       } else {
  387   push(@row,&$named_extension(&$new_name(ANS_NAME($ename,$i,$j)),$size));
  388       }
  389     }
  390     push(@array,[@row]);
  391   }
  392   $self->format_matrix([@array],open=>$open,close=>$close,sep=>$sep);
  393 }
  394 
  395 sub ANS_NAME {
  396   my ($name,$i,$j) = @_;
  397   $name.'_'.$i.'_'.$j;
  398 }
  399 
  400 
  401 #
  402 #  Lay out an arbitrary matrix
  403 #
  404 sub format_matrix {
  405   my $self = shift; my $array = shift;
  406   my $displayMode = $self->getPG('$displayMode');
  407   $array = [$array] unless ref($array->[0]) eq 'ARRAY';
  408   return $self->format_matrix_tex($array,@_) if ($displayMode eq 'TeX');
  409   return $self->format_matrix_HTML($array,@_);
  410 }
  411 
  412 sub format_matrix_tex {
  413   my $self = shift; my $array = shift;
  414   my %options = (open=>'.',close=>'.',sep=>'',@_);
  415   $self->{format_options} = [%options] unless $self->{format_options};
  416   my ($open,$close,$sep) = ($options{open},$options{close},$options{sep});
  417   my ($rows,$cols) = (scalar(@{$array}),scalar(@{$array->[0]}));
  418   my $tex = "";
  419   $open = '\\'.$open if $open =~ m/[{}]/; $close = '\\'.$close if $close =~ m/[{}]/;
  420   $tex .= '\(\left'.$open;
  421   $tex .= '\setlength{\arraycolsep}{2pt}', $sep = '\,'.$sep if $sep;
  422   $tex .= '\begin{array}{'.('c'x$cols).'}';
  423   foreach my $i (0..$rows-1) {$tex .= join($sep.'&',@{$array->[$i]}).'\cr'."\n"}
  424   $tex .= '\end{array}\right'.$close.'\)';
  425   return $tex;
  426 }
  427 
  428 sub format_matrix_HTML {
  429   my $self = shift; my $array = shift;
  430   my %options = (open=>'',close=>'',sep=>'',tth_delims=>0,@_);
  431   $self->{format_options} = [%options] unless $self->{format_options};
  432   my ($open,$close,$sep) = ($options{open},$options{close},$options{sep});
  433   my ($rows,$cols) = (scalar(@{$array}),scalar(@{$array->[0]}));
  434   my $HTML = "";
  435   if ($sep) {$sep = '</TD><TD STYLE="padding: 0px 1px">'.$sep.'</TD><TD>'}
  436        else {$sep = '</TD><TD WIDTH="8px"></TD><TD>'}
  437   foreach my $i (0..$rows-1) {
  438     $HTML .= '<TR><TD HEIGHT="6px"></TD></TR>' if $i;
  439     $HTML .= '<TR ALIGN="MIDDLE"><TD>'.join($sep,EVALUATE(@{$array->[$i]})).'</TD></TR>'."\n";
  440   }
  441   $open = $self->format_delimiter($open,$rows,$options{tth_delims});
  442   $close = $self->format_delimiter($close,$rows,$options{tth_delims});
  443   if ($open ne '' || $close ne '') {
  444     $HTML = '<TR ALIGN="MIDDLE">'
  445           . '<TD>'.$open.'</TD>'
  446           . '<TD WIDTH="2"></TD>'
  447           . '<TD><TABLE BORDER="0" CELLSPACING="0" CELLPADDING="0" CLASS="ArrayLayout">'
  448           .   $HTML
  449           . '</TABLE></TD>'
  450           . '<TD WIDTH="4"></TD>'
  451           . '<TD>'.$close.'</TD>'
  452           . '</TR>'."\n";
  453   }
  454   return '<TABLE BORDER="0" CELLSPACING="0" CELLPADDING="0" CLASS="ArrayLayout"'
  455           . ' STYLE="display:inline;vertical-align:-'.(1.1*$rows-.6).'em">'
  456           . $HTML
  457           . '</TABLE>';
  458 }
  459 
  460 sub EVALUATE {map {(Value::isFormula($_) && $_->isConstant? $_->eval: $_)} @_}
  461 
  462 sub VERBATIM {
  463   my $string = shift;
  464   my $displayMode = Value->getPG('$displayMode');
  465   $string = '\end{verbatim}'.$string.'\begin{verbatim}' if $displayMode eq 'TeX';
  466   return $string;
  467 }
  468 
  469 #
  470 #  Create a tall delimiter to match the line height
  471 #
  472 sub format_delimiter {
  473   my $self = shift; my $delim = shift; my $rows = shift; my $tth = shift;
  474   return '' if $delim eq '' || $delim eq '.';
  475   my $displayMode = $self->getPG('$displayMode');
  476   return $self->format_delimiter_tth($delim,$rows,$tth)
  477     if $tth || $displayMode eq 'HTML_tth' || $displayMode !~ m/^HTML_/;
  478   my $rule = '\vrule width 0pt height '.(.8*$rows).'em depth 0pt';
  479   $rule = '\rule 0pt '.(.8*$rows).'em 0pt' if $displayMode eq 'HTML_jsMath';
  480   $delim = '\\'.$delim if $delim eq '{' || $delim eq '}';
  481   return '\(\left'.$delim.$rule.'\right.\)';
  482 }
  483 
  484 #
  485 #  Data for tth delimiters [top,mid,bot,rep]
  486 #
  487 my %tth_delim = (
  488   '[' => ['&#xF8EE;','','&#xF8F0;','&#xF8EF;'],
  489   ']' => ['&#xF8F9;','','&#xF8FB;','&#xF8FA;'],
  490   '(' => ['&#xF8EB;','','&#xF8ED;','&#xF8EC;'],
  491   ')' => ['&#xF8F6;','','&#xF8F8;','&#xF8F7;'],
  492   '{' => ['&#xF8F1;','&#xF8F2;','&#xF8F3;','&#xF8F4;'],
  493   '}' => ['&#xF8FC;','&#xF8FD;','&#xF8FE;','&#xF8F4;'],
  494   '|' => ['|','','|','|'],
  495   '<' => ['&lt;'],
  496   '>' => ['&gt;'],
  497   '\lgroup' => ['&#xF8F1;','','&#xF8F3;','&#xF8F4;'],
  498   '\rgroup' => ['&#xF8FC;','','&#xF8FE;','&#xF8F4;'],
  499 );
  500 
  501 #
  502 #  Make delimiters as stacks of characters
  503 #
  504 sub format_delimiter_tth {
  505   my $self = shift;
  506   my $delim = shift; my $rows = shift; my $tth = shift;
  507   return '' if $delim eq '' || !defined($tth_delim{$delim});
  508   my $c = $delim; $delim = $tth_delim{$delim};
  509   $c = $delim->[0] if scalar(@{$delim}) == 1;
  510   my $size = ($tth? "": "font-size:175%; ");
  511   return '<SPAN STYLE="'.$size.'margin:0px 2px">'.$c.'</SPAN>'
  512     if $rows == 1 || scalar(@{$delim}) == 1;
  513   my $HTML = "";
  514   if ($delim->[1] eq '') {
  515     $HTML = join('<BR>',$delim->[0],($delim->[3])x(2*($rows-1)),$delim->[2]);
  516   } else {
  517     $HTML = join('<BR>',$delim->[0],($delim->[3])x($rows-1),
  518             $delim->[1],($delim->[3])x($rows-1),
  519             $delim->[2]);
  520   }
  521   return '<DIV STYLE="line-height:90%; margin: 0px 2px">'.$HTML.'</DIV>';
  522 }
  523 
  524 
  525 #
  526 #  Look up the values of the answer array entries, and check them
  527 #  for syntax and other errors.  Build the student answer
  528 #  based on these, and keep track of error messages.
  529 #
  530 
  531 my @ans_cmp_defaults = (showCoodinateHints => 0, checker => sub {0});
  532 
  533 sub ans_collect {
  534   my $self = shift; my $ans = shift;
  535   my $inputs = $self->getPG('$inputs_ref');
  536   my $blank = ($self->getPG('$displayMode') eq 'TeX') ? '\_\_' : '__';
  537   my ($rows,$cols) = ($self->{ans_rows},$self->{ans_cols});
  538   my @array = (); my $data = [$self->value]; my $errors = []; my $OK = 1;
  539   if ($self->{ColumnVector}) {foreach my $x (@{$data}) {$x = [$x]}}
  540   $data = [$data] unless ref($data->[0]) eq 'ARRAY';
  541   foreach my $i (0..$rows-1) {
  542     my @row = (); my $entry;
  543     foreach my $j (0..$cols-1) {
  544       if ($i || $j) {
  545   $entry = $inputs->{ANS_NAME($self->{ans_name},$i,$j)};
  546       } else {
  547   $entry = $ans->{original_student_ans};
  548   $ans->{student_formula} = $ans->{student_value} = undef unless $entry =~ m/\S/;
  549       }
  550       my $result = $data->[$i][$j]->cmp(@ans_cmp_defaults)->evaluate($entry);
  551       $OK &= entryCheck($result,$blank);
  552       push(@row,$result->{student_formula});
  553       entryMessage($result->{ans_message},$errors,$i,$j,$rows,$cols);
  554     }
  555     push(@array,[@row]);
  556   }
  557   $ans->{student_formula} = [@array];
  558   $ans->{ans_message} = $ans->{error_message} = "";
  559   if (scalar(@{$errors})) {
  560     $ans->{ans_message} = $ans->{error_message} =
  561       '<TABLE BORDER="0" CELLSPACING="0" CELLPADDING="0" CLASS="ArrayLayout">'.
  562       join('<TR><TD HEIGHT="4"></TD></TR>',@{$errors}).
  563       '</TABLE>';
  564     $OK = 0;
  565   }
  566   return $OK;
  567 }
  568 
  569 sub entryMessage {
  570   my $message = shift; return unless $message;
  571   my ($errors,$i,$j,$rows,$cols) = @_; $i++; $j++;
  572   my $title;
  573   if ($rows == 1) {$title = "In entry $j"}
  574   elsif ($cols == 1) {$title = "In entry $i"}
  575   else {$title = "In entry ($i,$j)"}
  576   push(@{$errors},"<TR VALIGN=\"TOP\"><TD NOWRAP STYLE=\"text-align:right; border:0px\"><I>$title</I>:&nbsp;</TD>".
  577                   "<TD STYLE=\"text-align:left; border:0px\">$message</TD></TR>");
  578 }
  579 
  580 sub entryCheck {
  581   my $ans = shift; my $blank = shift;
  582   return 1 if defined($ans->{student_value});
  583   if (!defined($ans->{student_formula})) {
  584     $ans->{student_formula} = $ans->{student_ans};
  585     $ans->{student_formula} = $blank unless $ans->{student_formula};
  586   }
  587   return 0
  588 }
  589 
  590 
  591 #
  592 #  Get and Set values in context
  593 #
  594 sub contextSet {
  595   my $context = shift; my %set = (@_);
  596   my $flags = $context->{flags}; my $get = {};
  597   foreach my $id (keys %set) {$get->{$id} = $flags->{$id}; $flags->{$id} = $set{$id}}
  598   return $get;
  599 }
  600 
  601 #
  602 #  Quote HTML characters
  603 #
  604 sub protectHTML {
  605   my $string = shift;
  606   return unless defined($string);
  607   return $string if eval ('$main::displayMode') eq 'TeX';
  608   $string =~ s/&/\&amp;/g;
  609   $string =~ s/</\&lt;/g;
  610   $string =~ s/>/\&gt;/g;
  611   $string;
  612 }
  613 
  614 #
  615 #  Convert newlines to <BR>
  616 #
  617 sub preformat {
  618   my $string = protectHTML(shift);
  619   $string =~ s!\n!<br />!g unless eval('$main::displayMode') eq 'TeX';
  620   $string;
  621 }
  622 
  623 #
  624 #  names for numbers
  625 #
  626 sub NameForNumber {
  627   my $self = shift; my $n = shift;
  628   my $name =  ('zeroth','first','second','third','fourth','fifth',
  629                'sixth','seventh','eighth','ninth','tenth')[$n];
  630   $name = "$n-th" if ($n > 10);
  631   return $name;
  632 }
  633 
  634 #
  635 #  Get a value from the safe compartment
  636 #
  637 sub getPG {
  638   my $self = shift;
  639 #  (WeBWorK::PG::Translator::PG_restricted_eval(shift))[0];
  640   eval ('package main; '.shift);  # faster
  641 }
  642 
  643 #############################################################
  644 #############################################################
  645 
  646 =head3 Value::Real
  647 
  648   Usage ANS( Real(3.56)->cmp() )
  649     Compares response to a real value using 'fuzzy' comparison
  650     compareOptions and default values:
  651         showTypeWarnings => 1,
  652         showEqualErrors  => 1,
  653         ignoreStrings    => 1,
  654 
  655 =cut
  656 
  657 
  658 package Value::Real;
  659 
  660 sub cmp_defaults {(
  661   shift->SUPER::cmp_defaults(@_),
  662   ignoreInfinity => 1,
  663 )}
  664 
  665 sub typeMatch {
  666   my $self = shift; my $other = shift; my $ans = shift;
  667   return 1 unless ref($other);
  668   return 0 if Value::isFormula($other);
  669   return 1 if $other->type eq 'Infinity' && $ans->{ignoreInfinity};
  670   $self->type eq $other->type;
  671 }
  672 
  673 #############################################################
  674 
  675 package Value::Infinity;
  676 
  677 sub cmp_class {'a Number'};
  678 
  679 sub typeMatch {
  680   my $self = shift; my $other = shift; my $ans = shift;
  681   return 1 unless ref($other);
  682   return 0 if Value::isFormula($other);
  683   return 1 if $other->type eq 'Number';
  684   $self->type eq $other->type;
  685 }
  686 
  687 #############################################################
  688 
  689 =head3 Value::String
  690 
  691   Usage:  $s = String("pole");
  692     ANS($s->cmp(typeMatch => Complex("4+i")));
  693         # compare to response 'pole', don't complain about complex number responses.
  694 
  695     compareOptions and default values:
  696       showTypeWarnings => 1,
  697       showEqualErrors  => 1,
  698       ignoreStrings    => 1   # don't complain about string-valued responses
  699       typeMatch        => 'Value::Real'
  700 
  701   Initial and final spaces are ignored when comparing strings.
  702 
  703 =cut
  704 
  705 package Value::String;
  706 
  707 sub cmp_defaults {(
  708   Value::Real->cmp_defaults(@_),
  709   typeMatch => 'Value::Real',
  710 )}
  711 
  712 sub cmp_class {
  713   my $self = shift; my $ans = shift; my $typeMatch = $ans->{typeMatch};
  714   return 'a Word' if !Value::isValue($typeMatch) || $typeMatch->classMatch('String');
  715   return $typeMatch->cmp_class;
  716 };
  717 
  718 sub typeMatch {
  719   my $self = shift; my $other = shift; my $ans = shift;
  720   my $typeMatch = $ans->{typeMatch};
  721   return &$typeMatch($other,$ans) if ref($typeMatch) eq 'CODE';
  722   return 1 if !Value::isValue($typeMatch) || $typeMatch->classMatch('String') ||
  723                  $self->type eq $other->type;
  724   return $typeMatch->typeMatch($other,$ans);
  725 }
  726 
  727 #
  728 #  Remove the blank-check prefilter when the string is empty,
  729 #  and add a filter that removes leading and trailing whitespace.
  730 #
  731 sub cmp {
  732   my $self = shift;
  733   my $cmp = $self->SUPER::cmp(@_);
  734   if ($self->value =~ m/^\s*$/) {
  735     $cmp->install_pre_filter('erase');
  736     $cmp->install_pre_filter(sub {
  737       my $ans = shift;
  738       $ans->{student_ans} =~ s/^\s+//g;
  739       $ans->{student_ans} =~ s/\s+$//g;
  740       return $ans;
  741     });
  742   }
  743   return $cmp;
  744 }
  745 
  746 #############################################################
  747 
  748 =head3 Value::Point
  749 
  750   Usage: $pt = Point("(3,6)"); # preferred
  751          or $pt = Point(3,6);
  752          or $pt = Point([3,6]);
  753          ANS($pt->cmp());
  754 
  755     compareOptions:
  756       showTypeWarnings => 1,   # warns if student response is of incorrect type
  757       showEqualErrors  => 1,
  758       ignoreStrings    => 1,
  759       showDimensionHints => 1, # reports incorrect number of coordinates
  760       showCoordinateHints =>1, # flags individual coordinates that are incorrect
  761 
  762 =cut
  763 
  764 package Value::Point;
  765 
  766 sub cmp_defaults {(
  767   shift->SUPER::cmp_defaults(@_),
  768   showDimensionHints => 1,
  769   showCoordinateHints => 1,
  770 )}
  771 
  772 sub typeMatch {
  773   my $self = shift; my $other = shift; my $ans = shift;
  774   return ref($other) && $other->type eq 'Point' && !$other->isFormula;
  775 }
  776 
  777 #
  778 #  Check for dimension mismatch and incorrect coordinates
  779 #
  780 sub cmp_postprocess {
  781   my $self = shift; my $ans = shift;
  782   return unless $ans->{score} == 0 && !$ans->{isPreview};
  783   my $student = $ans->{student_value};
  784   return if $ans->{ignoreStrings} && (!Value::isValue($student) || $student->type eq 'String');
  785   if ($ans->{showDimensionHints} && $self->length != $student->length) {
  786     $self->cmp_Error($ans,"The number of coordinates is incorrect"); return;
  787   }
  788   if ($ans->{showCoordinateHints}) {
  789     my @errors;
  790     foreach my $i (1..$self->length) {
  791       push(@errors,"The ".$self->NameForNumber($i)." coordinate is incorrect")
  792   if ($self->{data}[$i-1] != $student->{data}[$i-1]);
  793     }
  794     $self->cmp_Error($ans,@errors); return;
  795   }
  796 }
  797 
  798 sub correct_ans {
  799   my $self = shift;
  800   return $self->SUPER::correct_ans unless $self->{ans_name};
  801   Value::VERBATIM($self->format_matrix([[@{$self->{data}}]],@{$self->{format_options}},tth_delims=>1));
  802 }
  803 
  804 sub ANS_MATRIX {
  805   my $self = shift;
  806   my $extend = shift; my $name = shift;
  807   my $size = shift || 5;
  808   my $def = $self->context->lists->get('Point');
  809   my $open = $self->{open} || $def->{open}; my $close = $self->{close} || $def->{close};
  810   $self->ans_matrix($extend,$name,1,$self->length,$size,$open,$close,',');
  811 }
  812 
  813 sub ans_array {my $self = shift; $self->ANS_MATRIX(0,'',@_)}
  814 sub named_ans_array {my $self = shift; $self->ANS_MATRIX(0,@_)}
  815 sub named_ans_array_extension {my $self = shift; $self->ANS_MATRIX(1,@_)}
  816 
  817 #############################################################
  818 
  819 =head3 Value::Vector
  820 
  821   Usage:  $vec = Vector("<3,6,7>");
  822           or $vec = Vector(3,6,7);
  823           or $vec = Vector([3,6,7]);
  824           ANS($vec->cmp());
  825 
  826     compareOptions:
  827       showTypeWarnings    => 1,   # warns if student response is of incorrect type
  828       showEqualErrors     => 1,
  829       ignoreStrings       => 1,
  830       showDimensionHints  => 1, # reports incorrect number of coordinates
  831       showCoordinateHints => 1, # flags individual coordinates which are incorrect
  832       promotePoints       => 0, # allow students to enter vectors as points (3,5,6)
  833       parallel            => 1, # response is correct if it is parallel to correct answer
  834       sameDirection       => 1, # response is correct if it has same orientation as correct answer
  835                                 #  (only has an effect when parallel => 1 is specified)
  836 
  837 
  838 =cut
  839 
  840 package Value::Vector;
  841 
  842 sub cmp_defaults {(
  843   shift->SUPER::cmp_defaults(@_),
  844   showDimensionHints => 1,
  845   showCoordinateHints => 1,
  846   promotePoints => 0,
  847   parallel => 0,
  848   sameDirection => 0,
  849 )}
  850 
  851 sub typeMatch {
  852   my $self = shift; my $other = shift; my $ans = shift;
  853   return 0 unless ref($other) && !$other->isFormula;
  854   return $other->type eq 'Vector' ||
  855      ($ans->{promotePoints} && $other->type eq 'Point');
  856 }
  857 
  858 #
  859 #  check for dimension mismatch
  860 #        for parallel vectors, and
  861 #        for incorrect coordinates
  862 #
  863 sub cmp_postprocess {
  864   my $self = shift; my $ans = shift;
  865   return unless $ans->{score} == 0 && !$ans->{isPreview};
  866   my $student = $ans->{student_value};
  867   return if $ans->{ignoreStrings} && (!Value::isValue($student) || $student->type eq 'String');
  868   if ($self->length != $student->length) {
  869     ($self,$student) = $self->cmp_pad($student);
  870     if ($ans->{showDimensionHints} && $self->length != $student->length) {
  871       $self->cmp_Error($ans,"The number of coordinates is incorrect"); return;
  872     }
  873   }
  874   if ($ans->{parallel} && !$student->isFormula && !$student->classMatch('String') &&
  875       $self->isParallel($student,$ans->{sameDirection})) {
  876     $ans->score(1); return;
  877   }
  878   if ($ans->{showCoordinateHints} && !$ans->{parallel}) {
  879     my @errors;
  880     foreach my $i (1..$self->length) {
  881       push(@errors,"The ".$self->NameForNumber($i)." coordinate is incorrect")
  882   if ($self->{data}[$i-1] != $student->{data}[$i-1]);
  883     }
  884     $self->cmp_Error($ans,@errors); return;
  885   }
  886 }
  887 
  888 #
  889 #  Pad the student or correct answer if either is in ijk notation
  890 #  and they are not the same dimension.  Only add zeros when the other one
  891 #  also has zeros in those places.
  892 #
  893 sub cmp_pad {
  894   my $self = shift; my $student = shift;
  895   if (($self->getFlag("ijk") || $student->getFlag("ijk")) && $self->getFlag("ijkAnyDimension")) {
  896     $self = $self->copy; $student = $student->copy;
  897     while ($self->length > $student->length && $self->{data}[$student->length] == 0)
  898       {push(@{$student->{data}},Value::Real->new(0))}
  899     while ($self->length < $student->length && $student->{data}[$self->length] == 0)
  900       {push(@{$self->{data}},Value::Real->new(0))}
  901   }
  902   return ($self,$student);
  903 }
  904 
  905 sub correct_ans {
  906   my $self = shift;
  907   return $self->SUPER::correct_ans unless $self->{ans_name};
  908   return Value::VERBATIM($self->format_matrix([[$self->value]],@{$self->{format_options}},tth_delims=>1))
  909     unless $self->{ColumnVector};
  910   my @array = (); foreach my $x ($self->value) {push(@array,[$x])}
  911   return Value::VERBATIM($self->format_matrix([@array],@{$self->{format_options}},tth_delims=>1));
  912 }
  913 
  914 sub ANS_MATRIX {
  915   my $self = shift;
  916   my $extend = shift; my $name = shift;
  917   my $size = shift || 5; my ($def,$open,$close);
  918   $def = $self->context->lists->get('Matrix');
  919   $open = $self->{open} || $def->{open}; $close = $self->{close} || $def->{close};
  920   return $self->ans_matrix($extend,$name,$self->length,1,$size,$open,$close)
  921     if ($self->{ColumnVector});
  922   $def = $self->context->lists->get('Vector');
  923   $open = $self->{open} || $def->{open}; $close = $self->{close} || $def->{close};
  924   $self->ans_matrix($extend,$name,1,$self->length,$size,$open,$close,',');
  925 }
  926 
  927 sub ans_array {my $self = shift; $self->ANS_MATRIX(0,'',@_)}
  928 sub named_ans_array {my $self = shift; $self->ANS_MATRIX(0,@_)}
  929 sub named_ans_array_extension {my $self = shift; $self->ANS_MATRIX(1,@_)}
  930 
  931 
  932 #############################################################
  933 
  934 =head3 Value::Matrix
  935 
  936   Usage   $ma = Matrix([[3,6],[2,5]]) or $ma =Matrix([3,6],[2,5])
  937           ANS($ma->cmp());
  938 
  939     compareOptions:
  940 
  941       showTypeWarnings    => 1, # warns if student response is of incorrect type
  942       showEqualErrors     => 1, # reports messages that occur during element comparisons
  943       ignoreStrings       => 1,
  944       showDimensionHints  => 1, # reports incorrect number of coordinates
  945       showCoordinateHints => 1, # flags individual coordinates which are incorrect
  946 
  947 
  948 =cut
  949 
  950 package Value::Matrix;
  951 
  952 sub cmp_defaults {(
  953   shift->SUPER::cmp_defaults(@_),
  954   showDimensionHints => 1,
  955   showEqualErrors => 0,
  956 )}
  957 
  958 sub typeMatch {
  959   my $self = shift; my $other = shift; my $ans = shift;
  960   return 0 unless ref($other) && !$other->isFormula;
  961   return $other->type eq 'Matrix' ||
  962     ($other->type =~ m/^(Point|list)$/ &&
  963      $other->{open}.$other->{close} eq $self->{open}.$self->{close});
  964 }
  965 
  966 sub cmp_preprocess {
  967   my $self = shift; my $ans = shift;
  968   my $student = $ans->{student_value};
  969   return if $student->type ne 'Matrix';
  970   my @d1 = $self->dimensions; my @d2 = $student->dimensions;
  971   $ans->{student_value} = $student->make([$student->value])
  972     if (scalar(@d2) == 1 && scalar(@d1) == 2);
  973 }
  974 
  975 sub cmp_postprocess {
  976   my $self = shift; my $ans = shift;
  977   return unless $ans->{score} == 0 &&
  978     !$ans->{isPreview} && $ans->{showDimensionHints};
  979   my $student = $ans->{student_value};
  980   return if $ans->{ignoreStrings} && (!Value::isValue($student) || $student->type eq 'String');
  981   my @d1 = $self->dimensions; my @d2 = $student->dimensions;
  982   if (scalar(@d1) != scalar(@d2)) {
  983     $self->cmp_Error($ans,"Matrix dimension is not correct");
  984     return;
  985   } else {
  986     foreach my $i (0..scalar(@d1)-1) {
  987       if ($d1[$i] != $d2[$i]) {
  988   $self->cmp_Error($ans,"Matrix dimension is not correct");
  989   return;
  990       }
  991     }
  992   }
  993 }
  994 
  995 sub correct_ans {
  996   my $self = shift;
  997   return $self->SUPER::correct_ans unless $self->{ans_name};
  998   my @array = $self->value; @array = ([@array]) if $self->isRow;
  999   Value::VERBATIM($self->format_matrix([$self->value],@{$self->{format_options}},tth_delims=>1));
 1000 }
 1001 
 1002 sub ANS_MATRIX {
 1003   my $self = shift;
 1004   my $extend = shift; my $name = shift;
 1005   my $size = shift || 5;
 1006   my $def = $self->context->lists->get('Matrix');
 1007   my $open = $self->{open} || $def->{open}; my $close = $self->{close} || $def->{close};
 1008   my @d = $self->dimensions;
 1009   Value::Error("Can't create ans_array for %d-dimensional matrix",scalar(@d))
 1010     if (scalar(@d) > 2);
 1011   @d = (1,@d) if (scalar(@d) == 1);
 1012   $self->ans_matrix($extend,$name,@d,$size,$open,$close,'');
 1013 }
 1014 
 1015 sub ans_array {my $self = shift; $self->ANS_MATRIX(0,'',@_)}
 1016 sub named_ans_array {my $self = shift; $self->ANS_MATRIX(0,@_)}
 1017 sub named_ans_array_extension {my $self = shift; $self->ANS_MATRIX(1,@_)}
 1018 
 1019 #############################################################
 1020 
 1021 =head3   Value::Interval
 1022 
 1023   Usage:    $interval = Interval("(1,2]");
 1024             or $interval = Interval('(',1,2,']');
 1025             ANS($inteval->cmp);
 1026 
 1027       compareOptions and defaults:
 1028       showTypeWarnings  => 1,
 1029       showEqualErrors   => 1,
 1030       ignoreStrings     => 1,
 1031       showEndpointHints => 1, # show hints about which end point values are correct
 1032       showEndTypeHints  => 1, # show hints about endpoint types
 1033       requireParenMatch => 1,
 1034 
 1035 
 1036 =cut
 1037 
 1038 package Value::Interval;
 1039 
 1040 sub cmp_defaults {(
 1041   shift->SUPER::cmp_defaults(@_),
 1042   showEndpointHints => 1,
 1043   showEndTypeHints => 1,
 1044   requireParenMatch => 1,
 1045 )}
 1046 
 1047 sub typeMatch {
 1048   my $self = shift; my $other = shift;
 1049   return 0 if !Value::isValue($other) || $other->isFormula;
 1050   return $other->canBeInUnion;
 1051 }
 1052 
 1053 #
 1054 #  Check for unreduced sets and unions
 1055 #
 1056 sub cmp_compare {
 1057   my $self = shift; my $student = shift; my $ans = shift;
 1058   my $error = $self->cmp_checkUnionReduce($student,$ans,@_);
 1059   if ($error) {$self->context->setError($error,'',undef,undef,$CMP_WARNING); return}
 1060   $self->SUPER::cmp_compare($student,$ans,@_);
 1061 }
 1062 
 1063 #
 1064 #  Check for wrong enpoints and wrong type of endpoints
 1065 #
 1066 sub cmp_postprocess {
 1067   my $self = shift; my $ans = shift;
 1068   return unless $ans->{score} == 0 && !$ans->{isPreview};
 1069   my $other = $ans->{student_value};
 1070   return if $ans->{ignoreStrings} && (!Value::isValue($other) || $other->type eq 'String');
 1071   return unless $other->classMatch('Interval');
 1072   my @errors;
 1073   if ($ans->{showEndpointHints}) {
 1074     push(@errors,"Your left endpoint is incorrect")
 1075       if ($self->{data}[0] != $other->{data}[0]);
 1076     push(@errors,"Your right endpoint is incorrect")
 1077       if ($self->{data}[1] != $other->{data}[1]);
 1078   }
 1079   if (scalar(@errors) == 0 && $ans->{showEndTypeHints} && $ans->{requireParenMatch}) {
 1080     push(@errors,"The type of interval is incorrect")
 1081       if ($self->{open}.$self->{close} ne $other->{open}.$other->{close});
 1082   }
 1083   $self->cmp_Error($ans,@errors);
 1084 }
 1085 
 1086 #############################################################
 1087 
 1088 =head3 Value::Set
 1089 
 1090   Usage:   $set = Set(5,6,'a', 'b')
 1091         or $set = Set("{5, 6, a, b}")
 1092 
 1093         The object is a finite set of real numbers. It can be used with Union and
 1094         Interval.
 1095 
 1096   Examples:  Interval("(-inf,inf)") - Set(0)
 1097              Compute("R-{0}")   # in Interval context: Context("Interval");
 1098 
 1099 =cut
 1100 
 1101 package Value::Set;
 1102 
 1103 sub typeMatch {
 1104   my $self = shift; my $other = shift;
 1105   return 0 if !Value::isValue($other) || $other->isFormula;
 1106   return $other->canBeInUnion;
 1107 }
 1108 
 1109 #
 1110 #  Use the List checker for sets, in order to get
 1111 #  partial credit.  Set the various types for error
 1112 #  messages.
 1113 #
 1114 sub cmp_defaults {(
 1115   Value::List::cmp_defaults(@_),
 1116   typeMatch => 'Value::Real',
 1117   list_type => 'a set',
 1118   entry_type => 'a number',
 1119   removeParens => 0,
 1120   showParenHints => 1,
 1121   implicitList => 0,
 1122 )}
 1123 
 1124 #
 1125 #  Use the list checker if the student answer is a set
 1126 #    otherwise use the standard compare (to get better
 1127 #    error messages).
 1128 #
 1129 sub cmp_equal {
 1130   my ($self,$ans) = @_;
 1131   return $self->SUPER::cmp_equal($ans) unless $ans->{student_value}->type eq 'Set';
 1132   my $error = $self->cmp_checkUnionReduce($ans->{student_value},$ans);
 1133   if ($error) {$self->cmp_Error($ans,$error); return}
 1134   return Value::List::cmp_equal(@_);
 1135 }
 1136 
 1137 #
 1138 #  Check for unreduced sets and unions
 1139 #
 1140 sub cmp_compare {
 1141   my $self = shift; my $student = shift; my $ans = shift;
 1142   my $error = $self->cmp_checkUnionReduce($student,$ans,@_);
 1143   if ($error) {$self->context->setError($error,'',undef,undef,$CMP_WARNING); return}
 1144   $self->SUPER::cmp_compare($student,$ans,@_);
 1145 }
 1146 
 1147 #############################################################
 1148 
 1149 =head3 Value::Union
 1150 
 1151   Usage: $union = Union("[4,5] U [6,7]");
 1152          or $union = Union(Interval("[4,5]",Interval("[6,7]"));
 1153          ANS($union->cmp());
 1154 
 1155 
 1156 =cut
 1157 
 1158 package Value::Union;
 1159 
 1160 sub typeMatch {
 1161   my $self = shift; my $other = shift;
 1162   return 0 unless ref($other) && !$other->isFormula;
 1163   return $other->length == 2 &&
 1164          ($other->{open} eq '(' || $other->{open} eq '[') &&
 1165          ($other->{close} eq ')' || $other->{close} eq ']')
 1166      if $other->type =~ m/^(Point|List)$/;
 1167   $other->isSetOfReals;
 1168 }
 1169 
 1170 #
 1171 #  Use the List checker for unions, in order to get
 1172 #  partial credit.  Set the various types for error
 1173 #  messages.
 1174 #
 1175 my $typeMatchInterval = Value::Interval->make(0,1);
 1176 sub cmp_defaults {(
 1177   Value::List::cmp_defaults(@_),
 1178   typeMatch => $typeMatchInterval,
 1179   list_type => 'an interval, set or union',
 1180   short_type => 'a union',
 1181   entry_type => 'an interval or set',
 1182 )}
 1183 
 1184 sub cmp_equal {
 1185   my $self = shift; my $ans = shift;
 1186   my $error = $self->cmp_checkUnionReduce($ans->{student_value},$ans);
 1187   if ($error) {$self->cmp_Error($ans,$error); return}
 1188   Value::List::cmp_equal($self,$ans);
 1189 }
 1190 
 1191 #
 1192 #  Check for unreduced sets and unions
 1193 #
 1194 sub cmp_compare {
 1195   my $self = shift; my $student = shift; my $ans = shift;
 1196   my $error = $self->cmp_checkUnionReduce($student,$ans,@_);
 1197   if ($error) {$self->context->setError($error,'',undef,undef,$CMP_WARNING); return}
 1198   $self->SUPER::cmp_compare($student,$ans,@_);
 1199 }
 1200 
 1201 #############################################################
 1202 
 1203 =head3 Value::List
 1204 
 1205   Usage:  $lst = List("1, x, <4,5,6>"); # list of a real, a formula and a vector.
 1206           or $lst = List(Real(1), Formula("x"), Vector(4,5,6));
 1207           ANS($lst->cmp(showHints=>1));
 1208 
 1209     compareOptions and defaults:
 1210       showTypeWarnings => 1,
 1211       showEqualErrors  => 1,         # show errors produced when checking equality of entries
 1212       ignoreStrings    => 1,         # don't show type warnings for strings
 1213       studentsMustReduceUnions => 1,
 1214       showUnionReduceWarnings => 1,
 1215       showHints => undef,            # automatically set to 1 if $showPartialCorrectAnswers == 1
 1216       showLengthHints => undef,      # automatically set to 1 if $showPartialCorrectAnswers == 1
 1217       showParenHints => undef,       # automatically set to 1 if $showPartialCorrectAnswers == 1
 1218       partialCredit => undef,        # automatically set to 1 if $showPartialCorrectAnswers == 1
 1219       ordered => 0,                  # 1 = must be in same order as correct answer
 1220       entry_type => undef,           # determined from first entry
 1221       list_type => undef,            # determined automatically
 1222       typeMatch => $element,         # used for type checking the entries
 1223       firstElement => $element,
 1224       extra => undef,                # used to check syntax of incorrect answers
 1225       requireParenMatch => 1,        # student parens must match correct parens
 1226       removeParens => 1,             # remove outermost parens, if any
 1227       implicitList => 1,             # force single answers to be lists (even if they ARE lists)
 1228 
 1229 
 1230 =cut
 1231 
 1232 package Value::List;
 1233 
 1234 sub cmp_defaults {
 1235   my $self = shift;
 1236   my %options = (@_);
 1237   my $element = Value::makeValue($self->{data}[0],context=>$self->context);
 1238   $element = $self->Package("Formula")->new($element) unless Value::isValue($element);
 1239   return (
 1240     Value::Real->cmp_defaults(@_),
 1241     showHints => undef,
 1242     showLengthHints => undef,
 1243     showParenHints => undef,
 1244     partialCredit => undef,
 1245     ordered => 0,
 1246     entry_type => undef,
 1247     list_type => undef,
 1248     typeMatch => $element,
 1249     firstElement => $element,
 1250     extra => undef,
 1251     requireParenMatch => 1,
 1252     removeParens => 1,
 1253     implicitList => 1,
 1254   );
 1255 }
 1256 
 1257 #
 1258 #  Match anything but formulas
 1259 #
 1260 sub typeMatch {return !ref($other) || !$other->isFormula}
 1261 
 1262 #
 1263 #  Handle removal of outermost parens in correct answer.
 1264 #
 1265 sub cmp {
 1266   my $self = shift;
 1267   my %params = @_;
 1268   my $cmp = $self->SUPER::cmp(@_);
 1269   if ($cmp->{rh_ans}{removeParens}) {
 1270     $self->{open} = $self->{close} = '';
 1271     $cmp->ans_hash(correct_ans => $self->stringify)
 1272       unless defined($self->{correct_ans}) || defined($params{correct_ans});
 1273   }
 1274   return $cmp;
 1275 }
 1276 
 1277 sub cmp_equal {
 1278   my $self = shift; my $ans = shift;
 1279   $ans->{showPartialCorrectAnswers} = $self->getPG('$showPartialCorrectAnswers');
 1280 
 1281   #
 1282   #  get the paramaters
 1283   #
 1284   my $showHints         = getOption($ans,'showHints');
 1285   my $showLengthHints   = getOption($ans,'showLengthHints');
 1286   my $showParenHints    = getOption($ans,'showParenHints');
 1287   my $partialCredit     = getOption($ans,'partialCredit');
 1288   my $requireParenMatch = $ans->{requireParenMatch};
 1289   my $implicitList      = $ans->{implicitList};
 1290   my $typeMatch         = $ans->{typeMatch};
 1291   my $value             = $ans->{entry_type};
 1292   my $ltype             = $ans->{list_type} || lc($self->type);
 1293   my $stype             = $ans->{short_type} || $ltype;
 1294 
 1295   $value = (Value::isValue($typeMatch)? lc($typeMatch->cmp_class): 'a value')
 1296     unless defined($value);
 1297   $value =~ s/(real|complex) //; $ans->{cmp_class} = $value;
 1298   $value =~ s/^an? //; $value = 'formula' if $value =~ m/formula/;
 1299   $ltype =~ s/^an? //; $stype =~ s/^an? //;
 1300   $showHints = $showLengthHints = 0 if $ans->{isPreview};
 1301 
 1302   #
 1303   #  Get the lists of correct and student answers
 1304   #   (split formulas that return lists or unions)
 1305   #
 1306   my @correct = (); my ($cOpen,$cClose);
 1307   if (!$self->isFormula) {
 1308     @correct = $self->value;
 1309     $cOpen = $ans->{correct_value}{open}; $cClose = $ans->{correct_value}{close};
 1310   } else {
 1311     @correct = Value::List->splitFormula($self,$ans);
 1312     $cOpen = $self->{tree}{open}; $cClose = $self->{tree}{close};
 1313   }
 1314   my $student = $ans->{student_value}; my @student = ($student);
 1315   my ($sOpen,$sClose) = ('','');
 1316   if (Value::isFormula($student) && $student->type eq $self->type) {
 1317     if ($implicitList && $student->{tree}{open} ne '') {
 1318       @student = ($student);
 1319     } else {
 1320       @student = Value::List->splitFormula($student,$ans);
 1321       $sOpen = $student->{tree}{open}; $sClose = $student->{tree}{close};
 1322     }
 1323   } elsif (!$student->isFormula && $student->classMatch($self->type)) {
 1324     if ($implicitList && $student->{open} ne '') {
 1325       @student = ($student);
 1326     } else {
 1327       @student = @{$student->{data}};
 1328       $sOpen = $student->{open}; $sClose = $student->{close};
 1329     }
 1330   }
 1331   foreach my $x (@correct) {$x->{equation} = $self};
 1332   foreach my $x (@student) {$x->{equation} = $self};
 1333   return if $ans->{split_error};
 1334   #
 1335   #  Check for parenthesis match
 1336   #
 1337   if ($requireParenMatch && ($sOpen ne $cOpen || $sClose ne $cClose)) {
 1338     if ($showParenHints && !($ans->{ignoreStrings} && $student->type eq 'String')) {
 1339       my $message = "The parentheses for your $ltype ";
 1340       if (($cOpen || $cClose) && ($sOpen || $sClose))
 1341                                 {$message .= "are of the wrong type"}
 1342       elsif ($sOpen || $sClose) {$message .= "should be removed"}
 1343       else                      {$message .= "seem to be missing"}
 1344       $self->cmp_Error($ans,$message) unless $ans->{isPreview};
 1345     }
 1346     return;
 1347   }
 1348 
 1349   #
 1350   #  Determine the maximum score
 1351   #
 1352   my $M = scalar(@correct);
 1353   my $m = scalar(@student);
 1354   my $maxscore = ($m > $M)? $m : $M;
 1355 
 1356   #
 1357   #  Compare the two lists
 1358   #  (Handle errors in user-supplied functions)
 1359   #
 1360   my ($score,@errors);
 1361   if (ref($ans->{list_checker}) eq 'CODE') {
 1362     eval {($score,@errors) = &{$ans->{list_checker}}([@correct],[@student],$ans,$value)};
 1363     if (!defined($score)) {
 1364       die $@ if $@ ne '' && $self->{context}{error}{flag} == 0;
 1365       $self->cmp_error($ans) if $self->{context}{error}{flag};
 1366     }
 1367   } else {
 1368     ($score,@errors) = $self->cmp_list_compare([@correct],[@student],$ans,$value);
 1369   }
 1370   return unless defined($score);
 1371 
 1372   #
 1373   #  Give hints about extra or missing answers
 1374   #
 1375   if ($showLengthHints) {
 1376     $value =~ s/( or|,) /s$1 /g; # fix "interval or union"
 1377     push(@errors,"There should be more ${value}s in your $stype")
 1378       if ($score < $maxscore && $score == $m);
 1379     push(@errors,"There should be fewer ${value}s in your $stype")
 1380       if ($score < $maxscore && $score == $M && !$showHints);
 1381   }
 1382 
 1383   #
 1384   #  If all the entries are in error, don't give individual messages
 1385   #
 1386   if ($score == 0) {
 1387     my $i = 0;
 1388     while ($i <= $#errors) {
 1389       if ($errors[$i++] =~ m/^Your .* is incorrect$/)
 1390         {splice(@errors,--$i,1)}
 1391     }
 1392   }
 1393 
 1394   #
 1395   #  Finalize the score
 1396   #
 1397   $score = 0 if ($score != $maxscore && !$partialCredit);
 1398   $ans->score($score/$maxscore);
 1399   push(@errors,"Score = $ans->{score}") if $ans->{debug};
 1400   my $error = join("\n",@errors); $error =~ s!</DIV>\n!</DIV>!g;
 1401   $ans->{error_message} = $ans->{ans_message} = $error;
 1402 }
 1403 
 1404 #
 1405 #  Compare the contents of the list to see of they are equal
 1406 #
 1407 sub cmp_list_compare {
 1408   my $self = shift; my $context = $self->context;
 1409   my $correct = shift; my $student = shift; my $ans = shift; my $value = shift;
 1410   my @correct = @{$correct}; my @student = @{$student}; my $m = scalar(@student);
 1411   my $ordered = $ans->{ordered};
 1412   my $showTypeWarnings = $ans->{showTypeWarnings} && !$ans->{isPreview};
 1413   my $typeMatch = $ans->{typeMatch};
 1414   my $extra = defined($ans->{extra}) ? $ans->{extra} :
 1415               (Value::isValue($typeMatch) ? $typeMatch: $ans->{firstElement});
 1416   $extra = $self->Package("List")->new() unless defined($extra);
 1417   my $showHints = getOption($ans,'showHints') && !$ans->{isPreview};
 1418   my $error = $context->{error};
 1419   my $score = 0; my @errors; my $i = 0;
 1420 
 1421   #
 1422   #  Check for empty lists
 1423   #
 1424   if (scalar(@correct) == 0) {$ans->score($m == 0); return}
 1425 
 1426   #
 1427   #  Loop through student answers looking for correct ones
 1428   #
 1429   ENTRY: foreach my $entry (@student) {
 1430     $i++; $context->clearError;
 1431     $entry = Value::makeValue($entry,$context);
 1432     $entry = $self->Package("Formula")->new($entry) if !Value::isValue($entry);
 1433 
 1434     #
 1435     #  Some words differ if there is only one entry in the student's list
 1436     #
 1437     my $nth = ''; my $answer = 'answer';
 1438     my $class = $ans->{list_type} || $ans->{cmp_class};
 1439     if ($m > 1) {
 1440       $nth = ' '.$self->NameForNumber($i);
 1441       $class = $ans->{cmp_class};
 1442       $answer = 'value';
 1443     }
 1444 
 1445     #
 1446     #  See if the entry matches the correct answer
 1447     #  and perform syntax checking if not
 1448     #
 1449     if ($ordered) {
 1450       if (scalar(@correct)) {
 1451   if (shift(@correct)->cmp_compare($entry,$ans,$nth,$value)) {$score++; next ENTRY}
 1452       } else {
 1453   # do syntax check
 1454   if (ref($extra) eq 'CODE') {&$extra($entry,$ans,$nth,$value)}
 1455     else {$extra->cmp_compare($entry,$ans,$nth,$value)}
 1456       }
 1457       if ($error->{flag} == $CMP_ERROR) {$self->cmp_error($ans); return}
 1458     } else {
 1459       foreach my $k (0..$#correct) {
 1460   if ($correct[$k]->cmp_compare($entry,$ans,$nth,$value)) {
 1461     splice(@correct,$k,1);
 1462     $score++; next ENTRY;
 1463   }
 1464   if ($error->{flag} == $CMP_ERROR) {$self->cmp_error($ans); return}
 1465       }
 1466       $context->clearError;
 1467       # do syntax check
 1468       if (ref($extra) eq 'CODE') {&$extra($entry,$ans,$nth,$value)}
 1469         else {$extra->cmp_compare($entry,$ans,$nth,$value)}
 1470     }
 1471     #
 1472     #  Give messages about incorrect answers
 1473     #
 1474     my $match = (ref($typeMatch) eq 'CODE')? &$typeMatch($entry,$ans) :
 1475                                              $typeMatch->typeMatch($entry,$ans);
 1476     if ($showTypeWarnings && !$match &&
 1477   !($ans->{ignoreStrings} && $entry->classMatch('String'))) {
 1478       push(@errors,"Your$nth $answer isn't ".lc($class).
 1479      " (it looks like ".lc($entry->showClass).")");
 1480     } elsif ($error->{flag} && $ans->{showEqualErrors}) {
 1481       my $message = $error->{message}; $message =~ s/\s+$//;
 1482       if ($m > 1 && $error->{flag} != $CMP_WARNING) {
 1483         push(@errors,"<SMALL>There is a problem with your$nth $value:</SMALL>",
 1484                '<DIV STYLE="margin-left:1em">'.$message.'</DIV>');
 1485       } else {push(@errors,$message)}
 1486     } elsif ($showHints && $m > 1) {
 1487       push(@errors,"Your$nth $value is incorrect");
 1488     }
 1489   }
 1490 
 1491   #
 1492   #  Return the score and errors
 1493   #
 1494   return ($score,@errors);
 1495 }
 1496 
 1497 
 1498 
 1499 #
 1500 #  Split a formula that is a list or union into a
 1501 #    list of formulas (or Value objects).
 1502 #
 1503 sub splitFormula {
 1504   my $self = shift; my $formula = shift; my $ans = shift;
 1505   my @formula; my @entries;
 1506   if ($formula->type eq 'Union') {@entries = $formula->{tree}->makeUnion}
 1507     else {@entries = @{$formula->{tree}{coords}}}
 1508   foreach my $entry (@entries) {
 1509     my $v = Parser::Formula($entry);
 1510        $v = Parser::Evaluate($v) if (defined($v) && $v->isConstant);
 1511     $v->{equation} = $self;
 1512     push(@formula,$v);
 1513     #
 1514     #  There shouldn't be an error evaluating the formula,
 1515     #    but you never know...
 1516     #
 1517     if (!defined($v)) {$ans->{split_error} = 1; $self->cmp_error; return}
 1518   }
 1519   return @formula;
 1520 }
 1521 
 1522 #  Override for List ?
 1523 #  Return the value if it is defined, otherwise use a default
 1524 #
 1525 sub getOption {
 1526   my $ans = shift; my $name = shift;
 1527   my $value = $ans->{$name};
 1528   return $value if defined($value);
 1529   return $ans->{showPartialCorrectAnswers};
 1530 }
 1531 
 1532 #############################################################
 1533 
 1534 =head3  Value::Formula
 1535 
 1536   Usage: $fun = Formula("x^2-x+1");
 1537          $set = Formula("[-1, x) U (x, 2]");
 1538 
 1539   A formula can have any of the other math object types as its range.
 1540     Union, List, Number (Complex or Real),
 1541 
 1542 
 1543 =cut
 1544 
 1545 package Value::Formula;
 1546 
 1547 sub cmp_defaults {
 1548   my $self = shift;
 1549 
 1550   return (
 1551     Value::Union::cmp_defaults($self,@_),
 1552     typeMatch => $self->Package("Formula")->new("(1,2]"),
 1553     showDomainErrors => 1,
 1554   ) if $self->type eq 'Union';
 1555 
 1556   my $type = $self->type;
 1557   $type = ($self->isComplex)? 'Complex': 'Real' if $type eq 'Number';
 1558   $type = $self->Package($type).'::';
 1559 
 1560   return (
 1561     &{$type.'cmp_defaults'}($self,@_),
 1562     upToConstant => 0,
 1563     showDomainErrors => 1,
 1564   ) if defined(%$type) && $self->type ne 'List';
 1565 
 1566   my $element;
 1567   if ($self->{tree}->class eq 'List') {$element = $self->Package("Formula")->new($self->{tree}{coords}[0])}
 1568     else {$element = $self->Package("Formula")->new(($self->createRandomPoints(1))[1]->[0]{data}[0])}
 1569   return (
 1570     Value::List::cmp_defaults($self,@_),
 1571     removeParens => $self->{autoFormula},
 1572     typeMatch => $element,
 1573     showDomainErrors => 1,
 1574   );
 1575 }
 1576 
 1577 #
 1578 #  Get the types from the values of the formulas
 1579 #     and compare those.
 1580 #
 1581 sub typeMatch {
 1582   my $self = shift; my $other = shift; my $ans = shift;
 1583   return 1 if $self->type eq $other->type;
 1584   my $typeMatch = ($self->createRandomPoints(1))[1]->[0];
 1585   $other = eval {($other->createRandomPoints(1))[1]->[0]} if Value::isFormula($other);
 1586   return 1 unless defined($other); # can't really tell, so don't report type mismatch
 1587   return 1 if $typeMatch->classMatch('String') && Value::isFormula($ans->{typeMatch});  # avoid infinite loop
 1588   $typeMatch->typeMatch($other,$ans);
 1589 }
 1590 
 1591 #
 1592 #  Handle removal of outermost parens in a list.
 1593 #  Evaluate answer, if the eval option is used.
 1594 #  Handle the UpToConstant option.
 1595 #
 1596 sub cmp {
 1597   my $self = shift;
 1598   my $cmp = $self->SUPER::cmp(@_);
 1599   if ($cmp->{rh_ans}{removeParens} && $self->type eq 'List') {
 1600     $self->{tree}{open} = $self->{tree}{close} = '';
 1601     $cmp->ans_hash(correct_ans => $self->stringify)
 1602       unless defined($self->{correct_ans});
 1603   }
 1604   if ($cmp->{rh_ans}{eval} && $self->isConstant) {
 1605     $cmp->ans_hash(correct_value => $self->eval);
 1606     return $cmp;
 1607   }
 1608   if ($cmp->{rh_ans}{upToConstant}) {
 1609     my $current = Parser::Context->current();
 1610     my $context = $self->{context} = $self->{context}->copy;
 1611     Parser::Context->current(undef,$context);
 1612     $context->variables->add('C0' => 'Parameter');
 1613     my $f = $self->Package("Formula")->new('C0')+$self;
 1614     for ('limits','test_points','test_values','num_points','granularity','resolution',
 1615    'checkUndefinedPoints','max_undefined')
 1616       {$f->{$_} = $self->{$_} if defined($self->{$_})}
 1617     $cmp->ans_hash(correct_value => $f);
 1618     Parser::Context->current(undef,$current);
 1619   }
 1620   $cmp->install_pre_filter(\&Value::Formula::cmp_call_filter,"cmp_prefilter");
 1621   $cmp->install_post_filter(\&Value::Formula::cmp_call_filter,"cmp_postfilter");
 1622   return $cmp;
 1623 }
 1624 
 1625 sub cmp_call_filter {
 1626   my $ans = shift; my $method = shift;
 1627   return $ans->{correct_value}->$method($ans);
 1628 }
 1629 
 1630 sub cmp_prefilter {
 1631   my $self = shift; my $ans = shift;
 1632   $ans->{_filter_name} = "fetch_previous_answer";
 1633   $ans->{prev_ans} = undef;
 1634   if (defined($ans->{ans_label})) {
 1635     my $label = "previous_".$ans->{ans_label};
 1636     my $inputs = $self->getPG('$inputs_ref');
 1637     if (defined $inputs->{$label} and $inputs->{$label} =~ /\S/) {
 1638       $ans->{prev_ans} = $inputs->{$label};
 1639       #FIXME -- previous answer item is not always being updated in inputs_ref (which comes from formField)
 1640     }
 1641   }
 1642   return $ans;
 1643 }
 1644 
 1645 sub cmp_postfilter {
 1646   my $self = shift; my $ans = shift;
 1647   $ans->{_filter_name} = "produce_equivalence_message";
 1648   return $ans if $ans->{ans_message}; # don't overwrite other messages
 1649   $ans->{prev_formula} = Parser::Formula($self->{context},$ans->{prev_ans});
 1650   if (defined($ans->{prev_formula}) && defined($ans->{student_formula})) {
 1651     my $prev = eval {$self->promote($ans->{prev_formula})}; break unless defined($prev);
 1652     $ans->{prev_equals_current} = Value::cmp_compare($prev,$ans->{student_formula},{});
 1653     if (   !$ans->{isPreview}                                 # not preview mode
 1654   and $ans->{prev_equals_current}                       # equivalent
 1655   and $ans->{prev_ans} ne $ans->{original_student_ans}) # but not identical
 1656       {$ans->{ans_message} = "This answer is equivalent to the one you just submitted."}
 1657   }
 1658   return $ans;
 1659 }
 1660 
 1661 
 1662 sub cmp_equal {
 1663   my $self = shift; my $ans = shift;
 1664   #
 1665   #  Get the problem's seed
 1666   #
 1667   $self->{context}->flags->set(
 1668     random_seed => $self->getPG('$PG_original_problemSeed')
 1669   );
 1670 
 1671   #
 1672   #  Use the list checker if the formula is a list or union
 1673   #    Otherwise use the normal checker
 1674   #
 1675   if ($self->type =~ m/^(List|Union|Set)$/) {
 1676     Value::List::cmp_equal($self,$ans);
 1677   } else {
 1678     $self->SUPER::cmp_equal($ans);
 1679   }
 1680 }
 1681 
 1682 sub cmp_postprocess {
 1683   my $self = shift; my $ans = shift;
 1684   return unless $ans->{score} == 0 && !$ans->{isPreview};
 1685   return if $ans->{ans_message};
 1686   if ($self->{domainMismatch} && $ans->{showDomainErrors}) {
 1687     $self->cmp_Error($ans,"The domain of your function doesn't match that of the correct answer");
 1688     return;
 1689   }
 1690   return if !$ans->{showDimensionHints};
 1691   my $other = $ans->{student_value};
 1692   return if $ans->{ignoreStrings} && (!Value::isValue($other) || $other->type eq 'String');
 1693   return unless $other->type =~ m/^(Point|Vector|Matrix)$/;
 1694   return unless $self->type  =~ m/^(Point|Vector|Matrix)$/;
 1695   return if Parser::Item::typeMatch($self->typeRef,$other->typeRef);
 1696   $self->cmp_Error($ans,"The dimension of your result is incorrect");
 1697 }
 1698 
 1699 #
 1700 #  Diagnostics for Formulas
 1701 #
 1702 sub cmp_diagnostics {
 1703   my $self = shift;  my $ans = shift;
 1704   my $isEvaluator = (ref($ans) =~ /Evaluator/)? 1: 0;
 1705   my $hash = $isEvaluator? $ans->rh_ans : $ans;
 1706   my $diagnostics = $self->{context}->diagnostics->merge("formulas",$self,$hash);
 1707   my $formulas = $diagnostics->{formulas};
 1708   return unless $formulas->{show};
 1709 
 1710   my $output = "";
 1711   if ($isEvaluator) {
 1712     #
 1713     #  The tests to be performed when the answer checker is created
 1714     #
 1715     $self->getPG('loadMacros("PGgraphmacros.pl")');
 1716     my ($inputs) = $self->getPG('$inputs_ref');
 1717     my $process = $inputs->{checkAnswers} || $inputs->{previewAnswers} || $inputs->{submitAnswers};
 1718     if ($formulas->{checkNumericStability} && !$process) {
 1719       ### still needs to be written
 1720     }
 1721   } else {
 1722     #
 1723     #  The checks to be performed when an answer is submitted
 1724     #
 1725     my $student = $ans->{student_formula};
 1726     #
 1727     #  Get the test points
 1728     #
 1729     my @names = $self->{context}->variables->names;
 1730     my $vx = (keys(%{$self->{variables}}))[0];
 1731     my $vi = 0; while ($names[$vi] ne $vx) {$vi++}
 1732     my $points = [map {$_->[$vi]} @{$self->{test_points}}];
 1733     my @params = $self->{context}->variables->parameters;
 1734        @names = $self->{context}->variables->variables;
 1735 
 1736     #
 1737     #  The graphs of the functions and errors
 1738     #
 1739     if ($formulas->{showGraphs}) {
 1740       my @G = ();
 1741       if ($formulas->{combineGraphs}) {
 1742   push(@G,$self->cmp_graph($diagnostics,[$student,$self],
 1743          title=>'Student Answer (red)<BR>Correct Answer (green)<BR>',
 1744          points=>$points,showDomain=>1));
 1745       } else {
 1746   push(@G,$self->cmp_graph($diagnostics,$self,title=>'Correct Answer'));
 1747   push(@G,$self->cmp_graph($diagnostics,$student,title=>'Student Answer'));
 1748       }
 1749       my $cutoff = $self->Package("Formula")->new($self->getFlag('tolerance'));
 1750       if ($formulas->{graphAbsoluteErrors}) {
 1751   push(@G,$self->cmp_graph($diagnostics,[abs($self-$student),$cutoff],
 1752          clip=>$formulas->{clipAbsoluteError},
 1753          title=>'Absolute Error',points=>$points));
 1754       }
 1755       if ($formulas->{graphRelativeErrors}) {
 1756   push(@G,$self->cmp_graph($diagnostics,[abs(($self-$student)/$self),$cutoff],
 1757          clip=>$formulas->{clipRelativeError},
 1758          title=>'Relative Error',points=>$points));
 1759       }
 1760       $output .= '<TABLE BORDER="0" CELLSPACING="0" CELLPADDING="0">'
 1761   . '<TR VALIGN="TOP">'.join('<TD WIDTH="20"></TD>',@G).'</TR></TABLE>';
 1762     }
 1763 
 1764     #
 1765     #  The adaptive parameters
 1766     #
 1767     if ($formulas->{showParameters} && scalar(@params) > 0) {
 1768       $output .= '<HR><TABLE BORDER="0" CELLSPACING="0" CELLPADDING="0"><TR><TD>Adaptive Parameters:<BR>';
 1769       $output .= join("<BR>",map {"&nbsp;&nbsp;$params[$_]: ".$self->{parameters}[$_]} (0..$#params));
 1770       $output .= '</TD></TR></TABLE>';
 1771     }
 1772 
 1773     #
 1774     #  The test points and values
 1775     #
 1776     my @rows = (); my $colsep = '</TD><TD WIDTH="20"></TD><TD ALIGN="RIGHT">';
 1777     my @P = (map {(scalar(@{$_}) == 1)? $_->[0]: $self->Package("Point")->make(@{$_})} @{$self->{test_points}});
 1778     my @i = sort {$P[$a] <=> $P[$b]} (0..$#P);
 1779     foreach $p (@P) {if (Value::isValue($p) && $p->length > 2) {$p = $p->string; $p =~ s|,|,<br />|g}}
 1780     my $zeroLevelTol = $self->getFlag('zeroLevelTol');
 1781     $self->{context}{flags}{zeroLevelTol} = 0; # always show full resolution in the tables below
 1782     my $names = join(',',@names); $names = '('.$names.')' if scalar(@names) > 1;
 1783 
 1784     $student->createPointValues($self->{test_points},0,1,1) unless $student->{test_values};
 1785 
 1786     my $cv = $self->{test_values};
 1787     my $sv = $student->{test_values};
 1788     my $av = $self->{test_adapt} || $cv;
 1789 
 1790     if ($formulas->{showTestPoints}) {
 1791       my @p = ("$names:", (map {$P[$i[$_]]} (0..$#P)));
 1792       push(@rows,'<TR><TD ALIGN="RIGHT">'.join($colsep,@p).'</TD></TR>');
 1793       push(@rows,'<TR><TD ALIGN="RIGHT">'.join($colsep,("<HR>")x scalar(@p)).'</TD></TR>');
 1794       push(@rows,'<TR><TD ALIGN="RIGHT">'
 1795      .join($colsep,($av == $cv)? "Correct Answer:" : "Adapted Answer:",
 1796      map {Value::isNumber($av->[$i[$_]])? $av->[$i[$_]]: "undefined"} (0..$#P))
 1797      .'</TD></TR>');
 1798       push(@rows,'<TR><TD ALIGN="RIGHT">'
 1799      .join($colsep,"Student Answer:",
 1800      map {Value::isNumber($sv->[$i[$_]])? $sv->[$i[$_]]: "undefined"} (0..$#P))
 1801      .'</TD></TR>');
 1802     }
 1803     #
 1804     #  The absolute errors (colored by whether they are ok or too big)
 1805     #
 1806     if ($formulas->{showAbsoluteErrors}) {
 1807       my @p = ("Absolute Error:");
 1808       my $tolerance = $self->getFlag('tolerance');
 1809       my $tolType = $self->getFlag('tolType'); my $error;
 1810       foreach my $j (0..$#P) {
 1811   if (Value::isNumber($sv->[$i[$j]])) {
 1812     $error = abs($av->[$i[$j]] - $sv->[$i[$j]]);
 1813     $error = '<SPAN STYLE="color:#'.($error->value<$tolerance ? '00AA00': 'AA0000').'">'.$error.'</SPAN>'
 1814       if $tolType eq 'absolute';
 1815   } else {$error = "---"}
 1816   push(@p,$error);
 1817       }
 1818       push(@rows,'<TR><TD ALIGN="RIGHT">'.join($colsep,@p).'</TD></TR>');
 1819     }
 1820     #
 1821     #  The relative errors (colored by whether they are OK or too big)
 1822     #
 1823     if ($formulas->{showRelativeErrors}) {
 1824       my @p = ("Relative Error:");
 1825       my $tolerance = $self->getFlag('tolerance'); my $tol;
 1826       my $tolType = $self->getFlag('tolType'); my $error;
 1827       my $zeroLevel = $self->getFlag('zeroLevel');
 1828       foreach my $j (0..$#P) {
 1829   if (Value::isNumber($sv->[$i[$j]])) {
 1830     my $c = $av->[$i[$j]]; my $s = $sv->[$i[$j]];
 1831     if (abs($cv->[$i[$j]]->value) < $zeroLevel || abs($s->value) < $zeroLevel)
 1832             {$error = abs($c-$s); $tol = $zeroLevelTol} else
 1833             {$error = abs(($c-$s)/($c||1E-10)); $tol = $tolerance}
 1834     $error = '<SPAN STYLE="color:#'.($error < $tol ? '00AA00': 'AA0000').'">'.$error.'</SPAN>'
 1835       if $tolType eq 'relative';
 1836   } else {$error = "---"}
 1837   push(@p,$error);
 1838       }
 1839       push(@rows,'<TR><TD ALIGN="RIGHT">'.join($colsep,@p).'</TD></TR>');
 1840     }
 1841     $self->{context}{flags}{zeroLevelTol} = $zeroLevelTol;
 1842     #
 1843     #  Put the data into a table
 1844     #
 1845     if (scalar(@rows)) {
 1846       $output .= '<p><HR><p><TABLE BORDER="0" CELLSPACING="0" CELLPADDING="0">'
 1847   . join('<TR><TD HEIGHT="3"></TD>',@rows)
 1848   . '</TABLE>';
 1849     }
 1850   }
 1851   #
 1852   #  Put all the diagnostic output into a frame
 1853   #
 1854   return unless $output;
 1855   $output
 1856     = '<TABLE BORDER="1" CELLSPACING="2" CELLPADDING="20" BGCOLOR="#F0F0F0">'
 1857     . '<TR><TD ALIGN="LEFT"><B>Diagnostics for '.$self->string .':</B>'
 1858     . '<P><CENTER>' . $output . '</CENTER></TD></TR></TABLE><P>';
 1859   warn $output;
 1860 }
 1861 
 1862 #
 1863 #  Draw a graph from a given Formula object
 1864 #
 1865 sub cmp_graph {
 1866   my $self = shift; my $diagnostics = shift;
 1867   my $F1 = shift; my $F2; ($F1,$F2) = @{$F1} if (ref($F1) eq 'ARRAY');
 1868   #
 1869   #  Get the various options
 1870   #
 1871   my %options = (title=>'',points=>[],@_);
 1872   my $graphs = $diagnostics->{graphs};
 1873   my $limits = $graphs->{limits}; $limits = $self->getFlag('limits',[-2,2]) unless $limits;
 1874   $limits = $limits->[0] while ref($limits) eq 'ARRAY' && ref($limits->[0]) eq 'ARRAY';
 1875   my $size = $graphs->{size}; $size = [$size,$size] unless ref($size) eq 'ARRAY';
 1876   my $steps = $graphs->{divisions};
 1877   my $points = $options{points}; my $clip = $options{clip};
 1878   my ($my,$My) = (0,0); my ($mx,$Mx) = @{$limits};
 1879   my $dx = ($Mx-$mx)/$steps; my $f; my $y;
 1880 
 1881   my @pnames = $self->{context}->variables->parameters;
 1882   my @pvalues = ($self->{parameters} ? @{$self->{parameters}} : (0) x scalar(@pnames));
 1883   my $x = "";
 1884 
 1885   #
 1886   #  Find the max and min values of the function
 1887   #
 1888   foreach $f ($F1,$F2) {
 1889     next unless defined($f);
 1890     foreach my $v (keys(%{$f->{variables}})) {
 1891       if ($v ne $x && !$f->{context}->variables->get($v)->{parameter}) {
 1892   if ($x) {
 1893     warn "Only formulas with one variable can be graphed" unless $self->{graphWarning};
 1894     $self->{graphWarning} = 1;
 1895     return "";
 1896   }
 1897   $x = $v;
 1898       }
 1899     }
 1900     unless ($f->typeRef->{length} == 1) {
 1901       warn "Only real-valued functions can be graphed" unless $self->{graphWarning};
 1902       $self->{graphWarning} = 1;
 1903       return "";
 1904     }
 1905     unless ($f->typeRef->{length} == 1) {
 1906       warn "Only real-valued functions can be graphed";
 1907       return "";
 1908     }
 1909     if ($f->isConstant) {
 1910       $y = $f->eval;
 1911       $my = $y if $y < $my; $My = $y if $y > $My;
 1912     } else {
 1913       my $F = $f->perlFunction(undef,[$x,@pnames]);
 1914       foreach my $i (0..$steps-1) {
 1915         $y = eval {&{$F}($mx+$i*$dx,@pvalues)};
 1916   next unless defined($y) && Value::isNumber($y);
 1917         $my = $y if $y < $my; $My = $y if $y > $My;
 1918       }
 1919     }
 1920   }
 1921   $My = 1 if abs($My - $my) < 1E-5;
 1922   $my *= 1.1; $My *= 1.1;
 1923   if ($clip) {
 1924     $my = -$clip if $my < -$clip;
 1925     $My = $clip if $My > $clip;
 1926   }
 1927   $my = -$My/10 if $my > -$My/10; $My = -$my/10 if $My < -$my/10;
 1928   my $a = $self->Package("Real")->new(($My-$my)/($Mx-$mx));
 1929 
 1930   #
 1931   #  Create the graph itself, with suitable title
 1932   #
 1933   my $grf = $self->getPG('$_grf_ = {n => 0}');
 1934   $grf->{Goptions} = [
 1935      $mx,$my,$Mx,$My,
 1936      axes => $graphs->{axes},
 1937      grid => $graphs->{grid},
 1938      size => $size,
 1939   ];
 1940   $grf->{params} = {
 1941     names => [$x,@pnames],
 1942     values => {map {$pnames[$_] => $pvalues[$_]} (0..scalar(@pnames)-1)},
 1943   };
 1944   $grf->{G} = $self->getPG('init_graph(@{$_grf_->{Goptions}})');
 1945   $grf->{G}->imageName($grf->{G}->imageName.'-'.time()); # avoid browser cache
 1946   $self->cmp_graph_function($grf,$F2,"green",$steps,$points) if defined($F2);
 1947   $self->cmp_graph_function($grf,$F1,"red",$steps,$points);
 1948   my $image = $self->getPG('alias(insertGraph($_grf_->{G}))');
 1949   $image = '<IMG SRC="'.$image.'" WIDTH="'.$size->[0].'" HEIGHT="'.$size->[1].'" BORDER="0" STYLE="margin-bottom:5px">';
 1950   my $title = $options{title}; $title .= '<DIV STYLE="margin-top:5px"></DIV>' if $title;
 1951   $title .= "<SMALL>Domain: [$mx,$Mx]</SMALL><BR>" if $options{showDomain};
 1952   $title .= "<SMALL>Range: [$my,$My]<BR>Aspect ratio: $a:1</SMALL>";
 1953   return '<TD ALIGN="CENTER" VALIGN="TOP" NOWRAP>'.$image.'<BR>'.$title.'</TD>';
 1954 }
 1955 
 1956 #
 1957 #  Add a function to a graph object, and plot the points
 1958 #  that are used to test the function
 1959 #
 1960 sub cmp_graph_function {
 1961   my $self = shift; my $grf = shift; my $F = shift;
 1962   my $color = shift; my $steps = shift; my $points = shift;
 1963   $grf->{n}++; my $Fn = "F".$grf->{n}; $grf->{$Fn} = $F; my $f;
 1964   if ($F->isConstant) {
 1965     my $y = $F->eval;
 1966     $f = $self->getPG('new Fun(sub {'.$y.'},$_grf_->{G})');
 1967   } else {
 1968     my $X = $grf->{params}{names}[0];
 1969     $f = $self->getPG('new Fun(sub {Parser::Evaluate($_grf_->{'.$Fn.'},'
 1970            .$X.'=>shift,%{$_grf_->{params}{values}})},$_grf_->{G})');
 1971     foreach my $x (@{$points}) {
 1972       my $y = Parser::Evaluate($F,($X)=>$x,%{$grf->{params}{values}});
 1973       next unless defined($y) && Value::isNumber($y);
 1974       $grf->{x} = $x; $grf->{'y'} = $y;
 1975       my $C = $self->getPG('new Circle($_grf_->{x},$_grf_->{y},4,"'.$color.'","'.$color.'")');
 1976       $grf->{G}->stamps($C);
 1977     }
 1978   }
 1979   $f->color($color); $f->weight(2); $f->steps($steps);
 1980 }
 1981 
 1982 #
 1983 #  If an answer array was used, get the data from the
 1984 #  Matrix, Vector or Point, and format the array of
 1985 #  data using the original parameter
 1986 #
 1987 sub correct_ans {
 1988   my $self = shift;
 1989   return $self->SUPER::correct_ans unless $self->{ans_name};
 1990   my @array = ();
 1991   if ($self->{tree}->type eq 'Matrix') {
 1992     foreach my $row (@{$self->{tree}{coords}}) {
 1993       my @row = ();
 1994       foreach my $x (@{$row->coords}) {push(@row,$x->string)}
 1995       push(@array,[@row]);
 1996     }
 1997   } else {
 1998     foreach my $x (@{$self->{tree}{coords}}) {push(@array,$x->string)}
 1999     if ($self->{tree}{ColumnVector}) {foreach my $x (@array) {$x = [$x]}}
 2000       else {@array = [@array]}
 2001   }
 2002   Value::VERBATIM($self->format_matrix([@array],@{$self->{format_options}},tth_delims=>1));
 2003 }
 2004 
 2005 #
 2006 #  Get the size of the array and create the appropriate answer array
 2007 #
 2008 sub ANS_MATRIX {
 2009   my $self = shift;
 2010   my $extend = shift; my $name = shift;
 2011   my $size = shift || 5; my $type = $self->type;
 2012   my $cols = $self->length; my $rows = 1; my $sep = ',';
 2013   if ($type eq 'Matrix') {
 2014     $sep = ''; $rows = $cols; $cols = $self->{tree}->typeRef->{entryType}{length};
 2015   }
 2016   if ($self->{tree}{ColumnVector}) {
 2017     $sep = ""; $type = "Matrix";
 2018     my $tmp = $rows; $rows = $cols; $cols = $tmp;
 2019     $self->{ColumnVector} = 1;
 2020   }
 2021   my $def = $self->context->lists->get($type);
 2022   my $open = $self->{open} || $self->{tree}{open} || $def->{open};
 2023   my $close = $self->{close} || $self->{tree}{close} || $def->{close};
 2024   $self->ans_matrix($extend,$name,$rows,$cols,$size,$open,$close,$sep);
 2025 }
 2026 
 2027 sub ans_array {
 2028   my $self = shift;
 2029   return $self->SUPER::ans_array(@_) unless $self->array_OK;
 2030   $self->ANS_MATRIX(0,'',@_);
 2031 }
 2032 sub named_ans_array {
 2033   my $self = shift;
 2034   return $self->SUPER::named_ans_array(@_) unless $self->array_OK;
 2035   $self->ANS_MATRIX(0,@_);
 2036 }
 2037 sub named_ans_array_extension {
 2038   my $self = shift;
 2039   return $self->SUPER::named_ans_array_extension(@_) unless $self->array_OK;
 2040   $self->ANS_MATRIX(1,@_);
 2041 }
 2042 
 2043 sub array_OK {
 2044   my $self = shift; my $tree = $self->{tree};
 2045   return $tree->type =~ m/^(Point|Vector|Matrix)$/ && $tree->class eq 'List';
 2046 }
 2047 
 2048 #
 2049 #  Get an array of values from a Matrix, Vector or Point
 2050 #  (this needs to be made more general)
 2051 #
 2052 sub value {
 2053   my $self = shift;
 2054   return $self unless defined $self->{tree}{coords};
 2055   my $context = $self->context;
 2056   my @array = ();
 2057   if ($self->{tree}->type eq 'Matrix') {
 2058     foreach my $row (@{$self->{tree}->coords}) {
 2059       my @row = ();
 2060       foreach my $x (@{$row->coords}) {push(@row,$context->Package("Formula")->new($context,$x))}
 2061       push(@array,[@row]);
 2062     }
 2063   } else {
 2064     foreach my $x (@{$self->{tree}->coords}) {
 2065       push(@array,$context->Package("Formula")->new($context,$x));
 2066     }
 2067   }
 2068   return @array;
 2069 }
 2070 
 2071 #############################################################
 2072 
 2073 1;

aubreyja at gmail dot com
ViewVC Help
Powered by ViewVC 1.0.9