--- loncom/homework/default_homework.lcpm	2002/05/31 22:19:06	1.47
+++ loncom/homework/default_homework.lcpm	2003/03/25 23:00:18	1.59
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA 
 # used by lonxml::xmlparse() as input variable $safeinit to Apache::run::run()
 #
-# $Id: default_homework.lcpm,v 1.47 2002/05/31 22:19:06 albertel Exp $
+# $Id: default_homework.lcpm,v 1.59 2003/03/25 23:00:18 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -57,13 +57,13 @@ sub caparesponse_check {
   #remove leading and trailing whitespace
   if ($response=~ /^\s|\s$/) {
     $response=~ s:^\s+|\s+$::g;
-    $message .="Removed ws now :$response:<br />";
+    $message .="Removed ws now :$response:\n";
   } else {
-    $message .="no ws in :$response:<br />";
+    $message .="no ws in :$response:\n";
   }
 
   if ($type eq '' ) {
-    $message .= "Didn't find a type :$type:$expr: defaulting<br />";
+    $message .= "Didn't find a type :$type:$expr: defaulting\n";
     if ( $answer eq ($answer *1.0)) { $type = 2;
     } else { $type = 3; }
   } else {
@@ -82,7 +82,7 @@ sub caparesponse_check {
   #formula type setup the sample points
   if ($type eq '8') {
     ($id_list,$points)=split(/@/,$samples);
-    $message.="Found :$points: points<br />";
+    $message.="Found :$points: points\n";
   }
   if ($tol eq '') {
     $tol=0.0;
@@ -101,11 +101,11 @@ sub caparesponse_check {
     $sig_ubound =15; #SIG_UB_DEFAULT
   } else {
     ($sig_lbound,$sig_ubound) = split /,/,$sig;
-    if (!$sig_lbound) {
+    if (!defined($sig_lbound)) {
       $sig_lbound = 0; #SIG_LB_DEFAULT
       $sig_ubound =15; #SIG_UB_DEFAULT
     }
-    if (!$sig_ubound) { $sig_ubound=$sig_lbound; }
+    if (!defined($sig_ubound)) { $sig_ubound=$sig_lbound; }
   }
   my $result = &caparesponse_capa_check_answer($response,$answer,$type,
 					       $tol_type,$tol,
@@ -127,7 +127,7 @@ sub caparesponse_check {
   elsif ($result =='12') { $result='WANTED_NUMERIC'; }
   else  {$result = "ERROR: Unknown Result:$result:$@:";}
 
-  return "$result:<br />Error $error:<br />Answer $answer:<br />Response $response:<br /> type-$type|$tol|$tol_type|$sig:$sig_lbound:$sig_ubound|$unit|<br />$message$expr";
+  return "$result:\nError $error:\nAnswer $answer:\nResponse $response:\n type-$type|$tol|$tol_type|$sig:$sig_lbound:$sig_ubound|$unit|\n$message$expr";
 }
 
 sub get_array_args {
@@ -140,10 +140,10 @@ sub get_array_args {
   if ($CAPARESPONSE_CHECK_LIST_answer =~ /^\s*[\$\@]/) {
     (@GET_ARRAY_ARGS_list) = eval $CAPARESPONSE_CHECK_LIST_answer;
   }
-  $GET_ARRAY_ARGS_result.="error:$@:<br />";
+  $GET_ARRAY_ARGS_result.="error:$@:\n";
   # if the eval fails just use what is in the answer exactly
   if (!defined(@GET_ARRAY_ARGS_list) || !defined($GET_ARRAY_ARGS_list[0])) {
-    $GET_ARRAY_ARGS_result.="list zero is undefined<br />";
+    $GET_ARRAY_ARGS_result.="list zero is undefined\n";
     $GET_ARRAY_ARGS_list[0]=$CAPARESPONSE_CHECK_LIST_answer;
   }
   return $GET_ARRAY_ARGS_result,@GET_ARRAY_ARGS_list;
@@ -152,11 +152,13 @@ sub get_array_args {
 sub caparesponse_check_list {
   my ($response,$expr)=@_;
   my $result;
+  $expr =~ s/\\/\\\\/g;
+  $expr =~ s/\'/\\\'/g;
   my ($result,@list) = &get_array_args($expr,'answer');
   my $aresult='';
   my $current_answer;
   my $answers=join(':',@list);
-  $result.="Got response :$answers:<br />";
+  $result.="Got response :$answers:\n";
   my @responselist;
   my $type =eval $expr.';return $answer;';
   if ($type ne '' && $#list > 0) {
@@ -165,7 +167,7 @@ sub caparesponse_check_list {
     (@responselist)=($response);
   }
   my $unit='';
-  $result.="Initial final response :$responselist['-1']:<br />";
+  $result.="Initial final response :$responselist['-1']:\n";
   if ($type eq '') {
     #for numerical problems split off the unit
     if ( $responselist['-1']=~ /(.*[^\s])\s+([^\s]+)/ ) {
@@ -173,39 +175,42 @@ sub caparesponse_check_list {
       $unit=$2;
     }
   }
-  $result.="Final final response :$responselist['-1']:<br />";
-  $result.=":$#list: answers<br />";
+  $result.="Final final response :$responselist['-1']:\n";
+  $result.=":$#list: answers\n";
   $unit=~s/\s//;
   my $i=0;
   my $awards='';
   for ($i=0; $i<@list;$i++) {
-    $result.="trying answer :$list[$i]:<br />";
+    $result.="trying answer :$list[$i]:\n";
+    my $thisanswer=$list[$i];
+    $thisanswer=~ s/\\/\\\\/g;
+    $thisanswer =~ s/\'/\\\'/g;
     if ($unit eq '') {
       $aresult=&caparesponse_check($responselist[$i],
-			     $expr.';my $answer=\''.$list[$i].'\';');
+			     $expr.';my $answer=\''.$thisanswer.'\';');
     } else {
       $aresult=&caparesponse_check($responselist[$i]." $unit",
-				   $expr.';my $answer=\''.$list[$i].'\';');
+				   $expr.';my $answer=\''.$thisanswer.'\';');
     }
     my ($temp)=split /:/, $aresult;
     $awards.="$temp,";
     $result.=$aresult;
   }
   chop $awards;
-  return "$awards:<br />$result";
+  return "$awards:\n$result";
 }
 
 sub tex {
   if ( $external::target eq "tex" ) {
-    return @_[0];
+    return $_[0];
   } else {
-    return @_[1];
+    return $_[1];
   }
 }
 
 sub var_in_tex {
   if ( $external::target eq "tex" ) {
-    return @_[0];
+    return $_[0];
   } else {
     return "";
   }
@@ -213,12 +218,12 @@ sub var_in_tex {
 
 sub web {
   if ( $external::target eq "tex" ) {
-    return @_[1];
+    return $_[1];
   } else {
     if ( $external::target eq "web" || $external::target eq "answer") {
-      return @_[2];
+      return $_[2];
     } else {
-      return @_[0];
+      return $_[0];
     }
   }
 }
@@ -229,10 +234,6 @@ sub html {
   }
 }
 
-sub problem {
-  return '1';
-}
-
 sub hinton {
   return 0;
 }
@@ -240,139 +241,173 @@ sub hinton {
 sub random {
   my ($start,$end,$step)=@_;
   if ( ! $hidden::RANDOMINIT ) {
-    srand($external::randomseed);
+    if ($external::randomseed == 0) { $external::randomseed=1; }
+    &random_set_seed(1,int(abs($external::randomseed)));
+    &math_random_uniform();
     $hidden::RANDOMINIT=1;
   }
   if (!defined($step)) { $step=1; }
   my $num=1+int(($end-$start)/$step);
-  my $result=$start + int(rand() * $num)*$step;
+  my $result=$start + int(&math_random_uniform() * $num)*$step;
   return $result;
 }
 
 sub random_normal {
   my ($item_cnt,$seed,$av,$std_dev) = @_;
+  my @oldseed=&random_get_seed();
   my @retArray;
   &random_set_seed_from_phrase($seed);
   @retArray=&math_random_normal($item_cnt,$av,$std_dev);
+  &random_set_seed(@oldseed);
   return @retArray;
 }
 
 sub random_beta {
   my ($item_cnt,$seed,$aa,$bb) = @_;
+  my @oldseed=&random_get_seed();
   my @retArray;
   &random_set_seed_from_phrase($seed);
   @retArray=&math_random_beta($item_cnt,$aa,$bb);
+  &random_set_seed(@oldseed);
   return @retArray;
 }
 
 sub random_gamma {
   my ($item_cnt,$seed,$a,$r) = @_;
+  my @oldseed=&random_get_seed();
   my @retArray;
   &random_set_seed_from_phrase($seed);
   @retArray=&math_random_gamma($item_cnt,$a,$r);
+  &random_set_seed(@oldseed);
   return @retArray;
 }
 
 sub random_exponential {
   my ($item_cnt,$seed,$av) = @_;
+  my @oldseed=&random_get_seed();
   my @retArray;
   &random_set_seed_from_phrase($seed);
   @retArray=&math_random_exponential($item_cnt,$av);
+  &random_set_seed(@oldseed);
   return @retArray;
 }
 
 sub random_poisson {
   my ($item_cnt,$seed,$mu) = @_;
+  my @oldseed=&random_get_seed();
   my @retArray;
   &random_set_seed_from_phrase($seed);
   @retArray=&math_random_poisson($item_cnt,$mu);
+  &random_set_seed(@oldseed);
   return @retArray;
 }
 
 sub random_chi {
   my ($item_cnt,$seed,$df) = @_;
+  my @oldseed=&random_get_seed();
   my @retArray;
   &random_set_seed_from_phrase($seed);
   @retArray=&math_random_chi_square($item_cnt,$df);
+  &random_set_seed(@oldseed);
   return @retArray;
 }
 
 sub random_noncentral_chi {
   my ($item_cnt,$seed,$df,$nonc) = @_;
+  my @oldseed=&random_get_seed();
   my @retArray;
   &random_set_seed_from_phrase($seed);
   @retArray=&math_random_noncentral_chi_square($item_cnt,$df,$nonc);
+  &random_set_seed(@oldseed);
   return @retArray;
 }
 
 sub random_f {
   my ($item_cnt,$seed,$dfn,$dfd) = @_;
+  my @oldseed=&random_get_seed();
   my @retArray;
   &random_set_seed_from_phrase($seed);
   @retArray=&math_random_f($item_cnt,$dfn,$dfd);
+  &random_set_seed(@oldseed);
   return @retArray;
 }
 
 sub random_noncentral_f {
   my ($item_cnt,$seed,$dfn,$dfd,$nonc) = @_;
+  my @oldseed=&random_get_seed();
   my @retArray;
   &random_set_seed_from_phrase($seed);
   @retArray=&math_random_noncentral_f($item_cnt,$dfn,$dfd,$nonc);
+  &random_set_seed(@oldseed);
   return @retArray;
 }
 
 sub random_multivariate_normal {
   my ($item_cnt,$seed,$mean,$covar) = @_;
+  my @oldseed=&random_get_seed();
   &random_set_seed_from_phrase($seed);
   @retArray=&math_random_multivariate_normal($item_cnt,@$mean,@$covar);
+  &random_set_seed(@oldseed);
   return @retArray;
 }
 
 sub random_multinomial {
   my ($item_cnt,$seed,@p) = @_;
+  my @oldseed=&random_get_seed();
   my @retArray;
   &random_set_seed_from_phrase($seed);
   @retArray=&math_random_multinomial($item_cnt,@p);
+  &random_set_seed(@oldseed);
   return @retArray;
 }
 
 sub random_permutation {
   my ($seed,@inArray) = @_;
+  my @oldseed=&random_get_seed();
   my @retArray;
   &random_set_seed_from_phrase($seed);
   @retArray=&math_random_permutation(@inArray);
+  &random_set_seed(@oldseed);
   return @retArray;
 }
 
 sub random_uniform {
   my ($item_cnt,$seed,$low,$high) = @_;
+  my @oldseed=&random_get_seed();
   my @retArray;
   &random_set_seed_from_phrase($seed);
   @retArray=&math_random_uniform($item_cnt,$low,$high);
+  &random_set_seed(@oldseed);
   return @retArray;
 }
 
 sub random_uniform_integer {
   my ($item_cnt,$seed,$low,$high) = @_;
+  my @oldseed=&random_get_seed();
   my @retArray;
   &random_set_seed_from_phrase($seed);
   @retArray=&math_random_uniform_integer($item_cnt,$low,$high);
+  &random_set_seed(@oldseed);
   return @retArray;
 }
 
 sub random_binomial {
   my ($item_cnt,$seed,$nt,$p) = @_;
+  my @oldseed=&random_get_seed();
   my @retArray;
   &random_set_seed_from_phrase($seed);
   @retArray=&math_random_binomial($item_cnt,$nt,$p);
+  &random_set_seed(@oldseed);
   return @retArray;
 }
 
 sub random_negative_binomial {
   my ($item_cnt,$seed,$ne,$p) = @_;
+  my @oldseed=&random_get_seed();
   my @retArray;
   &random_set_seed_from_phrase($seed);
   @retArray=&math_random_negative_binomial($item_cnt,$ne,$p);
+  &random_set_seed(@oldseed);
   return @retArray;
 }
 
@@ -385,15 +420,15 @@ sub log { log(shift) }
 sub atan2 { atan2($_[0],$_[1]) }
 sub sqrt { sqrt(shift) }
 
-sub tan  { sin($_[0]) / cos($_[0]) }
+sub tan  { CORE::sin($_[0]) / CORE::cos($_[0]) }
 #sub atan { atan2($_[0], 1); }
 #sub acos { atan2(sqrt(1 - $_[0] * $_[0]), $_[0] ); }
 #sub asin { atan2($_[0], sqrt(1- $_[0] * $_[0]) );  }
 
-sub log10 { log($_[0])/log(10); }
+sub log10 { CORE::log($_[0])/CORE::log(10); }
 
 sub factorial {
-    my $input = int(shift);
+    my $input = CORE::int(shift);
     return "Error - unable to take factorial of an negative number ($input)" if $input < 0;
     return "Error - factorial result is greater than system limit ($input)" if $input > 170;
     return 1 if $input == 0;
@@ -436,39 +471,72 @@ sub sub_string {
 }
 
 sub pow   {return $_[0] ** $_[1]; }
-sub ceil  {return (($_[0]-int($_[0]))== 0.0) ? $_[0] : (($_[0] > 0) ? (int($_[0])+ 1) : int($_[0])); }
-sub floor  {return (($_[0]-int($_[0]))== 0.0) ? $_[0] : (($_[0] > 0) ? int($_[0]) : (int($_[0])-1)); }
+sub ceil  {return (($_[0]-CORE::int($_[0]))== 0.0) ? $_[0] : (($_[0] > 0) ? (CORE::int($_[0])+ 1) : CORE::int($_[0])); }
+sub floor  {return (($_[0]-CORE::int($_[0]))== 0.0) ? $_[0] : (($_[0] > 0) ? CORE::int($_[0]) : (CORE::int($_[0])-1)); }
 #sub floor {return int($_[0]); }
 
 sub format {
   my ($value,$fmt)=@_;
-  return sprintf('%.'.$fmt,$value);
+  my $dollarmode;
+  if ($fmt =~ /^\$(.*)/) { $fmt=$1; $dollarmode=1; } 
+  my $result=sprintf('%.'.$fmt,$value);
+  $result=~s/(E[+-]*)0/$1/;
+  if ($dollarmode) {$result=&dollarmode($result);}
+  return $result;
 }
 
 sub prettyprint {
   my ($value,$fmt)=@_;
   my $result;
+  my $dollarmode;
+  if ($fmt =~ /^\$(.*)/) { $fmt=$1; $dollarmode=1; } 
   if ($fmt) { $value=sprintf('%.'.$fmt,$value); }
   if ($value =~ /([0-9\.\-\+]+)E([0-9\-\+]+)/ ) {
     my $frac=$1;
+    if ($dollarmode) { $frac=&dollarformat($frac); }
     my $exponent=$2;
     $exponent=~s/^\+0*//;
-    if (!$exponent) { return $frac; }
-    if ($external::target eq 'web') {
-      $result=$frac.'&#215;10<sup>'.$exponent.'</sup>';
-    } elsif ($external::target eq 'tex') {
-      $result='\ensuremath{'.$frac.'\times 10^{'.$exponent.'}}';
+    $exponent=~s/^-0*/-/;
+    if ($exponent) {
+      if ($external::target eq 'web') {
+	$result=$frac.'&#215;10<sup>'.$exponent.'</sup>';
+      } elsif ($external::target eq 'tex') {
+	$result='\ensuremath{'.$frac.'\times 10^{'.$exponent.'}}';
+      } else {
+	$result=$value;
+      }
     } else {
-      $result=$value;
+      $result=$frac;
     }
   } else {
     $result=$value;
+    if ($dollarmode) { $result=&dollarformat($result); }
   }
   return $result;
 }
 
+sub dollarformat {
+  my ($number) = @_;
+  if ($number =~ /\./) {
+    while ($number =~ /([^\.,]+)([^\.,][^\.,][^\.,])([,0-9]*\.[0-9]*$)/) {
+      $number = $1.','.$2.$3;
+    }
+  } else {
+    while ($number =~ /([^,]+)([^,][^,][^,])([,0-9]*)$/) {
+      $number = $1.','.$2.$3;
+    }
+  }
+  if ($external::target eq 'tex') {
+    $number='\$'.$number; #' stupid emacs
+  } else {
+    $number='$'.$number; #' stupid emacs
+  }
+  return $number; 
+}
+
 sub map {
     my ($phrase,$dest,$source)=@_;
+    my @oldseed=&random_get_seed();
     my @seed = &random_seed_from_phrase($phrase);
     &random_set_seed(@seed);
     my $destct = scalar(@$dest);
@@ -480,6 +548,7 @@ sub map {
 	    $output[$ctr] = $$dest[$idx[$ctr]];
 	    $ctr++;
 	}
+        &random_set_seed(@oldseed);
 	return @output;
     } else {
 	my $num = scalar(@$source);
@@ -499,10 +568,13 @@ sub map {
 	    }
 	}
     }
+    &random_set_seed(@oldseed);
+    return '';
 }
 
 sub rmap {
     my ($phrase,$dest,$source)=@_;
+    my @oldseed=&random_get_seed();
     my @seed = &random_seed_from_phrase($phrase);
     &random_set_seed(@seed);
     my $destct = scalar(@$dest);
@@ -520,6 +592,7 @@ sub rmap {
 	    $output[$ctr] = $$dest[$r_idx[$ctr]];
 	    $ctr++;
 	}
+        &random_set_seed(@oldseed);
 	return @output;
     } else {
 	my $num = scalar(@$source);
@@ -545,6 +618,8 @@ sub rmap {
 	    }
 	}
     }
+    &random_set_seed(@oldseed);
+    return '';
 }
 
 sub capa_id { return }
@@ -640,7 +715,7 @@ sub array_moments {
     $kurt+=$x**4;
   }
   $output[2]=$var/($N-1);
-  $sdev=sqrt($output[2]);
+  $sdev=CORE::sqrt($output[2]);
   if ($sdev == 0) {
      $output[3]="inf-variance=0";
      $output[4]="inf-variance=0";
@@ -656,4 +731,13 @@ sub choose {
   return $_[$num];
 }
 
+# expiremental idea
+sub proper_path {
+  my ($path)=@_;
+  if ( $external::target eq "tex" ) {
+    return '/home/httpd/html'.$path;
+  } else {
+    return $path;
+  }
+}