--- loncom/homework/default_homework.lcpm	2001/02/19 20:31:53	1.17
+++ loncom/homework/default_homework.lcpm	2006/06/13 14:57:54	1.107
@@ -1,189 +1,936 @@
-# file name (temp): default_homework 
+# The LearningOnline Network with CAPA 
 # used by lonxml::xmlparse() as input variable $safeinit to Apache::run::run()
-# 
 #
+# $Id: default_homework.lcpm,v 1.107 2006/06/13 14:57:54 albertel Exp $
+#
+# Copyright Michigan State University Board of Trustees
+#
+# This file is part of the LearningOnline Network with CAPA (LON-CAPA).
+#
+# LON-CAPA is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# LON-CAPA is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with LON-CAPA; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+#
+# /home/httpd/html/adm/gpl.txt
+#
+# http://www.lon-capa.org/
+#
+#
+
 #init some globals
-$RANDOMINIT=0;
+$hidden::RANDOMINIT=0;
 $pi=atan2(1,1)*4;
+$rad2deg=180.0/$pi;
+$deg2rad=$pi/180.0;
+$"=' ';
+
+sub check_commas {
+    my ($response)=@_;
+    #print("$response ");
+    my @numbers=split(',',$response);
+    #print(" numbers ".join('-',@numbers)." ");
+    if (scalar(@numbers) > 1) {
+        #print(" numbers[0] ".$numbers[0]." "); 
+	if (length($numbers[0]) > 3 || length($numbers[0]) == 0) { return -1; }
+	shift(@numbers);
+	#print(" numbers ".scalar(@numbers)." ");
+	while (scalar(@numbers) > 1) {
+	    #print(" numbers ".join('-',@numbers)." ");
+	    if (length($numbers[0]) != 3) { return -2; }
+	    shift(@numbers);
+	}
+	my ($number)=split('\.',$numbers[0]);
+	#print(" number ".$number." ");
+	#print(" numbers[0] ".$numbers[0]." ");
+	if (length($number) != 3) { return -3; }
+    } else {
+	my ($number)=split('\.',$numbers[0]);
+	if (length($number) > 3) { return -4; }
+    }
+    return 1;
+}
 
 sub caparesponse_check {
-  my $answer='';  #done
-  my $type='';    #done
-  my $tol_type=''; # gets it's value from whether tol has a % or not done
-  my $tol='';     #done
-  my $sig='';
-  my $sig_lbound='';
-  my $sig_ubound='';
-  my $ans_fmt='';
-  my $units='';
-  my $calc='';
-  my ($response,$expr)=@_;
-  
-  ($answer,$type,$tol,$sig,$ans_fmt,
-   $units,$calc) = eval $expr.';return $answer,$type,$tol,$sig,$ans_fmt,$units,$calc';
-  #type's definitons come from capaParser.h
-  if ($type eq '' ) {
-    if ( $answer eq ($answer *1.0)) { $type = 2;
-    } else { $type = 3; }
-  } else {
-         if ($type eq 'cs')    { $type = 4;
-    } elsif ($type eq 'ci')    { $type = 3;
-    } elsif ($type eq 'mc')    { $type = 5;
-    } elsif ($type eq 'fml')   { $type = 8;
-    } elsif ($type eq 'subj')  { $type = 7;
-    } else { return "ERROR: Unknown type of answer: $type" }
-  }
-
-  if ($tol eq '') {
-    $tol=0.0;
-    $tol_type=1; #TOL_ABSOLUTE
-  } else {
-    if ($tol =~ /%$/) {
-      chop $tol;
-      $tol_type=2; #TOL_PERCENTAGE
-    } else {
-      $tol_type=1; #TOL_ABSOLUTE
-    }
-  }
-
-  if ($sig eq '') {
-    $sig_lbound = 0; #SIG_LB_DEFAULT
-    $sig_ubound =15; #SIG_UB_DEFAULT
-  } else {
-    ($sig_lbound,$sig_ubound) = split /,/,$sig;
-  }
-  my $result = &caparesponse_capa_check_answer($response,$answer,$type,
-					       $tol_type,$tol,
-					       $sig_lbound,$sig_ubound,
-					       $ans_fmt,$units,$calc);
-
-  if    ($result == '1') { $result='EXACT_ANS'; } 
-  elsif ($result == '2') { $result='APPROX_ANS'; }
-  elsif ($result == '3') { $result='SIG_FAIL'; }
-  elsif ($result == '4') { $result='UNIT_FAIL'; }
-  elsif ($result == '5') { $result='NO_UNIT'; }
-  elsif ($result == '6') { $result='UNIT_OK'; }
-  elsif ($result == '7') { $result='INCORRECT'; }
-  elsif ($result == '8') { $result='UNIT_NOTNEEDED'; }
-  elsif ($result == '9') { $result='ANS_CNT_NOT_MATCH'; }
-  elsif ($result =='10') { $result='SUB_RECORDED'; }
-  elsif ($result =='11') { $result='BAD_FORMULA'; }
-  elsif ($result =='12') { $result='WANTED_NUMERIC'; }
-  else  {$result = "ERROR: Unknown Result:$result:$@:";}
+    my ($answer,$response)=@_;
+    #not properly used yet: calc
+    #not to be used: $ans_fmt
+    my $type=$LONCAPA::CAPAresponse_args{'type'};
+    my $tol=$LONCAPA::CAPAresponse_args{'tol'};
+    my $sig=$LONCAPA::CAPAresponse_args{'sig'};
+    my $ans_fmt=$LONCAPA::CAPAresponse_args{'format'};
+    my $unit=$LONCAPA::CAPAresponse_args{'unit'};
+    my $calc=$LONCAPA::CAPAresponse_args{'calc'};
+    my $samples=$LONCAPA::CAPAresponse_args{'samples'};
+    
+    my $tol_type=''; # gets it's value from whether tol has a % or not done
+    my $sig_lbound=''; #done
+    my $sig_ubound=''; #done
+
+
+    #type's definitons come from capaParser.h
+    my $message='';
+    #remove leading and trailing whitespace
+    if (!defined($response)) {
+	$response='';
+    }
+    if ($response=~ /^\s|\s$/) {
+	$response=~ s:^\s+|\s+$::g;
+	$message .="Removed ws now :$response:\n";
+    } else {
+	$message .="no ws in :$response:\n";
+    }
+    &LONCAPA_INTERNAL_DEBUG(" type is $type ");
+    if ($type eq 'cs' || $type eq 'ci') {
+	#for string answers make surec all places spaces occur, there is 
+        #really only 1 space, in both the answer and the response
+	$answer=~s/ +/ /g;
+	$response=~s/ +/ /g;
+    } elsif ($type eq 'mc') {
+	$answer=~s/[\s,]//g;
+	$response=~s/[\s,]//g;
+    }
+    if ($type eq 'float' && $unit=~/\$/) {
+	if ($response!~/^\$/)  { return "NO_UNIT: Missing \$ "; }
+	$response=~s/\$//g;
+    }
+    if ($type eq 'float' && $unit=~/\,/ && (&check_commas($response)<0)) {
+	return "COMMA_FAIL:";
+    }
+    $ans_fmt=~s/\W//g;
+    $unit=~s/[\$,]//g;
+    if ($type eq 'float') { $response=~s/,//g; }
+
+    if (length($response) > 500) { return "TOO_LONG: Answer too long"; }
+
+    if ($type eq '' ) {
+	$message .= "Didn't find a type :$type: defaulting\n";
+	if ( $answer eq ($answer *1.0)) { $type = 2;
+				      } else { $type = 3; }
+    } else {
+	if    ($type eq 'cs')    { $type = 4; }
+	elsif ($type eq 'ci')    { $type = 3 }
+	elsif ($type eq 'mc')    { $type = 5; }
+	elsif ($type eq 'fml')   { $type = 8; }
+        elsif ($type eq 'math')  { $type = 9; }
+	elsif ($type eq 'subj')  { $type = 7; }
+	elsif ($type eq 'float') { $type = 2; }
+	elsif ($type eq 'int')   { $type = 1; }
+	else { return "ERROR: Unknown type of answer: $type" }
+    }
+
+    my $points;
+    my $id_list;
+    #formula type setup the sample points
+    if ($type eq '8') {
+	($id_list,$points)=split(/@/,$samples);
+	$message.="Found :$id_list:$points: points in $samples\n";
+    }
+    if ($tol eq '') {
+	$tol=0.0;
+	$tol_type=1; #TOL_ABSOLUTE
+    } else {
+	if ($tol =~ /%$/) {
+	    chop $tol;
+	    $tol_type=2; #TOL_PERCENTAGE
+	} else {
+	    $tol_type=1; #TOL_ABSOLUTE
+	}
+    }
 
-  return "$result:<br />Error $error:<br />Answer $answer:<br />Response $response:<br />$type|$tol|$tol_type|$sig:$sig_lbound:$sig_ubound|$units<br />";
+    ($sig_ubound,$sig_lbound)=&LONCAPA_INTERNAL_get_sigrange($sig);
+
+    my $reterror="";
+    my $result;
+    if ($type eq '9') {
+      $result = &maxima_check($response,$answer,\$reterror);
+    } else {
+       $result = &caparesponse_capa_check_answer($response,$answer,$type,
+						 $tol_type,$tol,
+						 $sig_lbound,$sig_ubound,
+						 $ans_fmt,$unit,$calc,$id_list,
+						 $points,$external::randomseed,
+						 \$reterror);
+    }
+    if    ($result == '1') { $result='EXACT_ANS'; } 
+    elsif ($result == '2') { $result='APPROX_ANS'; }
+    elsif ($result == '3') { $result='SIG_FAIL'; }
+    elsif ($result == '4') { $result='UNIT_FAIL'; }
+    elsif ($result == '5') { $result='NO_UNIT'; }
+    elsif ($result == '6') { $result='UNIT_OK'; }
+    elsif ($result == '7') { $result='INCORRECT'; }
+    elsif ($result == '8') { $result='UNIT_NOTNEEDED'; }
+    elsif ($result == '9') { $result='ANS_CNT_NOT_MATCH'; }
+    elsif ($result =='10') { $result='SUB_RECORDED'; }
+    elsif ($result =='11') { $result='BAD_FORMULA'; }
+    elsif ($result =='12' && !$response) { $result='MISSING_ANSWER'; }
+    elsif ($result =='12') { $result='WANTED_NUMERIC'; }
+    elsif ($result =='13') { $result='UNIT_INVALID_INSTRUCTOR'; }
+    elsif ($result =='141') { $result='UNIT_INVALID_STUDENT'; }
+    elsif ($result =='142') { $result='UNIT_INVALID_STUDENT'; }
+    elsif ($result =='143') { $result='UNIT_INVALID_STUDENT'; }
+    elsif ($result =='15') { $result='UNIT_IRRECONCIBLE'; }
+    else  {$result = "ERROR: Unknown Result:$result:$@:";}
+
+    return ("$result:\nRetError $reterror:\nAnswer $answer:\nResponse $response:\n type-$type|$tol|$tol_type|$sig:$sig_lbound:$sig_ubound|$unit|\n$message",$reterror);
 }
 
+
 sub caparesponse_check_list {
-  my ($response,$expr)=@_;
-  my $result='';
-  my $aresult='';
-  my $current_answer;
-  my $answer = eval $expr.';return $answer';
-  my (@list) = eval $answer;
-  my (@responselist)=split /,/,$response;
-  my $unit='';
-  $result.="Final response :$responselist['-1']:<br />";
-  if ( $responselist['-1']=~ /(.*[^\s])\s+([^\s]+)/ ) {
-    $responselist['-1']=$1;
-    $unit=$2;
-  }
-  $result.="Final response :$responselist['-1']:<br />";
-  $unit=~s/\s//;
-  my $i=0;
-  my $awards='';
-  for ($i=0; $i<@list;$i++) {
-    $aresult=&caparesponse_check($responselist[$i]." $unit",
-				 $expr.';my $answer='.$list[$i].';');
-    my ($temp)=split /:/, $aresult;
-    $awards.="$temp,";
-    $result.=$aresult;
-  }
-  chop $awards;
-  return "$awards:<br />$result";
+    my $response=$LONCAPA::CAPAresponse_args{'response'};
+    my $result="Got response :".join(':',@LONCAPA::CAPAresponse_answer).":\n";
+    &LONCAPA_INTERNAL_DEBUG("args ".join(':',%LONCAPA::CAPAresponse_args));
+    my @responselist;
+    my $type = $LONCAPA::CAPAresponse_args{'type'};
+    $result.="Got type :$type:\n";
+    if ($type ne '' && $#LONCAPA::CAPAresponse_answer > 0) {
+	(@responselist)=split(/,/,$response);
+	if (@responselist < @LONCAPA::CAPAresponse_answer) {
+	    return 'MISSING_ANSWER';
+	}
+	if (@responselist > @LONCAPA::CAPAresponse_answer) {
+	    return 'EXTRA_ANSWER';
+	}
+    } else {
+	(@responselist)=($response);
+    }
+    $result.="Initial final response :$responselist['-1']:\n";
+    my $unit;
+    if ($type eq '' || $type eq 'float') {
+	#for numerical problems split off the unit
+	if ( $responselist['-1']=~ /(.*[^\s])\s+([^\s]+)/ ) {
+	    $responselist['-1']=$1;
+	    $unit=$2;
+	}
+    }
+    $result.="Final final response :$responselist['-1']:$unit:\n";
+    $unit=~s/\s//;
+
+    my ($awards, @msgs, $i);
+    foreach my $thisanswer (@LONCAPA::CAPAresponse_answer) {
+	my ($msg,$aresult);
+	$result.="trying answer :$thisanswer:\n";
+	if (defined($thisanswer)) {
+	    if ($unit eq '') {
+		($aresult,$msg)=&caparesponse_check($thisanswer,
+						    $responselist[$i]);
+	    } else {
+		($aresult,$msg)=&caparesponse_check($thisanswer,
+						    $responselist[$i]." $unit");
+	    }
+	} else {
+	    $aresult='ERROR';
+	    $msg='answer was undefined';
+	}
+	&LONCAPA_INTERNAL_DEBUG("after if $aresult -- $msg");
+	my ($temp)=split(/:/, $aresult);
+	$awards.="$temp,";
+	$result.=$aresult;
+	push(@msgs,$msg);
+	$i++;
+    }
+    chop($awards);
+    return ("$awards:\n$result",@msgs);
 }
 
 sub tex {
-  if ( $external::target eq "tex" ) {
-    return @_[0];
-  } else {
-    return @_[1];
-  }
+    if ( $external::target eq "tex" ) {
+	return $_[0];
+    } else {
+	return $_[1];
+    }
+}
+
+sub var_in_tex {
+    if ( $external::target eq "tex" ) {
+	return $_[0];
+    } else {
+	return "";
+    }
 }
 
 sub web {
-  if ( $external::target eq "tex" ) {
-    return @_[1];
-  } else {
-    if ( $external::target eq "web") {
-      return @_[0];
+    if ( $external::target eq "tex" ) {
+	return $_[1];
     } else {
-      return @_[2];
+	if ( $external::target eq "web" || $external::target eq "answer") {
+	    return $_[2];
+	} else {
+	    return $_[0];
+	}
     }
-  }
 }
 
-sub problem {
-  return '1';
+sub html {
+    if ( $external::target eq "web" ) {
+	return shift;
+    }
 }
 
 sub hinton {
-  return 0;
+    return 0;
 }
 
 sub random {
-  my ($start,$end,$step)=@_;
-  if ( ! $RANDOMINIT ) { srand($external::randomseed); $RANDOMINIT=1; }
-  my $num=1+int(($end-$start)/$step);
-  my $result=$start + int(rand() * $num)*$step;
-  return $result;
+    my ($start,$end,$step)=@_;
+    if ( ! $hidden::RANDOMINIT ) {
+	if ($external::randomseed == 0) { $external::randomseed=1; }
+	if ($external::randomseed =~/,/) {
+	    my ($num1,$num2)=split(/,/,$external::randomseed);
+	    &random_set_seed(1,abs($num1));
+	} elsif ($external::randomseed =~/:/) {
+	    my ($num1,$num2)=split(/:/,$external::randomseed);
+	    &random_set_seed(abs($num1),abs($num2));
+	} else {
+	    &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(&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);
+    my @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);
+    my @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,$p);
+    &random_set_seed(@oldseed);
+    return @retArray;
+}
+
+sub abs { CORE::abs(shift) }
+sub sin { CORE::sin(shift) }
+sub cos { CORE::cos(shift) }
+sub exp { CORE::exp(shift) }
+sub int { CORE::int(shift) }
+sub log { CORE::log(shift) }
+sub atan2 { CORE::atan2($_[0],$_[1]) }
+sub sqrt { CORE::sqrt(shift) }
+
+sub tan  { CORE::sin($_[0]) / CORE::cos($_[0]) }
+#sub atan { atan2($_[0], 1); }
+#sub acos { atan2(sqrt(1 - $_[0] * $_[0]), $_[0] ); }
+#sub asin { atan2($_[0], sqrt(1- $_[0] * $_[0]) );  }
+
+sub log10 { CORE::log($_[0])/CORE::log(10); }
+
+sub factorial {
+    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;
+    my $result = 1; 
+    for (my $i=2; $i<=$input; $i++) { $result *= $i }
+    return $result;
+}
+
+sub sgn {
+    return -1 if $_[0] < 0;
+    return 0 if $_[0] == 0;
+    return 1 if $_[0] > 0;
+}
+
+sub min {
+    my @sorted = sort { $a <=> $b || $a cmp $b } @_;
+    return shift @sorted;
+}
+
+sub max {
+    my @sorted = sort { $a <=> $b || $a cmp $b } @_;
+    return pop @sorted;
+}
+
+sub roundto {
+    my ($input,$n) = @_;
+    return sprintf('%.'.$n.'f',$input);
+}
+
+sub to_string {
+    my ($input,$n) = @_;
+    return sprintf($input) if $n eq "";
+    $n = '.'.$n if $n !~ /^\./;
+    return sprintf('%'.$n,$input) if $n ne "";
+}
+
+sub sub_string {
+    my ($str,$start,$len) = @_;
+    return substr($str,$start-1,$len);
 }
 
-sub tan  { sin($_[0]) / cos($_[0]) }
-sub acos { atan2(sqrt(1 - $_[0] * $_[0]), $_[0] ); }
-sub asin { atan2($_[0], sqrt(1- $_[0] * $_[0]) );  }
+sub pow   {return $_[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 html {
-  if ( $external::target eq "web" ) {
-    return @_[0];
-  }
+sub format {
+    my ($value,$fmt)=@_;
+    my ($dollarmode,$commamode,$alwaysperiod,$options);
+    if ($fmt =~ /^([^\d]*)(.*)/) { $options=$1; $fmt=$2; } 
+    #if ($options =~ /\$/) { $dollamode=1; }
+    #if ($options =~ /,/)  { $commamode=1; }
+    if ($options =~ /\./) { $alwaysperiod=1; }
+    my $result;
+    if ($fmt=~/s$/i) {
+	$result=&format_significant_figures($value,$fmt);
+    } else {
+	$fmt=~s/e/E/g;
+	$result=sprintf('%.'.$fmt,$value);
+	if ($alwaysperiod && $fmt eq '0f') { $result .='.'; }
+	$result=~s/(E[+-]*)0/$1/;
+    }
+    #if ($dollarmode) {$result=&dollarformat($result);}
+    #if ($commamode) {$result=&commaformat($result);}
+    return $result;
+}
+
+sub chemparse {
+    my ($reaction) = @_;
+    my @tokens = split(/(\s\+|\->|<=>|<\-|\.)/,$reaction);
+    my $formula = '';
+    foreach my $token (@tokens) {
+	if ($token eq '->' ) {
+	    $formula .= '<m>\ensuremath{\rightarrow}</m> ';
+	    next;
+	}
+	if ($token eq '<-' ) {
+	    $formula .= '<m>\ensuremath{\leftarrow}</m> ';
+	    next;
+	}  
+	if ($token eq '<=>') {
+	    if ($external::target eq 'web' &&
+		&EXT('request.browser.unicode')) {
+		$formula .= '&#8652; ';
+	    } else {
+		$formula .= &web('<=> ','<m>\ensuremath{\rightleftharpoons}</m> ',
+				 '&lt;=&gt; ');
+	    }
+	    next;
+	}
+	if ($token eq '.') {
+	  $formula =~ s/(\&nbsp\;| )$//;
+	  $formula .= '&middot;';
+	  next;
+	}
+	$token =~ /^\s*([\d|\/]*(?:&frac\d\d)?)(.*)/;
+        $formula .= $1 if ($1 ne '1');  # stoichiometric coefficient
+	
+	my $molecule = $2;
+	# subscripts
+	$molecule =~ s|(?<=[a-zA-Z\)\]\s])(\d+)|<sub>$1</sub>|g;
+	# superscripts
+	$molecule =~ s|\^(\d*[+\-]*)|<sup>$1</sup>|g;
+	# strip whitespace
+	$molecule =~ s/\s*//g;
+	# forced space
+	$molecule =~ s/_/ /g;
+	$molecule =~ s/-/&minus;/g;
+	$formula .= $molecule.'&nbsp;';
+    }
+    # get rid of trailing space
+    $formula =~ s/(\&nbsp\;| )$//;
+    return &xmlparse($formula);
+}
+
+sub prettyprint {
+    my ($value,$fmt,$target)=@_;
+    my $result;
+    if (!$target) { $target = $external::target; }
+    if ($fmt =~ /chem/i) { return(&chemparse($value)); }
+    my ($dollarmode,$commamode,$alwaysperiod,$options);
+    if ($fmt =~ /^([^\d]*)(.*)/) { $options=$1; $fmt=$2; } 
+    if ($options =~ /\$/) { $dollarmode=1; }
+    if ($options =~ /,/)  { $commamode=1; }
+    if ($options =~ /\./) { $alwaysperiod=1; }
+    if ($fmt=~/s$/i) {
+	$value=&format_significant_figures($value,$fmt);
+    } elsif ($fmt) {
+	$value=sprintf('%.'.$fmt,$value);
+    }
+    if ($alwaysperiod && $fmt eq '0f') {
+	if ($target eq 'tex') {
+	    $value .='\\ensuremath{.}';
+	} else {
+	    $value .='.';
+	}
+    }
+    if ($value =~ /([0-9\.\-\+]+)E([0-9\-\+]+)/i ) {
+	my $frac=$1;
+	if ($dollarmode) { $frac=&dollarformat($frac); }
+	if ($commamode) { $frac=&commaformat($frac); }
+	my $exponent=$2;
+	$exponent=~s/^\+0*//;
+	$exponent=~s/^-0*/-/;
+	$exponent=~s/^-0*/-/;
+	if ($exponent eq '-') { undef($exponent); }
+	if ($exponent) {
+	    if ($target eq 'web') {
+		$result=$frac.'&#215;10<sup>'.$exponent.'</sup>';
+	    } elsif ($target eq 'tex') {
+		$result='\ensuremath{'.$frac.'\times 10^{'.$exponent.'}}';
+	    } else {
+		$result=$value;
+	    }
+	} else {
+	    $result=$frac;
+	}
+    } else {
+	$result=$value;
+	if    ($dollarmode) { $result=&dollarformat($result,$target); }
+	elsif ($commamode)  { $result=&commaformat($result,$target); }
+    }
+    return $result;
 }
 
+sub commaformat {
+    my ($number,$target) = @_;
+    if ($number =~ /\./) {
+	while ($number =~ /([^0-9]*)([0-9]+)([^\.,][^\.,][^\.,])([,0-9]*\.[0-9]*)$/) {
+	    $number = $1.$2.','.$3.$4;
+	}
+    } else {
+	while ($number =~ /^([^0-9]*)([0-9]+)([^,][^,][^,])([,0-9]*)$/) {
+	    $number = $1.$2.','.$3.$4;
+	}
+    }
+    return $number;
+}
 
-sub pow   {return $_[0] ** $_[1]; }
-sub ceil  {return (($_[0]-int($_[0]))== 0.0) ? $_[0] : (int($_[0])+ 1); }
-sub floor {return int($_[0]);  }
+sub dollarformat {
+    my ($number,$target) = @_;
+    if (!$target) { $target = $external::target; }
+    $number=&commaformat($number,$target);
+    if ($target eq 'tex') {
+	$number='\$'.$number; #' stupid emacs
+    } else {
+	$number='$'.$number; #' stupid emacs
+    }
+    return $number; 
+}
+
+# format of form ns or nS where n is an integer
+sub format_significant_figures {
+    my ($number,$format) = @_; 
+    return '0' if ($number == 0);
+    # extract number of significant figures needed
+    my ($sig) = ($format =~ /(\d+)s/i);
+    # arbitrary choice - suggestions ?? or throw error message?
+    $sig = 3 if ($sig eq '');
+    # save the minus sign
+    my $sign = ($number < 0) ? '-' : '';
+    $number = abs($number);
+    # needed to correct for a number greater than 1 (or
+    my $power = ($number < 1) ? 0 : 1;
+    # could round up. Take the integer part of log10.
+    my $x10 = int(log($number)/log(10));
+    # find number with values left of decimal pt = # of sign figs.
+    my $xsig = $number*10**($sig-$x10-$power);
+    # get just digits left of decimal pt - also rounds off correctly
+    my $xint  = sprintf('%.0f',$xsig);
+    # save any trailing zero's
+    my ($zeros) = ($xint =~ /(0+)$/);
+    # return number to original magnitude
+    my $numSig = $xint*10**($x10-$sig+$power);
+    # insert trailing zero's if have decimal point
+    $numSig =~ s/^(\d+)\.(\d+)(\e?(.*)?)$/$1\.$2$zeros$3/;
+    # put a decimal pt for number ending with 0 and length = # of sig fig
+    $numSig.='.' if (length($numSig) == $sig && $numSig =~ /0$/);
+    if (length($numSig) < $sig) {
+	$numSig.='.'.substr($zeros,0,($sig-length($numSig)));
+    }
+    # return number with sign
+    return $sign.$numSig;
 
-sub format {
-  my ($value,$fmt)=@_;
-  return sprintf('%.'.$fmt,$value);
 }
 
 sub map {
-  my $num = $#_/2;
-  my $i;
-  my @used;
-  my @permutation;
-  for ($i=0; $i < $num;) {
-    $rand = &random(1,$num,1);
-    if ( $used[$rand] == '0' ) {
-      $i++;
-      $used[$rand]='1';
-      $permutation[$i]=$rand;
-    }
-  }
-  for ( $i=1 ; $i<$num+1 ; $i++ ) {
-    ${$_[$permutation[$i]]}=$_[$i+$num]
-  }
+    my ($phrase,$dest,$source)=@_;
+    my @oldseed=&random_get_seed();
+    my @seed = &random_seed_from_phrase($phrase);
+    &random_set_seed(@seed);
+    my $destct = scalar(@$dest);
+    if (!$source) {
+	my @output;
+	my @idx = &math_random_permuted_index($destct);
+	my $ctr = 0;
+	while ($ctr < $destct) {
+	    $output[$ctr] = $$dest[$idx[$ctr]];
+	    $ctr++;
+	}
+        &random_set_seed(@oldseed);
+	return @output;
+    } else {
+	my $num = scalar(@$source);
+	my @idx = &math_random_permuted_index($num);
+	my $ctr = 0;
+	my $tot = $num;
+	$tot = $destct if $destct < $num;
+	if (ref($$dest[0])) {
+	    while ($ctr < $tot) {
+		${$$dest[$ctr]} = $$source[$idx[$ctr]];
+	        $ctr++;
+            }
+        } else {
+	    while ($ctr < $tot) {
+		$$dest[$ctr] = $$source[$idx[$ctr]];
+		$ctr++;
+	    }
+	}
+    }
+    &random_set_seed(@oldseed);
+    return '';
+}
+
+sub rmap {
+    my ($phrase,$dest,$source)=@_;
+    my @oldseed=&random_get_seed();
+    my @seed = &random_seed_from_phrase($phrase);
+    &random_set_seed(@seed);
+    my $destct = scalar(@$dest);
+    if (!$source) {
+	my @idx = &math_random_permuted_index($destct);
+	my $ctr = 0;
+	my @r_idx;
+	while ($ctr < $destct) {
+	    $r_idx[$idx[$ctr]] = $ctr;
+	    $ctr++;
+	}
+	my @output;
+	$ctr = 0;
+	while ($ctr < $destct) {
+	    $output[$ctr] = $$dest[$r_idx[$ctr]];
+	    $ctr++;
+	}
+        &random_set_seed(@oldseed);
+	return @output;
+    } else {
+	my $num = scalar(@$source);
+	my @idx = &math_random_permuted_index($num);
+	my $ctr = 0;
+	my $tot = $num;
+	$tot = $destct if $destct < $num;
+	my @r_idx;
+	while ($ctr < $tot) {
+	    $r_idx[$idx[$ctr]] = $ctr;
+	    $ctr++;
+	}
+	$ctr = 0;
+	if (ref($$dest[0])) {
+	    while ($ctr < $tot) {
+		${$$dest[$ctr]} = $$source[$r_idx[$ctr]];
+	        $ctr++;
+            }
+        } else {
+	    while ($ctr < $tot) {
+		$$dest[$ctr] = $$source[$r_idx[$ctr]];
+		$ctr++;
+	    }
+	}
+    }
+    &random_set_seed(@oldseed);
+    return '';
+}
+
+sub capa_id { return }
+
+sub problem { return }
+
+sub name{
+    my $fullname = &EXT('environment.lastname').', '.&EXT('environment.firstname').' '.&EXT('environment.middlename');
+    $fullname = "" if $fullname eq ",  ";
+    $fullname =~ s/\%2d/-/g;
+    return $fullname;
+}
+
+sub student_number { 
+    my $id = &EXT('environment.id');
+    $id = '' if $id eq "";
+    return $id;
+}
+
+sub class {
+    my $course = &EXT('course.description');
+    $course = '' if $course eq "";
+    return $course;
+}
+
+sub sec { 
+    my $sec = &EXT('request.course.sec');
+    $sec = '' if $sec eq "";
+    return $sec;
+}
+
+sub open_date { 
+    my @dc = split(/\s+/,localtime(&EXT('resource.0.opendate')));
+    return '' if ($dc[0] eq "Wed" and $dc[2] == 31 and $dc[4] == 1969);
+    my @hm = split(/:/,$dc[3]);
+    my $ampm = " am";
+    if ($hm[0] > 12) {
+	$hm[0]-=12;
+	$ampm = " pm";
+    }
+    return $dc[0].', '.$dc[1].' '.$dc[2].', '.$dc[4].' at '.$hm[0].':'.$hm[1].$ampm;
+}
+
+sub due_date { 
+    my @dc = split(/\s+/,localtime(&EXT('resource.0.duedate')));
+    return '' if ($dc[0] eq "Wed" and $dc[2] == 31 and $dc[4] == 1969);
+    my @hm = split(/:/,$dc[3]);
+    my $ampm = " am";
+    if ($hm[0] > 12) {
+	$hm[0]-=12;
+	$ampm = " pm";
+    }
+    return $dc[0].', '.$dc[1].' '.$dc[2].', '.$dc[4].' at '.$hm[0].':'.$hm[1].$ampm;
+}
+
+sub answer_date { 
+    my @dc = split(/\s+/,localtime(&EXT('resource.0.answerdate')));
+    return '' if ($dc[0] eq "Wed" and $dc[2] == 31 and $dc[4] == 1969);
+    my @hm = split(/:/,$dc[3]);
+    my $ampm = " am";
+    if ($hm[0] > 12) {
+	$hm[0]-=12;
+	$ampm = " pm";
+    }
+    return $dc[0].', '.$dc[1].' '.$dc[2].', '.$dc[4].' at '.$hm[0].':'.$hm[1].$ampm;
+}
+
+sub array_moments {
+    my @input=@_;
+    my (@output,$N);
+    $N=scalar (@input);
+    $output[0]=$N;
+    if ($N <= 1) {
+	$output[1]=$input[0];
+	$output[1]="Input array not defined" if ($N == 0);
+	$output[2]="variance undefined for N<=1";
+	$output[3]="skewness undefined for N<=1";
+	$output[4]="kurtosis undefined for N<=1";
+	return @output;
+    }
+    my $sum=0;
+    foreach my $line (@input) {
+	$sum+=$line;
+    }
+    $output[1] = $sum/$N;
+    my ($x,$sdev,$var,$skew,$kurt) = 0;
+    foreach my $line (@input) {
+	$x=$line-$output[1];
+	$var+=$x**2;
+	$skew+=$x**3;
+	$kurt+=$x**4;
+    }
+    $output[2]=$var/($N-1);
+    $sdev=CORE::sqrt($output[2]);
+    if ($sdev == 0) {
+	$output[3]="inf-variance=0";
+	$output[4]="inf-variance=0";
+	return @output;
+    }
+    $output[3]=$skew/($sdev**3*$N);
+    $output[4]=$kurt/($sdev**4*$N)-3;
+    return @output;
 }
 
 sub choose {
-  my $num = $_[0];
-  return $_[$num];
+    my $num = $_[0];
+    return $_[$num];
+}
+
+#&sum1(1,$x,sub { &sum1($_[0],2*$_[0], sub { fact($_[0])**2 })});
+#sub sum1 {
+#    my ($start,$end,$sub)=@_;
+#    my $sum=0;
+#    for (my $i=$start;$i<=$end;$i++) {
+#        $sum+=&$sub($i);
+#    }
+#    return $sum
+#}
+
+#&sum2('a',1,$x,'&sum2(\'b\',$a,2*$a, \'&factorial($b)**2\')');
+#sub sum2 {
+#    my ($varname,$start,$end,$line)=@_;
+#    my $sum=0;
+#    for (my $i=$start;$i<=$end;$i++) {
+#	my $func=sub {
+#	    eval("\$".$varname."=$i");
+#	    eval($line);
+#	};
+#        $sum+=&$func($i);
+#    }
+#    return $sum
+#}
+
+# expiremental idea
+sub proper_path {
+    my ($path)=@_;
+    if ( $external::target eq "tex" ) {
+	return '/home/httpd/html'.$path;
+    } else {
+	return $path;
+    }
 }
-#$external::randomseed=time;
-#$a=2;
-#$b=2;
-#$c=2;
-#&map(1,\$a,\$b,\$c,3,4,5);
-#print $a."\n".$b."\n";
+