loncom/homework/default_homework.lcpm - view

File: [LON-CAPA] / loncom / homework / default_homework.lcpm
Revision 1.151: download - view: text, annotated - select for diffs
Thu Dec 16 16:01:01 2010 UTC (13 years, 4 months ago) by raeburn
Branches: MAIN
CVS tags: version_2_10_0_RC2, HEAD

- Bug 5531.
 caparesponse.pm
  - For stringresponse: (case (in)sensitive) computer's answer available
    in detailed submission display.
  - Student username in warnings on control characters etc. renamed $sname
    instead of $name (already in use in different scope) to improve code
    readability
  - computer answer available for legacy stringresponse submission (e.g.,
    for bug 5531 detection script -see neutrinohavest.pl)
    if grade_retrieveanswers included in form for answer target.

 default_homework.pm
  - fix detection of control characters in answers - answers will be in
    an array
  - computer's answer returned by &caparesponse_check_list()

 loncommon.pm
  - &format_previous_attempt_value() handles display of computer's answer.
  - fix typo in phrase for localization (no current translations in
    localize/*.pm to update).

1: # The LearningOnline Network with CAPA 2: # used by lonxml::xmlparse() as input variable $safeinit to Apache::run::run() 3: # 4: # $Id: default_homework.lcpm,v 1.151 2010/12/16 16:01:01 raeburn Exp $ 5: # 6: # Copyright Michigan State University Board of Trustees 7: # 8: # This file is part of the LearningOnline Network with CAPA (LON-CAPA). 9: # 10: # LON-CAPA is free software; you can redistribute it and/or modify 11: # it under the terms of the GNU General Public License as published by 12: # the Free Software Foundation; either version 2 of the License, or 13: # (at your option) any later version. 14: # 15: # LON-CAPA is distributed in the hope that it will be useful, 16: # but WITHOUT ANY WARRANTY; without even the implied warranty of 17: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18: # GNU General Public License for more details. 19: # 20: # You should have received a copy of the GNU General Public License 21: # along with LON-CAPA; if not, write to the Free Software 22: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 23: # 24: # /home/httpd/html/adm/gpl.txt 25: # 26: # http://www.lon-capa.org/ 27: # 28: # 29: 30: #init some globals 31: $hidden::RANDOMINIT=0; 32: $pi=atan2(1,1)*4; 33: $rad2deg=180.0/$pi; 34: $deg2rad=$pi/180.0; 35: $"=' '; 36: use strict; 37: { 38: my $n = 0; 39: my $total = 0; 40: my $num_left = 0; 41: my @order; 42: my $type; 43: 44: sub init_permutation { 45: my ($size,$requested_type) = @_; 46: @order = (0..$size-1); 47: $n = $size; 48: $type = $requested_type; 49: if ($type eq 'ordered') { 50: $total = $num_left = 1; 51: } elsif ($type eq 'unordered') { 52: $total = $num_left = &factorial($size); 53: } else { 54: die("Unkown type: $type"); 55: } 56: } 57: 58: sub get_next_permutation { 59: if ($num_left == $total) { 60: $num_left--; 61: return \@order; 62: } 63: 64: # Find largest index j with a[j] < a[j+1] 65: 66: my $j = scalar(@order) - 2; 67: while ($order[$j] > $order[$j+1]) { 68: $j--; 69: } 70: 71: # Find index k such that a[k] is smallest integer 72: # greater than a[j] to the right of a[j] 73: 74: my $k = scalar(@order) - 1; 75: while ($order[$j] > $order[$k]) { 76: $k--; 77: } 78: 79: # Interchange a[j] and a[k] 80: 81: @order[($k,$j)] = @order[($j,$k)]; 82: 83: # Put tail end of permutation after jth position in increasing order 84: 85: my $r = scalar(@order) - 1; 86: my $s = $j + 1; 87: 88: while ($r > $s) { 89: @order[($s,$r)]=@order[($r,$s)]; 90: $r--; 91: $s++; 92: } 93: 94: $num_left--; 95: return(\@order); 96: } 97: 98: sub get_permutations_left { 99: return $num_left; 100: } 101: } 102: 103: sub check_commas { 104: my ($response)=@_; 105: #print("$response "); 106: my @numbers=split(',',$response); 107: #print(" numbers ".join('-',@numbers)." "); 108: if (scalar(@numbers) > 1) { 109: #print(" numbers[0] ".$numbers[0]." "); 110: if (length($numbers[0]) > 3 || length($numbers[0]) == 0) { return -1; } 111: shift(@numbers); 112: #print(" numbers ".scalar(@numbers)." "); 113: while (scalar(@numbers) > 1) { 114: #print(" numbers ".join('-',@numbers)." "); 115: if (length($numbers[0]) != 3) { return -2; } 116: shift(@numbers); 117: } 118: my ($number)=split('\.',$numbers[0]); 119: #print(" number ".$number." "); 120: #print(" numbers[0] ".$numbers[0]." "); 121: if (length($number) != 3) { return -3; } 122: } else { 123: my ($number)=split('\.',$numbers[0]); 124: if (length($number) > 3) { return -4; } 125: } 126: return 1; 127: } 128: 129: 130: sub caparesponse_check { 131: my ($answer,$response)=@_; 132: #not properly used yet: calc 133: #not to be used: $ans_fmt 134: my $type=$LONCAPA::CAPAresponse_args{'type'}; 135: my $tol=$LONCAPA::CAPAresponse_args{'tol'}; 136: my $sig=$LONCAPA::CAPAresponse_args{'sig'}; 137: my $ans_fmt=$LONCAPA::CAPAresponse_args{'format'}; 138: my $unit=$LONCAPA::CAPAresponse_args{'unit'}; 139: my $calc=$LONCAPA::CAPAresponse_args{'calc'}; 140: my $samples=$LONCAPA::CAPAresponse_args{'samples'}; 141: 142: my $tol_type=''; # gets it's value from whether tol has a % or not done 143: my $sig_lbound=''; #done 144: my $sig_ubound=''; #done 145: 146: 147: #type's definitons come from capaParser.h 148: 149: #remove leading and trailing whitespace 150: if (!defined($response)) { 151: $response=''; 152: } 153: if ($response=~ /^\s|\s$/) { 154: $response=~ s:^\s+|\s+$::g; 155: &LONCAPA_INTERNAL_DEBUG("Removed ws now :$response:"); 156: } 157: 158: #&LONCAPA_INTERNAL_DEBUG(" type is $type "); 159: if ($type eq 'cs' || $type eq 'ci') { 160: #for string answers make sure all places spaces occur, there is 161: #really only 1 space, in both the answer and the response 162: $answer=~s/ +/ /g; 163: $response=~s/ +/ /g; 164: } elsif ($type eq 'mc') { 165: $answer=~s/[\s,]//g; 166: $response=~s/[\s,]//g; 167: } 168: if ($type eq 'float' && $unit=~/\$/) { 169: if ($response!~/^\$|\$$/) { return ('NO_UNIT', undef); } 170: $response=~s/\$//g; 171: } 172: if ($type eq 'float' && $unit=~/\,/ && (&check_commas($response)<0)) { 173: return "COMMA_FAIL:"; 174: } 175: $ans_fmt=~s/\W//g; 176: $unit=~s/[\$,]//g; 177: if ($type eq 'float') { $response=~s/,//g; } 178: 179: if (length($response) > 500) { return ('TOO_LONG',undef); } 180: 181: if ($type eq '' ) { 182: &LONCAPA_INTERNAL_DEBUG("Didn't find a type :$type: defaulting"); 183: if ( $answer eq ($answer *1.0)) { $type = 2; 184: } else { $type = 3; } 185: } else { 186: if ($type eq 'cs') { $type = 4; } 187: elsif ($type eq 'ci') { $type = 3 } 188: elsif ($type eq 'mc') { $type = 5; } 189: elsif ($type eq 'fml') { $type = 8; } 190: elsif ($type eq 'math') { $type = 9; } 191: elsif ($type eq 'subj') { $type = 7; } 192: elsif ($type eq 'float') { $type = 2; } 193: elsif ($type eq 'int') { $type = 1; } 194: else { return ('ERROR', "Unknown type of answer: $type") } 195: } 196: 197: my $points; 198: my $id_list; 199: #formula type setup the sample points 200: if ($type eq '8') { 201: ($id_list,$points)=split(/@/,$samples); 202: &LONCAPA_INTERNAL_DEBUG("Found :$id_list:$points: points in $samples"); 203: } 204: if ($tol eq '') { 205: $tol=0.0; 206: $tol_type=1; #TOL_ABSOLUTE 207: } else { 208: if ($tol =~ /%$/) { 209: chop $tol; 210: $tol_type=2; #TOL_PERCENTAGE 211: } else { 212: $tol_type=1; #TOL_ABSOLUTE 213: } 214: } 215: 216: ($sig_ubound,$sig_lbound)=&LONCAPA_INTERNAL_get_sigrange($sig); 217: 218: my $reterror=""; 219: my $result; 220: if (($type eq '9') || ($type eq '8')) { 221: if ($response=~/\=/) { 222: return ('BAD_FORMULA','Please submit just an expression, not an equation.'); 223: } elsif ($response =~ /\,/ and $response !~ /^\s*\{.*\}\s*$/) { 224: return ('BAD_FORMULA'); 225: } 226: } 227: if ($type eq '9') { 228: $result = &maxima_check(&maxima_cas_formula_fix($response),&maxima_cas_formula_fix($answer),\$reterror); 229: } else { 230: if ($type eq '8') { # fml type 231: $response = &capa_formula_fix($response); 232: $answer = &capa_formula_fix($answer); 233: } 234: $result = &caparesponse_capa_check_answer($response,$answer,$type, 235: $tol_type,$tol, 236: $sig_lbound,$sig_ubound, 237: $ans_fmt,$unit,$calc,$id_list, 238: $points,$external::randomseed, 239: \$reterror); 240: } 241: if ($result == '1') { $result='EXACT_ANS'; } 242: elsif ($result == '2') { $result='APPROX_ANS'; } 243: elsif ($result == '3') { $result='SIG_FAIL'; } 244: elsif ($result == '4') { $result='UNIT_FAIL'; } 245: elsif ($result == '5') { $result='NO_UNIT'; } 246: elsif ($result == '6') { $result='UNIT_OK'; } 247: elsif ($result == '7') { $result='INCORRECT'; } 248: elsif ($result == '8') { $result='UNIT_NOTNEEDED'; } 249: elsif ($result == '9') { $result='ANS_CNT_NOT_MATCH'; } 250: elsif ($result =='10') { $result='SUB_RECORDED'; } 251: elsif ($result =='11') { $result='BAD_FORMULA'; } 252: elsif ($result =='12' && !$response) { $result='MISSING_ANSWER'; } 253: elsif ($result =='12') { $result='WANTED_NUMERIC'; } 254: elsif ($result =='13') { $result='UNIT_INVALID_INSTRUCTOR'; } 255: elsif ($result =='141') { $result='UNIT_INVALID_STUDENT'; } 256: elsif ($result =='142') { $result='UNIT_INVALID_STUDENT'; } 257: elsif ($result =='143') { $result='UNIT_INVALID_STUDENT'; } 258: elsif ($result =='15') { $result='UNIT_IRRECONCIBLE'; } 259: else {$result = "ERROR: Unknown Result:$result:$@:";} 260: 261: &LONCAPA_INTERNAL_DEBUG("RetError $reterror: Answer $answer: Response $response: type-$type|$tol|$tol_type|$sig:$sig_lbound:$sig_ubound|$unit|"); 262: &LONCAPA_INTERNAL_DEBUG(" $answer $response $result "); 263: return ($result,$reterror); 264: } 265: 266: 267: sub caparesponse_check_list { 268: my $responses=$LONCAPA::CAPAresponse_args{'response'}; 269: &LONCAPA_INTERNAL_DEBUG("args ".join(':',%LONCAPA::CAPAresponse_args)); 270: my $type = $LONCAPA::CAPAresponse_args{'type'}; 271: my $answerunit=$LONCAPA::CAPAresponse_args{'unit'}; 272: &LONCAPA_INTERNAL_DEBUG("Got type :$type: answer unit :$answerunit:\n"); 273: 274: my $num_input_lines = 275: scalar(@{$LONCAPA::CAPAresponse_answer->{'answers'}}); 276: 277: if ($type ne '' ) { 278: if (scalar(@$responses) < $num_input_lines) { 279: return 'MISSING_ANSWER'; 280: } 281: if (scalar(@$responses) > $num_input_lines) { 282: return 'EXTRA_ANSWER'; 283: } 284: 285: } 286: 287: foreach my $which (0..($num_input_lines-1)) { 288: my $answer_size = 289: scalar(@{$LONCAPA::CAPAresponse_answer->{'answers'}[$which]}); 290: if ($type ne '' 291: && $answer_size > 1) { 292: $responses->[$which]=[split(/,/,$responses->[$which])]; 293: } else { 294: $responses->[$which]=[$responses->[$which]]; 295: } 296: } 297: foreach my $which (0..($num_input_lines-1)) { 298: my $answer_size = 299: scalar(@{$LONCAPA::CAPAresponse_answer->{'answers'}[$which]}); 300: my $response_size = 301: scalar(@{$responses->[$which]}); 302: if ($answer_size > $response_size) { 303: return 'MISSING_ANSWER'; 304: } 305: if ($answer_size < $response_size) { 306: return 'EXTRA_ANSWER'; 307: } 308: } 309: 310: &LONCAPA_INTERNAL_DEBUG("Initial final response :$responses->[0][-1]:"); 311: my $unit; 312: if ($type eq 'float' || $type eq '') { 313: #for numerical problems split off the unit 314: # if ( $responses->[0][-1]=~ /(.*[^\s])\s+([^\s]+)/ ) { 315: if ( $responses->[0][-1]=~ /^([\d\.\,\s\$]*(?:(?:[xX\*]10[\^\*]*|[eE]*)[\+\-]*\d*)*(?:^|\S)\d+)([\$\s\w\^\*\/\+\-]*[^\d\.\s\,][\$\s\w\^\*\/\+\-]*)$/ ) { 316: $responses->[0][-1]=$1; 317: $unit=&capa_formula_fix($2); 318: &LONCAPA_INTERNAL_DEBUG("Found unit :$unit:"); 319: } 320: } 321: &LONCAPA_INTERNAL_DEBUG("Final final response :$responses->[0][-1]:$unit:"); 322: $unit=~s/\s//; 323: my $error; 324: foreach my $response (@$responses) { 325: foreach my $element (@$response) { 326: if (($type eq 'float') || (($type eq '') && ($unit ne ''))) { 327: $element =~ s/\s//g; 328: } 329: my $appendunit=$unit; 330: # Deal with percentages 331: # unit is unit entered by student, answerunit is unit by author 332: # Deprecated: divide answer by 100 if student entered percent, 333: # but author did not. Too much confusion 334: # if (($unit=~/\%/) && ($answerunit ne '%')) { 335: # $element=$element/100; 336: # $appendunit=~s/\%//; 337: # } 338: # Author entered percent, student did not 339: if (($unit!~/\%/) && ($answerunit=~/\%/)) { 340: $element=$element*100; 341: $appendunit='%'.$appendunit; 342: } 343: # Zero does not need a dimension 344: if (($element==0) && ($unit!~/\w/) && ($answerunit=~/\w/)) { 345: $appendunit=$answerunit; 346: } 347: if ($appendunit ne '') { 348: $element .= " $appendunit"; 349: } 350: &LONCAPA_INTERNAL_DEBUG("Made response element :$element:"); 351: } 352: } 353: 354: foreach my $thisanswer (@{ $LONCAPA::CAPAresponse_answer->{'answers'} }) { 355: if (!defined($thisanswer)) { 356: return ('ERROR','answer was undefined'); 357: } 358: } 359: 360: my $allow_control_char = 0; 361: my $control_chars_removed = 0; 362: my $ansstring; 363: if ($type eq 'cs' || $type eq 'ci') { 364: if (ref($LONCAPA::CAPAresponse_answer->{'answers'}) eq 'ARRAY') { 365: foreach my $strans (@{$LONCAPA::CAPAresponse_answer->{'answers'}}) { 366: if (ref($strans) eq 'ARRAY') { 367: foreach my $item (@{$strans}) { 368: if ($item =~ /[\000-\037]/) { 369: $allow_control_char = 1; 370: } 371: } 372: } 373: } 374: } 375: } 376: if (($type eq 'cs') || ($type eq 'ci')) { 377: if (ref($LONCAPA::CAPAresponse_answer->{'answers'}) eq 'ARRAY') { 378: foreach my $answer (@{ $LONCAPA::CAPAresponse_answer->{'answers'} }) { 379: if (ref($answer) eq 'ARRAY') { 380: $ansstring = join("\0",@{$answer}); 381: } 382: } 383: } 384: } 385: 386: # &LONCAPA_INTERNAL_DEBUG(&LONCAPA_INTERNAL_Dumper($responses)); 387: my %memoized; 388: if ($LONCAPA::CAPAresponse_answer->{'type'} eq 'ordered') { 389: for (my $i=0; $i<scalar(@$responses);$i++) { 390: my $answer = $LONCAPA::CAPAresponse_answer->{'answers'}[$i]; 391: my $response = $responses->[$i]; 392: my $key = "$answer\0$response"; 393: my (@awards,@msgs); 394: for (my $j=0; $j<scalar(@$response); $j++) { 395: if ($type eq 'cs' || $type eq 'ci') { 396: unless ($allow_control_char) { 397: if ($response->[$j] =~ /[\000-\037]/) { 398: $response->[$j] =~ s/[\000-\037]//g; 399: $control_chars_removed = 1; 400: } 401: } 402: } 403: my ($award,$msg) = &caparesponse_check($answer->[$j], 404: $response->[$j]); 405: if ($type eq 'cs' || $type eq 'ci') { 406: $error = &verify_stringresponse($type,$award,$response->[$j], 407: $answer->[$j]); 408: } 409: push(@awards,$award); 410: push(@msgs, $msg); 411: } 412: my ($award,$msg) = 413: &LONCAPA_INTERNAL_FINALIZEAWARDS(\@awards,\@msgs); 414: $memoized{$key} = [$award,$msg]; 415: } 416: } else { 417: #FIXME broken with unorder responses where one is a <value> 418: # and the other is a <vector> (need to delay parse til 419: # inside the loop?) 420: foreach my $response (@$responses) { 421: my $response_size = scalar(@{$response}); 422: foreach my $answer (@{ $LONCAPA::CAPAresponse_answer->{'answers'} }) { 423: my $key = "$answer\0$response"; 424: my $answer_size = scalar(@{$answer}); 425: my ($award,$msg); 426: if ($answer_size > $response_size) { 427: $award = 'MISSING_ANSWER'; 428: } elsif ($answer_size < $response_size) { 429: $award = 'EXTRA_ANSWER'; 430: } else { 431: my (@awards,@msgs); 432: for (my $j=0; $j<scalar(@$response); $j++) { 433: if ($type eq 'cs' || $type eq 'ci') { 434: unless ($allow_control_char) { 435: if ($response->[$j] =~ /[\000-\037]/) { 436: $response->[$j] =~ s/[\000-\037]//g; 437: $control_chars_removed = 1; 438: } 439: } 440: } 441: my ($award,$msg) = &caparesponse_check($answer->[$j], 442: $response->[$j]); 443: if ($type eq 'cs' || $type eq 'ci') { 444: $error = &verify_stringresponse($type,$award,$response->[$j], 445: $answer->[$j]); 446: } 447: push(@awards,$award); 448: push(@msgs, $msg); 449: } 450: ($award,$msg) = 451: &LONCAPA_INTERNAL_FINALIZEAWARDS(\@awards,\@msgs); 452: } 453: $memoized{$key} = [$award,$msg]; 454: } 455: } 456: } 457: 458: my ($final_award,$final_msg); 459: &init_permutation(scalar(@$responses), 460: $LONCAPA::CAPAresponse_answer->{'type'}); 461: 462: # possible FIXMEs 463: # - significant time is spent calling non-safe space routine 464: # from safe space 465: # - early outs could be possible with classifying awards is to stratas 466: # and stopping as so as hitting the top strata 467: # - some early outs also might be possible with check ing the 468: # memoized hash of results (is correct even possible? etc.) 469: 470: my (@final_awards,@final_msg); 471: while( &get_permutations_left() ) { 472: my $order = &get_next_permutation(); 473: my (@awards, @msgs, $i); 474: foreach my $thisanswer (@{ $LONCAPA::CAPAresponse_answer->{'answers'} }) { 475: my $key = "$thisanswer\0".$responses->[$order->[$i]]; 476: push(@awards,$memoized{$key}[0]); 477: push(@msgs,$memoized{$key}[1]); 478: $i++; 479: 480: } 481: &LONCAPA_INTERNAL_DEBUG(" all awards ".join(':',@awards)); 482: 483: my ($possible_award,$possible_msg) = 484: &LONCAPA_INTERNAL_FINALIZEAWARDS(\@awards,\@msgs); 485: &LONCAPA_INTERNAL_DEBUG(" pos awards ".$possible_award); 486: push(@final_awards,$possible_award); 487: push(@final_msg,$possible_msg); 488: } 489: 490: &LONCAPA_INTERNAL_DEBUG(" all final_awards ".join(':',@final_awards)); 491: my ($final_award,$final_msg) = 492: &LONCAPA_INTERNAL_FINALIZEAWARDS(\@final_awards,\@final_msg,undef,1); 493: return ($final_award,$final_msg,$error,$control_chars_removed,$ansstring); 494: } 495: 496: sub verify_stringresponse { 497: my ($type,$award,$resp,$ans) = @_; 498: return if ($award eq 'EXACT_ANS'); 499: my $error; 500: if ($resp =~ /^\s|\s$/) { 501: $resp =~ s{^\s+|\s+$}{}g; 502: } 503: if ($ans =~ /^\s|\s$/) { 504: $ans =~ s{^\s+|\s+$}{}g; 505: } 506: if ($type eq 'ci') { 507: $resp = lc($resp); 508: $ans = lc($ans); 509: } 510: if ($resp eq $ans) { 511: if ($award eq 'INCORRECT') { 512: $error = 'MISGRADED'; 513: } 514: } 515: return $error; 516: } 517: 518: sub cas { 519: my ($system,$input,$library)=@_; 520: my $output; 521: my $dump; 522: if ($system eq 'maxima') { 523: $output=&maxima_eval($input,$library); 524: } elsif ($system eq 'R') { 525: ($output,$dump)=&r_eval($input,$library,0); 526: } else { 527: $output='Error: unrecognized CAS'; 528: } 529: return $output; 530: } 531: 532: sub cas_hashref { 533: my ($system,$input,$library)=@_; 534: if ($system eq 'maxima') { 535: return 'Error: unsupported CAS'; 536: } elsif ($system eq 'R') { 537: return &r_eval($input,$library,1); 538: } else { 539: return 'Error: unrecognized CAS'; 540: } 541: } 542: 543: # 544: # cas_hashref_entry takes a list of indices and gets the entry in a hash generated by Rreturn. 545: # Call: cas_hashref_entry(Rvalue, index1, index2, ...) where Rvalue is a hash returned by Rreturn. 546: # Rentry will return the first scalar value it encounters (ignoring excess indices). 547: # If an invalid key is given, it returns undef. 548: # 549: sub cas_hashref_entry { 550: return &Rentry(@_); 551: } 552: 553: # 554: # cas_hashref_array takes a list of indices and gets a column array from a hash generated by Rreturn. 555: # Call: cas_hashref_array(Rvalue, index1, index2, ...) where Rvalue is a hash returned by Rreturn. 556: # If an invalid key is given, it returns undef. 557: # 558: sub cas_hashref_array { 559: return &Rarray(@_); 560: } 561: 562: sub tex { 563: if ( $external::target eq "tex" ) { 564: return $_[0]; 565: } else { 566: return $_[1]; 567: } 568: } 569: 570: sub var_in_tex { 571: if ( $external::target eq "tex" ) { 572: return $_[0]; 573: } else { 574: return ""; 575: } 576: } 577: 578: sub web { 579: if ( $external::target eq "tex" ) { 580: return $_[1]; 581: } else { 582: if ( $external::target eq "web" || $external::target eq "answer") { 583: return $_[2]; 584: } else { 585: return $_[0]; 586: } 587: } 588: } 589: 590: sub html { 591: if ( $external::target eq "web" ) { 592: return shift; 593: } 594: } 595: 596: sub hinton { 597: return 0; 598: } 599: 600: sub random { 601: my ($start,$end,$step)=@_; 602: if ( ! $hidden::RANDOMINIT ) { 603: if ($external::randomseed == 0) { $external::randomseed=1; } 604: if ($external::randomseed =~/,/) { 605: my ($num1,$num2)=split(/,/,$external::randomseed); 606: &random_set_seed(1,abs($num1)); 607: } elsif ($external::randomseed =~/:/) { 608: my ($num1,$num2)=split(/:/,$external::randomseed); 609: &random_set_seed(abs($num1),abs($num2)); 610: } else { 611: &random_set_seed(1,int(abs($external::randomseed))); 612: } 613: &math_random_uniform(); 614: $hidden::RANDOMINIT=1; 615: } 616: if (!defined($step)) { $step=1; } 617: my $num=1+int(($end-$start)/$step); 618: my $result=$start + int(&math_random_uniform() * $num)*$step; 619: return $result; 620: } 621: 622: sub random_normal { 623: my ($item_cnt,$seed,$av,$std_dev) = @_; 624: my @oldseed=&random_get_seed(); 625: my @retArray; 626: &random_set_seed_from_phrase($seed); 627: @retArray=&math_random_normal($item_cnt,$av,$std_dev); 628: &random_set_seed(@oldseed); 629: return @retArray; 630: } 631: 632: sub random_beta { 633: my ($item_cnt,$seed,$aa,$bb) = @_; 634: my @oldseed=&random_get_seed(); 635: my @retArray; 636: &random_set_seed_from_phrase($seed); 637: @retArray=&math_random_beta($item_cnt,$aa,$bb); 638: &random_set_seed(@oldseed); 639: return @retArray; 640: } 641: 642: sub random_gamma { 643: my ($item_cnt,$seed,$a,$r) = @_; 644: my @oldseed=&random_get_seed(); 645: my @retArray; 646: &random_set_seed_from_phrase($seed); 647: @retArray=&math_random_gamma($item_cnt,$a,$r); 648: &random_set_seed(@oldseed); 649: return @retArray; 650: } 651: 652: sub random_exponential { 653: my ($item_cnt,$seed,$av) = @_; 654: my @oldseed=&random_get_seed(); 655: my @retArray; 656: &random_set_seed_from_phrase($seed); 657: @retArray=&math_random_exponential($item_cnt,$av); 658: &random_set_seed(@oldseed); 659: return @retArray; 660: } 661: 662: sub random_poisson { 663: my ($item_cnt,$seed,$mu) = @_; 664: my @oldseed=&random_get_seed(); 665: my @retArray; 666: &random_set_seed_from_phrase($seed); 667: @retArray=&math_random_poisson($item_cnt,$mu); 668: &random_set_seed(@oldseed); 669: return @retArray; 670: } 671: 672: sub random_chi { 673: my ($item_cnt,$seed,$df) = @_; 674: my @oldseed=&random_get_seed(); 675: my @retArray; 676: &random_set_seed_from_phrase($seed); 677: @retArray=&math_random_chi_square($item_cnt,$df); 678: &random_set_seed(@oldseed); 679: return @retArray; 680: } 681: 682: sub random_noncentral_chi { 683: my ($item_cnt,$seed,$df,$nonc) = @_; 684: my @oldseed=&random_get_seed(); 685: my @retArray; 686: &random_set_seed_from_phrase($seed); 687: @retArray=&math_random_noncentral_chi_square($item_cnt,$df,$nonc); 688: &random_set_seed(@oldseed); 689: return @retArray; 690: } 691: 692: sub random_f { 693: my ($item_cnt,$seed,$dfn,$dfd) = @_; 694: my @oldseed=&random_get_seed(); 695: my @retArray; 696: &random_set_seed_from_phrase($seed); 697: @retArray=&math_random_f($item_cnt,$dfn,$dfd); 698: &random_set_seed(@oldseed); 699: return @retArray; 700: } 701: 702: sub random_noncentral_f { 703: my ($item_cnt,$seed,$dfn,$dfd,$nonc) = @_; 704: my @oldseed=&random_get_seed(); 705: my @retArray; 706: &random_set_seed_from_phrase($seed); 707: @retArray=&math_random_noncentral_f($item_cnt,$dfn,$dfd,$nonc); 708: &random_set_seed(@oldseed); 709: return @retArray; 710: } 711: 712: sub random_multivariate_normal { 713: my ($item_cnt,$seed,$mean,$covar) = @_; 714: my @oldseed=&random_get_seed(); 715: &random_set_seed_from_phrase($seed); 716: my @retArray=&math_random_multivariate_normal($item_cnt,@$mean,@$covar); 717: &random_set_seed(@oldseed); 718: return @retArray; 719: } 720: 721: sub random_multinomial { 722: my ($item_cnt,$seed,@p) = @_; 723: my @oldseed=&random_get_seed(); 724: my @retArray; 725: &random_set_seed_from_phrase($seed); 726: my @retArray=&math_random_multinomial($item_cnt,@p); 727: &random_set_seed(@oldseed); 728: return @retArray; 729: } 730: 731: sub random_permutation { 732: my ($seed,@inArray) = @_; 733: my @oldseed=&random_get_seed(); 734: my @retArray; 735: &random_set_seed_from_phrase($seed); 736: @retArray=&math_random_permutation(@inArray); 737: &random_set_seed(@oldseed); 738: return @retArray; 739: } 740: 741: sub random_uniform { 742: my ($item_cnt,$seed,$low,$high) = @_; 743: my @oldseed=&random_get_seed(); 744: my @retArray; 745: &random_set_seed_from_phrase($seed); 746: @retArray=&math_random_uniform($item_cnt,$low,$high); 747: &random_set_seed(@oldseed); 748: return @retArray; 749: } 750: 751: sub random_uniform_integer { 752: my ($item_cnt,$seed,$low,$high) = @_; 753: my @oldseed=&random_get_seed(); 754: my @retArray; 755: &random_set_seed_from_phrase($seed); 756: @retArray=&math_random_uniform_integer($item_cnt,$low,$high); 757: &random_set_seed(@oldseed); 758: return @retArray; 759: } 760: 761: sub random_binomial { 762: my ($item_cnt,$seed,$nt,$p) = @_; 763: my @oldseed=&random_get_seed(); 764: my @retArray; 765: &random_set_seed_from_phrase($seed); 766: @retArray=&math_random_binomial($item_cnt,$nt,$p); 767: &random_set_seed(@oldseed); 768: return @retArray; 769: } 770: 771: sub random_negative_binomial { 772: my ($item_cnt,$seed,$ne,$p) = @_; 773: my @oldseed=&random_get_seed(); 774: my @retArray; 775: &random_set_seed_from_phrase($seed); 776: @retArray=&math_random_negative_binomial($item_cnt,$ne,$p); 777: &random_set_seed(@oldseed); 778: return @retArray; 779: } 780: 781: sub abs { CORE::abs(shift) } 782: sub sin { CORE::sin(shift) } 783: sub cos { CORE::cos(shift) } 784: sub exp { CORE::exp(shift) } 785: sub int { CORE::int(shift) } 786: sub log { CORE::log(shift) } 787: sub atan2 { CORE::atan2($_[0],$_[1]) } 788: sub sqrt { CORE::sqrt(shift) } 789: 790: sub tan { CORE::sin($_[0]) / CORE::cos($_[0]) } 791: #sub atan { atan2($_[0], 1); } 792: #sub acos { atan2(sqrt(1 - $_[0] * $_[0]), $_[0] ); } 793: #sub asin { atan2($_[0], sqrt(1- $_[0] * $_[0]) ); } 794: 795: sub log10 { CORE::log($_[0])/CORE::log(10); } 796: 797: sub factorial { 798: my $input = CORE::int(shift); 799: return "Error - unable to take factorial of an negative number ($input)" if $input < 0; 800: return "Error - factorial result is greater than system limit ($input)" if $input > 170; 801: return 1 if $input == 0; 802: my $result = 1; 803: for (my $i=2; $i<=$input; $i++) { $result *= $i } 804: return $result; 805: } 806: 807: sub sgn { 808: return -1 if $_[0] < 0; 809: return 0 if $_[0] == 0; 810: return 1 if $_[0] > 0; 811: } 812: 813: sub min { 814: my @sorted = sort { $a <=> $b || $a cmp $b } @_; 815: return shift @sorted; 816: } 817: 818: sub max { 819: my @sorted = sort { $a <=> $b || $a cmp $b } @_; 820: return pop @sorted; 821: } 822: 823: sub roundto { 824: my ($input,$n) = @_; 825: return sprintf('%.'.$n.'f',$input); 826: } 827: 828: sub to_string { 829: my ($input,$n) = @_; 830: return sprintf($input) if $n eq ""; 831: $n = '.'.$n if $n !~ /^\./; 832: return sprintf('%'.$n,$input) if $n ne ""; 833: } 834: 835: sub sub_string { 836: my ($str,$start,$len) = @_; 837: return substr($str,$start-1,$len); 838: } 839: 840: sub pow {return $_[0] ** $_[1]; } 841: sub ceil {return (($_[0]-CORE::int($_[0]))== 0.0) ? $_[0] : (($_[0] > 0) ? (CORE::int($_[0])+ 1) : CORE::int($_[0])); } 842: sub floor {return (($_[0]-CORE::int($_[0]))== 0.0) ? $_[0] : (($_[0] > 0) ? CORE::int($_[0]) : (CORE::int($_[0])-1)); } 843: #sub floor {return int($_[0]); } 844: 845: sub format { 846: my ($value,$fmt)=@_; 847: my ($dollarmode,$commamode,$alwaysperiod,$options); 848: if ($fmt =~ /^([^\d]*)(.*)/) { $options=$1; $fmt=$2; } 849: #if ($options =~ /\$/) { $dollamode=1; } 850: #if ($options =~ /,/) { $commamode=1; } 851: if ($options =~ /\./) { $alwaysperiod=1; } 852: my $result; 853: if ($fmt=~/s$/i) { 854: $result=&format_significant_figures($value,$fmt); 855: } else { 856: $fmt=~s/e/E/g; 857: $result=sprintf('%.'.$fmt,$value); 858: if ($alwaysperiod && $fmt eq '0f') { $result .='.'; } 859: $result=~s/(E[+-]*)0/$1/; 860: } 861: #if ($dollarmode) {$result=&dollarformat($result);} 862: #if ($commamode) {$result=&commaformat($result);} 863: return $result; 864: } 865: 866: sub chemparse { 867: my ($reaction) = @_; 868: my @tokens = split(/(\s\+|\->|<=>|<\-|\.)/,$reaction); 869: my $formula = ''; 870: foreach my $token (@tokens) { 871: if ($token eq '->' ) { 872: $formula .= '<m>\ensuremath{\rightarrow}</m> '; 873: next; 874: } 875: if ($token eq '<-' ) { 876: $formula .= '<m>\ensuremath{\leftarrow}</m> '; 877: next; 878: } 879: if ($token eq '<=>') { 880: if ($external::target eq 'web' && 881: &EXT('request.browser.unicode')) { 882: $formula .= '⇌ '; 883: } else { 884: $formula .= &web('<=> ','<m>\ensuremath{\rightleftharpoons}</m> ', 885: '<=> '); 886: } 887: next; 888: } 889: if ($token eq '.') { 890: $formula =~ s/(\&nbsp\;| )$//; 891: $formula .= '·'; 892: next; 893: } 894: $token =~ /^\s*([\d|\/]*(?:&frac\d\d)?)(.*)/; 895: $formula .= $1 if ($1 ne '1'); # stoichiometric coefficient 896: 897: my $molecule = $2; 898: # subscripts 899: $molecule =~ s|(?<=[a-zA-Z\)\]\s])(\d+)|$1|g; 900: # superscripts 901: $molecule =~ s|\^(\d*[+\-]*)|$1|g; 902: # strip whitespace 903: $molecule =~ s/\s*//g; 904: # forced space 905: $molecule =~ s/_/ /g; 906: $molecule =~ s/-/−/g; 907: $formula .= $molecule.' '; 908: } 909: # get rid of trailing space 910: $formula =~ s/(\&nbsp\;| )$//; 911: return &xmlparse($formula); 912: } 913: 914: sub prettyprint { 915: my ($value,$fmt,$target)=@_; 916: my $result; 917: if (!$target) { $target = $external::target; } 918: if ($fmt =~ /chem/i) { return(&chemparse($value)); } 919: my ($dollarmode,$commamode,$alwaysperiod,$options); 920: if ($fmt =~ /^([^\d]*)(.*)/) { $options=$1; $fmt=$2; } 921: if ($options =~ /\$/) { $dollarmode=1; } 922: if ($options =~ /,/) { $commamode=1; } 923: if ($options =~ /\./) { $alwaysperiod=1; } 924: if ($fmt=~/s$/i) { 925: $value=&format_significant_figures($value,$fmt); 926: } elsif ($fmt) { 927: $value=sprintf('%.'.$fmt,$value); 928: } 929: if ($alwaysperiod && $fmt eq '0f') { 930: if ($target eq 'tex') { 931: $value .='\\ensuremath{.}'; 932: } else { 933: $value .='.'; 934: } 935: } 936: if ($value =~ /([0-9\.\-\+]+)E([0-9\-\+]+)/i ) { 937: my $frac=$1; 938: if ($dollarmode) { $frac=&dollarformat($frac); } 939: if ($commamode) { $frac=&commaformat($frac); } 940: my $exponent=$2; 941: $exponent=~s/^\+0*//; 942: $exponent=~s/^-0*/-/; 943: $exponent=~s/^-0*/-/; 944: if ($exponent eq '-') { undef($exponent); } 945: if ($exponent) { 946: if ($target eq 'web') { 947: $result=$frac.'×10'.$exponent.''; 948: } elsif ($target eq 'tex') { 949: $result='\ensuremath{'.$frac.'\times 10^{'.$exponent.'}}'; 950: } else { 951: $result=$value; 952: } 953: } else { 954: $result=$frac; 955: } 956: } else { 957: $result=$value; 958: if ($dollarmode) { $result=&dollarformat($result,$target); } 959: elsif ($commamode) { $result=&commaformat($result,$target); } 960: } 961: return $result; 962: } 963: 964: sub commaformat { 965: my ($number,$target) = @_; 966: if ($number =~ /\./) { 967: while ($number =~ /([^0-9]*)([0-9]+)([^\.,][^\.,][^\.,])([,0-9]*\.[0-9]*)$/) { 968: $number = $1.$2.','.$3.$4; 969: } 970: } else { 971: while ($number =~ /^([^0-9]*)([0-9]+)([^,][^,][^,])([,0-9]*)$/) { 972: $number = $1.$2.','.$3.$4; 973: } 974: } 975: return $number; 976: } 977: 978: sub dollarformat { 979: my ($number,$target) = @_; 980: if (!$target) { $target = $external::target; } 981: $number=&commaformat($number,$target); 982: if ($target eq 'tex') { 983: $number='\$'.$number; #' stupid emacs 984: } else { 985: $number='$'.$number; #' stupid emacs 986: } 987: return $number; 988: } 989: 990: # format of form ns or nS where n is an integer 991: sub format_significant_figures { 992: my ($number,$format) = @_; 993: return '0' if ($number == 0); 994: # extract number of significant figures needed 995: my ($sig) = ($format =~ /(\d+)s/i); 996: # arbitrary choice - suggestions ?? or throw error message? 997: $sig = 3 if ($sig eq ''); 998: # save the minus sign 999: my $sign = ($number < 0) ? '-' : ''; 1000: $number = abs($number); 1001: # needed to correct for a number greater than 1 (or 1002: my $power = ($number < 1) ? 0 : 1; 1003: # could round up. Take the integer part of log10. 1004: my $x10 = int(log($number)/log(10)); 1005: # find number with values left of decimal pt = # of sign figs. 1006: my $xsig = $number*10**($sig-$x10-$power); 1007: # get just digits left of decimal pt - also rounds off correctly 1008: my $xint = sprintf('%.0f',$xsig); 1009: # save any trailing zero's 1010: my ($zeros) = ($xint =~ /(0+)$/); 1011: # return number to original magnitude 1012: my $numSig = $xint*10**($x10-$sig+$power); 1013: # insert trailing zero's if have decimal point 1014: $numSig =~ s/^(\d+)\.(\d+)(\e?(.*)?)$/$1\.$2$zeros$3/; 1015: # put a decimal pt for number ending with 0 and length = # of sig fig 1016: $numSig.='.' if (length($numSig) == $sig && $numSig =~ /0$/); 1017: if (length($numSig) < $sig) { 1018: $numSig.='.'.substr($zeros,0,($sig-length($numSig))); 1019: } 1020: # return number with sign 1021: return $sign.$numSig; 1022: 1023: } 1024: 1025: sub map { 1026: my ($phrase,$dest,$source)=@_; 1027: my @oldseed=&random_get_seed(); 1028: my @seed = &random_seed_from_phrase($phrase); 1029: &random_set_seed(@seed); 1030: my $destct = scalar(@$dest); 1031: if (!$source) { 1032: my @output; 1033: my @idx = &math_random_permuted_index($destct); 1034: my $ctr = 0; 1035: while ($ctr < $destct) { 1036: $output[$ctr] = $$dest[$idx[$ctr]]; 1037: $ctr++; 1038: } 1039: &random_set_seed(@oldseed); 1040: return @output; 1041: } else { 1042: my $num = scalar(@$source); 1043: my @idx = &math_random_permuted_index($num); 1044: my $ctr = 0; 1045: my $tot = $num; 1046: $tot = $destct if $destct < $num; 1047: if (ref($$dest[0])) { 1048: while ($ctr < $tot) { 1049: ${$$dest[$ctr]} = $$source[$idx[$ctr]]; 1050: $ctr++; 1051: } 1052: } else { 1053: while ($ctr < $tot) { 1054: $$dest[$ctr] = $$source[$idx[$ctr]]; 1055: $ctr++; 1056: } 1057: } 1058: } 1059: &random_set_seed(@oldseed); 1060: return ''; 1061: } 1062: 1063: sub rmap { 1064: my ($phrase,$dest,$source)=@_; 1065: my @oldseed=&random_get_seed(); 1066: my @seed = &random_seed_from_phrase($phrase); 1067: &random_set_seed(@seed); 1068: my $destct = scalar(@$dest); 1069: if (!$source) { 1070: my @idx = &math_random_permuted_index($destct); 1071: my $ctr = 0; 1072: my @r_idx; 1073: while ($ctr < $destct) { 1074: $r_idx[$idx[$ctr]] = $ctr; 1075: $ctr++; 1076: } 1077: my @output; 1078: $ctr = 0; 1079: while ($ctr < $destct) { 1080: $output[$ctr] = $$dest[$r_idx[$ctr]]; 1081: $ctr++; 1082: } 1083: &random_set_seed(@oldseed); 1084: return @output; 1085: } else { 1086: my $num = scalar(@$source); 1087: my @idx = &math_random_permuted_index($num); 1088: my $ctr = 0; 1089: my $tot = $num; 1090: $tot = $destct if $destct < $num; 1091: my @r_idx; 1092: while ($ctr < $tot) { 1093: $r_idx[$idx[$ctr]] = $ctr; 1094: $ctr++; 1095: } 1096: $ctr = 0; 1097: if (ref($$dest[0])) { 1098: while ($ctr < $tot) { 1099: ${$$dest[$ctr]} = $$source[$r_idx[$ctr]]; 1100: $ctr++; 1101: } 1102: } else { 1103: while ($ctr < $tot) { 1104: $$dest[$ctr] = $$source[$r_idx[$ctr]]; 1105: $ctr++; 1106: } 1107: } 1108: } 1109: &random_set_seed(@oldseed); 1110: return ''; 1111: } 1112: 1113: sub capa_id { return } 1114: 1115: sub problem { return } 1116: 1117: sub name{ 1118: my $fullname = &EXT('environment.lastname').', '.&EXT('environment.firstname').' '.&EXT('environment.middlename'); 1119: $fullname = "" if $fullname eq ", "; 1120: $fullname =~ s/\%2d/-/g; 1121: return $fullname; 1122: } 1123: 1124: sub student_number { 1125: my $id = &EXT('environment.id'); 1126: $id = '' if $id eq ""; 1127: return $id; 1128: } 1129: 1130: sub class { 1131: my $course = &EXT('course.description'); 1132: $course = '' if $course eq ""; 1133: return $course; 1134: } 1135: 1136: sub firstname { 1137: my $firstname = &EXT('environment.firstname'); 1138: $firstname = '' if $firstname eq ""; 1139: return $firstname; 1140: } 1141: 1142: sub lastname { 1143: my $lastname = &EXT('environment.lastname'); 1144: $lastname = '' if $lastname eq ""; 1145: return $lastname; 1146: } 1147: 1148: sub sec { 1149: my $sec = &EXT('request.course.sec'); 1150: $sec = '' if $sec eq ""; 1151: return $sec; 1152: } 1153: 1154: sub submission { 1155: my ($partid,$responseid,$subnumber)=@_; 1156: my $sub=''; 1157: if ($subnumber) { $sub=$subnumber.':'; } 1158: return &EXT('user.resource.'.$sub.'resource.'.$partid.'.'.$responseid.'.submission'); 1159: } 1160: 1161: sub currentpart { 1162: return $external::part; 1163: } 1164: 1165: sub eval_time { 1166: my ($timestamp)=@_; 1167: unless ($timestamp) { return ''; } 1168: return &locallocaltime($timestamp); 1169: } 1170: 1171: sub open_date { 1172: my ($partid)=@_; 1173: unless ($partid) { $partid=0; } 1174: return &eval_time(&EXT('resource.'.$partid.'.opendate')); 1175: } 1176: 1177: sub due_date { 1178: my ($partid)=@_; 1179: unless ($partid) { $partid=0; } 1180: return &eval_time(&EXT('resource.'.$partid.'.duedate')); 1181: } 1182: 1183: sub answer_date { 1184: my ($partid)=@_; 1185: unless ($partid) { $partid=0; } 1186: return &eval_time(&EXT('resource.'.$partid.'.answerdate')); 1187: } 1188: 1189: sub open_date_epoch { 1190: my ($partid)=@_; 1191: unless ($partid) { $partid=0; } 1192: return &EXT('resource.'.$partid.'.opendate'); 1193: } 1194: 1195: sub due_date_epoch { 1196: my ($partid)=@_; 1197: unless ($partid) { $partid=0; } 1198: return &EXT('resource.'.$partid.'.duedate'); 1199: } 1200: 1201: sub answer_date_epoch { 1202: my ($partid)=@_; 1203: unless ($partid) { $partid=0; } 1204: return &EXT('resource.'.$partid.'.answerdate'); 1205: } 1206: 1207: sub array_moments { 1208: my @input=@_; 1209: my (@output,$N); 1210: $N=scalar (@input); 1211: $output[0]=$N; 1212: if ($N <= 1) { 1213: $output[1]=$input[0]; 1214: $output[1]="Input array not defined" if ($N == 0); 1215: $output[2]="variance undefined for N<=1"; 1216: $output[3]="skewness undefined for N<=1"; 1217: $output[4]="kurtosis undefined for N<=1"; 1218: return @output; 1219: } 1220: my $sum=0; 1221: foreach my $line (@input) { 1222: $sum+=$line; 1223: } 1224: $output[1] = $sum/$N; 1225: my ($x,$sdev,$var,$skew,$kurt) = 0; 1226: foreach my $line (@input) { 1227: $x=$line-$output[1]; 1228: $var+=$x**2; 1229: $skew+=$x**3; 1230: $kurt+=$x**4; 1231: } 1232: $output[2]=$var/($N-1); 1233: $sdev=CORE::sqrt($output[2]); 1234: if ($sdev == 0) { 1235: $output[3]="inf-variance=0"; 1236: $output[4]="inf-variance=0"; 1237: return @output; 1238: } 1239: $output[3]=$skew/($sdev**3*$N); 1240: $output[4]=$kurt/($sdev**4*$N)-3; 1241: return @output; 1242: } 1243: 1244: sub choose { 1245: my $num = $_[0]; 1246: return $_[$num]; 1247: } 1248: 1249: #&sum1(1,$x,sub { &sum1($_[0],2*$_[0], sub { fact($_[0])**2 })}); 1250: #sub sum1 { 1251: # my ($start,$end,$sub)=@_; 1252: # my $sum=0; 1253: # for (my $i=$start;$i<=$end;$i++) { 1254: # $sum+=&$sub($i); 1255: # } 1256: # return $sum 1257: #} 1258: 1259: #&sum2('a',1,$x,'&sum2(\'b\',$a,2*$a, \'&factorial($b)**2\')'); 1260: #sub sum2 { 1261: # my ($varname,$start,$end,$line)=@_; 1262: # my $sum=0; 1263: # for (my $i=$start;$i<=$end;$i++) { 1264: # my $func=sub { 1265: # eval("\$".$varname."=$i"); 1266: # eval($line); 1267: # }; 1268: # $sum+=&$func($i); 1269: # } 1270: # return $sum 1271: #} 1272: 1273: # expiremental idea 1274: sub proper_path { 1275: my ($path)=@_; 1276: if ( $external::target eq "tex" ) { 1277: return '/home/httpd/html'.$path; 1278: } else { 1279: return $path; 1280: } 1281: } 1282: