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 1.74 2004/03/16 19:47:47 albertel 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: # Guy Albertelli
30: #
31: # 05/25/2001 H. K. Ng
32: # 05/31/2001 H. K. Ng
33: # 12/21/2001 Matthew
34: #
35: #init some globals
36: $hidden::RANDOMINIT=0;
37: $pi=atan2(1,1)*4;
38: $rad2deg=180.0/$pi;
39: $deg2rad=$pi/180.0;
40: $"=' ';
41:
42: sub caparesponse_check {
43: my ($answer,$response)=@_;
44: #not properly used yet: calc
45: #not to be used: $ans_fmt
46: my $type=$LONCAPA::CAPAresponse_args{'type'};
47: my $tol=$LONCAPA::CAPAresponse_args{'tol'};
48: my $sig=$LONCAPA::CAPAresponse_args{'sig'};
49: my $ans_fmt=$LONCAPA::CAPAresponse_args{'ans_fmt'};
50: my $unit=$LONCAPA::CAPAresponse_args{'unit'};
51: my $calc=$LONCAPA::CAPAresponse_args{'calc'};
52: my $samples=$LONCAPA::CAPAresponse_args{'samples'};
53:
54: my $tol_type=''; # gets it's value from whether tol has a % or not done
55: my $sig_lbound=''; #done
56: my $sig_ubound=''; #done
57:
58:
59: #type's definitons come from capaParser.h
60: my $message='';
61: #remove leading and trailing whitespace
62: if (!defined($response)) {
63: $response='';
64: }
65: if ($response=~ /^\s|\s$/) {
66: $response=~ s:^\s+|\s+$::g;
67: $message .="Removed ws now :$response:\n";
68: } else {
69: $message .="no ws in :$response:\n";
70: }
71:
72: if (length($response) > 500) { return "TOO_LONG: Answer too long"; }
73:
74: if ($type eq '' ) {
75: $message .= "Didn't find a type :$type: defaulting\n";
76: if ( $answer eq ($answer *1.0)) { $type = 2;
77: } else { $type = 3; }
78: } else {
79: if ($type eq 'cs') { $type = 4; }
80: elsif ($type eq 'ci') { $type = 3 }
81: elsif ($type eq 'mc') { $type = 5; }
82: elsif ($type eq 'fml') { $type = 8; }
83: elsif ($type eq 'subj') { $type = 7; }
84: elsif ($type eq 'float') { $type = 2; }
85: elsif ($type eq 'int') { $type = 1; }
86: else { return "ERROR: Unknown type of answer: $type" }
87: }
88:
89: my $points;
90: my $id_list;
91: #formula type setup the sample points
92: if ($type eq '8') {
93: ($id_list,$points)=split(/@/,$samples);
94: $message.="Found :$id_list:$points: points in $samples\n";
95: }
96: if ($tol eq '') {
97: $tol=0.0;
98: $tol_type=1; #TOL_ABSOLUTE
99: } else {
100: if ($tol =~ /%$/) {
101: chop $tol;
102: $tol_type=2; #TOL_PERCENTAGE
103: } else {
104: $tol_type=1; #TOL_ABSOLUTE
105: }
106: }
107:
108: if ($sig eq '') {
109: $sig_lbound = 0; #SIG_LB_DEFAULT
110: $sig_ubound =15; #SIG_UB_DEFAULT
111: } else {
112: ($sig_lbound,$sig_ubound) = split /,/,$sig;
113: if (!defined($sig_lbound)) {
114: $sig_lbound = 0; #SIG_LB_DEFAULT
115: $sig_ubound =15; #SIG_UB_DEFAULT
116: }
117: if (!defined($sig_ubound)) { $sig_ubound=$sig_lbound; }
118: }
119: my $reterror="";
120: my $result = &caparesponse_capa_check_answer($response,$answer,$type,
121: $tol_type,$tol,
122: $sig_lbound,$sig_ubound,
123: $ans_fmt,$unit,$calc,$id_list,
124: $points,$external::randomseed,
125: \$reterror);
126:
127: if ($result == '1') { $result='EXACT_ANS'; }
128: elsif ($result == '2') { $result='APPROX_ANS'; }
129: elsif ($result == '3') { $result='SIG_FAIL'; }
130: elsif ($result == '4') { $result='UNIT_FAIL'; }
131: elsif ($result == '5') { $result='NO_UNIT'; }
132: elsif ($result == '6') { $result='UNIT_OK'; }
133: elsif ($result == '7') { $result='INCORRECT'; }
134: elsif ($result == '8') { $result='UNIT_NOTNEEDED'; }
135: elsif ($result == '9') { $result='ANS_CNT_NOT_MATCH'; }
136: elsif ($result =='10') { $result='SUB_RECORDED'; }
137: elsif ($result =='11') { $result='BAD_FORMULA'; }
138: elsif ($result =='12') { $result='WANTED_NUMERIC'; }
139: else {$result = "ERROR: Unknown Result:$result:$@:";}
140:
141: return ("$result:\nRetError $reterror:\nError $error:\nAnswer $answer:\nResponse $response:\n type-$type|$tol|$tol_type|$sig:$sig_lbound:$sig_ubound|$unit|\n$message",$reterror);
142: }
143:
144:
145: sub caparesponse_check_list {
146: my $response=$LONCAPA::CAPAresponse_args{'response'};
147: my ($result,@list);
148: @list=@LONCAPA::CAPAresponse_answer;
149: my $aresult='';
150: my $current_answer;
151: my $answers=join(':',@list);
152: $result.="Got response :$answers:\n";
153: &LONCAPA_INTERNAL_DEBUG("<blink>Yo!</blink> got ".join(':',%LONCAPA::CAPAresponse_args));
154: my @responselist;
155: my $type = $LONCAPA::CAPAresponse_args{'type'};
156: $result.="Got type :$type:\n";
157: if ($type ne '' && $#list > 0) {
158: (@responselist)=split /,/,$response;
159: } else {
160: (@responselist)=($response);
161: }
162: my $unit='';
163: $result.="Initial final response :$responselist['-1']:\n";
164: if ($type eq '' || $type eq 'float') {
165: #for numerical problems split off the unit
166: if ( $responselist['-1']=~ /(.*[^\s])\s+([^\s]+)/ ) {
167: $responselist['-1']=$1;
168: $unit=$2;
169: }
170: }
171: $result.="Final final response :$responselist['-1']:\n";
172: $result.=":$#list: answers\n";
173: $unit=~s/\s//;
174: my $i=0;
175: my $awards='';
176: my @msgs;
177: for ($i=0; $i<@list;$i++) {
178: my $msg;
179: $result.="trying answer :$list[$i]:\n";
180: my $thisanswer=$list[$i];
181: $result.="trying answer :$thisanswer:\n";
182: if ($unit eq '') {
183: ($aresult,$msg)=&caparesponse_check($thisanswer,$responselist[$i]);
184: } else {
185: ($aresult,$msg)=&caparesponse_check($thisanswer,
186: $responselist[$i]." $unit");
187: }
188: my ($temp)=split /:/, $aresult;
189: $awards.="$temp,";
190: $result.=$aresult;
191: push(@msgs,$msg);
192: }
193: chop $awards;
194: return ("$awards:\n$result",@msgs);
195: }
196:
197: sub tex {
198: if ( $external::target eq "tex" ) {
199: return $_[0];
200: } else {
201: return $_[1];
202: }
203: }
204:
205: sub var_in_tex {
206: if ( $external::target eq "tex" ) {
207: return $_[0];
208: } else {
209: return "";
210: }
211: }
212:
213: sub web {
214: if ( $external::target eq "tex" ) {
215: return $_[1];
216: } else {
217: if ( $external::target eq "web" || $external::target eq "answer") {
218: return $_[2];
219: } else {
220: return $_[0];
221: }
222: }
223: }
224:
225: sub html {
226: if ( $external::target eq "web" ) {
227: return shift;
228: }
229: }
230:
231: sub hinton {
232: return 0;
233: }
234:
235: sub random {
236: my ($start,$end,$step)=@_;
237: if ( ! $hidden::RANDOMINIT ) {
238: if ($external::randomseed == 0) { $external::randomseed=1; }
239: if ($external::randomseed =~/,/) {
240: my ($num1,$num2)=split(/,/,$seed);
241: &random_set_seed(abs($num1),abs($num2));
242: } else {
243: &random_set_seed(1,int(abs($external::randomseed)));
244: }
245: &math_random_uniform();
246: $hidden::RANDOMINIT=1;
247: }
248: if (!defined($step)) { $step=1; }
249: my $num=1+int(($end-$start)/$step);
250: my $result=$start + int(&math_random_uniform() * $num)*$step;
251: return $result;
252: }
253:
254: sub random_normal {
255: my ($item_cnt,$seed,$av,$std_dev) = @_;
256: my @oldseed=&random_get_seed();
257: my @retArray;
258: &random_set_seed_from_phrase($seed);
259: @retArray=&math_random_normal($item_cnt,$av,$std_dev);
260: &random_set_seed(@oldseed);
261: return @retArray;
262: }
263:
264: sub random_beta {
265: my ($item_cnt,$seed,$aa,$bb) = @_;
266: my @oldseed=&random_get_seed();
267: my @retArray;
268: &random_set_seed_from_phrase($seed);
269: @retArray=&math_random_beta($item_cnt,$aa,$bb);
270: &random_set_seed(@oldseed);
271: return @retArray;
272: }
273:
274: sub random_gamma {
275: my ($item_cnt,$seed,$a,$r) = @_;
276: my @oldseed=&random_get_seed();
277: my @retArray;
278: &random_set_seed_from_phrase($seed);
279: @retArray=&math_random_gamma($item_cnt,$a,$r);
280: &random_set_seed(@oldseed);
281: return @retArray;
282: }
283:
284: sub random_exponential {
285: my ($item_cnt,$seed,$av) = @_;
286: my @oldseed=&random_get_seed();
287: my @retArray;
288: &random_set_seed_from_phrase($seed);
289: @retArray=&math_random_exponential($item_cnt,$av);
290: &random_set_seed(@oldseed);
291: return @retArray;
292: }
293:
294: sub random_poisson {
295: my ($item_cnt,$seed,$mu) = @_;
296: my @oldseed=&random_get_seed();
297: my @retArray;
298: &random_set_seed_from_phrase($seed);
299: @retArray=&math_random_poisson($item_cnt,$mu);
300: &random_set_seed(@oldseed);
301: return @retArray;
302: }
303:
304: sub random_chi {
305: my ($item_cnt,$seed,$df) = @_;
306: my @oldseed=&random_get_seed();
307: my @retArray;
308: &random_set_seed_from_phrase($seed);
309: @retArray=&math_random_chi_square($item_cnt,$df);
310: &random_set_seed(@oldseed);
311: return @retArray;
312: }
313:
314: sub random_noncentral_chi {
315: my ($item_cnt,$seed,$df,$nonc) = @_;
316: my @oldseed=&random_get_seed();
317: my @retArray;
318: &random_set_seed_from_phrase($seed);
319: @retArray=&math_random_noncentral_chi_square($item_cnt,$df,$nonc);
320: &random_set_seed(@oldseed);
321: return @retArray;
322: }
323:
324: sub random_f {
325: my ($item_cnt,$seed,$dfn,$dfd) = @_;
326: my @oldseed=&random_get_seed();
327: my @retArray;
328: &random_set_seed_from_phrase($seed);
329: @retArray=&math_random_f($item_cnt,$dfn,$dfd);
330: &random_set_seed(@oldseed);
331: return @retArray;
332: }
333:
334: sub random_noncentral_f {
335: my ($item_cnt,$seed,$dfn,$dfd,$nonc) = @_;
336: my @oldseed=&random_get_seed();
337: my @retArray;
338: &random_set_seed_from_phrase($seed);
339: @retArray=&math_random_noncentral_f($item_cnt,$dfn,$dfd,$nonc);
340: &random_set_seed(@oldseed);
341: return @retArray;
342: }
343:
344: sub random_multivariate_normal {
345: my ($item_cnt,$seed,$mean,$covar) = @_;
346: my @oldseed=&random_get_seed();
347: &random_set_seed_from_phrase($seed);
348: @retArray=&math_random_multivariate_normal($item_cnt,@$mean,@$covar);
349: &random_set_seed(@oldseed);
350: return @retArray;
351: }
352:
353: sub random_multinomial {
354: my ($item_cnt,$seed,@p) = @_;
355: my @oldseed=&random_get_seed();
356: my @retArray;
357: &random_set_seed_from_phrase($seed);
358: @retArray=&math_random_multinomial($item_cnt,@p);
359: &random_set_seed(@oldseed);
360: return @retArray;
361: }
362:
363: sub random_permutation {
364: my ($seed,@inArray) = @_;
365: my @oldseed=&random_get_seed();
366: my @retArray;
367: &random_set_seed_from_phrase($seed);
368: @retArray=&math_random_permutation(@inArray);
369: &random_set_seed(@oldseed);
370: return @retArray;
371: }
372:
373: sub random_uniform {
374: my ($item_cnt,$seed,$low,$high) = @_;
375: my @oldseed=&random_get_seed();
376: my @retArray;
377: &random_set_seed_from_phrase($seed);
378: @retArray=&math_random_uniform($item_cnt,$low,$high);
379: &random_set_seed(@oldseed);
380: return @retArray;
381: }
382:
383: sub random_uniform_integer {
384: my ($item_cnt,$seed,$low,$high) = @_;
385: my @oldseed=&random_get_seed();
386: my @retArray;
387: &random_set_seed_from_phrase($seed);
388: @retArray=&math_random_uniform_integer($item_cnt,$low,$high);
389: &random_set_seed(@oldseed);
390: return @retArray;
391: }
392:
393: sub random_binomial {
394: my ($item_cnt,$seed,$nt,$p) = @_;
395: my @oldseed=&random_get_seed();
396: my @retArray;
397: &random_set_seed_from_phrase($seed);
398: @retArray=&math_random_binomial($item_cnt,$nt,$p);
399: &random_set_seed(@oldseed);
400: return @retArray;
401: }
402:
403: sub random_negative_binomial {
404: my ($item_cnt,$seed,$ne,$p) = @_;
405: my @oldseed=&random_get_seed();
406: my @retArray;
407: &random_set_seed_from_phrase($seed);
408: @retArray=&math_random_negative_binomial($item_cnt,$ne,$p);
409: &random_set_seed(@oldseed);
410: return @retArray;
411: }
412:
413: sub abs { abs(shift) }
414: sub sin { sin(shift) }
415: sub cos { cos(shift) }
416: sub exp { exp(shift) }
417: sub int { int(shift) }
418: sub log { log(shift) }
419: sub atan2 { atan2($_[0],$_[1]) }
420: sub sqrt { sqrt(shift) }
421:
422: sub tan { CORE::sin($_[0]) / CORE::cos($_[0]) }
423: #sub atan { atan2($_[0], 1); }
424: #sub acos { atan2(sqrt(1 - $_[0] * $_[0]), $_[0] ); }
425: #sub asin { atan2($_[0], sqrt(1- $_[0] * $_[0]) ); }
426:
427: sub log10 { CORE::log($_[0])/CORE::log(10); }
428:
429: sub factorial {
430: my $input = CORE::int(shift);
431: return "Error - unable to take factorial of an negative number ($input)" if $input < 0;
432: return "Error - factorial result is greater than system limit ($input)" if $input > 170;
433: return 1 if $input == 0;
434: my $result = 1;
435: for (my $i=2; $i<=$input; $i++) { $result *= $i }
436: return $result;
437: }
438:
439: sub sgn {
440: return -1 if $_[0] < 0;
441: return 0 if $_[0] == 0;
442: return 1 if $_[0] > 0;
443: }
444:
445: sub min {
446: my @sorted = sort { $a <=> $b || $a cmp $b } @_;
447: return shift @sorted;
448: }
449:
450: sub max {
451: my @sorted = sort { $a <=> $b || $a cmp $b } @_;
452: return pop @sorted;
453: }
454:
455: sub roundto {
456: my ($input,$n) = @_;
457: return sprintf('%.'.$n.'f',$input);
458: }
459:
460: sub to_string {
461: my ($input,$n) = @_;
462: return sprintf($input) if $n eq "";
463: $n = '.'.$n if $n !~ /^\./;
464: return sprintf('%'.$n,$input) if $n ne "";
465: }
466:
467: sub sub_string {
468: my ($str,$start,$len) = @_;
469: return substr($str,$start-1,$len);
470: }
471:
472: sub pow {return $_[0] ** $_[1]; }
473: sub ceil {return (($_[0]-CORE::int($_[0]))== 0.0) ? $_[0] : (($_[0] > 0) ? (CORE::int($_[0])+ 1) : CORE::int($_[0])); }
474: sub floor {return (($_[0]-CORE::int($_[0]))== 0.0) ? $_[0] : (($_[0] > 0) ? CORE::int($_[0]) : (CORE::int($_[0])-1)); }
475: #sub floor {return int($_[0]); }
476:
477: sub format {
478: my ($value,$fmt)=@_;
479: my $dollarmode;
480: if ($fmt =~ /^\$(.*)/) { $fmt=$1; $dollarmode=1; }
481: $fmt=~s/e/E/g;
482: my $result=sprintf('%.'.$fmt,$value);
483: $result=~s/(E[+-]*)0/$1/;
484: if ($dollarmode) {$result=&dollarmode($result);}
485: return $result;
486: }
487:
488: sub prettyprint {
489: my ($value,$fmt,$target)=@_;
490: my $result;
491: my $dollarmode;
492: if (!$target) { $target = $external::target; }
493: if ($fmt =~ /^\$(.*)/) { $fmt=$1; $dollarmode=1; }
494: if ($fmt) { $value=sprintf('%.'.$fmt,$value); }
495: if ($value =~ /([0-9\.\-\+]+)E([0-9\-\+]+)/i ) {
496: my $frac=$1;
497: if ($dollarmode) { $frac=&dollarformat($frac); }
498: my $exponent=$2;
499: $exponent=~s/^\+0*//;
500: $exponent=~s/^-0*/-/;
501: $exponent=~s/^-0*/-/;
502: if ($exponent eq '-') { undef($exponent); }
503: if ($exponent) {
504: if ($target eq 'web') {
505: $result=$frac.'×10<sup>'.$exponent.'</sup>';
506: } elsif ($target eq 'tex') {
507: $result='\ensuremath{'.$frac.'\times 10^{'.$exponent.'}}';
508: } else {
509: $result=$value;
510: }
511: } else {
512: $result=$frac;
513: }
514: } else {
515: $result=$value;
516: if ($dollarmode) { $result=&dollarformat($result,$target); }
517: }
518: return $result;
519: }
520:
521: sub dollarformat {
522: my ($number,$target) = @_;
523: if (!$target) { $target = $external::target; }
524: if ($number =~ /\./) {
525: while ($number =~ /([^\.,]+)([^\.,][^\.,][^\.,])([,0-9]*\.[0-9]*)$/) {
526: $number = $1.','.$2.$3;
527: }
528: } else {
529: while ($number =~ /([^,]+)([^,][^,][^,])([,0-9]*)$/) {
530: $number = $1.','.$2.$3;
531: }
532: }
533: if ($target eq 'tex') {
534: $number='\$'.$number; #' stupid emacs
535: } else {
536: $number='$'.$number; #' stupid emacs
537: }
538: return $number;
539: }
540:
541: sub map {
542: my ($phrase,$dest,$source)=@_;
543: my @oldseed=&random_get_seed();
544: my @seed = &random_seed_from_phrase($phrase);
545: &random_set_seed(@seed);
546: my $destct = scalar(@$dest);
547: if (!$source) {
548: my @output;
549: my @idx = &math_random_permuted_index($destct);
550: my $ctr = 0;
551: while ($ctr < $destct) {
552: $output[$ctr] = $$dest[$idx[$ctr]];
553: $ctr++;
554: }
555: &random_set_seed(@oldseed);
556: return @output;
557: } else {
558: my $num = scalar(@$source);
559: my @idx = &math_random_permuted_index($num);
560: my $ctr = 0;
561: my $tot = $num;
562: $tot = $destct if $destct < $num;
563: if (ref($$dest[0])) {
564: while ($ctr < $tot) {
565: ${$$dest[$ctr]} = $$source[$idx[$ctr]];
566: $ctr++;
567: }
568: } else {
569: while ($ctr < $tot) {
570: $$dest[$ctr] = $$source[$idx[$ctr]];
571: $ctr++;
572: }
573: }
574: }
575: &random_set_seed(@oldseed);
576: return '';
577: }
578:
579: sub rmap {
580: my ($phrase,$dest,$source)=@_;
581: my @oldseed=&random_get_seed();
582: my @seed = &random_seed_from_phrase($phrase);
583: &random_set_seed(@seed);
584: my $destct = scalar(@$dest);
585: if (!$source) {
586: my @idx = &math_random_permuted_index($destct);
587: my $ctr = 0;
588: my @r_idx;
589: while ($ctr < $destct) {
590: $r_idx[$idx[$ctr]] = $ctr;
591: $ctr++;
592: }
593: my @output;
594: $ctr = 0;
595: while ($ctr < $destct) {
596: $output[$ctr] = $$dest[$r_idx[$ctr]];
597: $ctr++;
598: }
599: &random_set_seed(@oldseed);
600: return @output;
601: } else {
602: my $num = scalar(@$source);
603: my @idx = &math_random_permuted_index($num);
604: my $ctr = 0;
605: my $tot = $num;
606: $tot = $destct if $destct < $num;
607: my @r_idx;
608: while ($ctr < $tot) {
609: $r_idx[$idx[$ctr]] = $ctr;
610: $ctr++;
611: }
612: $ctr = 0;
613: if (ref($$dest[0])) {
614: while ($ctr < $tot) {
615: ${$$dest[$ctr]} = $$source[$r_idx[$ctr]];
616: $ctr++;
617: }
618: } else {
619: while ($ctr < $tot) {
620: $$dest[$ctr] = $$source[$r_idx[$ctr]];
621: $ctr++;
622: }
623: }
624: }
625: &random_set_seed(@oldseed);
626: return '';
627: }
628:
629: sub capa_id { return }
630:
631: sub problem { return }
632:
633: sub name{
634: my $fullname = &EXT('environment.lastname').', '.&EXT('environment.firstname').' '.&EXT('environment.middlename');
635: $fullname = "" if $fullname eq ", ";
636: $fullname =~ s/\%2d/-/g;
637: return $fullname;
638: }
639:
640: sub student_number {
641: my $id = &EXT('environment.id');
642: $id = '' if $id eq "";
643: return $id;
644: }
645:
646: sub class {
647: my $course = &EXT('course.description');
648: $course = '' if $course eq "";
649: return $course;
650: }
651:
652: sub sec {
653: my $sec = &EXT('request.course.sec');
654: $sec = '' if $sec eq "";
655: return $sec;
656: }
657:
658: sub open_date {
659: my @dc = split(/\s+/,localtime(&EXT('resource.0.opendate')));
660: return '' if ($dc[0] eq "Wed" and $dc[2] == 31 and $dc[4] == 1969);
661: my @hm = split(/:/,$dc[3]);
662: my $ampm = " am";
663: if ($hm[0] > 12) {
664: $hm[0]-=12;
665: $ampm = " pm";
666: }
667: return $dc[0].', '.$dc[1].' '.$dc[2].', '.$dc[4].' at '.$hm[0].':'.$hm[1].$ampm;
668: }
669:
670: sub due_date {
671: my @dc = split(/\s+/,localtime(&EXT('resource.0.duedate')));
672: return '' if ($dc[0] eq "Wed" and $dc[2] == 31 and $dc[4] == 1969);
673: my @hm = split(/:/,$dc[3]);
674: my $ampm = " am";
675: if ($hm[0] > 12) {
676: $hm[0]-=12;
677: $ampm = " pm";
678: }
679: return $dc[0].', '.$dc[1].' '.$dc[2].', '.$dc[4].' at '.$hm[0].':'.$hm[1].$ampm;
680: }
681:
682: sub answer_date {
683: my @dc = split(/\s+/,localtime(&EXT('resource.0.answerdate')));
684: return '' if ($dc[0] eq "Wed" and $dc[2] == 31 and $dc[4] == 1969);
685: my @hm = split(/:/,$dc[3]);
686: my $ampm = " am";
687: if ($hm[0] > 12) {
688: $hm[0]-=12;
689: $ampm = " pm";
690: }
691: return $dc[0].', '.$dc[1].' '.$dc[2].', '.$dc[4].' at '.$hm[0].':'.$hm[1].$ampm;
692: }
693:
694: sub array_moments {
695: my @input=@_;
696: my (@output,$N);
697: $N=scalar (@input);
698: $output[0]=$N;
699: if ($N <= 1) {
700: $output[1]=$input[0];
701: $output[1]="Input array not defined" if ($N == 0);
702: $output[2]="variance undefined for N<=1";
703: $output[3]="skewness undefined for N<=1";
704: $output[4]="kurtosis undefined for N<=1";
705: return @output;
706: }
707: my $sum=0;
708: foreach my $line (@input) {
709: $sum+=$line;
710: }
711: $output[1] = $sum/$N;
712: my ($x,$sdev,$var,$skew,$kurt) = 0;
713: foreach my $line (@input) {
714: $x=$line-$output[1];
715: $var+=$x**2;
716: $skew+=$x**3;
717: $kurt+=$x**4;
718: }
719: $output[2]=$var/($N-1);
720: $sdev=CORE::sqrt($output[2]);
721: if ($sdev == 0) {
722: $output[3]="inf-variance=0";
723: $output[4]="inf-variance=0";
724: return @output;
725: }
726: $output[3]=$skew/($sdev**3*$N);
727: $output[4]=$kurt/($sdev**4*$N)-3;
728: return @output;
729: }
730:
731: sub choose {
732: my $num = $_[0];
733: return $_[$num];
734: }
735:
736: # expiremental idea
737: sub proper_path {
738: my ($path)=@_;
739: if ( $external::target eq "tex" ) {
740: return '/home/httpd/html'.$path;
741: } else {
742: return $path;
743: }
744: }
745:
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