Annotation of doc/homework/homework5.html, revision 1.4

1.1       albertel    1: <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
                      2: <html>
                      3:   <head>
                      4:     <title>LON-CAPA Homework System</title>
                      5:   </head>
                      6: 
                      7:   <body>
                      8:     <h1>LON-CAPA Homework System</h1>
                      9: 
                     10:     <h2>Tags</h2>
                     11:     <ul>
                     12:       <li>
                     13: 	Response tags
                     14: 	<p>
                     15: 	  Arguments for all response tags
                     16: 	</p>
                     17: 	<ul>
                     18: 	  <li>
                     19: 	    <i>ID</i>, if this isn't set it will be set during
                     20: 	    the publication step. It is used to assign parameters names
                     21: 	    in a way that can be tracked if an instructor modifies
                     22: 	    things by hand.
                     23: 	  </li>
                     24: 	  <li>
                     25: 	    <i>name</i> optional, if set, it will be used by the
                     26: 	    resource assembly tool when one is modifying parameters.
                     27: 	    </li>
                     28: 	</ul>
                     29: 	<p>
                     30: 	  Implemented response tags
                     31: 	</p>
                     32: 	<ul>
                     33: 	  <li>
1.2       albertel   34: 	    <b>&lt;responseparam&gt;</b> if it appears it should be
                     35: 	    inside of a &lt;*response&gt; tag, defines an externally
                     36: 	    adjustable parameter for this question. Arguments:
                     37: 	    <ul>
                     38: 	      <li>
                     39: 		<i>default</i> required, specifies a default value for
                     40: 		the parameter
                     41: 	      </li>
                     42: 	      <li>
                     43: 		<i>name</i> required, specifies an internal name for
                     44: 		the parameter
                     45: 	      </li>
                     46: 	      <li>
                     47: 		<i>type</i> required specifies the type of parameter,
                     48: 		one of "tolerance", "int", "float", "string", "date"
                     49: 		(configuration of paramters is handled by
                     50: 		lonparmset.pm and parameter.html)
                     51: 	      </li>
                     52: 	      <li>
                     53: 		<i>description</i> a string describing the parameter,
                     54: 		this is what is used to talk about a parameter outside
                     55: 		of a problem
                     56: 	      </li>
                     57: 	    </ul>
                     58: 	  </li>
                     59: 	  <li>
1.1       albertel   60: 	    <b>&lt;numericalresponse&gt;</b> implements a numerical
                     61: 	    answer, it needs an internal <b>&lt;textline&gt;</b> for
                     62: 	    the response to go in. It checks all styles of numerical
                     63: 	    supported in CAPA. Possible args are:
                     64: 	    <ul>
                     65: 	      <li><i>answer</i> required, specifies the correct answer, must be a perl list</li>
                     66: 	      <li><i>type</i> optional, CAPA style str args, cs/ci/mc</li>
                     67: 	      <li><i>units</i> optional, specifies unit of correct answer, CAPA style</li>
                     68: 	    </ul>
                     69: 	  </li>
                     70: 	  <li>
                     71: 	    <b>&lt;essayresponse&gt;</b> implements a ungraded large
                     72: 	    text response, it need an internal <b>&lt;textarea&gt;</b>
                     73: 	    for the response to go in.
                     74: 	  </li>
                     75: 	  <li>
                     76: 	    <b>&lt;imageresponse&gt;</b> implements a image click
                     77: 	    style image submission, uses the foil structure tags <a
                     78: 	    href="#foil">below</a>. Additional tags that should appear
                     79: 	    in a &lt;foil&gt; are:
                     80: 	    <ul>
                     81: 	      <li><b>&lt;image&gt;</b> required, the contained text
                     82: 	      specifies a published graphical resource that is the
                     83: 	      image used, should only appear once per foil</li>
                     84: 	      <li><b>&lt;rectangle&gt;</b> required, the contained text
                     85: 	      specifies a rectangular area that is correct, should
                     86: 	      look like (1,2)-(3,4), at least 1 required</li>
                     87: 	      <li><b>&lt;text&gt;</b> required, the contained text is
                     88: 	      printed on top of the image.</li>
                     89: 	    </ul>
                     90: 	  </li>
                     91: 	  <li>
                     92: 	    <b>&lt;optionresponse&gt;</b> implements a "select from
                     93: 	    these choices" style question, the choices are specified
                     94: 	    by the instructor, it uses the foil structure tags <a
                     95: 	    href="#foil">below</a> with this additional args: 
                     96: 	    <ul>
                     97: 	      <li>
                     98: 		<b>&lt;foilgroup&gt;</b> is required to have
                     99: 		<i>options</i> which should be a perl list of possible
                    100: 		options for the student.
                    101: 	      </li>
                    102: 	    </ul>
                    103: 	  </li>
                    104: 	  <li>
                    105: 	    <b>&lt;radiobuttonresponse&gt;</b> implements a true / false
                    106: 	    style question with 1 correct answer.it uses the foil
                    107: 	    structure tags <a href="#foil">below</a> but the
                    108: 	    <i>value</i> of a &lt;foil&gt;can only be "true" or
                    109: 	    "false" or "unused"
                    110: 	  </li>
                    111: 	</ul>
                    112: 	<li>
                    113: 	<a name="foil">Foil Structure Tags</a>
                    114: 	<p>
                    115: 	  All tags that implement a foil structure have an optional
                    116: 	  arg of <i>max</i> that controls the maximum number of total
                    117: 	  foils to show.
                    118: 	</p>
                    119: 	<ul>
                    120: 	  <li>
                    121: 	    <b>&lt;foilgroup&gt;</b> required, must be the tag that
                    122: 	    surrounds all foil definitions	    
                    123: 	  </li>
                    124: 	  <li>
                    125: 	    <b>&lt;foil&gt;</b> required, all data inside is a possible foil
                    126: 	  </li>
                    127: 	  <li>
                    128: 	    <b>&lt;conceptgroup&gt;</b> optional, surrounds a
                    129: 	    collection of &lt;foil&gt;, when a problem is displayed
                    130: 	    only one of the contained &lt;foil&gt;is selected for
                    131: 	    display. It receives one required argument
                    132: 	    <i>concept</i>.
                    133: 	  </li>
                    134: 	</ul>
                    135:       </li>
                    136:       <li>
                    137: 	Hint structure
                    138: 	<p>
                    139: 	  All of these tags must appear inside a <b>&lt;*response&gt;</b> tag.
                    140: 	</p>
                    141: 	<ul>
                    142: 	  <li>
                    143: 	    <b>&lt;hintgroup&gt;</b> Tag that surrounds all of a hint.
                    144: 	  </li>
                    145: 	  <li>
                    146: 	    <b>&lt;hintpart&gt;</b> required, Tag to implement
                    147: 	    conditional hints. It has a required argument
                    148: 	    <i>on</i>. When a &lt;*hint&gt; tag named the same as the
                    149: 	    value the </i>on</i> attribute evaluates to be correct the
                    150: 	    &lt;hintpart&gt; will show. If no other &lt;hintpart&gt;
                    151: 	    are to show then all hintparts with a <i>on</i> of
                    152: 	    "default" will show
                    153: 	  </li>
                    154: 	  <li>
                    155: 	    <b>&lt;numericalhint&gt;</b> has all the arguments that
                    156: 	    &lt;numericalresponse&gt;, does and the required attribute
                    157: 	    <i>name</i> which should be set to the value of which
                    158: 	    &lt;hintpart&gt; will be shown. 
                    159: 	  </li>
                    160: 	</ul>
                    161:       </li>
                    162:       <li>
                    163: 	Input Tags
                    164: 	<p>
                    165: 	  This group of tags implement a mechanism for getting data
                    166: 	  for students, they will usually be used by a
                    167: 	  &lt;*response&gt;.
                    168: 	</p>
                    169: 	<ul>
                    170: 	  <li>
                    171: 	    <b>&lt;textarea&gt;</b> creates a Large text input box, If
                    172: 	    data appears between the start and end tags, the data will
                    173: 	    appear i the textarea if the student has not yet made a
                    174: 	    submission. Additionally it takes two arguments <i>rows</i>
                    175: 	    and <i>cols</i> which control the height and width of the
                    176: 	    area respectively. It defaults to 10 and 80.
                    177: 	  </li>
                    178: 	  <li>
                    179: 	    <b>&lt;textline&gt;</b> creates a single line of input
                    180: 	    element, it accepts 1 argument <i>size</i> which controls
                    181: 	    the width on the textline, it defaults to 20.
                    182: 	  </li>
                    183: 	</ul>
                    184:       </li>
                    185:       <li>
                    186: 	Output Tags
                    187: 	<p>
                    188: 	  This group of tags generate useful pieces of output.
                    189: 	</p>
                    190: 	<ul>
                    191: 	  <li>
                    192: 	    <b>&lt;displayduedate&gt;</b> this will insert the current
                    193: 	    duedate if one is set into the document. It is generated
                    194: 	    to be inside a table of 1x1 elements
                    195: 	  </li>
                    196: 	  <li>
                    197: 	    <b>&lt;displaytitle&gt;</b> this will insert the title of
                    198: 	    the problem from the metadata of the problem
                    199: 	  </li>
                    200: 	  <li>
                    201: 	    <b>&lt;window&gt;</b> the text in between is put in a
                    202: 	    popup javascript window
                    203: 	  </li>
                    204: 	</ul>
                    205:       </li>
                    206:       <li>
                    207: 	Scripting
                    208: 	<p>
                    209: 	  These tags allow the document to behave programatically
                    210: 	</p>
                    211: 	<ul>
                    212: 	  <li>
                    213: 	    <b>&lt;display&gt;</b> the intervening perl script is
                    214: 	    evaluated in the safe space and the return value of the
                    215: 	    script replaces the entire tag
                    216: 	  </li>
                    217: 	  <li>
                    218: 	    <b>&lt;import&gt;</b> causes the parse to read in the file
                    219: 	    named in the body of the tag and parse it as if the entire
                    220: 	    text of the file had existed at location of the tag
                    221: 	  </li>
                    222: 	  <li>
                    223: 	    <b>&lt;parserlib&gt;</b> the enclosed filename contains
                    224: 	    definitions for new tags
                    225: 	  </li>
                    226: 	  <li>
                    227: 	    <b>&lt;script&gt;</b> if the argument <i>type</i> is set
                    228: 	    to "loncapa/perl" the enclosed data is a perl script which
                    229: 	    is evaluated inside the perl Safe space. The return value
                    230: 	    of the script is ignored.
                    231: 	  </li>
                    232: 	  <li>
                    233: 	    <b>&lt;scriptlib&gt;</b> the enclosed filename contains
                    234: 	    perl code to run in the safe space
                    235: 	  </li>
                    236: 	  <li>
                    237: 	    <b>&lt;block&gt;</b> has a required argument
                    238: 	    <i>condition</i> that is evaluated, it the condition is
                    239: 	    true everything inside the tag is evaluated, if it is false
                    240: 	    everything inside the block tag is skipped
                    241: 	  </li>
                    242: 	  <li>
                    243: 	    <b>&lt;notsolved&gt;</b> everything inside the tag is
                    244: 	    skipped if the problem is "solved"
                    245: 	  </li>
                    246: 	  <li>
                    247: 	    <b>&lt;postanswerdate&gt;</b> everything inside the tag is
                    248: 	    skipped if the problem is before the answer date
                    249: 	  </li>
                    250: 	  <li>
                    251: 	    <b>&lt;preduedate&gt;</b> everything inside the tag is
                    252: 	    skipped if the problem is after the due date
                    253: 	  </li>
                    254: 	  <li>
                    255: 	    <b>&lt;randomlist&gt;</b> the enclosed tags are parsed in
                    256: 	    a stable random order
                    257: 	  </li>
                    258: 	  <li>
                    259: 	    <b>&lt;solved&gt;</b> everything inside the tag is
                    260: 	    skipped if the problem is "not solved"
                    261: 	  </li>
                    262: 	  <li>
                    263: 	    <b>&lt;while&gt;</b> implements a while loop, required
                    264: 	    argument <i>condition</i> is a perl scriptlet that when
                    265: 	    evaluated results in a true or false value, on true the
                    266: 	    entirety of the text between the whiles is parsed. The
                    267: 	    condition is tested again, etc. If false it goes to the
                    268: 	    next node in the parse.
                    269: 	  </li>
                    270: 	</ul>
                    271:       </li>
                    272:       <li>
                    273: 	Structure Tags
                    274: 	<p>
                    275: 	  These tags give the problem a structure and take care of the
                    276: 	  recording of data and giving the student messages.
                    277: 	</p>
                    278: 	<ul>
                    279: 	  <li>
                    280: 	    <b>&lt;problem&gt;</b> must be the first tag in the file,
                    281: 	    this tag sets up the header of the webpage and generates
                    282: 	    the submit buttons, it also handles due dates properly
                    283: 	  </li>
                    284: 	  <li>
                    285: 	    <b>&lt;part&gt;</b> must be below &lt;problem&gt; if it is
                    286: 	    going to be used. It does many of the same tasks as
                    287: 	    &lt;problem&gt; but allows multiple separate problems to
                    288: 	    exist in a single file.
                    289: 	  </li>
                    290: 	  <li>
                    291: 	    <b>&lt;startouttext&gt;</b><b>&lt;endouttext&gt;</b> these
                    292: 	    tags are somewhat special, they must have no internal text
                    293: 	    and occur in pairs. Their use is to mark up the problem so
                    294: 	    the web editor knows what sections should be edited in a
                    295: 	    plain text block on the web.
                    296: 	  </li>
                    297: 	</ul>
                    298:       </li>
                    299:     </ul>
                    300:     <h2>&lt;script&gt; Functions</h2>
                    301:     <p> 
                    302:       A list of functions that have been written that are available in 
                    303:       the Safe space scripting environment inside a problem. The eventual
1.3       ng        304:       goal is to provide all of the functions available in CAPA. Detailed
                    305:       descriptions of each function and comparison with CAPA is given in
                    306:       <a href="homework6.html">CAPA to LON-CAPA Functions</a>.
1.1       albertel  307:     </p>
                    308:     <ul>
1.3       ng        309:       <li>sin(x), cos(x), tan(x)</li>
                    310:       <li>asin(x), acos(x), atan(x), atan2(y,x)</li>
                    311:       <li>log(x), log10(x)</li>
                    312:       <li>exp(), pow(x,y), sqrt(x)</li>
                    313:       <li>abs(x), sgn(x)</li>
                    314:       <li>erf(x), erfc(x)</li>
                    315:       <li>ceil(x), floor(x)</li>
                    316:       <li>min(...), max(...)</li>
                    317:       <li>factorial(n)</li>
                    318:       <li>N%M</li>
                    319:       <li>sinh(x), cosh(x), tanh(x)</li>
                    320:       <li>asinh(x), acosh(x), atanh(x)</li>
                    321:       <li>roundto(x,n)</li>
                    322:       <li>web("a","b","c") or web(a,b,c)</li>
                    323:       <li>html("a") or html(a)</li>
                    324:       <li>j0(x), j1(x), jn(n,x), jv(y,x)</li>
                    325:       <li>y0(x), y1(x), yn(n,x), yv(y,x)</li>
1.1       albertel  326:       <li>random</li>
                    327:       <li>choose</li>
1.3       ng        328:       <li>tex("a","b") or tex(a,b)</li>
                    329:       <li>var_in_tex(a)</li>
                    330:       <li>to_string(x), to_string(x,y)</li>
                    331:       <li>class(), section()</li>
                    332:       <li>name(), student_number()</li>
                    333:       <li>open_date(), due_date(), answer_date()</li>
                    334:       <li>sub_string()</li>
                    335:       <li>array_moments(array)</li>
                    336:       <li>format(x,y)</li>
                    337:       <li>map(...)</li>
1.1       albertel  338:       <li>caparesponse_check</li>
                    339:       <li>caparesponse_check_list</li>
                    340:     </ul>
1.4     ! ng        341: 
        !           342:   <table border=1>
        !           343:       <tr>
        !           344:             <td valign="top"><b>CAPA Functions</b</td>
        !           345:             <td valign="top"><b>LON-CAPA</b</td>
        !           346:             <td valign="top"><b>Descriptions</b</td>
        !           347:             <td valign="top"><b>Differences (if any)</b</td>
        !           348:      </tr>
        !           349: 
        !           350:      <tr>
        !           351:              <td valign="top">sin(x), cos(x), tan(x)</td>
        !           352:              <td valign="top">&amp;sin($x), &amp;cos($x), &amp;tan($x)</td>
        !           353:              <td valign="top">Trigonometric functions where x is in radians. $x
        !           354:          can be a pure number, i.e., you can call &amp;sin(3.1415)</td>
        !           355:              <td valign="top">&nbsp</td>
        !           356:     </tr>
        !           357: 
        !           358:     <tr>
        !           359:              <td valign="top">sin(x), cos(x), tan(x)</td>
        !           360:              <td valign="top">&amp;sin($x), &amp;cos($x), &amp;tan($x)</td>
        !           361:              <td valign="top">Trigonometric functions where x is in radians. $x
        !           362:          can be a pure number, i.e., you can call &amp;sin(3.1415)</td>
        !           363:               <td valign="top">&nbsp</td>
        !           364:     </tr>
        !           365: 
        !           366:     <tr>
        !           367:              <td valign="top">asin(x), acos(x), atan(x), atan2(y,x)</td>
        !           368:              <td valign="top">&amp;asin($x), &amp;acos($x), &amp;atan($x), &amp;atan2($y,$x)</td>
        !           369:              <td valign="top">Inverse trigonometric functions. Return value is
        !           370:                  in radians. For asin and acos the value of x must be between -1 and 1.
        !           371:                  The atan2 returns a value between -pi and pi the sign of which is determined
        !           372:                  by y. $x and $y can be pure numbers</td>
        !           373:              <td valign="top">&nbsp;</td>
        !           374:     </tr>
        !           375: 
        !           376:     <tr>
        !           377:              <td valign="top">log(x), log10(x)</td>
        !           378:              <td valign="top">&amp;log($x), &amp;log10($x)</td>
        !           379:              <td valign="top">Natural and base-10 logarithm. $x can be a pure number</td>
        !           380:              <td valign="top">&nbsp;</td>
        !           381:     </tr>
        !           382: 
        !           383:     <tr>
        !           384:              <td valign="top">exp(x), pow(x,y), sqrt(x)</td>
        !           385:              <td valign="top">&amp;exp($x), &amp;pow($x,$y), &amp;sqrt($x)</td>
        !           386:              <td valign="top">Exponential, power and square root, i.e.,e<sup>x</sup>, x<sup>y</sup> and /x.                  $x and $y can be pure numbers</td>
        !           387: 
        !           388:              <td valign="top">&nbsp;</td>
        !           389:     </tr>
        !           390: 
        !           391:     <tr>
        !           392:              <td valign="top">abs(x), sgn(x)</td>
        !           393:              <td valign="top">&amp;abs($x), &amp;sgn($x)</td>
        !           394:              <td valign="top">Abs takes the absolute value of x while sgn(x) returns
        !           395:                  1, 0 or -1 depending on the value of x. For x>0, sgn(x) = 1, for x=0, sgn(x)
        !           396:                  = 0 and for x&lt;0, sgn(x) = -1. $x can be a pure number</td>
        !           397:              <td valign="top">&nbsp;</td>
        !           398:     </tr>
        !           399: 
        !           400:     <tr>
        !           401:              <td valign="top">erf(x), erfc(x)</td>
        !           402:              <td valign="top">&amp;erf($x), &amp;erfc($x)</td>
        !           403:              <td valign="top">Error function.&nbsp; erf = 2/sqrt(pi) integral (0,x) e<sup>t-sq</sup> and <i>                 erfx(x)</i> = 1.0 - <i>erf(x)</i>.&nbsp; $x can be a pure number</td>
        !           404:              <td valign="top">&nbsp;</td>
        !           405:     </tr>
        !           406: 
        !           407:     <tr>
        !           408:              <td valign="top">ceil(x), floor(x)</td>
        !           409:              <td valign="top">&amp;ceil($x), &amp;floor($x)</td>
        !           410:              <td valign="top">Ceil function returns an integer rounded up whereas
        !           411:                  floor function returns and integer rounded down. If x is an integer than
        !           412:                  it returns the value of the integer. $x can be a pure number</td>
        !           413:              <td valign="top">&nbsp;</td>
        !           414:     </tr>
        !           415: 
        !           416:     <tr>
        !           417:              <td valign="top">min(...), max(...)</td>
        !           418:              <td valign="top">&amp;min(...), &amp;max(...)</td>
        !           419:              <td valign="top">Returns the minimum/ maximum value of a list of
        !           420:                  arguments if the arguments are numbers. If the arguments are strings then
        !           421:                  it returns a string sorted according to the ASCII codes</td>
        !           422:              <td valign="top">&nbsp;</td>
        !           423:     </tr>
        !           424: 
        !           425:     <tr>
        !           426:              <td valign="top">factorial(n)</td>
        !           427:              <td valign="top">&amp;factorial($n)</td>
        !           428:              <td valign="top">Argument (n) must be an integer else it will round
        !           429:                  down. The largest value for n is 170. $n can be a pure number</td>
        !           430:              <td valign="top">&nbsp;</td>
        !           431:     </tr>
        !           432: 
        !           433:     <tr>
        !           434:              <td valign="top">N%M</td>
        !           435:              <td valign="top">$N%$M</td>
        !           436: 
        !           437:              <td valign="top">N and M are integers and returns the remainder (in
        !           438:                  integer) of N/M. $N and $M can be pure numbers</td>
        !           439:              <td valign="top">&nbsp;</td>
        !           440:     </tr>
        !           441: 
        !           442:     <tr>
        !           443:              <td valign="top">sinh(x), cosh(x), tanh(x)</td>
        !           444:              <td valign="top">&amp;sinh($x), &amp;cosh($x), &amp;tanh($x)</td>
        !           445:              <td valign="top">Hyperbolic functions. $x can be a pure number</td>
        !           446:              <td valign="top">&nbsp;</td>
        !           447:     </tr>
        !           448: 
        !           449:     <tr>
        !           450:              <td valign="top">asinh(x), acosh(x), atanh(x)</td>
        !           451:              <td valign="top">&amp;asinh($x), &amp;acosh($x), &amp;atanh($x)</td>
        !           452:              <td valign="top">Inverse hyperbolic functions. $x can be a pure number</td>
        !           453:              <td valign="top">&nbsp;</td>
        !           454:     </tr>
        !           455: 
        !           456:     <tr>
        !           457:              <td valign="top">roundto(x,n)</td>
        !           458:              <td valign="top">&amp;roundto($x,$n)</td>
        !           459:              <td valign="top">Rounds a real number to n decimal points. $x and
        !           460:                  $n can be pure numbers</td>
        !           461:              <td valign="top">&nbsp;</td>
        !           462:     </tr>
        !           463: 
        !           464:     <tr>
        !           465:              <td valign="top">web("a","b","c") or web(a,b,c)</td>
        !           466:              <td valign="top">&amp;web("a","b","c") or &amp;web($a,$b,$c)</td>
        !           467:              <td valign="top">Returns either a, b or c depending on the output
        !           468:                  medium. a is for plain ASCII, b for tex output and c for html output</td>
        !           469:              <td valign="top">&nbsp</td>
        !           470:     </tr>
        !           471: 
        !           472:     <tr>
        !           473:              <td valign="top">html("a") or html(a)</td>
        !           474:              <td valign="top">&amp;html("a") or &amp;html($a)</td>
        !           475:              <td valign="top">Output only if the output mode chosen is in html
        !           476:                  format</td>
        !           477:              <td valign="top">&nbsp;</td>
        !           478:     </tr>
        !           479: 
        !           480:     <tr>
        !           481:              <td valign="top">jn(m,x)</td>
        !           482:              <td valign="top">&amp;j0($x), &amp;j1($x), &amp;jn($m,$x), &amp;jv($y,$x)</td>
        !           483:              <td valign="top">Bessel functions of the first kind with orders 0,
        !           484:                  1 and m respectively. For jn(m,x), m must be an integer whereas for jv(y,x),
        !           485:                  y is real. $x can be a pure number. $m must be an integer and can be a
        !           486:                  pure integer number. $y can be a pure real number</td>
        !           487:              <td valign="top">In CAPA, j0, j1 and jn are contained in one function,
        !           488:                  jn(m,x) where m takes the value of 0, 1 or 2. jv(y,x) was not implemented</td>
        !           489:     </tr>
        !           490: 
        !           491:     <tr>
        !           492:              <td valign="top">yn(m,x)</td>
        !           493:              <td valign="top">&amp;y0($x), &amp;y1($x), &amp;yn($m,$x), &amp;yv($y,$x)</td>
        !           494:              <td valign="top">Bessel functions of the second kind with orders
        !           495:                  0, 1 and m respectively. For yn(m,x), m must be an integer whereas for
        !           496:                  yv(y,x), y is real. $x can be a pure number. $m must be an integer and
        !           497:                  can be a pure integer number. $y can be a pure real number</td>
        !           498:              <td valign="top">In CAPA, y0, y1 and yn are contained in one function,
        !           499:                  yn(m,x) where m takes the value of 0, 1 or 2. yv(y,x) was not implemented</td>
        !           500:     </tr>
        !           501: 
        !           502:     <tr>
        !           503:              <td valign="top">random(l,u,d)</td>
        !           504:              <td valign="top">&amp;random($l,$u,$d)</td>
        !           505:              <td valign="top">Returns a uniformly distributed random number between
        !           506:                  the lower bound, l and upper bound, u in steps of d. $l, $u and $d can
        !           507:                  be pure numbers</td>
        !           508:              <td valign="top">In CAPA, all the 3 arguments must be of the same
        !           509:                  type. However, now you can mix the type</td>
        !           510:     </tr>
        !           511: 
        !           512:     <tr>
        !           513:              <td valign="top">choose(i,...)</td>
        !           514:              <td valign="top">&amp;choose($i,...)</td>
        !           515:              <td valign="top">Choose the ith item from the argument list. i must
        !           516:                  be an integer greater than 0 and the value of i should not exceed the number
        !           517:                  of items. $i can be a pure integer</td>
        !           518:              <td valign="top">&nbsp;</td>
        !           519:     </tr>
        !           520: 
        !           521:     <tr>
        !           522:              <td valign="top">tex(a,b), tex("a","b")</td>
        !           523:              <td valign="top">&amp;tex($a,$b), &amp;tex("a","b")</td>
        !           524:              <td valign="top">Returns a if the output mode is in tex otherwise
        !           525:                   returns b</td>
        !           526:              <td valign="top">&nbsp;</td>
        !           527:     </tr>
        !           528: 
        !           529:     <tr>
        !           530:              <td valign="top">var_in_tex(a)</td>
        !           531:              <td valign="top">&amp;var_in_tex($a)</td>
        !           532:              <td valign="top">Equivalent to tex("a","")</td>
        !           533:              <td valign="top">&nbsp;</td>
        !           534:     </tr>
        !           535: 
        !           536:     <tr>
        !           537:              <td valign="top">to_string(x), to_string(x,y)</td>
        !           538:              <td valign="top">&amp;to_string($x), &amp;to_string($x,$y)</td>
        !           539:              <td valign="top">If x is an integer, returns a string. If x is real
        !           540:                 than the output is a string with format given by y. For example, if x =
        !           541:                 12.3456, &amp;to_string(x,".3F") = 12.345 and &amp;to_string(x,".3E") =
        !           542:                 1.234E+01.</td>
        !           543:              <td valign="top">&nbsp;</td>
        !           544:     </tr>
        !           545: 
        !           546:     <tr>
        !           547:              <td valign="top">capa_id(), class(), section(), set(), problem()</td>
        !           548:              <td valign="top">&amp;class(), &amp;section()</td>
        !           549:              <td valign="top">Returns null string, class descriptive name, section
        !           550:                     number, set number and null string.</td>
        !           551:              <td valign="top">capa_id(), set() and problem() are no longer used.
        !           552:                     Currently, they return a null value.</td>
        !           553:     </tr>
        !           554: 
        !           555:     <tr>
        !           556:              <td valign="top">name(), student_number()</td>
        !           557:              <td valign="top">&amp;name(), &amp;student_number()</td>
        !           558:              <td valign="top">Return the full name in the following format: lastname,
        !           559:                     firstname initial. Student_number returns the student 9-alphanumeric string.
        !           560:                     If undefined, the functions return null.</td>
        !           561:              <td valign="top">&nbsp;</td>
        !           562:     </tr>
        !           563: 
        !           564:     <tr>
        !           565:              <td valign="top">open_date(), due_date(), answer_date()</td>
        !           566:              <td valign="top">&amp;open_date(), &amp;due_date(), &amp;answer_date()</td>
        !           567:              <td valign="top">Problem open date, due date and answer date. The
        !           568:                     time is also included in 24-hr format.</td>
        !           569:              <td valign="top">Output format for time is changed slightly. If pass
        !           570:                     noon, it displays ..pm else it displays ..am. So 23:59 is displayed as
        !           571:                     11:59 pm.</td>
        !           572:     </tr>
        !           573: 
        !           574:     <tr>
        !           575:              <td valign="top">get_seed(), set_seed()</td>
        !           576:              <td valign="top">Not implemented</td>
        !           577:              <td valign="top">Get and set the random seed.</td>
        !           578:              <td valign="top">&nbsp;</td>
        !           579:     </tr>
        !           580: 
        !           581:     <tr>
        !           582:              <td valign="top">sub_string(a,b,c)</td>
        !           583:              <td valign="top">&amp;sub_string($a,$b,$c) <br>perl&nbsp; substr function. 
        !           584:                  However, note the differences</td>
        !           585:              <td valign="top">Retrieve a portion of string a starting from b and
        !           586:                     length c. For example,&nbsp; $a = "Welcome to LON-CAPA"; 
        !           587:                     $result=&amp;sub_string($a,4,4); then $result is "come"</td>
        !           588:              <td valign="top">Perl intrinsic function, substr(string,b,c) starts
        !           589:                     counting from 0 (as opposed to 1). In the example to the left, substr($a,4,4)
        !           590:                     returns "ome ".</td>
        !           591:     </tr>
        !           592: 
        !           593:     <tr>
        !           594:              <td valign="top">array[xx]</td>
        !           595:              <td valign="top">@arrayname <br>Array is intrinsic in perl. 
        !           596:                  To access a specific element use $arrayname[$n] where $n 
        !           597:                  is the $n+1 element since the array count starts from 0</td>
        !           598:              <td valign="top">"xx" can be a variable or a calculation.</td>
        !           599:              <td valign="top">In LON-CAPA, an array is defined by @arrayname.
        !           600:                   It is not necessary to specify the dimension of the array.&nbsp;</td>
        !           601:     </tr>
        !           602: 
        !           603:     <tr>
        !           604:              <td valign="top">array_moments(B,A)</td>
        !           605:              <td valign="top">@B=&amp;array_moments(@A)</td>
        !           606:              <td valign="top">Evaluates the moments of an array A and place the
        !           607:                   result in array B[i] where i = 0 to 4. The contents of B are as follows:
        !           608:                   B[0] = number of elements, B[1] = mean, B[2] = variance, B[3] = skewness
        !           609:                   and B[4] = kurtosis.</td>
        !           610:              <td valign="top">&nbsp;</td>
        !           611:     </tr>
        !           612: 
        !           613:     <tr>
        !           614:              <td valign="top">array_max(Name), array_min(Name)</td>
        !           615:              <td valign="top">&amp;min(@Name), &amp;max(@Name)</td>
        !           616:              <td valign="top">In LON-CAPA to find the maximum value of an array, use
        !           617:                    &amp;max(@arrayname)&nbsp; and to find the minimum value of an array, use
        !           618:                    &amp;min(@arrayname)</td>
        !           619:              <td valign="top">Combined with the min and max functions defined
        !           620:                 earlier.</td>
        !           621:     </tr>
        !           622: 
        !           623:     <tr>
        !           624:              <td valign="top">init_array(Name)</td>
        !           625:              <td valign="top">undef @name</td>
        !           626:              <td valign="top">To destroy the contents of an array, use</td>
        !           627:              <td valign="top">Use perl intrinsic undef function.</td>
        !           628:     </tr>
        !           629: 
        !           630:     <tr>
        !           631:              <td valign="top">random_norma(...), random_beta(...), random_gamma(...),
        !           632:                random_exponential(...), random_poisson(...), random_chi(...), random_noncentral(...)</td>
        !           633:              <td valign="top">Not yet implemented.</td>
        !           634:              <td valign="top">&nbsp;</td>
        !           635:              <td valign="top">&nbsp;</td>
        !           636:     </tr>
        !           637:   </table>
        !           638: 
        !           639: 
1.1       albertel  640:     <h2>&lt;script&gt; Variables</h2>
                    641:     <ul>
                    642:       <li>
                    643: 	$external::target - set to the current target the xml parser
                    644: 	is parsing for
                    645:       </li>
                    646:       <li>
                    647: 	$external::part - set to the <i>id</i> of the current problem
                    648: 	&lt;part&gt;; zero if there are now &lt;part&gt;
                    649:       </li>
                    650:       <li>
                    651: 	$external::gradestatus - set to the value of the current
                    652: 	resource.partid.solved value
                    653:       </li>
                    654:       <li>
                    655: 	$external::datestatus - set to the current status of the clock
                    656: 	either CLOSED, CAN_ANSWER, CANNOT_ANSWER, or SHOW_ANSWER
                    657:       </li>
                    658:       <li>
                    659: 	$external::randomseed - set to the number that was used to
                    660: 	seed the random number generator
                    661:       </li>
                    662:       <li>$pi - set to PI </li>
1.3       ng        663:       <li>$rad2deg - converts radians to degrees </li>
                    664:       <li>$deg2rad - converts degrees to radians </li>
1.1       albertel  665:     </ul>
                    666:     
                    667:     <hr>
                    668:     <address><a href="mailto:albertel@marvin.lite.msu.edu">Guy Albertelli</a></address>
                    669: <!-- Created: Thu May 17 15:05:35 EDT 2001 -->
                    670: <!-- hhmts start -->
1.2       albertel  671: Last modified: Fri May 18 21:29:39 EDT 2001
1.1       albertel  672: <!-- hhmts end -->
                    673:   </body>
                    674: </html>

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