Diff for /doc/homework/homework5.html between versions 1.3 and 1.17

version 1.3, 2001/05/31 20:51:31 version 1.17, 2002/06/07 06:39:00
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     <title>LON-CAPA Homework System</title>      <title>LON-CAPA Homework System</title>
   </head>    </head>
   
   <body>    <body bgcolor="white">
     <h1>LON-CAPA Homework System</h1>      <h1>LON-CAPA Homework System</h1>
   
     <h2>Tags</h2>      <h2>Tags</h2>
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     </ul>      </ul>
   </li>    </li>
   <li>    <li>
       <b>&lt;parameter&gt;</b> exactly the same as
       &lt;responseparam&gt; currently, but should not appear
       inside of a &lt;*response&gt;
     </li>
     <li>
     <b>&lt;numericalresponse&gt;</b> implements a numerical      <b>&lt;numericalresponse&gt;</b> implements a numerical
     answer, it needs an internal <b>&lt;textline&gt;</b> for      answer, it needs an internal <b>&lt;textline&gt;</b> for
     the response to go in. It checks all styles of numerical      the response to go in. It checks all styles of numerical
     supported in CAPA. Possible args are:      supported in CAPA. Possible args are:
     <ul>      <ul>
       <li><i>answer</i> required, specifies the correct answer, must be a perl list</li>        <li><i>answer</i> required, specifies the correct answer, may be either a perl list or scalar</li>
       <li><i>type</i> optional, CAPA style str args, cs/ci/mc</li>  
       <li><i>units</i> optional, specifies unit of correct answer, CAPA style</li>        <li><i>units</i> optional, specifies unit of correct answer, CAPA style</li>
     </ul>      </ul>
   </li>    </li>
   <li>    <li>
       <b>&lt;stringresponse&gt;</b> implements a string answer,
       it needs an internal <b>&lt;textline&gt;</b> for the
       response to go in. It can check the string for either case
       or order.
       <ul>
         <li><i>answer</i> required, specifies the correct answer, may be either a perl list or scalar</li>
         <li><i>type</i> optional, CAPA style str args, cs/ci/mc
    <ul>
     <li>cs - case senesitive, order important</li>
     <li>ci - case insenesitive, order important</li>
     <li>mc - case insenesitive, order unimportant</li>
    </ul>
         </li>
       </ul>
     <li>
     <b>&lt;essayresponse&gt;</b> implements a ungraded large      <b>&lt;essayresponse&gt;</b> implements a ungraded large
     text response, it need an internal <b>&lt;textarea&gt;</b>      text response, it need an internal <b>&lt;textfield&gt;</b>
     for the response to go in.      for the response to go in.
   </li>    </li>
   <li>    <li>
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     <i>value</i> of a &lt;foil&gt;can only be "true" or      <i>value</i> of a &lt;foil&gt;can only be "true" or
     "false" or "unused"      "false" or "unused"
   </li>    </li>
     <li>
       <b>&lt;dataresponse&gt;</b> implements a straight data
       storage entry idea, needs and interveing input tag like
       &lt;textline&gt; to work correctly.<br>
       Arguments:
       <ul>
         <li>
    <i>name</i> internal name for the value, it will have
    the part id and respose id added on to it
         </li>
         <li>
    <i>type</i> type of data stored in this response
    field, should be one of the types supported by
    parameter.html
         </li> 
         <li>
    <i>display</i> a string that will be used to describe
    the field when interfacing with humans
         </li>
       </ul>
     </li>
     <li>
       <p>
         <b>&lt;externalresponse&gt;</b> implements the ability to have
         an external program grade a response, expects either a
         &lt;textline&gt; or &lt;textfield&gt; inside the tag. <br />
       </p>
       Arguments:
       <ul>
         <li>
    <i>url</i> the url to submit the answer and form to,
    does not need to be a LON-CAPA machine.
         </li>
         <li>
    <i>answer</i> a string or scalar variable that can
    encode something that should encode the correct
    answer, in some cases this may be nothing.
         </li>
         <li>
    <i>form</i> a hash variable name that will be
    submitted to the remote site as a HTTP form.
         </li>
       </ul>
       <p>
         The response of the remote server needs to be in XML as follows.
       </p>
       <pre>
   &lt;loncapagrade&gt;
       &lt;awardetail&gt;
   CORRECT
       &lt;/awardetail&gt;
       &lt;message&gt;
   A message to be shown to the students
       &lt;/message&gt;
   &lt;/loncapagrade&gt;
       </pre>
       <ul>
         <li>
    <b>&lt;loncapagrade&gt;</b> no arguments but must
    surround the response.
         </li>
         <li>
    <b>&lt;awardetail&gt;</b> required inner tag, the
    response inside must be one of the detailed responses
    that appears in the data storage documentation
    (CVS:loncapa/doce/homework/datastorage)
         </li>
         <li>
    <b>&lt;message&gt;</b> optional message to have shown
    to the student
         </li>
       </ul>
     </li>
  </ul>   </ul>
  <li>   <li>
  <a name="foil">Foil Structure Tags</a>   <a name="foil">Foil Structure Tags</a>
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  </p>   </p>
  <ul>   <ul>
   <li>    <li>
     <b>&lt;textarea&gt;</b> creates a Large text input box, If      <b>&lt;textfield&gt;</b> creates a Large text input box, If
     data appears between the start and end tags, the data will      data appears between the start and end tags, the data will
     appear i the textarea if the student has not yet made a      appear in the textfield if the student has not yet made a
     submission. Additionally it takes two arguments <i>rows</i>      submission. Additionally it takes two arguments <i>rows</i>
     and <i>cols</i> which control the height and width of the      and <i>cols</i> which control the height and width of the
     area respectively. It defaults to 10 and 80.      area respectively. It defaults to 10 and 80.
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  </p>   </p>
  <ul>   <ul>
   <li>    <li>
       <b>&lt;standalone&gt;</b> everything in between the start
       and end tag is shown only on the web, and only if the
       resource is not part of a course.
     </li>
     <li>
     <b>&lt;displayduedate&gt;</b> this will insert the current      <b>&lt;displayduedate&gt;</b> this will insert the current
     duedate if one is set into the document. It is generated      duedate if one is set into the document. It is generated
     to be inside a table of 1x1 elements      to be inside a table of 1x1 elements
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     <b>&lt;window&gt;</b> the text in between is put in a      <b>&lt;window&gt;</b> the text in between is put in a
     popup javascript window      popup javascript window
   </li>    </li>
     <li>
       <b>&lt;m&gt;</b> the inside text is LaTeX, and is
       converted to HTML (or MathML) on the fly, if the argument
       <i>eval</i> is set to "on" the intervening text will have
       a perl var expansion done to it before being converted.
     </li>
     <li>
       <b>&lt;randomlabel&gt;</b> shows a specified image with
       images or text labels randomly assigned to a set of
       specific locations, those locations may also have values
       assigned to them. There is a hash generated conating the
       mapping of labels to locations, labels to values, and
       locations to values. Example:
       <pre>
    &lt;randomlabel bgimg=&quot;URL&quot; width=&quot;12&quot; height=&quot;45&quot; texwidth=&quot;50&quot;&gt;
       &lt;labelgroup name=&quot;GroupOne&quot; type=&quot;image&quot;&gt;
         &lt;location x=&quot;123&quot; y=&quot;456&quot; value=&quot;10&quot; /&gt;
         &lt;location x=&quot;321&quot; y=&quot;654&quot; value=&quot;20&quot; /&gt;
         &lt;location x=&quot;213&quot; y=&quot;546&quot; value=&quot;13&quot; /&gt;
         &lt;label description=&quot;TEXT-1&quot;&gt;IMG-URL&lt;/label&gt;
         &lt;label description=&quot;TEXT-2&quot;&gt;IMG-URL&lt;/label&gt;
         &lt;label description=&quot;TEXT-3&quot;&gt;IMG-URL&lt;/label&gt;
       &lt;/labelgroup&gt;
       &lt;labelgroup name=&quot;GroupTwo&quot; type=&quot;text&quot;&gt;
         &lt;location x=&quot;12&quot; y=&quot;45&quot; /&gt;
         &lt;location x=&quot;32&quot; y=&quot;65&quot; /&gt;
         &lt;location x=&quot;21&quot; y=&quot;54&quot; /&gt;
         &lt;label&gt;TEXT-1&lt;/label&gt;
         &lt;label&gt;TEXT-2&lt;/label&gt;
         &lt;label&gt;TEXT-3&lt;/label&gt;
       &lt;/labelgroup&gt;
      &lt;/randomlabel&gt;
       </pre>
       Arguments:
       <ul>
         <li>
    <i>bgimg</i> either a fully qualified URL for an
    external image, or a loncapa resource, it supports
    relative references (../images/apicture.gif), the
    image must either be a GIF or JPEG
         </li>
         <li>
    <i>width</i> the width of the image in pixels
         </li>
         <li>
    <i>height</i> the height of the image in pixels
         </li>
         <li>
    <i>texwidth</i> the width of the image in millimeters
         </li>
       </ul>
       Internal tags:
       <ul>
         <li>
    <b>&lt;labelgroup&gt;</b> 1 required, multiple
    allowed. Declares a group of locations and labels
    associated with them.  <br />Arguments:
    <ul>
     <li>
       <i>name</i> this is the name of the group, a hash
       with this name will be generated holding the
       mappings for later use in the problem. For each
       location a value will be set for which label is
       there, (EX. $hash{'1'}="TEXT-2"). For locations
       with values the hash will contain 2 items, a
       location to value mapping ($hash{'value_1'}=10),
       and a label to value mapping
       ($hash{'labelvalue_2'}=10). For all image style of
       labels there will also be a label description to
       label URL mapping ($hash{'image_2'}=IMG-URL). Also
       the entry 'numlocations will be set to the total
       number of locations that exist.
       (Note that locations and labels start counting from 1.)
     </li>
     <li>
       <i>type</i> the type of labels in this group,
       either 'image' or 'text'
     </li>
    </ul>
         </li>
         <li>
    <b>&lt;location&gt;</b> declares a location on the
    image that a label should appear at <br />Arguments:
    <ul>
     <li>
       <i>x</i> the x value of the location in pixels 
     </li>
     <li>
       <i>y</i> the y value of the location in pixels 
     </li>
     <li>
       <i>value</i> a scalar value to associate at this
       location (optional)
     </li>
    </ul>
         </li>
         <li>
    <b>&lt;label&gt;</b> declaration of a label, if this
    is a text type labelgroup the internal text should be
    the text of the label (HTML is not currently
    supported), if this is an image type of label the
    internal text must be a LON-CAPA resource
    specification, and the description filed must be set.
    <br />Arguments:
    <ul>
     <li>
       <i>description</i> a required field for image
       labels, it will be used when setting values in the
       hash.
     </li>
    </ul>
         </li>
       </ul>
     </li>
  </ul>   </ul>
       </li>        </li>
       <li>        <li>
  Scripting   Scripting
  <p>        <p>
   These tags allow the document to behave programatically   These tags allow the document to behave programatically
  </p>        </p>
  <ul>        <ul>
   <li>   <li>
     <b>&lt;display&gt;</b> the intervening perl script is      <b>&lt;display&gt;</b> the intervening perl script is
     evaluated in the safe space and the return value of the      evaluated in the safe space and the return value of the
     script replaces the entire tag      script replaces the entire tag
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   </li>    </li>
   <li>    <li>
     <b>&lt;randomlist&gt;</b> the enclosed tags are parsed in      <b>&lt;randomlist&gt;</b> the enclosed tags are parsed in
     a stable random order      a stable random order, optional argument <i>show</i>
       restricts the number of tags indie that are actually
       parsed the no more than <i>show</i>.
   </li>    </li>
   <li>    <li>
     <b>&lt;solved&gt;</b> everything inside the tag is      <b>&lt;solved&gt;</b> everything inside the tag is
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     <h2>&lt;script&gt; Functions</h2>      <h2>&lt;script&gt; Functions</h2>
     <p>       <p> 
       A list of functions that have been written that are available in         A list of functions that have been written that are available in 
       the Safe space scripting environment inside a problem. The eventual        the Safe space scripting environment inside a problem. 
       goal is to provide all of the functions available in CAPA. Detailed  
       descriptions of each function and comparison with CAPA is given in  
       <a href="homework6.html">CAPA to LON-CAPA Functions</a>.  
     </p>      </p>
     <ul>      <ul>
       <li>sin(x), cos(x), tan(x)</li>        <li>sin(x), cos(x), tan(x)</li>
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       <li>open_date(), due_date(), answer_date()</li>        <li>open_date(), due_date(), answer_date()</li>
       <li>sub_string()</li>        <li>sub_string()</li>
       <li>array_moments(array)</li>        <li>array_moments(array)</li>
       <li>format(x,y)</li>        <li>format(x,y),prettyprint(x,y)</li>
       <li>map(...)</li>        <li>map(...)</li>
       <li>caparesponse_check</li>        <li>caparesponse_check</li>
       <li>caparesponse_check_list</li>        <li>caparesponse_check_list</li>
     </ul>      </ul>
   <!-- Table inserted by H. K. Ng 
       06/01/2001
       06/12/2001
   -->
       <p> 
         Detailed descriptions of each function and comparison with CAPA.
       </p>
   
     <table border=1>
         <tr>
               <td valign="top"><b>CAPA Functions</b</td>
               <td valign="top"><b>LON-CAPA</b</td>
               <td valign="top"><b>Descriptions</b</td>
               <td valign="top"><b>Differences (if any)</b</td>
        </tr>
   
       <tr>
                <td valign="top">sin(x), cos(x), tan(x)</td>
                <td valign="top">&amp;sin($x), &amp;cos($x), &amp;tan($x)</td>
                <td valign="top">Trigonometric functions where x is in radians. $x
            can be a pure number, i.e., you can call &amp;sin(3.1415)</td>
                 <td valign="top">&nbsp</td>
       </tr>
   
       <tr>
                <td valign="top">asin(x), acos(x), atan(x), atan2(y,x)</td>
                <td valign="top">&amp;asin($x), &amp;acos($x), &amp;atan($x), &amp;atan2($y,$x)</td>
                <td valign="top">Inverse trigonometric functions. Return value is
                    in radians. For asin and acos the value of x must be between -1 and 1.
                    The atan2 returns a value between -pi and pi the sign of which is determined
                    by y. $x and $y can be pure numbers</td>
                <td valign="top">&nbsp;</td>
       </tr>
   
       <tr>
                <td valign="top">log(x), log10(x)</td>
                <td valign="top">&amp;log($x), &amp;log10($x)</td>
                <td valign="top">Natural and base-10 logarithm. $x can be a pure number</td>
                <td valign="top">&nbsp;</td>
       </tr>
   
       <tr>
                <td valign="top">exp(x), pow(x,y), sqrt(x)</td>
                <td valign="top">&amp;exp($x), &amp;pow($x,$y), &amp;sqrt($x)</td>
                <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>
   
                <td valign="top">&nbsp;</td>
       </tr>
   
       <tr>
                <td valign="top">abs(x), sgn(x)</td>
                <td valign="top">&amp;abs($x), &amp;sgn($x)</td>
                <td valign="top">Abs takes the absolute value of x while sgn(x) returns
                    1, 0 or -1 depending on the value of x. For x>0, sgn(x) = 1, for x=0, sgn(x)
                    = 0 and for x&lt;0, sgn(x) = -1. $x can be a pure number</td>
                <td valign="top">&nbsp;</td>
       </tr>
   
       <tr>
                <td valign="top">erf(x), erfc(x)</td>
                <td valign="top">&amp;erf($x), &amp;erfc($x)</td>
                <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>
                <td valign="top">&nbsp;</td>
       </tr>
   
       <tr>
                <td valign="top">ceil(x), floor(x)</td>
                <td valign="top">&amp;ceil($x), &amp;floor($x)</td>
                <td valign="top">Ceil function returns an integer rounded up whereas
                    floor function returns and integer rounded down. If x is an integer than
                    it returns the value of the integer. $x can be a pure number</td>
                <td valign="top">&nbsp;</td>
       </tr>
   
       <tr>
                <td valign="top">min(...), max(...)</td>
                <td valign="top">&amp;min(...), &amp;max(...)</td>
                <td valign="top">Returns the minimum/ maximum value of a list of
                    arguments if the arguments are numbers. If the arguments are strings then
                    it returns a string sorted according to the ASCII codes</td>
                <td valign="top">&nbsp;</td>
       </tr>
   
       <tr>
                <td valign="top">factorial(n)</td>
                <td valign="top">&amp;factorial($n)</td>
                <td valign="top">Argument (n) must be an integer else it will round
                    down. The largest value for n is 170. $n can be a pure number</td>
                <td valign="top">&nbsp;</td>
       </tr>
   
       <tr>
                <td valign="top">N%M</td>
                <td valign="top">$N%$M</td>
   
                <td valign="top">N and M are integers and returns the remainder (in
                    integer) of N/M. $N and $M can be pure numbers</td>
                <td valign="top">&nbsp;</td>
       </tr>
   
       <tr>
                <td valign="top">sinh(x), cosh(x), tanh(x)</td>
                <td valign="top">&amp;sinh($x), &amp;cosh($x), &amp;tanh($x)</td>
                <td valign="top">Hyperbolic functions. $x can be a pure number</td>
                <td valign="top">&nbsp;</td>
       </tr>
   
       <tr>
                <td valign="top">asinh(x), acosh(x), atanh(x)</td>
                <td valign="top">&amp;asinh($x), &amp;acosh($x), &amp;atanh($x)</td>
                <td valign="top">Inverse hyperbolic functions. $x can be a pure number</td>
                <td valign="top">&nbsp;</td>
       </tr>
   
       <tr>
                <td valign="top">/DIS($x,"nn")</td>
                <td valign="top">&amp;format($x,"nn")</td>
                <td valign="top">Display or format $x as nn where nn is nF or nE and n is an integer.</td>
                <td valign="top">&nbsp;The difference is obvious.</td>
       </tr>
   
       <tr>
                <td valign="top">Not in CAPA</td>
                <td valign="top">&amp;prettyprint($x,"nn")</td>
                <td valign="top">Display or format $x as nn where nn is nF or nE and n is an integer. In E mode it will attempt to generate a pretty x10^3 rather than a E3 following the number</td>
                <td valign="top">&nbsp;</td>
       </tr>
   
       <tr>
                <td valign="top">roundto(x,n)</td>
                <td valign="top">&amp;roundto($x,$n)</td>
                <td valign="top">Rounds a real number to n decimal points. $x and
                    $n can be pure numbers</td>
                <td valign="top">&nbsp;</td>
       </tr>
   
       <tr>
                <td valign="top">web("a","b","c") or web(a,b,c)</td>
                <td valign="top">&amp;web("a","b","c") or &amp;web($a,$b,$c)</td>
                <td valign="top">Returns either a, b or c depending on the output
                    medium. a is for plain ASCII, b for tex output and c for html output</td>
                <td valign="top">&nbsp</td>
       </tr>
   
       <tr>
                <td valign="top">html("a") or html(a)</td>
                <td valign="top">&amp;html("a") or &amp;html($a)</td>
                <td valign="top">Output only if the output mode chosen is in html
                    format</td>
                <td valign="top">&nbsp;</td>
       </tr>
   
       <tr>
                <td valign="top">jn(m,x)</td>
                <td valign="top">&amp;j0($x), &amp;j1($x), &amp;jn($m,$x), &amp;jv($y,$x)</td>
                <td valign="top">Bessel functions of the first kind with orders 0,
                    1 and m respectively. For jn(m,x), m must be an integer whereas for jv(y,x),
                    y is real. $x can be a pure number. $m must be an integer and can be a
                    pure integer number. $y can be a pure real number</td>
                <td valign="top">In CAPA, j0, j1 and jn are contained in one function,
                    jn(m,x) where m takes the value of 0, 1 or 2. jv(y,x) is new to LON-CAPA.</td>
       </tr>
   
       <tr>
                <td valign="top">yn(m,x)</td>
                <td valign="top">&amp;y0($x), &amp;y1($x), &amp;yn($m,$x), &amp;yv($y,$x)</td>
                <td valign="top">Bessel functions of the second kind with orders
                    0, 1 and m respectively. For yn(m,x), m must be an integer whereas for
                    yv(y,x), y is real. $x can be a pure number. $m must be an integer and
                    can be a pure integer number. $y can be a pure real number</td>
                <td valign="top">In CAPA, y0, y1 and yn are contained in one function,
                    yn(m,x) where m takes the value of 0, 1 or 2. yv(y,x) is new to LON-CAPA.</td>
       </tr>
   
       <tr>
                <td valign="top">random(l,u,d)</td>
                <td valign="top">&amp;random($l,$u,$d)</td>
                <td valign="top">Returns a uniformly distributed random number between
                    the lower bound, l and upper bound, u in steps of d. $l, $u and $d can
                    be pure numbers</td>
                <td valign="top">In CAPA, all the 3 arguments must be of the same
                    type. However, now you can mix the type</td>
       </tr>
   
       <tr>
                <td valign="top">choose(i,...)</td>
                <td valign="top">&amp;choose($i,...)</td>
                <td valign="top">Choose the ith item from the argument list. i must
                    be an integer greater than 0 and the value of i should not exceed the number
                    of items. $i can be a pure integer</td>
                <td valign="top">&nbsp;</td>
       </tr>
   
       <tr>
                <td valign="top">/MAP(seed;w,x,y,z;a,b,c,d)</td>
                <td valign="top">Option 1 - &amp;map($seed,[\$w,\$x,\$y,\$z],[$a,$b,$c,$d]) or <br> 
                     Option 2 - &amp;map($seed,\@mappedArray,[$a,$b,$c,$d]) <br>
                     Option 3 - @mappedArray = &amp;map($seed,[$a,$b,$c,$d]) <br>
                     Option 4 - ($w,$x,$y,$z) = &amp;map($seed,\@a) <br>
                     where $a='A'<br>
                           $b='B'<br>
                           $c='B'<br>
                           $d='B'<br>
                           $w, $x, $y, and $z are variables</td>
                <td valign="top">Assigns to the variables $w, $x, $y and $z the values of the
                     $a, $b, $c and $c (A, B, C and D). The precise value for $w .. depends
                     on the seed. (Option 1 of calling map). 
                     In option 2, the values of $a, $b .. are mapped into the array, @mappedArray. The two
                     options illustrate the different grouping. Options 3 and 4 give a consistent 
                     way (with other functions) of mapping the items. For each option, the group can
                     be passed as an array, for example, [$a,$b,$c,$d] => \@a.</td>
                <td valign="top">In CAPA, the arguments are divided into three groups separated
                     by a semicolon ;. In LON-CAPA, the separation is done by using [] brackets or
                     using an array @a. Note the backslash (\) before the arguments in the
                     second and third groups.</td>
       </tr>
   
   
       <tr>
                <td valign="top">rmap(seed;a,b,c,d;w,x,y,z)</td>
                <td valign="top">Option 1 - &amp;rmap($seed,[\$w,\$x,\$y,\$z],[$a,$b,$c,$d]) or <br> 
                     Option 2 - &amp;rmap($seed,\@rmappedArray,[$a,$b,$c,$d]) <br>
                     Option 3 - @rmapped_array = &amp;rmap($seed,[$a,$b,$c,$d]) <br>
                     Option 4 - ($w,$x,$y,$z) = &amp;rmap($seed,\@a) <br>
                     where $a='A'<br>
                           $b='B'<br>
                           $c='B'<br>
                           $d='B'<br>
                           $w, $x, $y, and $z are variables</td>
                <td valign="top">The rmap functions does the reverse action of map if the same seed
                     is used in calling map and rmap. </td>
                <td valign="top">In CAPA, the arguments are divided into
                three groups separated by a semicolon ;. In LON-CAPA, the
                separation is done by using [] brackets (with create an
                unamed vector reference) or using an array @a. Note the
                backslash (\) before the arguments in the second and
                third groups (Which cause Perl to send to variable
                locations rather than the variable values, similar to a C
                pointer).</td>
       </tr>
         
        <tr>
                <td valign="top">NOT IMPLEMENTED IN CAPA</td>
                <td valign="top">$a=&amp;xmlparse($string) </td>
                <td valign="top">Runs the internal parser over the
     argument parsing for display. <b>Warning</b> This will
     result in different strings in different targets. Don't use
     the results of this function as an answer.</td>
                <td valign="top">New to LON-CAPA</td>
       </tr>
   
       <tr>
                <td valign="top">tex(a,b), tex("a","b")</td>
                <td valign="top">&amp;tex($a,$b), &amp;tex("a","b")</td>
                <td valign="top">Returns a if the output mode is in tex otherwise
                     returns b</td>
                <td valign="top">&nbsp;</td>
       </tr>
   
       <tr>
                <td valign="top">var_in_tex(a)</td>
                <td valign="top">&amp;var_in_tex($a)</td>
                <td valign="top">Equivalent to tex("a","")</td>
                <td valign="top">&nbsp;</td>
       </tr>
   
       <tr>
                <td valign="top">to_string(x), to_string(x,y)</td>
                <td valign="top">&amp;to_string($x), &amp;to_string($x,$y)</td>
                <td valign="top">If x is an integer, returns a string. If x is real
                   than the output is a string with format given by y. For example, if x =
                   12.3456, &amp;to_string(x,".3F") = 12.345 and &amp;to_string(x,".3E") =
                   1.234E+01.</td>
                <td valign="top">&nbsp;</td>
       </tr>
   
       <tr>
                <td valign="top">capa_id(), class(), section(), set(), problem()</td>
                <td valign="top">&amp;class(), &amp;section()</td>
                <td valign="top">Returns null string, class descriptive name, section
                       number, set number and null string.</td>
                <td valign="top">capa_id(), set() and problem() are no longer used.
                       Currently, they return a null value.</td>
       </tr>
   
       <tr>
                <td valign="top">name(), student_number()</td>
                <td valign="top">&amp;name(), &amp;student_number()</td>
                <td valign="top">Return the full name in the following format: lastname,
                       firstname initial. Student_number returns the student 9-alphanumeric string.
                       If undefined, the functions return null.</td>
                <td valign="top">&nbsp;</td>
       </tr>
   
       <tr>
                <td valign="top">open_date(), due_date(), answer_date()</td>
                <td valign="top">&amp;open_date(), &amp;due_date(), &amp;answer_date()</td>
                <td valign="top">Problem open date, due date and answer date. The
                       time is also included in 24-hr format.</td>
                <td valign="top">Output format for time is changed slightly. If pass
                       noon, it displays ..pm else it displays ..am. So 23:59 is displayed as
                       11:59 pm.</td>
       </tr>
   
       <tr>
                <td valign="top">get_seed(), set_seed()</td>
                <td valign="top">Not implemented</td>
                <td valign="top">Get and set the random seed.</td>
                <td valign="top">&nbsp;</td>
       </tr>
   
       <tr>
                <td valign="top">sub_string(a,b,c)</td>
                <td valign="top">&amp;sub_string($a,$b,$c) <br>perl&nbsp; substr function. 
                    However, note the differences</td>
                <td valign="top">Retrieve a portion of string a starting from b and
                       length c. For example,&nbsp; $a = "Welcome to LON-CAPA"; 
                       $result=&amp;sub_string($a,4,4); then $result is "come"</td>
                <td valign="top">Perl intrinsic function, substr(string,b,c) starts
                       counting from 0 (as opposed to 1). In the example to the left, substr($a,4,4)
                       returns "ome ".</td>
       </tr>
   
       <tr>
                <td valign="top">array[xx]</td>
                <td valign="top">@arrayname <br>Array is intrinsic in perl. 
                    To access a specific element use $arrayname[$n] where $n 
                    is the $n+1 element since the array count starts from 0</td>
                <td valign="top">"xx" can be a variable or a calculation.</td>
                <td valign="top">In LON-CAPA, an array is defined by @arrayname.
                     It is not necessary to specify the dimension of the array.&nbsp;</td>
       </tr>
   
       <tr>
                <td valign="top">array_moments(B,A)</td>
                <td valign="top">@B=&amp;array_moments(@A)</td>
                <td valign="top">Evaluates the moments of an array A and place the
                     result in array B[i] where i = 0 to 4. The contents of B are as follows:
                     B[0] = number of elements, B[1] = mean, B[2] = variance, B[3] = skewness
                     and B[4] = kurtosis.</td>
                <td valign="top">In CAPA, the moments are passed as an array in the first argument whereas
                     in LON-CAPA, the array containing the moments are set equal to the function.</td>
       </tr>
   
       <tr>
                <td valign="top">array_max(Name), array_min(Name)</td>
                <td valign="top">&amp;min(@Name), &amp;max(@Name)</td>
                <td valign="top">In LON-CAPA to find the maximum value of an array, use
                      &amp;max(@arrayname)&nbsp; and to find the minimum value of an array, use
                      &amp;min(@arrayname)</td>
                <td valign="top">Combined with the min and max functions defined
                   earlier.</td>
       </tr>
   
       <tr>
                <td valign="top">init_array(Name)</td>
                <td valign="top">undef @name</td>
                <td valign="top">To destroy the contents of an array, use</td>
                <td valign="top">Use perl intrinsic undef function.</td>
       </tr>
        <tr>
                <td valign="top">random_normal (return_array,item_cnt,seed,av,std_dev)</td>
                <td valign="top">@return_array=&random_normal ($item_cnt,$seed,$av,$std_dev)</td>
                <td valign="top">Generate $item_cnt deviates of normal distribution of average $av and
                           standard deviation $std_dev. The distribution is generated from seed $seed</td>
                <td valign="top">In CAPA the results are passed as the first argument whereas in LON-CAPA 
                           the results are set equal to the function.</td>
       </tr>
        <tr>
                <td valign="top">random_beta (return_array,item_cnt,seed,aa,bb)</td>
                <td valign="top">@return_array=&random_beta ($item_cnt,$seed,$aa,$bb) <br>
                           NOTE: Both $aa and $bb MUST be greater than 1.0E-37.</td>
                <td valign="top">Generate $item_cnt deviates of beta distribution. 
                           The density of beta is:
                           X^($aa-1) *(1-X)^($bb-1) /B($aa,$bb) for 0&lt;X&lt;1.</td>
                <td valign="top">In CAPA the results are passed as the first argument whereas in LON-CAPA 
                           the results are set equal to the function.</td>
       </tr>
        <tr>
                <td valign="top">random_gamma (return_array,item_cnt,seed,a,r)</td>
                <td valign="top">@return_array=&random_gamma ($item_cnt,$seed,$a,$r) <br>
                           NOTE: Both $a and $r MUST be positive.</td>
                <td valign="top">Generate $item_cnt deviates of gamma distribution. 
                           The density of gamma is:
                           ($a**$r)/gamma($r) * X**($r-1) * exp(-$a*X).</td>
                <td valign="top">In CAPA the results are passed as the first argument whereas in LON-CAPA 
                           the results are set equal to the function.</td>
       </tr>
        <tr>
                <td valign="top">random_exponential (return_array,item_cnt,seed,av)</td>
                <td valign="top">@return_array=&random_exponential ($item_cnt,$seed,$av) <br>
                           NOTE: $av MUST be non-negative.</td>
                <td valign="top">Generate $item_cnt deviates of exponential distribution. </td>
                <td valign="top">In CAPA the results are passed as the first argument whereas in LON-CAPA 
                           the results are set equal to the function.</td>
       </tr>
        <tr>
                <td valign="top">random_poisson (return_array,item_cnt,seed,mu)</td>
                <td valign="top">@return_array=&random_poisson ($item_cnt,$seed,$mu) <br>
                           NOTE: $mu MUST be non-negative.</td>
                <td valign="top">Generate $item_cnt deviates of poisson distribution. </td>
                <td valign="top">In CAPA the results are passed as the first argument whereas in LON-CAPA 
                           the results are set equal to the function.</td>
       </tr>
        <tr>
                <td valign="top">random_chi (return_array,item_cnt,seed,df)</td>
                <td valign="top">@return_array=&random_chi ($item_cnt,$seed,$df) <br>
                           NOTE: $df MUST be positive.</td>
                <td valign="top">Generate $item_cnt deviates of chi_square distribution with $df 
                           degrees of freedom. </td>
                <td valign="top">In CAPA the results are passed as the first argument whereas in LON-CAPA 
                           the results are set equal to the function.</td>
       </tr>
        <tr>
                <td valign="top">random_noncentral_chi (return_array,item_cnt,seed,df,nonc)</td>
                <td valign="top">@return_array=&random_noncentral_chi ($item_cnt,$seed,$df,$nonc) <br>
                           NOTE: $df MUST be at least 1 and $nonc MUST be non-negative.</td>
                <td valign="top">Generate $item_cnt deviates of noncentral_chi_square 
                           distribution with $df 
                           degrees of freedom and noncentrality parameter $nonc. </td>
                <td valign="top">In CAPA the results are passed as the first argument whereas in LON-CAPA 
                           the results are set equal to the function.</td>
       </tr>
        <tr>
                <td valign="top">NOT IMPLEMENTED IN CAPA</td>
                <td valign="top">@return_array=&random_f ($item_cnt,$seed,$dfn,$dfd) <br>
                           NOTE: Both $dfn and $dfd MUST be positive.</td>
                <td valign="top">Generate $item_cnt deviates of F (variance ratio) distribution with  
                           degrees of freedom $dfn (numerator) and $dfd (denominator). </td>
                <td valign="top">New to LON-CAPA</td>
       </tr>
        <tr>
                <td valign="top">NOT IMPLEMENTED IN CAPA</td>
                <td valign="top">@return_array=&random_noncentral_f ($item_cnt,$seed,$dfn,$dfd,$nonc) <br>
                           NOTE: $dfn must be at least 1, $dfd MUST be positive, and $nonc must
                           be non-negative.</td>
                <td valign="top">Generate $item_cnt deviates of noncentral F (variance ratio) 
                           distribution with degrees of freedom $dfn (numerator) and $dfd (denominator).
                           $nonc is the noncentrality parameter. </td>
                <td valign="top">New to LON-CAPA</td>
       </tr>
        <tr>
                <td valign="top">NOT DOCUMENTED IN CAPA</td>
                <td valign="top">@return_array=&random_multivariate_normal ($item_cnt,$seed,\@mean,\@covar) <br>
                           NOTE: @mean should be of length p array of real numbers. @covar should be a length
                           p array of references to length p arrays of real numbers (i.e. a p by p matrix.</td>
                <td valign="top">Generate $item_cnt deviates of multivariate_normal distribution with  
                           mean vector @mean and variance-covariance matrix. </td>
                <td valign="top">Note the backslash before the @mean and @covar arrays.</td>
       </tr>
        <tr>
                <td valign="top">NOT IMPLEMENTED IN CAPA</td>
                <td valign="top">@return_array=&random_multinomial ($item_cnt,$seed,@p) <br>
                           NOTE: $item_cnt is rounded with int() and the result must be non-negative. 
                           The number of elements in @p must be at least 2.</td>
                <td valign="top">Returns single observation from multinomial distribution with  
                           $item_cnt events classified into as many categories as the length of @p.
                           The probability of an event being classified into category i is given by 
                           ith element of @p. The observation is an array with length equal to @p, so
                           when called in a scalar context it returns the length of @p. The sum of the
                           elements of the obervation is equal to $item_cnt.</td>
                <td valign="top">New to LON-CAPA</td>
       </tr>
        <tr>
                <td valign="top">NOT IMPLEMENTED IN CAPA</td>
                <td valign="top">@return_array=&random_permutation ($item_cnt,@array) </td>
                <td valign="top">Returns @array randomly permuted.</td>
                <td valign="top">New to LON-CAPA</td>
       </tr>
        <tr>
                <td valign="top">NOT IMPLEMENTED IN CAPA</td>
                <td valign="top">@return_array=&random_uniform ($item_cnt,$seed,$low,$high) <br>
                           NOTE: $low must be less than or equal to $high.</td>
                <td valign="top">Generate $item_cnt deviates from a uniform distribution. </td>
                <td valign="top">New to LON-CAPA</td>
       </tr>
        <tr>
                <td valign="top">NOT IMPLEMENTED IN CAPA</td>
                <td valign="top">@return_array=&random_uniform_integer ($item_cnt,$seed,$low,$high) <br>
                           NOTE: $low and $high are both passed through int().
                                 $low must be less than or equal to $high.</td>
                <td valign="top">Generate $item_cnt deviates from a uniform distribution in integers. </td>
                <td valign="top">New to LON-CAPA</td>
       </tr>
        <tr>
                <td valign="top">NOT IMPLEMENTED IN CAPA</td>
                <td valign="top">@return_array=&random_binomial ($item_cnt,$seed,$nt,$p) <br>
                           NOTE: $nt is rounded using int() and the result must be non-negative. 
                                 $p must be between 0 and 1 inclusive.</td>
                <td valign="top">Generate $item_cnt deviates from the binomial distribution with
                           $nt trials and the probabilty of an event in each trial is $p. </td>
                <td valign="top">New to LON-CAPA</td>
       </tr>
        <tr>
                <td valign="top">NOT IMPLEMENTED IN CAPA</td>
                <td valign="top">@return_array=&random_negative_binomial ($item_cnt,$seed,$ne,$p) <br>
                           NOTE: $ne is rounded using int() and the result must be positive. 
                                 $p must be between 0 and 1 exclusive.</td>
                <td valign="top">Generate an array of $item_cnt outcomes generated from 
                           negative binomial distribution with
                           $ne events and the probabilty of an event in each trial is $p. </td>
                <td valign="top">New to LON-CAPA</td>
       </tr>
    </table>
   <!-- insertion ends -->
   
     <h2>&lt;script&gt; Variables</h2>      <h2>&lt;script&gt; Variables</h2>
     <ul>      <ul>
       <li>        <li>
Line 346 Line 1062
       </li>        </li>
       <li>        <li>
  $external::part - set to the <i>id</i> of the current problem   $external::part - set to the <i>id</i> of the current problem
  &lt;part&gt;; zero if there are now &lt;part&gt;   &lt;part&gt;; zero if there are no &lt;part&gt;
       </li>        </li>
       <li>        <li>
  $external::gradestatus - set to the value of the current   $external::gradestatus - set to the value of the current
Line 354 Line 1070
       </li>        </li>
       <li>        <li>
  $external::datestatus - set to the current status of the clock   $external::datestatus - set to the current status of the clock
  either CLOSED, CAN_ANSWER, CANNOT_ANSWER, or SHOW_ANSWER   either CLOSED, CAN_ANSWER, CANNOT_ANSWER, SHOW_ANSWER, or UNCHECKEDOUT
       </li>        </li>
       <li>        <li>
  $external::randomseed - set to the number that was used to   $external::randomseed - set to the number that was used to
Line 364 Line 1080
       <li>$rad2deg - converts radians to degrees </li>        <li>$rad2deg - converts radians to degrees </li>
       <li>$deg2rad - converts degrees to radians </li>        <li>$deg2rad - converts degrees to radians </li>
     </ul>      </ul>
       
       <h2> Form internals </h2>
       <p> Form elements used for homework editing/response </p>
       <p> the form is named lonhomework </p>
       <h3> Viewing a problem (either CSTR or RES space)</h3>
       <ul>
         <li>
    grade_target, grade_username, grade_domain, grade_symb - the
    vaules take precedence over the the normal ENV settings of
    these, use &Apache::lonxml::whichuser() to get back the
    correct vaues of the items
         </li>
         <li>
    HWVAL_response:number - the name of the input elements for each response. The response is the response's ID, and the :number part exists only for response with multiple foils, and is a unique number in order of the submission
         </li>
         <li>
    changerandseed - the 'Change' button, only exists right after
    the Change button is clicked
         </li>
         <li>
    problemmode - in CSTR, it is either 'View','Edit','EditXML' or
    'Analyze' depending on the desired view
         </li>
         <li>
    rndseed - the currently requested random seed
         </li>
         <li>
    showallfoils - if it exists, and we are in CSTR space, the
    problem should ignore &lt;conceptgroup&gt; and the response's
    max setting and show all possible foils
         </li>
         <li>
    submit - the name of the Submit button
         </li>
         <li>
    submitted - a hidden form parameter that can be used to tell
    if the student has submitted answers or not, if it is set,
    there should be answers to grade.
         </li>
       </ul>
       <h3> Editing a problem (Edit mode)</h3>
       <p> tagdepth referes to the current value of the xmlparsers tagdepth couter ($Apache::lonxml::currentdepth)</p>
   <p> Note: the file edit.pm has many helper functions for creating the standard elements for editing a tag and it's attributes, all of those functions follow these conventions </p>
       <ul>
         <li>
    tagdepth_argname - I.E. 1_3.max, a parameter editing value,
    max is the name of the parameter and it is for the third tag
    inside the first tag
         </li>
         <li>
    delete_tagdepth - if set to yes, delete tag tagdepth and all
    tags inside of it
         </li>
         <li>
    homework_edit_tagdepth - used by both &Apache::edit::editline
    and &Apache::edit::editfield for the &lt;textarea&gt; and
    &lt;input&gt; form elements they create
         </li>
         <li>
    insert_tagdepth - used to request an tag insert, it is set to
    the id number of the requested tag in the
    %Apache::lonxml::insertlist
       </ul>
     <hr>      <hr>
     <address><a href="mailto:albertel@marvin.lite.msu.edu">Guy Albertelli</a></address>      <address><a href="mailto:albertel@marvin.lite.msu.edu">Guy Albertelli</a></address>
 <!-- Created: Thu May 17 15:05:35 EDT 2001 -->  <!-- Created: Thu May 17 15:05:35 EDT 2001 -->
 <!-- hhmts start -->  <!-- hhmts start -->
 Last modified: Fri May 18 21:29:39 EDT 2001  Last modified: Thu Jun  6 04:28:33 EDT 2002
 <!-- hhmts end -->  <!-- hhmts end -->
   </body>    </body>
 </html>  </html>

Removed from v.1.3  
changed lines
  Added in v.1.17


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