doc/homework/homework5.html - view

File: [LON-CAPA] / doc / homework / homework5.html
Revision 1.13: download - view: text, annotated - select for diffs
Thu Mar 28 22:55:35 2002 UTC (22 years, 1 month ago) by albertel
Branches: MAIN
CVS tags: stable_2002_april, HEAD

- updated <randomlist> description

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 bgcolor="white"> 8: <h1>LON-CAPA Homework System</h1> 9: 10: <h2>Tags</h2> 11: <ul> 12: <li> 13: Response tags 14: 15: Arguments for all response tags 16: 17: <ul> 18: <li> 19: ID, 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: name optional, if set, it will be used by the 26: resource assembly tool when one is modifying parameters. 27: </li> 28: </ul> 29: 30: Implemented response tags 31: 32: <ul> 33: <li> 34: <responseparam> if it appears it should be 35: inside of a <*response> tag, defines an externally 36: adjustable parameter for this question. Arguments: 37: <ul> 38: <li> 39: default required, specifies a default value for 40: the parameter 41: </li> 42: <li> 43: name required, specifies an internal name for 44: the parameter 45: </li> 46: <li> 47: type 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: description 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> 60: <numericalresponse> implements a numerical 61: answer, it needs an internal <textline> for 62: the response to go in. It checks all styles of numerical 63: supported in CAPA. Possible args are: 64: <ul> 65: <li>answer required, specifies the correct answer, may be either a perl list or scalar</li> 66: <li>units optional, specifies unit of correct answer, CAPA style</li> 67: </ul> 68: </li> 69: <li> 70: <stringresponse> implements a string answer, 71: it needs an internal <textline> for the 72: response to go in. It can check the string for either case 73: or order. 74: <ul> 75: <li>answer required, specifies the correct answer, may be either a perl list or scalar</li> 76: <li>type optional, CAPA style str args, cs/ci/mc 77: <ul> 78: <li>cs - case senesitive, order important</li> 79: <li>ci - case insenesitive, order important</li> 80: <li>mc - case insenesitive, order unimportant</li> 81: </ul> 82: </li> 83: </ul> 84: <li> 85: <essayresponse> implements a ungraded large 86: text response, it need an internal <textarea> 87: for the response to go in. 88: </li> 89: <li> 90: <imageresponse> implements a image click 91: style image submission, uses the foil structure tags <a 92: href="#foil">below</a>. Additional tags that should appear 93: in a <foil> are: 94: <ul> 95: <li><image> required, the contained text 96: specifies a published graphical resource that is the 97: image used, should only appear once per foil</li> 98: <li><rectangle> required, the contained text 99: specifies a rectangular area that is correct, should 100: look like (1,2)-(3,4), at least 1 required</li> 101: <li><text> required, the contained text is 102: printed on top of the image.</li> 103: </ul> 104: </li> 105: <li> 106: <optionresponse> implements a "select from 107: these choices" style question, the choices are specified 108: by the instructor, it uses the foil structure tags <a 109: href="#foil">below</a> with this additional args: 110: <ul> 111: <li> 112: <foilgroup> is required to have 113: options which should be a perl list of possible 114: options for the student. 115: </li> 116: </ul> 117: </li> 118: <li> 119: <radiobuttonresponse> implements a true / false 120: style question with 1 correct answer.it uses the foil 121: structure tags <a href="#foil">below</a> but the 122: value of a <foil>can only be "true" or 123: "false" or "unused" 124: </li> 125: <li> 126: <dataresponse> implements a straight data 127: storage entry idea, needs and interveing input tag like 128: <textline> to work correctly. 129: Arguments: 130: <ul> 131: <li> 132: name internal name for the value, it will have 133: the part id and respose id added on to it 134: </li> 135: <li> 136: type type of data stored in this response 137: field, should be one of the types supported by 138: parameter.html 139: </li> 140: <li> 141: display a string that will be used to describe 142: the field when interfacing with humans 143: </li> 144: </ul> 145: <li> 146: </ul> 147: <li> 148: <a name="foil">Foil Structure Tags</a> 149: 150: All tags that implement a foil structure have an optional 151: arg of max that controls the maximum number of total 152: foils to show. 153: 154: <ul> 155: <li> 156: <foilgroup> required, must be the tag that 157: surrounds all foil definitions 158: </li> 159: <li> 160: <foil> required, all data inside is a possible foil 161: </li> 162: <li> 163: <conceptgroup> optional, surrounds a 164: collection of <foil>, when a problem is displayed 165: only one of the contained <foil>is selected for 166: display. It receives one required argument 167: concept. 168: </li> 169: </ul> 170: </li> 171: <li> 172: Hint structure 173: 174: All of these tags must appear inside a <*response> tag. 175: 176: <ul> 177: <li> 178: <hintgroup> Tag that surrounds all of a hint. 179: </li> 180: <li> 181: <hintpart> required, Tag to implement 182: conditional hints. It has a required argument 183: on. When a <*hint> tag named the same as the 184: value the on attribute evaluates to be correct the 185: <hintpart> will show. If no other <hintpart> 186: are to show then all hintparts with a on of 187: "default" will show 188: </li> 189: <li> 190: <numericalhint> has all the arguments that 191: <numericalresponse>, does and the required attribute 192: name which should be set to the value of which 193: <hintpart> will be shown. 194: </li> 195: </ul> 196: </li> 197: <li> 198: Input Tags 199: 200: This group of tags implement a mechanism for getting data 201: for students, they will usually be used by a 202: <*response>. 203: 204: <ul> 205: <li> 206: <textarea> creates a Large text input box, If 207: data appears between the start and end tags, the data will 208: appear i the textarea if the student has not yet made a 209: submission. Additionally it takes two arguments rows 210: and cols which control the height and width of the 211: area respectively. It defaults to 10 and 80. 212: </li> 213: <li> 214: <textline> creates a single line of input 215: element, it accepts 1 argument size which controls 216: the width on the textline, it defaults to 20. 217: </li> 218: </ul> 219: </li> 220: <li> 221: Output Tags 222: 223: This group of tags generate useful pieces of output. 224: 225: <ul> 226: <li> 227: <displayduedate> this will insert the current 228: duedate if one is set into the document. It is generated 229: to be inside a table of 1x1 elements 230: </li> 231: <li> 232: <displaytitle> this will insert the title of 233: the problem from the metadata of the problem 234: </li> 235: <li> 236: <window> the text in between is put in a 237: popup javascript window 238: </li> 239: <li> 240: <m> the inside text is LaTeX, and is 241: converted to HTML (or MathML) on the fly, if the argument 242: eval is set to "on" the intervening text will have 243: a perl var expansion done to it before being converted. 244: </li> 245: </ul> 246: </li> 247: <li> 248: Scripting 249: 250: These tags allow the document to behave programatically 251: 252: <ul> 253: <li> 254: <display> the intervening perl script is 255: evaluated in the safe space and the return value of the 256: script replaces the entire tag 257: </li> 258: <li> 259: <import> causes the parse to read in the file 260: named in the body of the tag and parse it as if the entire 261: text of the file had existed at location of the tag 262: </li> 263: <li> 264: <parserlib> the enclosed filename contains 265: definitions for new tags 266: </li> 267: <li> 268: <script> if the argument type is set 269: to "loncapa/perl" the enclosed data is a perl script which 270: is evaluated inside the perl Safe space. The return value 271: of the script is ignored. 272: </li> 273: <li> 274: <scriptlib> the enclosed filename contains 275: perl code to run in the safe space 276: </li> 277: <li> 278: <block> has a required argument 279: condition that is evaluated, it the condition is 280: true everything inside the tag is evaluated, if it is false 281: everything inside the block tag is skipped 282: </li> 283: <li> 284: <notsolved> everything inside the tag is 285: skipped if the problem is "solved" 286: </li> 287: <li> 288: <postanswerdate> everything inside the tag is 289: skipped if the problem is before the answer date 290: </li> 291: <li> 292: <preduedate> everything inside the tag is 293: skipped if the problem is after the due date 294: </li> 295: <li> 296: <randomlist> the enclosed tags are parsed in 297: a stable random order, optional argument show 298: restricts the number of tags indie that are actually 299: parsed the no more than show. 300: </li> 301: <li> 302: <solved> everything inside the tag is 303: skipped if the problem is "not solved" 304: </li> 305: <li> 306: <while> implements a while loop, required 307: argument condition is a perl scriptlet that when 308: evaluated results in a true or false value, on true the 309: entirety of the text between the whiles is parsed. The 310: condition is tested again, etc. If false it goes to the 311: next node in the parse. 312: </li> 313: </ul> 314: </li> 315: <li> 316: Structure Tags 317: 318: These tags give the problem a structure and take care of the 319: recording of data and giving the student messages. 320: 321: <ul> 322: <li> 323: <problem> must be the first tag in the file, 324: this tag sets up the header of the webpage and generates 325: the submit buttons, it also handles due dates properly 326: </li> 327: <li> 328: <part> must be below <problem> if it is 329: going to be used. It does many of the same tasks as 330: <problem> but allows multiple separate problems to 331: exist in a single file. 332: </li> 333: <li> 334: <startouttext><endouttext> these 335: tags are somewhat special, they must have no internal text 336: and occur in pairs. Their use is to mark up the problem so 337: the web editor knows what sections should be edited in a 338: plain text block on the web. 339: </li> 340: </ul> 341: </li> 342: </ul> 343: <h2><script> Functions</h2> 344: 345: A list of functions that have been written that are available in 346: the Safe space scripting environment inside a problem. 347: 348: <ul> 349: <li>sin(x), cos(x), tan(x)</li> 350: <li>asin(x), acos(x), atan(x), atan2(y,x)</li> 351: <li>log(x), log10(x)</li> 352: <li>exp(), pow(x,y), sqrt(x)</li> 353: <li>abs(x), sgn(x)</li> 354: <li>erf(x), erfc(x)</li> 355: <li>ceil(x), floor(x)</li> 356: <li>min(...), max(...)</li> 357: <li>factorial(n)</li> 358: <li>N%M</li> 359: <li>sinh(x), cosh(x), tanh(x)</li> 360: <li>asinh(x), acosh(x), atanh(x)</li> 361: <li>roundto(x,n)</li> 362: <li>web("a","b","c") or web(a,b,c)</li> 363: <li>html("a") or html(a)</li> 364: <li>j0(x), j1(x), jn(n,x), jv(y,x)</li> 365: <li>y0(x), y1(x), yn(n,x), yv(y,x)</li> 366: <li>random</li> 367: <li>choose</li> 368: <li>tex("a","b") or tex(a,b)</li> 369: <li>var_in_tex(a)</li> 370: <li>to_string(x), to_string(x,y)</li> 371: <li>class(), section()</li> 372: <li>name(), student_number()</li> 373: <li>open_date(), due_date(), answer_date()</li> 374: <li>sub_string()</li> 375: <li>array_moments(array)</li> 376: <li>format(x,y)</li> 377: <li>map(...)</li> 378: <li>caparesponse_check</li> 379: <li>caparesponse_check_list</li> 380: </ul> 381:  385: 386: Detailed descriptions of each function and comparison with CAPA. 387: 388: 389: <table border=1> 390: <tr> 391: <td valign="top">CAPA Functions</b</td> 392: <td valign="top">LON-CAPA</b</td> 393: <td valign="top">Descriptions</b</td> 394: <td valign="top">Differences (if any)</b</td> 395: </tr> 396: 397: <tr> 398: <td valign="top">sin(x), cos(x), tan(x)</td> 399: <td valign="top">&sin($x), &cos($x), &tan($x)</td> 400: <td valign="top">Trigonometric functions where x is in radians. $x 401: can be a pure number, i.e., you can call &sin(3.1415)</td> 402: <td valign="top">&nbsp</td> 403: </tr> 404: 405: <tr> 406: <td valign="top">asin(x), acos(x), atan(x), atan2(y,x)</td> 407: <td valign="top">&asin($x), &acos($x), &atan($x), &atan2($y,$x)</td> 408: <td valign="top">Inverse trigonometric functions. Return value is 409: in radians. For asin and acos the value of x must be between -1 and 1. 410: The atan2 returns a value between -pi and pi the sign of which is determined 411: by y. $x and $y can be pure numbers</td> 412: <td valign="top"> </td> 413: </tr> 414: 415: <tr> 416: <td valign="top">log(x), log10(x)</td> 417: <td valign="top">&log($x), &log10($x)</td> 418: <td valign="top">Natural and base-10 logarithm. $x can be a pure number</td> 419: <td valign="top"> </td> 420: </tr> 421: 422: <tr> 423: <td valign="top">exp(x), pow(x,y), sqrt(x)</td> 424: <td valign="top">&exp($x), &pow($x,$y), &sqrt($x)</td> 425: <td valign="top">Exponential, power and square root, i.e.,ex, xy and /x. $x and $y can be pure numbers</td> 426: 427: <td valign="top"> </td> 428: </tr> 429: 430: <tr> 431: <td valign="top">abs(x), sgn(x)</td> 432: <td valign="top">&abs($x), &sgn($x)</td> 433: <td valign="top">Abs takes the absolute value of x while sgn(x) returns 434: 1, 0 or -1 depending on the value of x. For x>0, sgn(x) = 1, for x=0, sgn(x) 435: = 0 and for x<0, sgn(x) = -1. $x can be a pure number</td> 436: <td valign="top"> </td> 437: </tr> 438: 439: <tr> 440: <td valign="top">erf(x), erfc(x)</td> 441: <td valign="top">&erf($x), &erfc($x)</td> 442: <td valign="top">Error function.  erf = 2/sqrt(pi) integral (0,x) et-sq and erfx(x) = 1.0 - erf(x).  $x can be a pure number</td> 443: <td valign="top"> </td> 444: </tr> 445: 446: <tr> 447: <td valign="top">ceil(x), floor(x)</td> 448: <td valign="top">&ceil($x), &floor($x)</td> 449: <td valign="top">Ceil function returns an integer rounded up whereas 450: floor function returns and integer rounded down. If x is an integer than 451: it returns the value of the integer. $x can be a pure number</td> 452: <td valign="top"> </td> 453: </tr> 454: 455: <tr> 456: <td valign="top">min(...), max(...)</td> 457: <td valign="top">&min(...), &max(...)</td> 458: <td valign="top">Returns the minimum/ maximum value of a list of 459: arguments if the arguments are numbers. If the arguments are strings then 460: it returns a string sorted according to the ASCII codes</td> 461: <td valign="top"> </td> 462: </tr> 463: 464: <tr> 465: <td valign="top">factorial(n)</td> 466: <td valign="top">&factorial($n)</td> 467: <td valign="top">Argument (n) must be an integer else it will round 468: down. The largest value for n is 170. $n can be a pure number</td> 469: <td valign="top"> </td> 470: </tr> 471: 472: <tr> 473: <td valign="top">N%M</td> 474: <td valign="top">$N%$M</td> 475: 476: <td valign="top">N and M are integers and returns the remainder (in 477: integer) of N/M. $N and $M can be pure numbers</td> 478: <td valign="top"> </td> 479: </tr> 480: 481: <tr> 482: <td valign="top">sinh(x), cosh(x), tanh(x)</td> 483: <td valign="top">&sinh($x), &cosh($x), &tanh($x)</td> 484: <td valign="top">Hyperbolic functions. $x can be a pure number</td> 485: <td valign="top"> </td> 486: </tr> 487: 488: <tr> 489: <td valign="top">asinh(x), acosh(x), atanh(x)</td> 490: <td valign="top">&asinh($x), &acosh($x), &atanh($x)</td> 491: <td valign="top">Inverse hyperbolic functions. $x can be a pure number</td> 492: <td valign="top"> </td> 493: </tr> 494: 495: <tr> 496: <td valign="top">/DIS($x,"nn")</td> 497: <td valign="top">&format($x,"nn")</td> 498: <td valign="top">Display or format $x as nn where nn is nF or nE and n is an integer.</td> 499: <td valign="top"> The difference is obvious.</td> 500: </tr> 501: 502: <tr> 503: <td valign="top">roundto(x,n)</td> 504: <td valign="top">&roundto($x,$n)</td> 505: <td valign="top">Rounds a real number to n decimal points. $x and 506: $n can be pure numbers</td> 507: <td valign="top"> </td> 508: </tr> 509: 510: <tr> 511: <td valign="top">web("a","b","c") or web(a,b,c)</td> 512: <td valign="top">&web("a","b","c") or &web($a,$b,$c)</td> 513: <td valign="top">Returns either a, b or c depending on the output 514: medium. a is for plain ASCII, b for tex output and c for html output</td> 515: <td valign="top">&nbsp</td> 516: </tr> 517: 518: <tr> 519: <td valign="top">html("a") or html(a)</td> 520: <td valign="top">&html("a") or &html($a)</td> 521: <td valign="top">Output only if the output mode chosen is in html 522: format</td> 523: <td valign="top"> </td> 524: </tr> 525: 526: <tr> 527: <td valign="top">jn(m,x)</td> 528: <td valign="top">&j0($x), &j1($x), &jn($m,$x), &jv($y,$x)</td> 529: <td valign="top">Bessel functions of the first kind with orders 0, 530: 1 and m respectively. For jn(m,x), m must be an integer whereas for jv(y,x), 531: y is real. $x can be a pure number. $m must be an integer and can be a 532: pure integer number. $y can be a pure real number</td> 533: <td valign="top">In CAPA, j0, j1 and jn are contained in one function, 534: jn(m,x) where m takes the value of 0, 1 or 2. jv(y,x) is new to LON-CAPA.</td> 535: </tr> 536: 537: <tr> 538: <td valign="top">yn(m,x)</td> 539: <td valign="top">&y0($x), &y1($x), &yn($m,$x), &yv($y,$x)</td> 540: <td valign="top">Bessel functions of the second kind with orders 541: 0, 1 and m respectively. For yn(m,x), m must be an integer whereas for 542: yv(y,x), y is real. $x can be a pure number. $m must be an integer and 543: can be a pure integer number. $y can be a pure real number</td> 544: <td valign="top">In CAPA, y0, y1 and yn are contained in one function, 545: yn(m,x) where m takes the value of 0, 1 or 2. yv(y,x) is new to LON-CAPA.</td> 546: </tr> 547: 548: <tr> 549: <td valign="top">random(l,u,d)</td> 550: <td valign="top">&random($l,$u,$d)</td> 551: <td valign="top">Returns a uniformly distributed random number between 552: the lower bound, l and upper bound, u in steps of d. $l, $u and $d can 553: be pure numbers</td> 554: <td valign="top">In CAPA, all the 3 arguments must be of the same 555: type. However, now you can mix the type</td> 556: </tr> 557: 558: <tr> 559: <td valign="top">choose(i,...)</td> 560: <td valign="top">&choose($i,...)</td> 561: <td valign="top">Choose the ith item from the argument list. i must 562: be an integer greater than 0 and the value of i should not exceed the number 563: of items. $i can be a pure integer</td> 564: <td valign="top"> </td> 565: </tr> 566: 567: <tr> 568: <td valign="top">/MAP(seed;w,x,y,z;a,b,c,d)</td> 569: <td valign="top">Option 1 - &map($seed,[\$w,\$x,\$y,\$z],[$a,$b,$c,$d]) or 570: Option 2 - &map($seed,\@mappedArray,[$a,$b,$c,$d]) 571: Option 3 - @mappedArray = &map($seed,[$a,$b,$c,$d]) 572: Option 4 - ($w,$x,$y,$z) = &map($seed,\@a) 573: where $a='A' 574: $b='B' 575: $c='B' 576: $d='B' 577: $w, $x, $y, and $z are variables</td> 578: <td valign="top">Assigns to the variables $w, $x, $y and $z the values of the 579: $a, $b, $c and $c (A, B, C and D). The precise value for $w .. depends 580: on the seed. (Option 1 of calling map). 581: In option 2, the values of $a, $b .. are mapped into the array, @mappedArray. The two 582: options illustrate the different grouping. Options 3 and 4 give a consistent 583: way (with other functions) of mapping the items. For each option, the group can 584: be passed as an array, for example, [$a,$b,$c,$d] => \@a.</td> 585: <td valign="top">In CAPA, the arguments are divided into three groups separated 586: by a semicolon ;. In LON-CAPA, the separation is done by using [] brackets or 587: using an array @a. Note the backslash (\) before the arguments in the 588: second and third groups.</td> 589: </tr> 590: 591: 592: <tr> 593: <td valign="top">rmap(seed;a,b,c,d;w,x,y,z)</td> 594: <td valign="top">Option 1 - &rmap($seed,[\$w,\$x,\$y,\$z],[$a,$b,$c,$d]) or 595: Option 2 - &rmap($seed,\@rmappedArray,[$a,$b,$c,$d]) 596: Option 3 - @rmapped_array = &rmap($seed,[$a,$b,$c,$d]) 597: Option 4 - ($w,$x,$y,$z) = &rmap($seed,\@a) 598: where $a='A' 599: $b='B' 600: $c='B' 601: $d='B' 602: $w, $x, $y, and $z are variables</td> 603: <td valign="top">The rmap functions does the reverse action of map if the same seed 604: is used in calling map and rmap. </td> 605: <td valign="top">In CAPA, the arguments are divided into 606: three groups separated by a semicolon ;. In LON-CAPA, the 607: separation is done by using [] brackets (with create an 608: unamed vector reference) or using an array @a. Note the 609: backslash (\) before the arguments in the second and 610: third groups (Which cause Perl to send to variable 611: locations rather than the variable values, similar to a C 612: pointer).</td> 613: </tr> 614: 615: <tr> 616: <td valign="top">NOT IMPLEMENTED IN CAPA</td> 617: <td valign="top">$a=&xmlparse($string) </td> 618: <td valign="top">Runs the internal parser over the 619: argument parsing for display. Warning This will 620: result in different strings in different targets. Don't use 621: the results of this function as an answer.</td> 622: <td valign="top">New to LON-CAPA</td> 623: </tr> 624: 625: <tr> 626: <td valign="top">tex(a,b), tex("a","b")</td> 627: <td valign="top">&tex($a,$b), &tex("a","b")</td> 628: <td valign="top">Returns a if the output mode is in tex otherwise 629: returns b</td> 630: <td valign="top"> </td> 631: </tr> 632: 633: <tr> 634: <td valign="top">var_in_tex(a)</td> 635: <td valign="top">&var_in_tex($a)</td> 636: <td valign="top">Equivalent to tex("a","")</td> 637: <td valign="top"> </td> 638: </tr> 639: 640: <tr> 641: <td valign="top">to_string(x), to_string(x,y)</td> 642: <td valign="top">&to_string($x), &to_string($x,$y)</td> 643: <td valign="top">If x is an integer, returns a string. If x is real 644: than the output is a string with format given by y. For example, if x = 645: 12.3456, &to_string(x,".3F") = 12.345 and &to_string(x,".3E") = 646: 1.234E+01.</td> 647: <td valign="top"> </td> 648: </tr> 649: 650: <tr> 651: <td valign="top">capa_id(), class(), section(), set(), problem()</td> 652: <td valign="top">&class(), &section()</td> 653: <td valign="top">Returns null string, class descriptive name, section 654: number, set number and null string.</td> 655: <td valign="top">capa_id(), set() and problem() are no longer used. 656: Currently, they return a null value.</td> 657: </tr> 658: 659: <tr> 660: <td valign="top">name(), student_number()</td> 661: <td valign="top">&name(), &student_number()</td> 662: <td valign="top">Return the full name in the following format: lastname, 663: firstname initial. Student_number returns the student 9-alphanumeric string. 664: If undefined, the functions return null.</td> 665: <td valign="top"> </td> 666: </tr> 667: 668: <tr> 669: <td valign="top">open_date(), due_date(), answer_date()</td> 670: <td valign="top">&open_date(), &due_date(), &answer_date()</td> 671: <td valign="top">Problem open date, due date and answer date. The 672: time is also included in 24-hr format.</td> 673: <td valign="top">Output format for time is changed slightly. If pass 674: noon, it displays ..pm else it displays ..am. So 23:59 is displayed as 675: 11:59 pm.</td> 676: </tr> 677: 678: <tr> 679: <td valign="top">get_seed(), set_seed()</td> 680: <td valign="top">Not implemented</td> 681: <td valign="top">Get and set the random seed.</td> 682: <td valign="top"> </td> 683: </tr> 684: 685: <tr> 686: <td valign="top">sub_string(a,b,c)</td> 687: <td valign="top">&sub_string($a,$b,$c) perl  substr function. 688: However, note the differences</td> 689: <td valign="top">Retrieve a portion of string a starting from b and 690: length c. For example,  $a = "Welcome to LON-CAPA"; 691: $result=&sub_string($a,4,4); then $result is "come"</td> 692: <td valign="top">Perl intrinsic function, substr(string,b,c) starts 693: counting from 0 (as opposed to 1). In the example to the left, substr($a,4,4) 694: returns "ome ".</td> 695: </tr> 696: 697: <tr> 698: <td valign="top">array[xx]</td> 699: <td valign="top">@arrayname Array is intrinsic in perl. 700: To access a specific element use $arrayname[$n] where $n 701: is the $n+1 element since the array count starts from 0</td> 702: <td valign="top">"xx" can be a variable or a calculation.</td> 703: <td valign="top">In LON-CAPA, an array is defined by @arrayname. 704: It is not necessary to specify the dimension of the array. </td> 705: </tr> 706: 707: <tr> 708: <td valign="top">array_moments(B,A)</td> 709: <td valign="top">@B=&array_moments(@A)</td> 710: <td valign="top">Evaluates the moments of an array A and place the 711: result in array B[i] where i = 0 to 4. The contents of B are as follows: 712: B[0] = number of elements, B[1] = mean, B[2] = variance, B[3] = skewness 713: and B[4] = kurtosis.</td> 714: <td valign="top">In CAPA, the moments are passed as an array in the first argument whereas 715: in LON-CAPA, the array containing the moments are set equal to the function.</td> 716: </tr> 717: 718: <tr> 719: <td valign="top">array_max(Name), array_min(Name)</td> 720: <td valign="top">&min(@Name), &max(@Name)</td> 721: <td valign="top">In LON-CAPA to find the maximum value of an array, use 722: &max(@arrayname)  and to find the minimum value of an array, use 723: &min(@arrayname)</td> 724: <td valign="top">Combined with the min and max functions defined 725: earlier.</td> 726: </tr> 727: 728: <tr> 729: <td valign="top">init_array(Name)</td> 730: <td valign="top">undef @name</td> 731: <td valign="top">To destroy the contents of an array, use</td> 732: <td valign="top">Use perl intrinsic undef function.</td> 733: </tr> 734: <tr> 735: <td valign="top">random_normal (return_array,item_cnt,seed,av,std_dev)</td> 736: <td valign="top">@return_array=&random_normal ($item_cnt,$seed,$av,$std_dev)</td> 737: <td valign="top">Generate $item_cnt deviates of normal distribution of average $av and 738: standard deviation $std_dev. The distribution is generated from seed $seed</td> 739: <td valign="top">In CAPA the results are passed as the first argument whereas in LON-CAPA 740: the results are set equal to the function.</td> 741: </tr> 742: <tr> 743: <td valign="top">random_beta (return_array,item_cnt,seed,aa,bb)</td> 744: <td valign="top">@return_array=&random_beta ($item_cnt,$seed,$aa,$bb) 745: NOTE: Both $aa and $bb MUST be greater than 1.0E-37.</td> 746: <td valign="top">Generate $item_cnt deviates of beta distribution. 747: The density of beta is: 748: X^($aa-1) *(1-X)^($bb-1) /B($aa,$bb) for 0<X<1.</td> 749: <td valign="top">In CAPA the results are passed as the first argument whereas in LON-CAPA 750: the results are set equal to the function.</td> 751: </tr> 752: <tr> 753: <td valign="top">random_gamma (return_array,item_cnt,seed,a,r)</td> 754: <td valign="top">@return_array=&random_gamma ($item_cnt,$seed,$a,$r) 755: NOTE: Both $a and $r MUST be positive.</td> 756: <td valign="top">Generate $item_cnt deviates of gamma distribution. 757: The density of gamma is: 758: ($a**$r)/gamma($r) * X**($r-1) * exp(-$a*X).</td> 759: <td valign="top">In CAPA the results are passed as the first argument whereas in LON-CAPA 760: the results are set equal to the function.</td> 761: </tr> 762: <tr> 763: <td valign="top">random_exponential (return_array,item_cnt,seed,av)</td> 764: <td valign="top">@return_array=&random_exponential ($item_cnt,$seed,$av) 765: NOTE: $av MUST be non-negative.</td> 766: <td valign="top">Generate $item_cnt deviates of exponential distribution. </td> 767: <td valign="top">In CAPA the results are passed as the first argument whereas in LON-CAPA 768: the results are set equal to the function.</td> 769: </tr> 770: <tr> 771: <td valign="top">random_poisson (return_array,item_cnt,seed,mu)</td> 772: <td valign="top">@return_array=&random_poisson ($item_cnt,$seed,$mu) 773: NOTE: $mu MUST be non-negative.</td> 774: <td valign="top">Generate $item_cnt deviates of poisson distribution. </td> 775: <td valign="top">In CAPA the results are passed as the first argument whereas in LON-CAPA 776: the results are set equal to the function.</td> 777: </tr> 778: <tr> 779: <td valign="top">random_chi (return_array,item_cnt,seed,df)</td> 780: <td valign="top">@return_array=&random_chi ($item_cnt,$seed,$df) 781: NOTE: $df MUST be positive.</td> 782: <td valign="top">Generate $item_cnt deviates of chi_square distribution with $df 783: degrees of freedom. </td> 784: <td valign="top">In CAPA the results are passed as the first argument whereas in LON-CAPA 785: the results are set equal to the function.</td> 786: </tr> 787: <tr> 788: <td valign="top">random_noncentral_chi (return_array,item_cnt,seed,df,nonc)</td> 789: <td valign="top">@return_array=&random_noncentral_chi ($item_cnt,$seed,$df,$nonc) 790: NOTE: $df MUST be at least 1 and $nonc MUST be non-negative.</td> 791: <td valign="top">Generate $item_cnt deviates of noncentral_chi_square 792: distribution with $df 793: degrees of freedom and noncentrality parameter $nonc. </td> 794: <td valign="top">In CAPA the results are passed as the first argument whereas in LON-CAPA 795: the results are set equal to the function.</td> 796: </tr> 797: <tr> 798: <td valign="top">NOT IMPLEMENTED IN CAPA</td> 799: <td valign="top">@return_array=&random_f ($item_cnt,$seed,$dfn,$dfd) 800: NOTE: Both $dfn and $dfd MUST be positive.</td> 801: <td valign="top">Generate $item_cnt deviates of F (variance ratio) distribution with 802: degrees of freedom $dfn (numerator) and $dfd (denominator). </td> 803: <td valign="top">New to LON-CAPA</td> 804: </tr> 805: <tr> 806: <td valign="top">NOT IMPLEMENTED IN CAPA</td> 807: <td valign="top">@return_array=&random_noncentral_f ($item_cnt,$seed,$dfn,$dfd,$nonc) 808: NOTE: $dfn must be at least 1, $dfd MUST be positive, and $nonc must 809: be non-negative.</td> 810: <td valign="top">Generate $item_cnt deviates of noncentral F (variance ratio) 811: distribution with degrees of freedom $dfn (numerator) and $dfd (denominator). 812: $nonc is the noncentrality parameter. </td> 813: <td valign="top">New to LON-CAPA</td> 814: </tr> 815: <tr> 816: <td valign="top">NOT DOCUMENTED IN CAPA</td> 817: <td valign="top">@return_array=&random_multivariate_normal ($item_cnt,$seed,\@mean,\@covar) 818: NOTE: @mean should be of length p array of real numbers. @covar should be a length 819: p array of references to length p arrays of real numbers (i.e. a p by p matrix.</td> 820: <td valign="top">Generate $item_cnt deviates of multivariate_normal distribution with 821: mean vector @mean and variance-covariance matrix. </td> 822: <td valign="top">Note the backslash before the @mean and @covar arrays.</td> 823: </tr> 824: <tr> 825: <td valign="top">NOT IMPLEMENTED IN CAPA</td> 826: <td valign="top">@return_array=&random_multinomial ($item_cnt,$seed,@p) 827: NOTE: $item_cnt is rounded with int() and the result must be non-negative. 828: The number of elements in @p must be at least 2.</td> 829: <td valign="top">Returns single observation from multinomial distribution with 830: $item_cnt events classified into as many categories as the length of @p. 831: The probability of an event being classified into category i is given by 832: ith element of @p. The observation is an array with length equal to @p, so 833: when called in a scalar context it returns the length of @p. The sum of the 834: elements of the obervation is equal to $item_cnt.</td> 835: <td valign="top">New to LON-CAPA</td> 836: </tr> 837: <tr> 838: <td valign="top">NOT IMPLEMENTED IN CAPA</td> 839: <td valign="top">@return_array=&random_permutation ($item_cnt,@array) </td> 840: <td valign="top">Returns @array randomly permuted.</td> 841: <td valign="top">New to LON-CAPA</td> 842: </tr> 843: <tr> 844: <td valign="top">NOT IMPLEMENTED IN CAPA</td> 845: <td valign="top">@return_array=&random_uniform ($item_cnt,$seed,$low,$high) 846: NOTE: $low must be less than or equal to $high.</td> 847: <td valign="top">Generate $item_cnt deviates from a uniform distribution. </td> 848: <td valign="top">New to LON-CAPA</td> 849: </tr> 850: <tr> 851: <td valign="top">NOT IMPLEMENTED IN CAPA</td> 852: <td valign="top">@return_array=&random_uniform_integer ($item_cnt,$seed,$low,$high) 853: NOTE: $low and $high are both passed through int(). 854: $low must be less than or equal to $high.</td> 855: <td valign="top">Generate $item_cnt deviates from a uniform distribution in integers. </td> 856: <td valign="top">New to LON-CAPA</td> 857: </tr> 858: <tr> 859: <td valign="top">NOT IMPLEMENTED IN CAPA</td> 860: <td valign="top">@return_array=&random_binomial ($item_cnt,$seed,$nt,$p) 861: NOTE: $nt is rounded using int() and the result must be non-negative. 862: $p must be between 0 and 1 inclusive.</td> 863: <td valign="top">Generate $item_cnt deviates from the binomial distribution with 864: $nt trials and the probabilty of an event in each trial is $p. </td> 865: <td valign="top">New to LON-CAPA</td> 866: </tr> 867: <tr> 868: <td valign="top">NOT IMPLEMENTED IN CAPA</td> 869: <td valign="top">@return_array=&random_negative_binomial ($item_cnt,$seed,$ne,$p) 870: NOTE: $ne is rounded using int() and the result must be positive. 871: $p must be between 0 and 1 exclusive.</td> 872: <td valign="top">Generate an array of $item_cnt outcomes generated from 873: negative binomial distribution with 874: $ne events and the probabilty of an event in each trial is $p. </td> 875: <td valign="top">New to LON-CAPA</td> 876: </tr> 877: </table> 878:  879: 880: <h2><script> Variables</h2> 881: <ul> 882: <li> 883: $external::target - set to the current target the xml parser 884: is parsing for 885: </li> 886: <li> 887: $external::part - set to the id of the current problem 888: <part>; zero if there are now <part> 889: </li> 890: <li> 891: $external::gradestatus - set to the value of the current 892: resource.partid.solved value 893: </li> 894: <li> 895: $external::datestatus - set to the current status of the clock 896: either CLOSED, CAN_ANSWER, CANNOT_ANSWER, or SHOW_ANSWER 897: </li> 898: <li> 899: $external::randomseed - set to the number that was used to 900: seed the random number generator 901: </li> 902: <li>$pi - set to PI </li> 903: <li>$rad2deg - converts radians to degrees </li> 904: <li>$deg2rad - converts degrees to radians </li> 905: </ul> 906: 907: <hr> 908: <address><a href="mailto:albertel@marvin.lite.msu.edu">Guy Albertelli</a></address> 909:  910:  911: Last modified: Thu Mar 28 17:59:42 EST 2002 912:  913: </body> 914: </html>