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add description for format and correct entry for random_multivariate

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: </ul> 126: <li> 127: <a name="foil">Foil Structure Tags</a> 128: 129: All tags that implement a foil structure have an optional 130: arg of max that controls the maximum number of total 131: foils to show. 132: 133: <ul> 134: <li> 135: <foilgroup> required, must be the tag that 136: surrounds all foil definitions 137: </li> 138: <li> 139: <foil> required, all data inside is a possible foil 140: </li> 141: <li> 142: <conceptgroup> optional, surrounds a 143: collection of <foil>, when a problem is displayed 144: only one of the contained <foil>is selected for 145: display. It receives one required argument 146: concept. 147: </li> 148: </ul> 149: </li> 150: <li> 151: Hint structure 152: 153: All of these tags must appear inside a <*response> tag. 154: 155: <ul> 156: <li> 157: <hintgroup> Tag that surrounds all of a hint. 158: </li> 159: <li> 160: <hintpart> required, Tag to implement 161: conditional hints. It has a required argument 162: on. When a <*hint> tag named the same as the 163: value the on attribute evaluates to be correct the 164: <hintpart> will show. If no other <hintpart> 165: are to show then all hintparts with a on of 166: "default" will show 167: </li> 168: <li> 169: <numericalhint> has all the arguments that 170: <numericalresponse>, does and the required attribute 171: name which should be set to the value of which 172: <hintpart> will be shown. 173: </li> 174: </ul> 175: </li> 176: <li> 177: Input Tags 178: 179: This group of tags implement a mechanism for getting data 180: for students, they will usually be used by a 181: <*response>. 182: 183: <ul> 184: <li> 185: <textarea> creates a Large text input box, If 186: data appears between the start and end tags, the data will 187: appear i the textarea if the student has not yet made a 188: submission. Additionally it takes two arguments rows 189: and cols which control the height and width of the 190: area respectively. It defaults to 10 and 80. 191: </li> 192: <li> 193: <textline> creates a single line of input 194: element, it accepts 1 argument size which controls 195: the width on the textline, it defaults to 20. 196: </li> 197: </ul> 198: </li> 199: <li> 200: Output Tags 201: 202: This group of tags generate useful pieces of output. 203: 204: <ul> 205: <li> 206: <displayduedate> this will insert the current 207: duedate if one is set into the document. It is generated 208: to be inside a table of 1x1 elements 209: </li> 210: <li> 211: <displaytitle> this will insert the title of 212: the problem from the metadata of the problem 213: </li> 214: <li> 215: <window> the text in between is put in a 216: popup javascript window 217: </li> 218: </ul> 219: </li> 220: <li> 221: Scripting 222: 223: These tags allow the document to behave programatically 224: 225: <ul> 226: <li> 227: <display> the intervening perl script is 228: evaluated in the safe space and the return value of the 229: script replaces the entire tag 230: </li> 231: <li> 232: <import> causes the parse to read in the file 233: named in the body of the tag and parse it as if the entire 234: text of the file had existed at location of the tag 235: </li> 236: <li> 237: <parserlib> the enclosed filename contains 238: definitions for new tags 239: </li> 240: <li> 241: <script> if the argument type is set 242: to "loncapa/perl" the enclosed data is a perl script which 243: is evaluated inside the perl Safe space. The return value 244: of the script is ignored. 245: </li> 246: <li> 247: <scriptlib> the enclosed filename contains 248: perl code to run in the safe space 249: </li> 250: <li> 251: <block> has a required argument 252: condition that is evaluated, it the condition is 253: true everything inside the tag is evaluated, if it is false 254: everything inside the block tag is skipped 255: </li> 256: <li> 257: <notsolved> everything inside the tag is 258: skipped if the problem is "solved" 259: </li> 260: <li> 261: <postanswerdate> everything inside the tag is 262: skipped if the problem is before the answer date 263: </li> 264: <li> 265: <preduedate> everything inside the tag is 266: skipped if the problem is after the due date 267: </li> 268: <li> 269: <randomlist> the enclosed tags are parsed in 270: a stable random order 271: </li> 272: <li> 273: <solved> everything inside the tag is 274: skipped if the problem is "not solved" 275: </li> 276: <li> 277: <while> implements a while loop, required 278: argument condition is a perl scriptlet that when 279: evaluated results in a true or false value, on true the 280: entirety of the text between the whiles is parsed. The 281: condition is tested again, etc. If false it goes to the 282: next node in the parse. 283: </li> 284: </ul> 285: </li> 286: <li> 287: Structure Tags 288: 289: These tags give the problem a structure and take care of the 290: recording of data and giving the student messages. 291: 292: <ul> 293: <li> 294: <problem> must be the first tag in the file, 295: this tag sets up the header of the webpage and generates 296: the submit buttons, it also handles due dates properly 297: </li> 298: <li> 299: <part> must be below <problem> if it is 300: going to be used. It does many of the same tasks as 301: <problem> but allows multiple separate problems to 302: exist in a single file. 303: </li> 304: <li> 305: <startouttext><endouttext> these 306: tags are somewhat special, they must have no internal text 307: and occur in pairs. Their use is to mark up the problem so 308: the web editor knows what sections should be edited in a 309: plain text block on the web. 310: </li> 311: </ul> 312: </li> 313: </ul> 314: <h2><script> Functions</h2> 315: 316: A list of functions that have been written that are available in 317: the Safe space scripting environment inside a problem. 318: 319: <ul> 320: <li>sin(x), cos(x), tan(x)</li> 321: <li>asin(x), acos(x), atan(x), atan2(y,x)</li> 322: <li>log(x), log10(x)</li> 323: <li>exp(), pow(x,y), sqrt(x)</li> 324: <li>abs(x), sgn(x)</li> 325: <li>erf(x), erfc(x)</li> 326: <li>ceil(x), floor(x)</li> 327: <li>min(...), max(...)</li> 328: <li>factorial(n)</li> 329: <li>N%M</li> 330: <li>sinh(x), cosh(x), tanh(x)</li> 331: <li>asinh(x), acosh(x), atanh(x)</li> 332: <li>roundto(x,n)</li> 333: <li>web("a","b","c") or web(a,b,c)</li> 334: <li>html("a") or html(a)</li> 335: <li>j0(x), j1(x), jn(n,x), jv(y,x)</li> 336: <li>y0(x), y1(x), yn(n,x), yv(y,x)</li> 337: <li>random</li> 338: <li>choose</li> 339: <li>tex("a","b") or tex(a,b)</li> 340: <li>var_in_tex(a)</li> 341: <li>to_string(x), to_string(x,y)</li> 342: <li>class(), section()</li> 343: <li>name(), student_number()</li> 344: <li>open_date(), due_date(), answer_date()</li> 345: <li>sub_string()</li> 346: <li>array_moments(array)</li> 347: <li>format(x,y)</li> 348: <li>map(...)</li> 349: <li>caparesponse_check</li> 350: <li>caparesponse_check_list</li> 351: </ul> 352:  356: 357: Detailed descriptions of each function and comparison with CAPA. 358: 359: 360: <table border=1> 361: <tr> 362: <td valign="top">CAPA Functions</b</td> 363: <td valign="top">LON-CAPA</b</td> 364: <td valign="top">Descriptions</b</td> 365: <td valign="top">Differences (if any)</b</td> 366: </tr> 367: 368: <tr> 369: <td valign="top">sin(x), cos(x), tan(x)</td> 370: <td valign="top">&sin($x), &cos($x), &tan($x)</td> 371: <td valign="top">Trigonometric functions where x is in radians. $x 372: can be a pure number, i.e., you can call &sin(3.1415)</td> 373: <td valign="top">&nbsp</td> 374: </tr> 375: 376: <tr> 377: <td valign="top">asin(x), acos(x), atan(x), atan2(y,x)</td> 378: <td valign="top">&asin($x), &acos($x), &atan($x), &atan2($y,$x)</td> 379: <td valign="top">Inverse trigonometric functions. Return value is 380: in radians. For asin and acos the value of x must be between -1 and 1. 381: The atan2 returns a value between -pi and pi the sign of which is determined 382: by y. $x and $y can be pure numbers</td> 383: <td valign="top"> </td> 384: </tr> 385: 386: <tr> 387: <td valign="top">log(x), log10(x)</td> 388: <td valign="top">&log($x), &log10($x)</td> 389: <td valign="top">Natural and base-10 logarithm. $x can be a pure number</td> 390: <td valign="top"> </td> 391: </tr> 392: 393: <tr> 394: <td valign="top">exp(x), pow(x,y), sqrt(x)</td> 395: <td valign="top">&exp($x), &pow($x,$y), &sqrt($x)</td> 396: <td valign="top">Exponential, power and square root, i.e.,ex, xy and /x. $x and $y can be pure numbers</td> 397: 398: <td valign="top"> </td> 399: </tr> 400: 401: <tr> 402: <td valign="top">abs(x), sgn(x)</td> 403: <td valign="top">&abs($x), &sgn($x)</td> 404: <td valign="top">Abs takes the absolute value of x while sgn(x) returns 405: 1, 0 or -1 depending on the value of x. For x>0, sgn(x) = 1, for x=0, sgn(x) 406: = 0 and for x<0, sgn(x) = -1. $x can be a pure number</td> 407: <td valign="top"> </td> 408: </tr> 409: 410: <tr> 411: <td valign="top">erf(x), erfc(x)</td> 412: <td valign="top">&erf($x), &erfc($x)</td> 413: <td valign="top">Error function.  erf = 2/sqrt(pi) integral (0,x) et-sq and erfx(x) = 1.0 - erf(x).  $x can be a pure number</td> 414: <td valign="top"> </td> 415: </tr> 416: 417: <tr> 418: <td valign="top">ceil(x), floor(x)</td> 419: <td valign="top">&ceil($x), &floor($x)</td> 420: <td valign="top">Ceil function returns an integer rounded up whereas 421: floor function returns and integer rounded down. If x is an integer than 422: it returns the value of the integer. $x can be a pure number</td> 423: <td valign="top"> </td> 424: </tr> 425: 426: <tr> 427: <td valign="top">min(...), max(...)</td> 428: <td valign="top">&min(...), &max(...)</td> 429: <td valign="top">Returns the minimum/ maximum value of a list of 430: arguments if the arguments are numbers. If the arguments are strings then 431: it returns a string sorted according to the ASCII codes</td> 432: <td valign="top"> </td> 433: </tr> 434: 435: <tr> 436: <td valign="top">factorial(n)</td> 437: <td valign="top">&factorial($n)</td> 438: <td valign="top">Argument (n) must be an integer else it will round 439: down. The largest value for n is 170. $n can be a pure number</td> 440: <td valign="top"> </td> 441: </tr> 442: 443: <tr> 444: <td valign="top">N%M</td> 445: <td valign="top">$N%$M</td> 446: 447: <td valign="top">N and M are integers and returns the remainder (in 448: integer) of N/M. $N and $M can be pure numbers</td> 449: <td valign="top"> </td> 450: </tr> 451: 452: <tr> 453: <td valign="top">sinh(x), cosh(x), tanh(x)</td> 454: <td valign="top">&sinh($x), &cosh($x), &tanh($x)</td> 455: <td valign="top">Hyperbolic functions. $x can be a pure number</td> 456: <td valign="top"> </td> 457: </tr> 458: 459: <tr> 460: <td valign="top">asinh(x), acosh(x), atanh(x)</td> 461: <td valign="top">&asinh($x), &acosh($x), &atanh($x)</td> 462: <td valign="top">Inverse hyperbolic functions. $x can be a pure number</td> 463: <td valign="top"> </td> 464: </tr> 465: 466: <tr> 467: <td valign="top">/DIS($x,"nn")</td> 468: <td valign="top">&format($x,"nn")</td> 469: <td valign="top">Display or format $x as nn where nn is nF or nE and n is an integer.</td> 470: <td valign="top"> The difference is obvious.</td> 471: </tr> 472: 473: <tr> 474: <td valign="top">roundto(x,n)</td> 475: <td valign="top">&roundto($x,$n)</td> 476: <td valign="top">Rounds a real number to n decimal points. $x and 477: $n can be pure numbers</td> 478: <td valign="top"> </td> 479: </tr> 480: 481: <tr> 482: <td valign="top">web("a","b","c") or web(a,b,c)</td> 483: <td valign="top">&web("a","b","c") or &web($a,$b,$c)</td> 484: <td valign="top">Returns either a, b or c depending on the output 485: medium. a is for plain ASCII, b for tex output and c for html output</td> 486: <td valign="top">&nbsp</td> 487: </tr> 488: 489: <tr> 490: <td valign="top">html("a") or html(a)</td> 491: <td valign="top">&html("a") or &html($a)</td> 492: <td valign="top">Output only if the output mode chosen is in html 493: format</td> 494: <td valign="top"> </td> 495: </tr> 496: 497: <tr> 498: <td valign="top">jn(m,x)</td> 499: <td valign="top">&j0($x), &j1($x), &jn($m,$x), &jv($y,$x)</td> 500: <td valign="top">Bessel functions of the first kind with orders 0, 501: 1 and m respectively. For jn(m,x), m must be an integer whereas for jv(y,x), 502: y is real. $x can be a pure number. $m must be an integer and can be a 503: pure integer number. $y can be a pure real number</td> 504: <td valign="top">In CAPA, j0, j1 and jn are contained in one function, 505: jn(m,x) where m takes the value of 0, 1 or 2. jv(y,x) is new to LON-CAPA.</td> 506: </tr> 507: 508: <tr> 509: <td valign="top">yn(m,x)</td> 510: <td valign="top">&y0($x), &y1($x), &yn($m,$x), &yv($y,$x)</td> 511: <td valign="top">Bessel functions of the second kind with orders 512: 0, 1 and m respectively. For yn(m,x), m must be an integer whereas for 513: yv(y,x), y is real. $x can be a pure number. $m must be an integer and 514: can be a pure integer number. $y can be a pure real number</td> 515: <td valign="top">In CAPA, y0, y1 and yn are contained in one function, 516: yn(m,x) where m takes the value of 0, 1 or 2. yv(y,x) is new to LON-CAPA.</td> 517: </tr> 518: 519: <tr> 520: <td valign="top">random(l,u,d)</td> 521: <td valign="top">&random($l,$u,$d)</td> 522: <td valign="top">Returns a uniformly distributed random number between 523: the lower bound, l and upper bound, u in steps of d. $l, $u and $d can 524: be pure numbers</td> 525: <td valign="top">In CAPA, all the 3 arguments must be of the same 526: type. However, now you can mix the type</td> 527: </tr> 528: 529: <tr> 530: <td valign="top">choose(i,...)</td> 531: <td valign="top">&choose($i,...)</td> 532: <td valign="top">Choose the ith item from the argument list. i must 533: be an integer greater than 0 and the value of i should not exceed the number 534: of items. $i can be a pure integer</td> 535: <td valign="top"> </td> 536: </tr> 537: 538: <tr> 539: <td valign="top">map(seed;a,b,c,d;w,x,y,z)</td> 540: <td valign="top">Option 1 - &map($seed,[\$w,\$x,\$y,\$z],[$a,$b,$c,$d]) or 541: Option 2 - &map($seed,\@mappedArray,[$a,$b,$c,$d]) 542: Option 3 - @mappedArray = &map($seed,[$a,$b,$c,$d]) 543: Option 4 - ($w,$x,$y,$z) = &map($seed,\@a) 544: where $a='A' 545: $b='B' 546: $c='B' 547: $d='B' 548: $w, $x, $y, and $z are variables</td> 549: <td valign="top">Assigns to the variables $w, $x, $y and $z the values of the 550: $a, $b, $c and $c (A, B, C and D). The precise value for $w .. depends 551: on the seed. (Option 1 of calling map). 552: In option 2, the values of $a, $b .. are mapped into the array, @mappedArray. The two 553: options illustrate the different grouping. Options 3 and 4 give a consistent 554: way (with other functions) of mapping the items. For each option, the group can 555: be passed as an array, for example, [$a,$b,$c,$d] => \@a.</td> 556: <td valign="top">In CAPA, the arguments are divided into three groups separated 557: by a semicolon ;. In LON-CAPA, the separation is done by using [] brackets or 558: using an array @a. Note the backslash (\) before the arguments in the 559: second and third groups.</td> 560: </tr> 561: 562: 563: <tr> 564: <td valign="top">rmap(seed;a,b,c,d;w,x,y,z)</td> 565: <td valign="top">Option 1 - &rmap($seed,[\$w,\$x,\$y,\$z],[$a,$b,$c,$d]) or 566: Option 2 - &rmap($seed,\@rmappedArray,[$a,$b,$c,$d]) 567: Option 3 - @rmapped_array = &rmap($seed,[$a,$b,$c,$d]) 568: Option 4 - ($w,$x,$y,$z) = &rmap($seed,\@a) 569: where $a='A' 570: $b='B' 571: $c='B' 572: $d='B' 573: $w, $x, $y, and $z are variables</td> 574: <td valign="top">The rmap functions does the reverse action of map if the same seed 575: is used in calling map and rmap. </td> 576: <td valign="top">In CAPA, the arguments are divided into three groups separated 577: by a semicolon ;. In LON-CAPA, the separation is done by using [] brackets or 578: using an array @a. Note the backslash (\) before the arguments in the 579: second and third groups.</td> 580: </tr> 581: 582: <tr> 583: <td valign="top">NOT IMPLEMENTED IN CAPA</td> 584: <td valign="top">$a=&xmlparse($string) </td> 585: <td valign="top">Runs the internal parser over the 586: argument parsing for display. Warning This will 587: result in different strings in different targets. Don't use 588: the results of this function as an answer.</td> 589: <td valign="top">New to LON-CAPA</td> 590: </tr> 591: 592: <tr> 593: <td valign="top">tex(a,b), tex("a","b")</td> 594: <td valign="top">&tex($a,$b), &tex("a","b")</td> 595: <td valign="top">Returns a if the output mode is in tex otherwise 596: returns b</td> 597: <td valign="top"> </td> 598: </tr> 599: 600: <tr> 601: <td valign="top">var_in_tex(a)</td> 602: <td valign="top">&var_in_tex($a)</td> 603: <td valign="top">Equivalent to tex("a","")</td> 604: <td valign="top"> </td> 605: </tr> 606: 607: <tr> 608: <td valign="top">to_string(x), to_string(x,y)</td> 609: <td valign="top">&to_string($x), &to_string($x,$y)</td> 610: <td valign="top">If x is an integer, returns a string. If x is real 611: than the output is a string with format given by y. For example, if x = 612: 12.3456, &to_string(x,".3F") = 12.345 and &to_string(x,".3E") = 613: 1.234E+01.</td> 614: <td valign="top"> </td> 615: </tr> 616: 617: <tr> 618: <td valign="top">capa_id(), class(), section(), set(), problem()</td> 619: <td valign="top">&class(), &section()</td> 620: <td valign="top">Returns null string, class descriptive name, section 621: number, set number and null string.</td> 622: <td valign="top">capa_id(), set() and problem() are no longer used. 623: Currently, they return a null value.</td> 624: </tr> 625: 626: <tr> 627: <td valign="top">name(), student_number()</td> 628: <td valign="top">&name(), &student_number()</td> 629: <td valign="top">Return the full name in the following format: lastname, 630: firstname initial. Student_number returns the student 9-alphanumeric string. 631: If undefined, the functions return null.</td> 632: <td valign="top"> </td> 633: </tr> 634: 635: <tr> 636: <td valign="top">open_date(), due_date(), answer_date()</td> 637: <td valign="top">&open_date(), &due_date(), &answer_date()</td> 638: <td valign="top">Problem open date, due date and answer date. The 639: time is also included in 24-hr format.</td> 640: <td valign="top">Output format for time is changed slightly. If pass 641: noon, it displays ..pm else it displays ..am. So 23:59 is displayed as 642: 11:59 pm.</td> 643: </tr> 644: 645: <tr> 646: <td valign="top">get_seed(), set_seed()</td> 647: <td valign="top">Not implemented</td> 648: <td valign="top">Get and set the random seed.</td> 649: <td valign="top"> </td> 650: </tr> 651: 652: <tr> 653: <td valign="top">sub_string(a,b,c)</td> 654: <td valign="top">&sub_string($a,$b,$c) perl  substr function. 655: However, note the differences</td> 656: <td valign="top">Retrieve a portion of string a starting from b and 657: length c. For example,  $a = "Welcome to LON-CAPA"; 658: $result=&sub_string($a,4,4); then $result is "come"</td> 659: <td valign="top">Perl intrinsic function, substr(string,b,c) starts 660: counting from 0 (as opposed to 1). In the example to the left, substr($a,4,4) 661: returns "ome ".</td> 662: </tr> 663: 664: <tr> 665: <td valign="top">array[xx]</td> 666: <td valign="top">@arrayname Array is intrinsic in perl. 667: To access a specific element use $arrayname[$n] where $n 668: is the $n+1 element since the array count starts from 0</td> 669: <td valign="top">"xx" can be a variable or a calculation.</td> 670: <td valign="top">In LON-CAPA, an array is defined by @arrayname. 671: It is not necessary to specify the dimension of the array. </td> 672: </tr> 673: 674: <tr> 675: <td valign="top">array_moments(B,A)</td> 676: <td valign="top">@B=&array_moments(@A)</td> 677: <td valign="top">Evaluates the moments of an array A and place the 678: result in array B[i] where i = 0 to 4. The contents of B are as follows: 679: B[0] = number of elements, B[1] = mean, B[2] = variance, B[3] = skewness 680: and B[4] = kurtosis.</td> 681: <td valign="top">In CAPA, the moments are passed as an array in the first argument whereas 682: in LON-CAPA, the array containing the moments are set equal to the function.</td> 683: </tr> 684: 685: <tr> 686: <td valign="top">array_max(Name), array_min(Name)</td> 687: <td valign="top">&min(@Name), &max(@Name)</td> 688: <td valign="top">In LON-CAPA to find the maximum value of an array, use 689: &max(@arrayname)  and to find the minimum value of an array, use 690: &min(@arrayname)</td> 691: <td valign="top">Combined with the min and max functions defined 692: earlier.</td> 693: </tr> 694: 695: <tr> 696: <td valign="top">init_array(Name)</td> 697: <td valign="top">undef @name</td> 698: <td valign="top">To destroy the contents of an array, use</td> 699: <td valign="top">Use perl intrinsic undef function.</td> 700: </tr> 701: <tr> 702: <td valign="top">random_normal (return_array,item_cnt,seed,av,std_dev)</td> 703: <td valign="top">@return_array=&random_normal ($item_cnt,$seed,$av,$std_dev)</td> 704: <td valign="top">Generate $item_cnt deviates of normal distribution of average $av and 705: standard deviation $std_dev. The distribution is generated from seed $seed</td> 706: <td valign="top">In CAPA the results are passed as the first argument whereas in LON-CAPA 707: the results are set equal to the function.</td> 708: </tr> 709: <tr> 710: <td valign="top">random_beta (return_array,item_cnt,seed,aa,bb)</td> 711: <td valign="top">@return_array=&random_beta ($item_cnt,$seed,$aa,$bb) 712: NOTE: Both $aa and $bb MUST be greater than 1.0E-37.</td> 713: <td valign="top">Generate $item_cnt deviates of beta distribution. 714: The density of beta is: 715: X^($aa-1) *(1-X)^($bb-1) /B($aa,$bb) for 0<X<1.</td> 716: <td valign="top">In CAPA the results are passed as the first argument whereas in LON-CAPA 717: the results are set equal to the function.</td> 718: </tr> 719: <tr> 720: <td valign="top">random_gamma (return_array,item_cnt,seed,a,r)</td> 721: <td valign="top">@return_array=&random_gamma ($item_cnt,$seed,$a,$r) 722: NOTE: Both $a and $r MUST be positive.</td> 723: <td valign="top">Generate $item_cnt deviates of gamma distribution. 724: The density of gamma is: 725: ($a**$r)/gamma($r) * X**($r-1) * exp(-$a*X).</td> 726: <td valign="top">In CAPA the results are passed as the first argument whereas in LON-CAPA 727: the results are set equal to the function.</td> 728: </tr> 729: <tr> 730: <td valign="top">random_exponential (return_array,item_cnt,seed,av)</td> 731: <td valign="top">@return_array=&random_exponential ($item_cnt,$seed,$av) 732: NOTE: $av MUST be non-negative.</td> 733: <td valign="top">Generate $item_cnt deviates of exponential distribution. </td> 734: <td valign="top">In CAPA the results are passed as the first argument whereas in LON-CAPA 735: the results are set equal to the function.</td> 736: </tr> 737: <tr> 738: <td valign="top">random_poisson (return_array,item_cnt,seed,mu)</td> 739: <td valign="top">@return_array=&random_poisson ($item_cnt,$seed,$mu) 740: NOTE: $mu MUST be non-negative.</td> 741: <td valign="top">Generate $item_cnt deviates of poisson distribution. </td> 742: <td valign="top">In CAPA the results are passed as the first argument whereas in LON-CAPA 743: the results are set equal to the function.</td> 744: </tr> 745: <tr> 746: <td valign="top">random_chi (return_array,item_cnt,seed,df)</td> 747: <td valign="top">@return_array=&random_chi ($item_cnt,$seed,$df) 748: NOTE: $df MUST be positive.</td> 749: <td valign="top">Generate $item_cnt deviates of chi_square distribution with $df 750: degrees of freedom. </td> 751: <td valign="top">In CAPA the results are passed as the first argument whereas in LON-CAPA 752: the results are set equal to the function.</td> 753: </tr> 754: <tr> 755: <td valign="top">random_noncentral_chi (return_array,item_cnt,seed,df,nonc)</td> 756: <td valign="top">@return_array=&random_noncentral_chi ($item_cnt,$seed,$df,$nonc) 757: NOTE: $df MUST be at least 1 and $nonc MUST be non-negative.</td> 758: <td valign="top">Generate $item_cnt deviates of noncentral_chi_square 759: distribution with $df 760: degrees of freedom and noncentrality parameter $nonc. </td> 761: <td valign="top">In CAPA the results are passed as the first argument whereas in LON-CAPA 762: the results are set equal to the function.</td> 763: </tr> 764: <tr> 765: <td valign="top">NOT IMPLEMENTED IN CAPA</td> 766: <td valign="top">@return_array=&random_f ($item_cnt,$seed,$dfn,$dfd) 767: NOTE: Both $dfn and $dfd MUST be positive.</td> 768: <td valign="top">Generate $item_cnt deviates of F (variance ratio) distribution with 769: degrees of freedom $dfn (numerator) and $dfd (denominator). </td> 770: <td valign="top">New to LON-CAPA</td> 771: </tr> 772: <tr> 773: <td valign="top">NOT IMPLEMENTED IN CAPA</td> 774: <td valign="top">@return_array=&random_noncentral_f ($item_cnt,$seed,$dfn,$dfd,$nonc) 775: NOTE: $dfn must be at least 1, $dfd MUST be positive, and $nonc must 776: be non-negative.</td> 777: <td valign="top">Generate $item_cnt deviates of noncentral F (variance ratio) 778: distribution with degrees of freedom $dfn (numerator) and $dfd (denominator). 779: $nonc is the noncentrality parameter. </td> 780: <td valign="top">New to LON-CAPA</td> 781: </tr> 782: <tr> 783: <td valign="top">NOT DOCUMENTED IN CAPA</td> 784: <td valign="top">@return_array=&random_multivariate_normal ($item_cnt,$seed,\@mean,\@covar) 785: NOTE: @mean should be of length p array of real numbers. @covar should be a length 786: p array of references to length p arrays of real numbers (i.e. a p by p matrix.</td> 787: <td valign="top">Generate $item_cnt deviates of multivariate_normal distribution with 788: mean vector @mean and variance-covariance matrix. </td> 789: <td valign="top">Note the backslash before the @mean and @covar arrays.</td> 790: </tr> 791: <tr> 792: <td valign="top">NOT IMPLEMENTED IN CAPA</td> 793: <td valign="top">@return_array=&random_multinomial ($item_cnt,$seed,@p) 794: NOTE: $item_cnt is rounded with int() and the result must be non-negative. 795: The number of elements in @p must be at least 2.</td> 796: <td valign="top">Returns single observation from multinomial distribution with 797: $item_cnt events classified into as many categories as the length of @p. 798: The probability of an event being classified into category i is given by 799: ith element of @p. The observation is an array with length equal to @p, so 800: when called in a scalar context it returns the length of @p. The sum of the 801: elements of the obervation is equal to $item_cnt.</td> 802: <td valign="top">New to LON-CAPA</td> 803: </tr> 804: <tr> 805: <td valign="top">NOT IMPLEMENTED IN CAPA</td> 806: <td valign="top">@return_array=&random_permutation ($item_cnt,@array) </td> 807: <td valign="top">Returns @array randomly permuted.</td> 808: <td valign="top">New to LON-CAPA</td> 809: </tr> 810: <tr> 811: <td valign="top">NOT IMPLEMENTED IN CAPA</td> 812: <td valign="top">@return_array=&random_uniform ($item_cnt,$seed,$low,$high) 813: NOTE: $low must be less than or equal to $high.</td> 814: <td valign="top">Generate $item_cnt deviates from a uniform distribution. </td> 815: <td valign="top">New to LON-CAPA</td> 816: </tr> 817: <tr> 818: <td valign="top">NOT IMPLEMENTED IN CAPA</td> 819: <td valign="top">@return_array=&random_uniform_integer ($item_cnt,$seed,$low,$high) 820: NOTE: $low and $high are both passed through int(). 821: $low must be less than or equal to $high.</td> 822: <td valign="top">Generate $item_cnt deviates from a uniform distribution in integers. </td> 823: <td valign="top">New to LON-CAPA</td> 824: </tr> 825: <tr> 826: <td valign="top">NOT IMPLEMENTED IN CAPA</td> 827: <td valign="top">@return_array=&random_binomial ($item_cnt,$seed,$nt,$p) 828: NOTE: $nt is rounded using int() and the result must be non-negative. 829: $p must be between 0 and 1 inclusive.</td> 830: <td valign="top">Generate $item_cnt deviates from the binomial distribution with 831: $nt trials and the probabilty of an event in each trial is $p. </td> 832: <td valign="top">New to LON-CAPA</td> 833: </tr> 834: <tr> 835: <td valign="top">NOT IMPLEMENTED IN CAPA</td> 836: <td valign="top">@return_array=&random_negative_binomial ($item_cnt,$seed,$ne,$p) 837: NOTE: $ne is rounded using int() and the result must be positive. 838: $p must be between 0 and 1 exclusive.</td> 839: <td valign="top">Generate an array of $item_cnt outcomes generated from 840: negative binomial distribution with 841: $ne events and the probabilty of an event in each trial is $p. </td> 842: <td valign="top">New to LON-CAPA</td> 843: </tr> 844: </table> 845:  846: 847: <h2><script> Variables</h2> 848: <ul> 849: <li> 850: $external::target - set to the current target the xml parser 851: is parsing for 852: </li> 853: <li> 854: $external::part - set to the id of the current problem 855: <part>; zero if there are now <part> 856: </li> 857: <li> 858: $external::gradestatus - set to the value of the current 859: resource.partid.solved value 860: </li> 861: <li> 862: $external::datestatus - set to the current status of the clock 863: either CLOSED, CAN_ANSWER, CANNOT_ANSWER, or SHOW_ANSWER 864: </li> 865: <li> 866: $external::randomseed - set to the number that was used to 867: seed the random number generator 868: </li> 869: <li>$pi - set to PI </li> 870: <li>$rad2deg - converts radians to degrees </li> 871: <li>$deg2rad - converts degrees to radians </li> 872: </ul> 873: 874: <hr> 875: <address><a href="mailto:albertel@marvin.lite.msu.edu">Guy Albertelli</a></address> 876:  877:  878: Last modified: Fri Jul 13 12:10:52 EDT 2001 879:  880: </body> 881: </html>