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Tue Jun 12 21:05:31 2001 UTC (22 years, 11 months ago) by ng
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added documentations for the random functions.
LON-CAPA has 8 additional functions.

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, must be a perl list</li> 66: <li>type optional, CAPA style str args, cs/ci/mc</li> 67: <li>units optional, specifies unit of correct answer, CAPA style</li> 68: </ul> 69: </li> 70: <li> 71: <essayresponse> implements a ungraded large 72: text response, it need an internal <textarea> 73: for the response to go in. 74: </li> 75: <li> 76: <imageresponse> implements a image click 77: style image submission, uses the foil structure tags <a 78: href="#foil">below</a>. Additional tags that should appear 79: in a <foil> are: 80: <ul> 81: <li><image> required, the contained text 82: specifies a published graphical resource that is the 83: image used, should only appear once per foil</li> 84: <li><rectangle> required, the contained text 85: specifies a rectangular area that is correct, should 86: look like (1,2)-(3,4), at least 1 required</li> 87: <li><text> required, the contained text is 88: printed on top of the image.</li> 89: </ul> 90: </li> 91: <li> 92: <optionresponse> implements a "select from 93: these choices" style question, the choices are specified 94: by the instructor, it uses the foil structure tags <a 95: href="#foil">below</a> with this additional args: 96: <ul> 97: <li> 98: <foilgroup> is required to have 99: options which should be a perl list of possible 100: options for the student. 101: </li> 102: </ul> 103: </li> 104: <li> 105: <radiobuttonresponse> implements a true / false 106: style question with 1 correct answer.it uses the foil 107: structure tags <a href="#foil">below</a> but the 108: value of a <foil>can only be "true" or 109: "false" or "unused" 110: </li> 111: </ul> 112: <li> 113: <a name="foil">Foil Structure Tags</a> 114: 115: All tags that implement a foil structure have an optional 116: arg of max that controls the maximum number of total 117: foils to show. 118: 119: <ul> 120: <li> 121: <foilgroup> required, must be the tag that 122: surrounds all foil definitions 123: </li> 124: <li> 125: <foil> required, all data inside is a possible foil 126: </li> 127: <li> 128: <conceptgroup> optional, surrounds a 129: collection of <foil>, when a problem is displayed 130: only one of the contained <foil>is selected for 131: display. It receives one required argument 132: concept. 133: </li> 134: </ul> 135: </li> 136: <li> 137: Hint structure 138: 139: All of these tags must appear inside a <*response> tag. 140: 141: <ul> 142: <li> 143: <hintgroup> Tag that surrounds all of a hint. 144: </li> 145: <li> 146: <hintpart> required, Tag to implement 147: conditional hints. It has a required argument 148: on. When a <*hint> tag named the same as the 149: value the on attribute evaluates to be correct the 150: <hintpart> will show. If no other <hintpart> 151: are to show then all hintparts with a on of 152: "default" will show 153: </li> 154: <li> 155: <numericalhint> has all the arguments that 156: <numericalresponse>, does and the required attribute 157: name which should be set to the value of which 158: <hintpart> will be shown. 159: </li> 160: </ul> 161: </li> 162: <li> 163: Input Tags 164: 165: This group of tags implement a mechanism for getting data 166: for students, they will usually be used by a 167: <*response>. 168: 169: <ul> 170: <li> 171: <textarea> creates a Large text input box, If 172: data appears between the start and end tags, the data will 173: appear i the textarea if the student has not yet made a 174: submission. Additionally it takes two arguments rows 175: and cols which control the height and width of the 176: area respectively. It defaults to 10 and 80. 177: </li> 178: <li> 179: <textline> creates a single line of input 180: element, it accepts 1 argument size which controls 181: the width on the textline, it defaults to 20. 182: </li> 183: </ul> 184: </li> 185: <li> 186: Output Tags 187: 188: This group of tags generate useful pieces of output. 189: 190: <ul> 191: <li> 192: <displayduedate> this will insert the current 193: duedate if one is set into the document. It is generated 194: to be inside a table of 1x1 elements 195: </li> 196: <li> 197: <displaytitle> this will insert the title of 198: the problem from the metadata of the problem 199: </li> 200: <li> 201: <window> the text in between is put in a 202: popup javascript window 203: </li> 204: </ul> 205: </li> 206: <li> 207: Scripting 208: 209: These tags allow the document to behave programatically 210: 211: <ul> 212: <li> 213: <display> the intervening perl script is 214: evaluated in the safe space and the return value of the 215: script replaces the entire tag 216: </li> 217: <li> 218: <import> causes the parse to read in the file 219: named in the body of the tag and parse it as if the entire 220: text of the file had existed at location of the tag 221: </li> 222: <li> 223: <parserlib> the enclosed filename contains 224: definitions for new tags 225: </li> 226: <li> 227: <script> if the argument type is set 228: to "loncapa/perl" the enclosed data is a perl script which 229: is evaluated inside the perl Safe space. The return value 230: of the script is ignored. 231: </li> 232: <li> 233: <scriptlib> the enclosed filename contains 234: perl code to run in the safe space 235: </li> 236: <li> 237: <block> has a required argument 238: condition that is evaluated, it the condition is 239: true everything inside the tag is evaluated, if it is false 240: everything inside the block tag is skipped 241: </li> 242: <li> 243: <notsolved> everything inside the tag is 244: skipped if the problem is "solved" 245: </li> 246: <li> 247: <postanswerdate> everything inside the tag is 248: skipped if the problem is before the answer date 249: </li> 250: <li> 251: <preduedate> everything inside the tag is 252: skipped if the problem is after the due date 253: </li> 254: <li> 255: <randomlist> the enclosed tags are parsed in 256: a stable random order 257: </li> 258: <li> 259: <solved> everything inside the tag is 260: skipped if the problem is "not solved" 261: </li> 262: <li> 263: <while> implements a while loop, required 264: argument condition is a perl scriptlet that when 265: evaluated results in a true or false value, on true the 266: entirety of the text between the whiles is parsed. The 267: condition is tested again, etc. If false it goes to the 268: next node in the parse. 269: </li> 270: </ul> 271: </li> 272: <li> 273: Structure Tags 274: 275: These tags give the problem a structure and take care of the 276: recording of data and giving the student messages. 277: 278: <ul> 279: <li> 280: <problem> must be the first tag in the file, 281: this tag sets up the header of the webpage and generates 282: the submit buttons, it also handles due dates properly 283: </li> 284: <li> 285: <part> must be below <problem> if it is 286: going to be used. It does many of the same tasks as 287: <problem> but allows multiple separate problems to 288: exist in a single file. 289: </li> 290: <li> 291: <startouttext><endouttext> these 292: tags are somewhat special, they must have no internal text 293: and occur in pairs. Their use is to mark up the problem so 294: the web editor knows what sections should be edited in a 295: plain text block on the web. 296: </li> 297: </ul> 298: </li> 299: </ul> 300: <h2><script> Functions</h2> 301: 302: A list of functions that have been written that are available in 303: the Safe space scripting environment inside a problem. 304: 305: <ul> 306: <li>sin(x), cos(x), tan(x)</li> 307: <li>asin(x), acos(x), atan(x), atan2(y,x)</li> 308: <li>log(x), log10(x)</li> 309: <li>exp(), pow(x,y), sqrt(x)</li> 310: <li>abs(x), sgn(x)</li> 311: <li>erf(x), erfc(x)</li> 312: <li>ceil(x), floor(x)</li> 313: <li>min(...), max(...)</li> 314: <li>factorial(n)</li> 315: <li>N%M</li> 316: <li>sinh(x), cosh(x), tanh(x)</li> 317: <li>asinh(x), acosh(x), atanh(x)</li> 318: <li>roundto(x,n)</li> 319: <li>web("a","b","c") or web(a,b,c)</li> 320: <li>html("a") or html(a)</li> 321: <li>j0(x), j1(x), jn(n,x), jv(y,x)</li> 322: <li>y0(x), y1(x), yn(n,x), yv(y,x)</li> 323: <li>random</li> 324: <li>choose</li> 325: <li>tex("a","b") or tex(a,b)</li> 326: <li>var_in_tex(a)</li> 327: <li>to_string(x), to_string(x,y)</li> 328: <li>class(), section()</li> 329: <li>name(), student_number()</li> 330: <li>open_date(), due_date(), answer_date()</li> 331: <li>sub_string()</li> 332: <li>array_moments(array)</li> 333: <li>format(x,y)</li> 334: <li>map(...)</li> 335: <li>caparesponse_check</li> 336: <li>caparesponse_check_list</li> 337: </ul> 338:  342: 343: Detailed descriptions of each function and comparison with CAPA. 344: 345: 346: <table border=1> 347: <tr> 348: <td valign="top">CAPA Functions</b</td> 349: <td valign="top">LON-CAPA</b</td> 350: <td valign="top">Descriptions</b</td> 351: <td valign="top">Differences (if any)</b</td> 352: </tr> 353: 354: <tr> 355: <td valign="top">sin(x), cos(x), tan(x)</td> 356: <td valign="top">&sin($x), &cos($x), &tan($x)</td> 357: <td valign="top">Trigonometric functions where x is in radians. $x 358: can be a pure number, i.e., you can call &sin(3.1415)</td> 359: <td valign="top">&nbsp</td> 360: </tr> 361: 362: <tr> 363: <td valign="top">sin(x), cos(x), tan(x)</td> 364: <td valign="top">&sin($x), &cos($x), &tan($x)</td> 365: <td valign="top">Trigonometric functions where x is in radians. $x 366: can be a pure number, i.e., you can call &sin(3.1415)</td> 367: <td valign="top">&nbsp</td> 368: </tr> 369: 370: <tr> 371: <td valign="top">asin(x), acos(x), atan(x), atan2(y,x)</td> 372: <td valign="top">&asin($x), &acos($x), &atan($x), &atan2($y,$x)</td> 373: <td valign="top">Inverse trigonometric functions. Return value is 374: in radians. For asin and acos the value of x must be between -1 and 1. 375: The atan2 returns a value between -pi and pi the sign of which is determined 376: by y. $x and $y can be pure numbers</td> 377: <td valign="top"> </td> 378: </tr> 379: 380: <tr> 381: <td valign="top">log(x), log10(x)</td> 382: <td valign="top">&log($x), &log10($x)</td> 383: <td valign="top">Natural and base-10 logarithm. $x can be a pure number</td> 384: <td valign="top"> </td> 385: </tr> 386: 387: <tr> 388: <td valign="top">exp(x), pow(x,y), sqrt(x)</td> 389: <td valign="top">&exp($x), &pow($x,$y), &sqrt($x)</td> 390: <td valign="top">Exponential, power and square root, i.e.,ex, xy and /x. $x and $y can be pure numbers</td> 391: 392: <td valign="top"> </td> 393: </tr> 394: 395: <tr> 396: <td valign="top">abs(x), sgn(x)</td> 397: <td valign="top">&abs($x), &sgn($x)</td> 398: <td valign="top">Abs takes the absolute value of x while sgn(x) returns 399: 1, 0 or -1 depending on the value of x. For x>0, sgn(x) = 1, for x=0, sgn(x) 400: = 0 and for x<0, sgn(x) = -1. $x can be a pure number</td> 401: <td valign="top"> </td> 402: </tr> 403: 404: <tr> 405: <td valign="top">erf(x), erfc(x)</td> 406: <td valign="top">&erf($x), &erfc($x)</td> 407: <td valign="top">Error function.  erf = 2/sqrt(pi) integral (0,x) et-sq and erfx(x) = 1.0 - erf(x).  $x can be a pure number</td> 408: <td valign="top"> </td> 409: </tr> 410: 411: <tr> 412: <td valign="top">ceil(x), floor(x)</td> 413: <td valign="top">&ceil($x), &floor($x)</td> 414: <td valign="top">Ceil function returns an integer rounded up whereas 415: floor function returns and integer rounded down. If x is an integer than 416: it returns the value of the integer. $x can be a pure number</td> 417: <td valign="top"> </td> 418: </tr> 419: 420: <tr> 421: <td valign="top">min(...), max(...)</td> 422: <td valign="top">&min(...), &max(...)</td> 423: <td valign="top">Returns the minimum/ maximum value of a list of 424: arguments if the arguments are numbers. If the arguments are strings then 425: it returns a string sorted according to the ASCII codes</td> 426: <td valign="top"> </td> 427: </tr> 428: 429: <tr> 430: <td valign="top">factorial(n)</td> 431: <td valign="top">&factorial($n)</td> 432: <td valign="top">Argument (n) must be an integer else it will round 433: down. The largest value for n is 170. $n can be a pure number</td> 434: <td valign="top"> </td> 435: </tr> 436: 437: <tr> 438: <td valign="top">N%M</td> 439: <td valign="top">$N%$M</td> 440: 441: <td valign="top">N and M are integers and returns the remainder (in 442: integer) of N/M. $N and $M can be pure numbers</td> 443: <td valign="top"> </td> 444: </tr> 445: 446: <tr> 447: <td valign="top">sinh(x), cosh(x), tanh(x)</td> 448: <td valign="top">&sinh($x), &cosh($x), &tanh($x)</td> 449: <td valign="top">Hyperbolic functions. $x can be a pure number</td> 450: <td valign="top"> </td> 451: </tr> 452: 453: <tr> 454: <td valign="top">asinh(x), acosh(x), atanh(x)</td> 455: <td valign="top">&asinh($x), &acosh($x), &atanh($x)</td> 456: <td valign="top">Inverse hyperbolic functions. $x can be a pure number</td> 457: <td valign="top"> </td> 458: </tr> 459: 460: <tr> 461: <td valign="top">roundto(x,n)</td> 462: <td valign="top">&roundto($x,$n)</td> 463: <td valign="top">Rounds a real number to n decimal points. $x and 464: $n can be pure numbers</td> 465: <td valign="top"> </td> 466: </tr> 467: 468: <tr> 469: <td valign="top">web("a","b","c") or web(a,b,c)</td> 470: <td valign="top">&web("a","b","c") or &web($a,$b,$c)</td> 471: <td valign="top">Returns either a, b or c depending on the output 472: medium. a is for plain ASCII, b for tex output and c for html output</td> 473: <td valign="top">&nbsp</td> 474: </tr> 475: 476: <tr> 477: <td valign="top">html("a") or html(a)</td> 478: <td valign="top">&html("a") or &html($a)</td> 479: <td valign="top">Output only if the output mode chosen is in html 480: format</td> 481: <td valign="top"> </td> 482: </tr> 483: 484: <tr> 485: <td valign="top">jn(m,x)</td> 486: <td valign="top">&j0($x), &j1($x), &jn($m,$x), &jv($y,$x)</td> 487: <td valign="top">Bessel functions of the first kind with orders 0, 488: 1 and m respectively. For jn(m,x), m must be an integer whereas for jv(y,x), 489: y is real. $x can be a pure number. $m must be an integer and can be a 490: pure integer number. $y can be a pure real number</td> 491: <td valign="top">In CAPA, j0, j1 and jn are contained in one function, 492: jn(m,x) where m takes the value of 0, 1 or 2. jv(y,x) is new to LON-CAPA.</td> 493: </tr> 494: 495: <tr> 496: <td valign="top">yn(m,x)</td> 497: <td valign="top">&y0($x), &y1($x), &yn($m,$x), &yv($y,$x)</td> 498: <td valign="top">Bessel functions of the second kind with orders 499: 0, 1 and m respectively. For yn(m,x), m must be an integer whereas for 500: yv(y,x), y is real. $x can be a pure number. $m must be an integer and 501: can be a pure integer number. $y can be a pure real number</td> 502: <td valign="top">In CAPA, y0, y1 and yn are contained in one function, 503: yn(m,x) where m takes the value of 0, 1 or 2. yv(y,x) is new to LON-CAPA.</td> 504: </tr> 505: 506: <tr> 507: <td valign="top">random(l,u,d)</td> 508: <td valign="top">&random($l,$u,$d)</td> 509: <td valign="top">Returns a uniformly distributed random number between 510: the lower bound, l and upper bound, u in steps of d. $l, $u and $d can 511: be pure numbers</td> 512: <td valign="top">In CAPA, all the 3 arguments must be of the same 513: type. However, now you can mix the type</td> 514: </tr> 515: 516: <tr> 517: <td valign="top">choose(i,...)</td> 518: <td valign="top">&choose($i,...)</td> 519: <td valign="top">Choose the ith item from the argument list. i must 520: be an integer greater than 0 and the value of i should not exceed the number 521: of items. $i can be a pure integer</td> 522: <td valign="top"> </td> 523: </tr> 524: 525: <tr> 526: <td valign="top">tex(a,b), tex("a","b")</td> 527: <td valign="top">&tex($a,$b), &tex("a","b")</td> 528: <td valign="top">Returns a if the output mode is in tex otherwise 529: returns b</td> 530: <td valign="top"> </td> 531: </tr> 532: 533: <tr> 534: <td valign="top">var_in_tex(a)</td> 535: <td valign="top">&var_in_tex($a)</td> 536: <td valign="top">Equivalent to tex("a","")</td> 537: <td valign="top"> </td> 538: </tr> 539: 540: <tr> 541: <td valign="top">to_string(x), to_string(x,y)</td> 542: <td valign="top">&to_string($x), &to_string($x,$y)</td> 543: <td valign="top">If x is an integer, returns a string. If x is real 544: than the output is a string with format given by y. For example, if x = 545: 12.3456, &to_string(x,".3F") = 12.345 and &to_string(x,".3E") = 546: 1.234E+01.</td> 547: <td valign="top"> </td> 548: </tr> 549: 550: <tr> 551: <td valign="top">capa_id(), class(), section(), set(), problem()</td> 552: <td valign="top">&class(), &section()</td> 553: <td valign="top">Returns null string, class descriptive name, section 554: number, set number and null string.</td> 555: <td valign="top">capa_id(), set() and problem() are no longer used. 556: Currently, they return a null value.</td> 557: </tr> 558: 559: <tr> 560: <td valign="top">name(), student_number()</td> 561: <td valign="top">&name(), &student_number()</td> 562: <td valign="top">Return the full name in the following format: lastname, 563: firstname initial. Student_number returns the student 9-alphanumeric string. 564: If undefined, the functions return null.</td> 565: <td valign="top"> </td> 566: </tr> 567: 568: <tr> 569: <td valign="top">open_date(), due_date(), answer_date()</td> 570: <td valign="top">&open_date(), &due_date(), &answer_date()</td> 571: <td valign="top">Problem open date, due date and answer date. The 572: time is also included in 24-hr format.</td> 573: <td valign="top">Output format for time is changed slightly. If pass 574: noon, it displays ..pm else it displays ..am. So 23:59 is displayed as 575: 11:59 pm.</td> 576: </tr> 577: 578: <tr> 579: <td valign="top">get_seed(), set_seed()</td> 580: <td valign="top">Not implemented</td> 581: <td valign="top">Get and set the random seed.</td> 582: <td valign="top"> </td> 583: </tr> 584: 585: <tr> 586: <td valign="top">sub_string(a,b,c)</td> 587: <td valign="top">&sub_string($a,$b,$c) perl  substr function. 588: However, note the differences</td> 589: <td valign="top">Retrieve a portion of string a starting from b and 590: length c. For example,  $a = "Welcome to LON-CAPA"; 591: $result=&sub_string($a,4,4); then $result is "come"</td> 592: <td valign="top">Perl intrinsic function, substr(string,b,c) starts 593: counting from 0 (as opposed to 1). In the example to the left, substr($a,4,4) 594: returns "ome ".</td> 595: </tr> 596: 597: <tr> 598: <td valign="top">array[xx]</td> 599: <td valign="top">@arrayname Array is intrinsic in perl. 600: To access a specific element use $arrayname[$n] where $n 601: is the $n+1 element since the array count starts from 0</td> 602: <td valign="top">"xx" can be a variable or a calculation.</td> 603: <td valign="top">In LON-CAPA, an array is defined by @arrayname. 604: It is not necessary to specify the dimension of the array. </td> 605: </tr> 606: 607: <tr> 608: <td valign="top">array_moments(B,A)</td> 609: <td valign="top">@B=&array_moments(@A)</td> 610: <td valign="top">Evaluates the moments of an array A and place the 611: result in array B[i] where i = 0 to 4. The contents of B are as follows: 612: B[0] = number of elements, B[1] = mean, B[2] = variance, B[3] = skewness 613: and B[4] = kurtosis.</td> 614: <td valign="top">In CAPA, the moments are passed as an array in the first argument whereas 615: in LON-CAPA, the array containing the moments are set equal to the function.</td> 616: </tr> 617: 618: <tr> 619: <td valign="top">array_max(Name), array_min(Name)</td> 620: <td valign="top">&min(@Name), &max(@Name)</td> 621: <td valign="top">In LON-CAPA to find the maximum value of an array, use 622: &max(@arrayname)  and to find the minimum value of an array, use 623: &min(@arrayname)</td> 624: <td valign="top">Combined with the min and max functions defined 625: earlier.</td> 626: </tr> 627: 628: <tr> 629: <td valign="top">init_array(Name)</td> 630: <td valign="top">undef @name</td> 631: <td valign="top">To destroy the contents of an array, use</td> 632: <td valign="top">Use perl intrinsic undef function.</td> 633: </tr> 634: <tr> 635: <td valign="top">random_normal (return_array,item_cnt,seed,av,std_dev)</td> 636: <td valign="top">@return_array=&random_normal ($item_cnt,$seed,$av,$std_dev)</td> 637: <td valign="top">Generate $item_cnt deviates of normal distribution of average $av and 638: standard deviation $std_dev. The distribution is generated from seed $seed</td> 639: <td valign="top">In CAPA the results are passed as the first argument whereas in LON-CAPA 640: the results are set equal to the function.</td> 641: </tr> 642: <tr> 643: <td valign="top">random_beta (return_array,item_cnt,seed,aa,bb)</td> 644: <td valign="top">@return_array=&random_beta ($item_cnt,$seed,$aa,$bb) 645: NOTE: Both $aa and $bb MUST be greater than 1.0E-37.</td> 646: <td valign="top">Generate $item_cnt deviates of beta distribution. 647: The density of beta is: 648: X^($aa-1) *(1-X)^($bb-1) /B($aa,$bb) for 0<X<1.</td> 649: <td valign="top">In CAPA the results are passed as the first argument whereas in LON-CAPA 650: the results are set equal to the function.</td> 651: </tr> 652: <tr> 653: <td valign="top">random_gamma (return_array,item_cnt,seed,a,r)</td> 654: <td valign="top">@return_array=&random_gamma ($item_cnt,$seed,$a,$r) 655: NOTE: Both $a and $r MUST be positive.</td> 656: <td valign="top">Generate $item_cnt deviates of gamma distribution. 657: The density of gamma is: 658: ($a**$r)/gamma($r) * X**($r-1) * exp(-$a*X).</td> 659: <td valign="top">In CAPA the results are passed as the first argument whereas in LON-CAPA 660: the results are set equal to the function.</td> 661: </tr> 662: <tr> 663: <td valign="top">random_exponential (return_array,item_cnt,seed,av)</td> 664: <td valign="top">@return_array=&random_exponential ($item_cnt,$seed,$av) 665: NOTE: $av MUST be non-negative.</td> 666: <td valign="top">Generate $item_cnt deviates of exponential distribution. </td> 667: <td valign="top">In CAPA the results are passed as the first argument whereas in LON-CAPA 668: the results are set equal to the function.</td> 669: </tr> 670: <tr> 671: <td valign="top">random_poisson (return_array,item_cnt,seed,mu)</td> 672: <td valign="top">@return_array=&random_poisson ($item_cnt,$seed,$mu) 673: NOTE: $mu MUST be non-negative.</td> 674: <td valign="top">Generate $item_cnt deviates of poisson distribution. </td> 675: <td valign="top">In CAPA the results are passed as the first argument whereas in LON-CAPA 676: the results are set equal to the function.</td> 677: </tr> 678: <tr> 679: <td valign="top">random_chi (return_array,item_cnt,seed,df)</td> 680: <td valign="top">@return_array=&random_chi ($item_cnt,$seed,$df) 681: NOTE: $df MUST be positive.</td> 682: <td valign="top">Generate $item_cnt deviates of chi_square distribution with $df 683: degrees of freedom. </td> 684: <td valign="top">In CAPA the results are passed as the first argument whereas in LON-CAPA 685: the results are set equal to the function.</td> 686: </tr> 687: <tr> 688: <td valign="top">random_noncentral_chi (return_array,item_cnt,seed,df,nonc)</td> 689: <td valign="top">@return_array=&random_noncentral_chi ($item_cnt,$seed,$df,$nonc) 690: NOTE: $df MUST be at least 1 and $nonc MUST be non-negative.</td> 691: <td valign="top">Generate $item_cnt deviates of noncentral_chi_square 692: distribution with $df 693: degrees of freedom and noncentrality parameter $nonc. </td> 694: <td valign="top">In CAPA the results are passed as the first argument whereas in LON-CAPA 695: the results are set equal to the function.</td> 696: </tr> 697: <tr> 698: <td valign="top">NOT IMPLEMENTED IN CAPA</td> 699: <td valign="top">@return_array=&random_f ($item_cnt,$seed,$dfn,$dfd) 700: NOTE: Both $dfn and $dfd MUST be positive.</td> 701: <td valign="top">Generate $item_cnt deviates of F (variance ratio) distribution with 702: degrees of freedom $dfn (numerator) and $dfd (denominator). </td> 703: <td valign="top">New to LON-CAPA</td> 704: </tr> 705: <tr> 706: <td valign="top">NOT IMPLEMENTED IN CAPA</td> 707: <td valign="top">@return_array=&random_noncentral_f ($item_cnt,$seed,$dfn,$dfd,$nonc) 708: NOTE: $dfn must be at least 1, $dfd MUST be positive, and $nonc must 709: be non-negative.</td> 710: <td valign="top">Generate $item_cnt deviates of noncentral F (variance ratio) 711: distribution with degrees of freedom $dfn (numerator) and $dfd (denominator). 712: $nonc is the noncentrality parameter. </td> 713: <td valign="top">New to LON-CAPA</td> 714: </tr> 715: <tr> 716: <td valign="top">NOT IMPLEMENTED IN CAPA</td> 717: <td valign="top">@return_array=&random_multivariate_normal ($item_cnt,$seed,@mean,@covar) 718: NOTE: @mean should be a length p array of real numbers. @covar should be a length 719: p array of references to length p arrays or real numbers (i.e. a p by p matrix.</td> 720: <td valign="top">Generate $item_cnt deviates of multivariate_normal distribution with 721: mean vector @mean and variance-covariance matrix. </td> 722: <td valign="top">New to LON-CAPA</td> 723: </tr> 724: <tr> 725: <td valign="top">NOT IMPLEMENTED IN CAPA</td> 726: <td valign="top">@return_array=&random_multinomial ($item_cnt,$seed,@p) 727: NOTE: $item_cnt is rounded with int() and the result must be non-negative. 728: The number of elements in @p must be at least 2.</td> 729: <td valign="top">Returns single observation from multinomial distribution with 730: $item_cnt events classified into as many categories as the length of @p. 731: The probability of an event being classified into category i is given by 732: ith element of @p. The observation is an array with length equal to @p, so 733: when called in a scalar context it returns the length of @p. The sum of the 734: elements of the obervation is equal to $item_cnt.</td> 735: <td valign="top">New to LON-CAPA</td> 736: </tr> 737: <tr> 738: <td valign="top">NOT IMPLEMENTED IN CAPA</td> 739: <td valign="top">@return_array=&random_permutation ($item_cnt,@array) </td> 740: <td valign="top">Returns @array randomly permuted.</td> 741: <td valign="top">New to LON-CAPA</td> 742: </tr> 743: <tr> 744: <td valign="top">NOT IMPLEMENTED IN CAPA</td> 745: <td valign="top">@return_array=&random_uniform ($item_cnt,$seed,$low,$high) 746: NOTE: $low must be less than or equal to $high.</td> 747: <td valign="top">Generate $item_cnt deviates from a uniform distribution. </td> 748: <td valign="top">New to LON-CAPA</td> 749: </tr> 750: <tr> 751: <td valign="top">NOT IMPLEMENTED IN CAPA</td> 752: <td valign="top">@return_array=&random_uniform_integer ($item_cnt,$seed,$low,$high) 753: NOTE: $low and $high are both passed through int(). 754: $low must be less than or equal to $high.</td> 755: <td valign="top">Generate $item_cnt deviates from a uniform distribution in integers. </td> 756: <td valign="top">New to LON-CAPA</td> 757: </tr> 758: <tr> 759: <td valign="top">NOT IMPLEMENTED IN CAPA</td> 760: <td valign="top">@return_array=&random_binomial ($item_cnt,$seed,$nt,$p) 761: NOTE: $nt is rounded using int() and the result must be non-negative. 762: $p must be between 0 and 1 inclusive.</td> 763: <td valign="top">Generate $item_cnt deviates from the binomial distribution with 764: $nt trials and the probabilty of an event in each trial is $p. </td> 765: <td valign="top">New to LON-CAPA</td> 766: </tr> 767: <tr> 768: <td valign="top">NOT IMPLEMENTED IN CAPA</td> 769: <td valign="top">@return_array=&random_negative_binomial ($item_cnt,$seed,$ne,$p) 770: NOTE: $ne is rounded using int() and the result must be positive. 771: $p must be between 0 and 1 exclusive.</td> 772: <td valign="top">Generate an array of $item_cnt outcomes generated from 773: negative binomial distribution with 774: $ne events and the probabilty of an event in each trial is $p. </td> 775: <td valign="top">New to LON-CAPA</td> 776: </tr> 777: </table> 778:  779: 780: <h2><script> Variables</h2> 781: <ul> 782: <li> 783: $external::target - set to the current target the xml parser 784: is parsing for 785: </li> 786: <li> 787: $external::part - set to the id of the current problem 788: <part>; zero if there are now <part> 789: </li> 790: <li> 791: $external::gradestatus - set to the value of the current 792: resource.partid.solved value 793: </li> 794: <li> 795: $external::datestatus - set to the current status of the clock 796: either CLOSED, CAN_ANSWER, CANNOT_ANSWER, or SHOW_ANSWER 797: </li> 798: <li> 799: $external::randomseed - set to the number that was used to 800: seed the random number generator 801: </li> 802: <li>$pi - set to PI </li> 803: <li>$rad2deg - converts radians to degrees </li> 804: <li>$deg2rad - converts degrees to radians </li> 805: </ul> 806: 807: <hr> 808: <address><a href="mailto:albertel@marvin.lite.msu.edu">Guy Albertelli</a></address> 809:  810:  811: Last modified: Tue June 12 15:25 EDT 2001 812:  813: </body> 814: </html>