Randomization of node-sets or node-lists

break, and I'd also like to be able to present a node-set in a new random order on each call. If either of these effects can be done directly with xsltproc, I'll be one happy camper. -- Gary Lawrence Murphy" I am pleased to present a complete solution for the problem of producing and processing randomized node-sets or node-lists (random indices). This is a XSLT 1.0 solution and can be used immediately. The code bellow is a complete, new module of FXSL, named randomList.xsl. It should be put in the same folder, where all other FXSL files reside. It imports and uses random.xsl. The main functions/templates are: 1. randomizeList -- given a node-set and an optional seed produces a new node-set, having nodes with the same values as the given node-set, but ordered randomly. 2. randomMap -- given a function f, a node-set and an optional seed, it produces a mapping of the given function f over the nodes of the node-set, which is applied in a random order, based on the given seed. It is efficient, because no intermediate randomized list is produced. 3. randListIndex -- given a node-set and an optional seed produces a random index (a random permutation of the numbers from 1 to count($node-set). This index can then be used e.g. in a xsl:for-each loop to index randomly the elements of any node-set with the same number of nodes. The basic idea standing behind a list randomisation is to follow the algorithm of producing a permutation of N elements -- that is to produce one random number out of N in the first stage, then to produce one random number out of the remaining N-1, etc... Actually, a random sequence of N random numbers is produced, and its elements are then individually scaled, so that its k-th element is in the interval [1, N-k+1] In the code section bellow is the complete FXSL module. To test it, we apply the following test transformation (at the end of the XSLT code section to the xml code bellow. And the result of the transformation is also there (because I cannot have any markup text in the "Description section"???). Do enjoy! Cheers, Dimitre Novatchev.

Summary I am pleased to present a complete solution for the problem of producing and processing randomized node-sets or node-lists (random indices). This is a XSLT 1.0 solution and can be used immediately. From http://sources.redhat.com/ml/xsl-list/2002-04/msg01225.html: "The two transforms I would like to implement seem easy and commonplace, but are proving elusive: I would like to render a node-set into rows of columns without resorting to disable-output-escaping to insert the modulo-column

Additional information

<!-- =================================================================== Stylesheet: random.xsl List Randomization Functions Version: 1.0 (2002-05-03) Author: Dimitre Novatchev Notice: Copyright (c)2002 D.Novatchev ALL RIGHTS RESERVED. No limitation on use - except this code may not be published, in whole or in part, without prior written consent of the copyright owner. ===================================================================--> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:vendor="urn:schemas-microsoft-com:xslt" xmlns:myIncrement="f:myIncrement" xmlns:x="f:fxslRandomList.xsl" exclude-result-prefixes="xsl vendor myIncrement x" > <!-- ================================================================= Imported files: ================================================================--> <xsl:import href="random.xsl"/> <!-- Template: randScale Purpose : Return an integer, scaled from [0, modulus-1~ to [s, t~ Parameters: $pStart - [optional~ the start of the target interval $pEnd - [optional~ the end of the target interval $pN - The number N to be scaled ============================================================--> <!-- > _randScale :: Float -> Float -> Int -> Int > randScale s t n = floor (rndScl ((t - s + 1)/dintRange ) s n) > where dintRange = fromInt (modulus - 1) > rndScl :: Float -> Float -> Int -> Float > rndScl a b n = a * fromInt n + b --> <xsl:template name="_randScale" > <xsl:param name="arg2" select="0"/> <!--pStart--> <xsl:param name="arg3" select="1"/> <!--pEnd --> <xsl:param name="arg1"/> <!--pN --> <xsl:value-of select="floor( ($arg3 - $arg2 + 1) div ($modulus - 1) * $arg1 + $arg2 )"/> </xsl:template> <!-- Template: _dScale Purpose : Used to prepare a random recursive index for a list from a random sequence with the same number of elements Parameters: $pRandSeq - a list of (random) numbers Result: - a random recursive index =========================================================--> <xsl:template name="_dScale"> <xsl:param name="pRandSeq" select="/.."/> <!-- > dScale :: [Int~ -> [Int~ > dScale [~ = [~ > dScale (x:xs) = fstScale : (dScale xs) > where fstScale = randScale 0 (fromInt (length xs)) x --> <xsl:if test="$pRandSeq"> <el> <xsl:call-template name="_randScale"> <xsl:with-param name="arg2" select="1"/> <!--s--> <xsl:with-param name="arg3" select="count($pRandSeq)"/> <!--end--> <xsl:with-param name="arg1" select="$pRandSeq[1~"/> </xsl:call-template> </el> <xsl:call-template name="_dScale"> <xsl:with-param name="pRandSeq" select="$pRandSeq[position() > 1~"/> </xsl:call-template> </xsl:if> </xsl:template> <!-- Template: _randomRecursiveIndex Purpose : Used to prepare a random recursive index for a list Parameters: $pList - a list to be presented in a random order $pSeed - [optional~ a seed for generation of the random sequence Result: - a random recursive index =========================================================--> <!-- > randomRecursiveIndex xs sd = dScale (take (length xs) (randomSequence sd)) --> <xsl:template name="_randomRecursiveIndex"> <xsl:param name="pList" select="/.."/> <xsl:param name="pSeed" select="$seed"/> <xsl:variable name="vRandSequence"> <xsl:call-template name="randomSequence"> <xsl:with-param name="pLength" select="count($pList)"/> <xsl:with-param name="pSeed" select="$pSeed"/> </xsl:call-template> </xsl:variable> <xsl:call-template name="_dScale"> <xsl:with-param name="pRandSeq" select="vendor:node-set($vRandSequence)/*"/> </xsl:call-template> </xsl:template> <!-- Template: _permutationFromRecursiveIndex Purpose : Produce a random permutation of a list based on a given random recursive index Parameters: $pList - a list to be presented in a random order $pIndex - a list with the same length as $pList containing the random recursive index Result: - a randomly permuted list =========================================================--> <xsl:template name="_permutationFromRecursiveIndex"> <xsl:param name="pList" select="/.."/> <xsl:param name="pRecIndex" select="/.."/> <xsl:if test="not(count($pList) = count($pRecIndex))"> <xsl:message terminate="yes"> Error[permutationFromRecursiveIndex~: The two lists are not the same length! </xsl:message> </xsl:if> <xsl:call-template name="_permRecIdx"> <xsl:with-param name="pList" select="$pList"/> <xsl:with-param name="pRecIndex" select="$pRecIndex"/> </xsl:call-template> </xsl:template> <xsl:template name="_permRecIdx"> <xsl:param name="pList" select="/.."/> <xsl:param name="pRecIndex" select="/.."/> <xsl:variable name="vIndex" select="number($pRecIndex[1~)"/> <xsl:if test="$pList"> <el> <xsl:value-of select="$pList[position() = $vIndex~"/> </el> <xsl:call-template name="_permRecIdx"> <xsl:with-param name="pList" select="$pList[position() != $vIndex~"/> <xsl:with-param name="pRecIndex" select="$pRecIndex[position() > 1~"/> </xsl:call-template> </xsl:if> </xsl:template> <!-- Template: randomizeList Purpose : Produce a random permutation of a list based on a given seed for randomisation Parameters: $pList - a list to be reproduced in a random order $pSeed - [optional~ the seed to be used =========================================================--> <xsl:template name="randomizeList"> <xsl:param name="pList" select="/.."/> <xsl:param name="pSeed" select="$seed"/> <xsl:variable name="vrtfRecIndex"> <xsl:call-template name="_randomRecursiveIndex"> <xsl:with-param name="pList" select="$pList"/> <xsl:with-param name="pSeed" select="$pSeed"/> </xsl:call-template> </xsl:variable> <xsl:variable name="vRecIndex" select="vendor:node-set($vrtfRecIndex)/*"/> <xsl:call-template name="_permutationFromRecursiveIndex"> <xsl:with-param name="pList" select="$pList"/> <xsl:with-param name="pRecIndex" select="$vRecIndex"/> </xsl:call-template> </xsl:template> <!-- Template: _mapFromRandIndex Purpose : Produce a mapping of a given function over a list, which will be applied randomly based on a given random recursive index Parameters: $pFun - a template reference to a function $pList - a list to be processed in a random order $pIndex - a list with the same length as $pList containing the random recursive index Result: - a mapping of pFun applied in random order (specified by pIndex) on pList =========================================================--> <xsl:template name="_mapFromRandIndex"> <xsl:param name="pFun" select="/.."/> <xsl:param name="pList" select="/.."/> <xsl:param name="pRecIndex" select="/.."/> <xsl:if test="not(count($pList) = count($pRecIndex))"> <xsl:message terminate="yes"> Error[mapFromRandIndex~: The two lists are not the same length! </xsl:message> </xsl:if> <xsl:call-template name="_mapRndIndex"> <xsl:with-param name="pFun" select="$pFun"/> <xsl:with-param name="pList" select="$pList"/> <xsl:with-param name="pRecIndex" select="$pRecIndex"/> </xsl:call-template> </xsl:template> <xsl:template name="_mapRndIndex"> <xsl:param name="pFun" select="/.."/> <xsl:param name="pList" select="/.."/> <xsl:param name="pRecIndex" select="/.."/> <xsl:variable name="vIndex" select="number($pRecIndex[1~)"/> <xsl:if test="$pList"> <el> <xsl:apply-templates select="$pFun"> <xsl:with-param name="arg1" select="$pList[position() = $vIndex~"/> </xsl:apply-templates> </el> <xsl:call-template name="_mapRndIndex"> <xsl:with-param name="pFun" select="$pFun"/> <xsl:with-param name="pList" select="$pList[position() != $vIndex~"/> <xsl:with-param name="pRecIndex" select="$pRecIndex[position() > 1~"/> </xsl:call-template> </xsl:if> </xsl:template> <!-- Template: randomMap Purpose : Produce a mapping of a given function over a list, which will be applied randomly based on a given seed for randomization Parameters: $pFun - a template reference to a function $pList - a list to be processed in a random order $pSeed - [optional~ the seed to be used for randomization =========================================================--> <xsl:template name="randomMap"> <xsl:param name="pFun" select="/.."/> <xsl:param name="pList" select="/.."/> <xsl:param name="pSeed" select="$seed"/> <xsl:variable name="vrtfRecIndex"> <xsl:call-template name="_randomRecursiveIndex"> <xsl:with-param name="pList" select="$pList"/> <xsl:with-param name="pSeed" select="$pSeed"/> </xsl:call-template> </xsl:variable> <xsl:variable name="vRecIndex" select="vendor:node-set($vrtfRecIndex)/*"/> <xsl:call-template name="_mapFromRandIndex"> <xsl:with-param name="pFun" select="$pFun"/> <xsl:with-param name="pList" select="$pList"/> <xsl:with-param name="pRecIndex" select="$vRecIndex"/> </xsl:call-template> </xsl:template> <!-- Template: randListIndex Purpose : Produce a random (non-recursive) index for a list Parameters: $pList - the list for which to produce a random index $pSeed - [optional~ the seed to be used for randomization =========================================================--> <xsl:template name="randListIndex"> <xsl:param name="pList" select="/.."/> <xsl:param name="pSeed" select="$seed"/> <xsl:variable name="vFunIncr" select="$x:st/myIncrement:*[1~"/> <xsl:variable name="vrtfNums"> <xsl:call-template name="scanIter"> <xsl:with-param name="arg1" select="count($pList) - 1"/> <xsl:with-param name="arg2" select="$vFunIncr"/> <xsl:with-param name="arg3" select="'1'"/> </xsl:call-template> </xsl:variable> <xsl:call-template name="randomizeList"> <xsl:with-param name="pList" select="vendor:node-set($vrtfNums)/*"/> <xsl:with-param name="pSeed" select="$pSeed"/> </xsl:call-template> </xsl:template> <xsl:template match="myIncrement:*"> <xsl:param name="arg1"/> <xsl:value-of select="$arg1 + 1"/> </xsl:template> <!-- ********************************************************* --> <!-- ********************* INTERNAL USE ONLY ***************** --> <!-- ********************************************************* --> <!-- defined constants --> <xsl:variable name="x:st" select="document('')/*"/> <!-- a template reference to an incrementing function ============================================================== --> <myIncrement:myIncrement/> </xsl:stylesheet> <!-- Testing it: --> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:vendor="urn:schemas-microsoft-com:xslt" xmlns:mySquare="f:mySquare" xmlns:myDouble="f:myDouble" exclude-result-prefixes="xsl vendor mySquare myDouble" > <xsl:import href="randomList.xsl"/> <xsl:output omit-xml-declaration="yes" indent="yes"/> <!-- This transformation must be applied to: numList.xml --> <mySquare:mySquare/> <myDouble:myDouble/> <xsl:template match="/"> <xsl:variable name="vrtfRands"> <xsl:call-template name="randomSequence"> <xsl:with-param name="pLength" select="100"/> </xsl:call-template> </xsl:variable> Random Recursive Index (dScale (randomSequence 100)): <xsl:call-template name="_dScale"> <xsl:with-param name="pRandSeq" select="vendor:node-set($vrtfRands)/*"/> </xsl:call-template> Random Recursive Index 10: <xsl:variable name="vrtfRecIndex"> <xsl:call-template name="_randomRecursiveIndex"> <xsl:with-param name="pList" select="/*/*"/> </xsl:call-template> </xsl:variable> <xsl:variable name="vRecIndex" select="vendor:node-set($vrtfRecIndex)/*"/> <xsl:for-each select="$vRecIndex"> <xsl:copy-of select="."/> </xsl:for-each> Randomized 10-elements list: <xsl:call-template name="_permutationFromRecursiveIndex"> <xsl:with-param name="pList" select="/*/*"/> <xsl:with-param name="pRecIndex" select="$vRecIndex"/> </xsl:call-template> RandomizeList: <xsl:call-template name="randomizeList"> <xsl:with-param name="pList" select="/*/*"/> </xsl:call-template> <xsl:variable name="vFunSquare" select="document('')/*/mySquare:*[1~"/> _mapFromRandIndex (^2) [1..10~ seed: <xsl:call-template name="_mapFromRandIndex"> <xsl:with-param name="pFun" select="$vFunSquare"/> <xsl:with-param name="pList" select="/*/*"/> <xsl:with-param name="pRecIndex" select="$vRecIndex"/> </xsl:call-template> <xsl:variable name="vFunDouble" select="document('')/*/myDouble:*[1~"/> randomMap (*2) [1..10~ seed: <xsl:call-template name="randomMap"> <xsl:with-param name="pFun" select="$vFunDouble"/> <xsl:with-param name="pList" select="/*/*"/> </xsl:call-template> randListIndex [1..10~ seed: <xsl:call-template name="randListIndex"> <xsl:with-param name="pList" select="/*/*"/> </xsl:call-template> </xsl:template> <xsl:template match="mySquare:*"> <xsl:param name="arg1"/> <xsl:value-of select="$arg1 * $arg1"/> </xsl:template> <xsl:template match="myDouble:*"> <xsl:param name="arg1"/> <xsl:value-of select="$arg1 + $arg1"/> </xsl:template> </xsl:stylesheet> <!-- and the Result is: --> Random Recursive Index (dScale (randomSequence 100)): <el>27</el> <el>90</el> <el>14</el> <el>78</el> <el>65</el> <el>13</el> <el>27</el> <el>85</el> <el>75</el> <el>33</el> <el>31</el> <el>26</el> <el>9</el> <el>40</el> <el>31</el> <el>80</el> <el>19</el> <el>44</el> <el>52</el> <el>7</el> <el>8</el> <el>73</el> <el>55</el> <el>16</el> <el>68</el> <el>20</el> <el>29</el> <el>4</el> <el>3</el> <el>30</el> <el>51</el> <el>41</el> <el>14</el> <el>32</el> <el>66</el> <el>4</el> <el>19</el> <el>51</el> <el>48</el> <el>59</el> <el>30</el> <el>1</el> <el>49</el> <el>57</el> <el>14</el> <el>53</el> <el>13</el> <el>10</el> <el>10</el> <el>38</el> <el>13</el> <el>37</el> <el>13</el> <el>36</el> <el>22</el> <el>7</el> <el>28</el> <el>25</el> <el>28</el> <el>7</el> <el>29</el> <el>3</el> <el>34</el> <el>28</el> <el>7</el> <el>13</el> <el>14</el> <el>5</el> <el>32</el> <el>25</el> <el>25</el> <el>24</el> <el>8</el> <el>26</el> <el>23</el> <el>14</el> <el>11</el> <el>18</el> <el>15</el> <el>6</el> <el>5</el> <el>6</el> <el>9</el> <el>4</el> <el>8</el> <el>14</el> <el>12</el> <el>12</el> <el>5</el> <el>2</el> <el>5</el> <el>1</el> <el>4</el> <el>1</el> <el>4</el> <el>4</el> <el>1</el> <el>2</el> <el>1</el> <el>1</el> Random Recursive Index 10: <el>3</el> <el>9</el> <el>2</el> <el>6</el> <el>5</el> <el>1</el> <el>2</el> <el>3</el> <el>2</el> <el>1</el> Randomized 10-elements list: <el>03</el> <el>10</el> <el>02</el> <el>08</el> <el>07</el> <el>01</el> <el>05</el> <el>09</el> <el>06</el> <el>04</el> RandomizeList: <el>03</el> <el>10</el> <el>02</el> <el>08</el> <el>07</el> <el>01</el> <el>05</el> <el>09</el> <el>06</el> <el>04</el> _mapFromRandIndex (^2) [1..10~ seed: <el>9</el> <el>100</el> <el>4</el> <el>64</el> <el>49</el> <el>1</el> <el>25</el> <el>81</el> <el>36</el> <el>16</el> randomMap (*2) [1..10~ seed: <el>6</el> <el>20</el> <el>4</el> <el>16</el> <el>14</el> <el>2</el> <el>10</el> <el>18</el> <el>12</el> <el>8</el> randListIndex [1..10~ seed: <el>3</el> <el>10</el> <el>2</el> <el>8</el> <el>7</el> <el>1</el> <el>5</el> <el>9</el> <el>6</el> <el>4</el>

Further additional information

<nums> <num>01</num> <num>02</num> <num>03</num> <num>04</num> <num>05</num> <num>06</num> <num>07</num> <num>08</num> <num>09</num> <num>10</num> </nums>

---