Re: [xsl] generating unique random numbers

[Dimitre Novatchev <dnovatchev@xxxxxxxxx>]

Hi Abel,

> course. But Dimitre's XSLT-only approach to pseudo-random numbers in FXSL,
> combined with distinct-values() will probably be a better course of action.

No need to add anything to the random - generating  functions of FXSL.
There is already one:

Templates: _

      _randomRecursiveIndex
and
     _permutationFromRecursiveIndex


Here is a fragment from the test file testRandomList.xsl, which can be
fuuly viewed at:

http://fxsl.cvs.sourceforge.net/viewvc/fxsl/fxsl-xslt2/Tests/testRandomList.x
sl?revision=1.2&view=markup


    Random Recursive Index 10:

    <xsl:variable name="vrtfRecIndex">
      <xsl:call-template name="_randomRecursiveIndex">
        <xsl:with-param name="pList"
        select="1  to 10"/>
      </xsl:call-template>
    </xsl:variable>

    <xsl:variable name="vRecIndex"
              select="$vrtfRecIndex/*"/>

    <xsl:for-each select="$vRecIndex">
      <xsl:copy-of select="."/>&#xA;
    </xsl:for-each>

    Randomized 10-elements list:
    <xsl:call-template name="_permutationFromRecursiveIndex">
      <xsl:with-param name="pList" select="1  to 10"/>
      <xsl:with-param name="pRecIndex" select="$vRecIndex"/>
    </xsl:call-template>


And this produces the following part of the output:

    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>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>




Anyone can use this *now* (or up to four years ago)  to get a
randomized permutation of the set [1 .. N]


--
Cheers,
Dimitre Novatchev
---------------------------------------
Truly great madness cannot be achieved without significant intelligence.
---------------------------------------
To invent, you need a good imagination and a pile of junk
-------------------------------------
Never fight an inanimate object
-------------------------------------
You've achieved success in your field when you don't know whether what
you're doing is work or play




On Mon, Feb 22, 2010 at 2:36 AM, Abel Braaksma <abel.online@xxxxxxxxx> wrote:
> As an alternative to the already proposed solutions, consider looking up
the
> pseudo-random method to create GUIDs in XSLT, which I cooked up a few years
> ago: http://markmail.org/message/4zxb654yeaf5twnv
>
> It is random enough between runs (and sequential, yet non-repeating, in one
> run), but maybe not random enough for you. You can elaborate on the code,
of
> course. But Dimitre's XSLT-only approach to pseudo-random numbers in FXSL,
> combined with distinct-values() will probably be a better course of action.
>
> Kind regards,
> Abel Braaksma
>
> Wolfgang Laun wrote:
>>
>> What you describe is not a sequence of random numbers; a rule such as
>> "no duplicates" contradicts most definitions of "randomness". What you
>> request is better described as "a random permutation of numbers". This
>> could
>> be produced by random draws from a set of numbers (without returning)
>> provided that you can, somehow, define this set. Can you?
>>
>> I regret that I'm not experienced enough to propose an XSLT solution
>> for such an algorithm.
>>
>> -W
>>
>> On Sun, Feb 21, 2010 at 3:02 AM, a kusa <akusa8@xxxxxxxxx> wrote:
>>
>>>
>>> Hi
>>>
>>> I have been raking my brains to achieve this. I am using math.random()
>>> to generate random numbers, but of course since they repeat, I want to
>>> be able to generate unique random numbers. Can anybody please help me
>>> here? How can I generate unique random numbers in xslt?
>>>
>>> Thanks in advance for all your support.