Re: [xsl] Random number seed generation

Subject: Re: [xsl] Random number seed generation
From: Michel Hendriksen <michel.hendriksen@xxxxxxxxx>
Date: Thu, 9 Dec 2010 16:13:53 +0100
Thats how it works in FXSL, there is no state that can be kept for the
next. Normally you would 'seed' it with the previous number, but that
is also hard to keep track of.

On Thu, Dec 9, 2010 at 4:00 PM, Wolfgang Laun <wolfgang.laun@xxxxxxxxx>
> Out of curiosity: Usually, a random generator's seed needs only one setting
> so that you get different sequences with different program runs. Resetting
> the RG with a different seed every now and then isn't bound to make the
> sequence any "randomer".
> So why?
> -W
> On 9 December 2010 15:04, Michel Hendriksen <michel.hendriksen@xxxxx>
>> Hi all,
>> I'm using Saxon9he processor XSLT 2.0, and I am trying to get some
>> random numbers. I'm currently using fxsl/random for this. The problem
>> is that it needs a seed.
>> I tried using current time stuff but that doesn't change during the
>> transfomation using the stylesheet.. So I tried an extension function
>> to cal to Java but that doesn't seem to work. Examples are probably
>> XSLT 1.0 but should be ok.
>> Is this possible on Home Edition? Did things change in transition to
>> 2.0? Is there an other way to get some seed for the random function? I
>> can't resuse the value as I would have to keep it somewhere in between
>> calls. One idea would be to use generate-id() but that gives a string.
>> Could be useful when this is always convertible to a number.
>> I'm running the processor from a Java application now. It is a
>> learning project and should be able to run Genetic Algorithm
>> functionality, so lots of random stuff is needed.
>> Tried:
>>   <xslt:value-of select="math:sqrt(10)" xmlns:math="java:java.lang.Math"/>
>>   <xslt:variable name="date" select="date:new()"
>> xmlns:date="java:java.util.Date"/>
>> As samples for getting something but errors are:
>> Error at xslt:value-of on line 62 column 74 of selector.xsl:
>>  XPST0017: XPath syntax error at char 13 on line 62 in {math:sqrt(10)}:
>>   Cannot find a matching 1-argument function named
>> Error at xslt:variable on line 64 column 83 of selector.xsl:
>>  XPST0017: XPath syntax error at char 10 on line 64 in {date:new()}:
>>   Cannot find a matching 0-argument function named
>> Michel Hendriksen

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