Re: Random number seed generation
Thnx This looks like something that I could work with. I only don't know how this will be effecting performance as I would need to call it often. Maybe I can combine this with keeping track of the seed in some parts of the code. Michel Hendriksen Kensas bv On Fri, Dec 10, 2010 at 12:38 AM, TW <zupftom@xxxxxxxxxxxxxx> wrote: > I don't know whether this would give reasonably results, but what > about generating a seed from the result of generate-id()? Maybe like > so, calculating kind of a digit sum (based on the the order the > variables occur in "name-chars"): > > <template name="create-seed"> > <param name="string" select="generate-id(.)"/> > <param name="preliminary-seed" select="0"/> > <param name="maximum-value" select="100"/> > > <variable name="name-chars" > select="':ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz-.0123456789'" /> > > <choose> > <when test="string-length($string) != 0"> > <call-template name="create-seed"> > <with-param name="string" select="substring($string,2)"/> > <with-param name="preliminary-seed" > select="($preliminary-seed + string-length( > > substring-before($name-chars,substring($string,1,1)) > ) > ) mod $maximum-value"/> > <with-param name="maximum-value" select="$maximum-value"/> > </call-template> > </when> > <otherwise> > <value-of select="$preliminary-seed"/> > </otherwise> > </choose> > </template> > > > Of course this only makes sense if you need at most one random number > per source document node (after all, the random number will be the > same if the seed is the same). Or you can pass the old seed as > parameter "preliminary-seed" when you create a new seed. > > Thomas W. > > > 2010/12/9 Michel Hendriksen <michel.hendriksen@xxxxxxxxx>: >> That is not an issue as that would be fixed easily. But I need to call >> the random functions from different places and that code would have to >> keep track of the last generated number. Also, when scaling the value >> (p.e.) to boolean I would need the original unscaled value for the >> next call. So results from any functions like that would have to >> return (combined) two values or would need two calls, one for the >> random number and one for the scaling. >> >> So time in millis from 1970 something would be a nice 'seed' and much >> easier to work with. >> >> Michel >> >> On Thu, Dec 9, 2010 at 4:58 PM, Tony Graham >> <Tony.Graham@xxxxxxxxxxxxxxxxxxxxxx> wrote: >>> On Thu, Dec 09 2010 14:04:57 +0000, michel.hendriksen@xxxxx wrote: >>>> 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 >>> >>> That would require "Extensibility using reflexion", which isn't in Saxon >>> 9 HE. See http://www.saxonica.com/feature-matrix.xml (ideally after it >>> has a stylesheet PI added to it). >>> >>>> 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 >>> >>> More in the transition from 'B' to 'HE', IIRC. >>> >>>> 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. >>> >>> Just pass a seed generated with Java as a stylesheet parameter. >>> >>> Regards, >>> >>> >>> Tony Graham Tony.Graham@xxxxxxxxxxxxxxxxxxxxxx >>> Director W3C XSL FO SG Invited Expert >>> Menteith Consulting Ltd XML Guild member >>> XML, XSL and XSLT consulting, programming and training >>> Registered Office: 13 Kelly's Bay Beach, Skerries, Co. Dublin, Ireland >>> Registered in Ireland - No. 428599 http://www.menteithconsulting.com >>> -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- >>> xmlroff XSL Formatter http://xmlroff.org >>> xslide Emacs mode http://www.menteith.com/wiki/xslide >>> Unicode: A Primer urn:isbn:0-7645-4625-2
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