On 7 May 2014, at 07:31, Wolfgang Laun wolfgang(_dot_)laun(_at_)gmail(_dot_)com
<xsl-list-service(_at_)lists(_dot_)mulberrytech(_dot_)com> wrote:
I think that a random() in XSLT should be provided in a way that lets
you call several random number generators (of the same kind) in
parallel. Generators may exhibit a big difference between a sequence
where all elements are due to successive calls of the same generator
and one where a sufficient number of generators is called one by one.
For instance: In Dimitre's example: values returned alternate between
even and odd, and using this to generate random points (x,y) in 2D
omits 50% of the possible points. And this is typical for an entire
class of random generators.
One of the inherent weaknesses of any pseudo-random number generator where the
N'th value in the sequence is a function of the (N-1)th value is that it can
get into loops. For example, if the same value appears twice consecutively
(which in a truly random sequence will sometimes happen), then all subsequent
values will be the same.
Michael Kay
Saxonica
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