Re: Curiosity about math.random in LuaTeX

[Otared Kavian <otared@gmail.com>]

Thomas and Taco: thanks to both of you for your insight. I overlooked  
the function math.randomseed() in Lua, and my question was mainly out  
of curioisty: in practive one doesn't need to reset the random seed,  
as Taco points out.

However I couldn't find the right usage of the command «  
\getrandomnumber »…

Best regards: OK

On 25 oct. 2009, at 10:50, Thomas A. Schmitz wrote:

>
> On Oct 25, 2009, at 9:26 AM, Taco Hoekwater wrote:
>
>> Otared KAVIAN wrote:
>>> Indeed I guess that this is due to the random seed used by LuaTeX:  
>>> is it
>>> possible to force a new random seed upon each typesetting?
>>
>> The randomseed is set by context, and saved between consecutive  
>> runs of
>> the same file. Normally, this is what you would want: just imagine  
>> what
>> happens if each of the luatex runs in a 'context' call used a  
>> different
>> value always.
>>
>> However (this is mostly for Hans), there is a bug in that process:  
>> all
>> randomseeds in mkiv appear to be between 0 and 1. Since  
>> math.randomseed() expects an integer, this gives almost no
>> randomness at all to the seed values.
>>
>> If you want near-random randomness, you can set the seed yourself
>> based on the return value of os.time():
>>
>> \ctxlua{math.randomseed(os.time())}
>
> Ah, that explains why I could never get random numbers in mkiv when  
> I tried a year ago. Another suggestion: there's also a  
> \getrandomnumber command available in ConTeXt, which seems to work  
> well.
>
> Thomas
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