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Re: Will Math.random return 0.0?

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On 7/16/2016 12:49 PM, Thomas Richter wrote:
> Am 16.07.2016 um 17:24 schrieb Stefan Ram:
>>   I wrote the following program.
>>
>> public final class Main
>> { public static void main( final java.lang.String[] args )
>>   { while( java.lang.Math.random() != 0.0 );
>>     java.lang.System.out.println( "0.0" ); }}
>>
>>   What do you expect it's (average) runtime to be
>>   on average hardware?
>>
>>   Can we be sure that it will ever terminate?
>
> No, you cannot.

Sure?

>             If random() is implemented by the average (=bad) linear
> congruence generator, then zero will never be the output of random().

Not true.

First LCG's can have seed zero and a good cycle as long as the add part 
is non-zero.

Second even for an MLCG (with add part zero) where seed can not be
zero, then the random numbers can include zero simply by subtracting
one.

Arne

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Re: Will Math.random return 0.0? Thomas Richter <thor@math.tu-berlin.de> - 2016-07-16 18:49 +0200
  Re: Will Math.random return 0.0? Arne Vajhøj <arne@vajhoej.dk> - 2016-07-16 14:15 -0400
    Re: Will Math.random return 0.0? Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-07-16 14:19 -0400

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