Re: Non-random numbers generated by excel's data analysis random gener

Allie wrote...
>I've been trying to generate random numbers using excel's random number
>generator in the analysis toolpak. I'm using Uniform number generation
>between 0 and 1, and I am using a random seed, as I would like to be able to
>re-generate the same numbers in the future.
>
>Using seeds from 1 to 10, when i fill a range of 16 cells with random
>numbers, the first cell filled is always the lowest. This is an extremely
>unlikely circumstance with a true RN generator. I just wanted to raise this
>flag, as it could be affecting others without their knowledge.

First, this isn't the appropriate newsgroup for this detailed level of
Excel functionality. You'd be better off posting in
microsoft.public.excel.misc, to which I've cross-posted this reply.

This is a know problem. See

http://groups.google.com/group/micro...36f9fec558b658

(or http://makeashorterlink.com/?G2C0129CB ).

Thanks for your response, Harlan. Your link doesn't seem to be the same
issue I am talking about here. The link says that large arrays can get
non-random, and that there are repeat sequences within 500 tries. The
apparent bug I noticed is not that.

And apologies for posting in an inappropriate place.

Allie

"Allie" wrote...
>Thanks for your response, Harlan. Your link doesn't seem to be
>the same issue I am talking about here. The link says that large
>arrays can get non-random, and that there are repeat sequences
>within 500 tries. The apparent bug I noticed is not that.
....

Not exactly the same, but another aspect of the poor quality of the
pseudorandom number generator in the ATP. In short, it's unwise to use the
ATP's random number generators for anything meaningful. Presumably Microsoft
has aware of the problem for years, but they haven't fixed it. That's not a
guarantee that they never will fix it, but it's pretty clear it's a very low
priority.

Another point made in the article I linked was Dave Braden's mention of
alternatives. You really can't use the ATP with any reliance, so you need to
find alternatives.