Number generator from a distribution with an specified mean and variance?

[javivi]

Hi all,

I would like to create a generator of numbers following a distributions with an specified mean and variance. Any of you knows how to do this?

Please, help me, i m quite blocked with this problem..

Thank you very much in advance!

Javi.

[DSPGuy]

Javi,

What distribution are you trying to generate?  Gaussian?

-Jim

[javivi]

Hi,

Not sure yet.. I m trying to emulete packets arrival to a netork node, so I guess I need Poisson and Gaussian.

Thanks.

[gwd]

This is a problem commonly encountered when doing Monte Carlo simulations (and it sounds like this is what you are doing).

I found a discussion if this at http://omlc.ogi.edu/news/sep98/montecarlosampling/montecarlo1.html. You will also find it in other references dealing with Monte Carlo simulation.

[DSPGuy]

Check out vi.lib\gmath\statdist.llb\Continuous Random.vi for Gaussian and ...\Discrete Random.vi for Poisson.
These are polymorphic VIs.  Just pull down the selector to choose the distribution you wish to generate.

-Jim

[javivi]

I have tried to look for this .vi, but i didn't find them in my computer. I guess it could be dued to the LabView version i am using is too old, v5.1, you think so? You think I could just paste the .vi in the folder of my computer? in that case, where could I find this file?

Thank you very much for your help... i'am a bit unexperienced in LabView.

Regards,

Javi.

[javivi]

Hi gwd,

I have taken a look at the link you gave me. If I have understood it correctly, it means than the computer can generate a number of a desired distribusion from a random number, am I right? If so, what do I need to implement it in my computer?

Thank you very much!!

[gwd]

Didn't know about these vis...but anyway...these are analysis vis, and you need a non-base version of Labview. I don't know if these even existed as far back as 5.

You can still do this the hard way if you are determined.

[javivi]

gwd,

What do you mean "hard way"? sorry, i'm spanish-speaking, i still have some problems with english..

thanx!

[gwd]

I just saw the previous message. Yes, you can do this the hard way. However the integral of a Gaussian is an error function and if you don't have the analysis vis you don't have that either. You would have to generate a text file of samples of the error function and use that as an approximation to the integral.

Time-consuming (although a good Labview exercise).

Another approach is to generate a large text file of random numbers with the right distribution (say, using Matlab or other computing software) and read them in sequentially with Labview.