How to simulate a Raleigh distribution with a Weibull one

[lorenzo.cioni]

Hi to everybody.
If I am not wrong it is possible to use a Weibull distribution to replace a Rayleigh one, not available in Vensim, simply putting the shape parameter at 2 but what about the ather parameters in
RANDOM WEIBULL( {min} , {max} , {S} , {shift} , {stretch} , {seed} )
if I want that my distribution has an average value of 0.97?
Best regards and best wishes.
Lorenzo

[Administrator]

I'm not familiar with this, but it makes sense to me to use the stretch paramter as the mean.

[lorenzo.cioni]

Thank you for your reply. I thought I had to modify the shft paramenter instead... could you be so kind of telling me which are the precise meanings of the shift and stretch parameters? I find the Vensim documentation about these topics rather confusing, to say the less...
Lorenzo

[Administrator]

"shift" can be thought of as adding/subtracting a value from the distribution. Stretch can be thought of as a multiplier.

I'll raise the documentation as an issue as I agree, it's hard to understand.

[tomfid]

I agree that the stretch parameter is the one to use.

For all the functions, the result is essentially
y = shift + stretch*x
where x is some kind of standard version of the distribution.