# [R] Simulation of data

Marcioestat marcioestat at POP.COM.BR
Tue Oct 21 18:13:54 CEST 2008

```Hi Barry,
As you explained I find out my mistake... I wasn't supposed to use a
recursive formula!
So, what I needed, it's just to use the proportion by the function mean to
reach my results...
Thanks,
Márcio

Barry Rowlingson wrote:
>
> 2008/10/21 Marcioestat <marcioestat at pop.com.br>:
>>
>> Hi listers,
>> I am working on a program of statistical analysis of simulated data and
>> I've
>> been searching the error at the program, but I didn't find it!
>> It is something about the WHILE procedure, the error says: Error in while
>> (ecart >= d) { : missing value where TRUE/FALSE needed
>
>  How much do you know about debugging programs? Read the R help for
> "debug" and "browser". These tools let you inspect your program at any
> point so you can see what the values of variables are.
>
>  Anyway, for you error message, I'd guess there was a missing value in
> 'ecart' or 'd' or both:
>
>  > ecart
>  [1] NaN
>  > d
>  [1] 0.00112
>
>  so, ecart is Not A Number. How could that happen? Well, ecart is a
> square root of something, so maybe that something is negative:
>
>  > proportion*(1-proportion)
> [1] -0.01874365
>
>  Hmmm
>
>  > proportion
>  [1] 1.018405
>
>  I would bet that proportion isn't supposed to be more than 1 (or less
> than 0). How did that happen?
>
>  This line looks a bit dodgy:
>
>   proportion<-proportion+(prop[k+1]-proportion/(k+1))
>
> since you're adding something to a proportion... Should that division
> be outside the parentheses? Hard to tell without knowing exactly what
> the code is trying to do. The proportion goes >1 when w is over your
> 1.75 threshold. Are you just trying to update proportion=mean(prop)
> again? Why not do that? If I replace your line with proportion =
> mean(prop) then it runs and terminates after about 32000 iterations.
>
>  Protip: Updating a mean like this is probably quicker but if you ever
> write a tricky bit of code test it first!
>
> Barry
>
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