# Re: [R] R: simulation

From: Dimitris Rizopoulos <dimitris.rizopoulos_at_med.kuleuven.ac.be>
Date: Fri 04 Mar 2005 - 23:32:37 EST

are you sure you tried the function I gave you? There is a "." that you might have missed. When I try it I get this:

```+      set.seed(seed)
+     rnorm(...)
+ }
```

> #########
> rnorm.(1, 1)

[1] -0.6264538
> rnorm.(1, 1)

[1] -0.6264538
> rnorm.(1, 1)

[1] -0.6264538
> rnorm.(1, 1)

[1] -0.6264538
> rnorm.(1, 1)

[1] -0.6264538
> rnorm.(1, 1)

[1] -0.6264538

Observe that the first argument is the seed, `...' is used to pass arguments to `rnorm()'!

x <- rnorm(100)
y <- rnorm(100)

are independent, however,

x <- rnorm.(1, 100)
y <- rnorm.(1, 100)

will be exactly the same.

Best,
Dimitris

Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

```Tel: +32/16/336899
Fax: +32/16/337015
Web: http://www.med.kuleuven.ac.be/biostat/
http://www.student.kuleuven.ac.be/~m0390867/dimitris.htm

```
• Original Message ----- From: "Clark Allan" <Allan@STATS.uct.ac.za> To: "Dimitris Rizopoulos" <dimitris.rizopoulos@med.kuleuven.ac.be>; <r-help@stat.math.ethz.ch> Sent: Friday, March 04, 2005 1:21 PM Subject: Re: [R] R: simulation

> Hi

```>
```

```>
```

> i used your code and pasted it into R and ran it a few times. the
> output
> is below. what i want is to get the same output every time the
> program
> is run. is this possible?
```>
```

> another question?
```>
```

> x<-rnorm(100)
> y<-rnorm(100)
```>
```

> is x and y independent?
```>
>
>> rnorm(1)
```

> [1] 0.4251004
```>> rnorm(1)
```

> [1] -0.2386471
```>> rnorm(1)
```

> [1] 1.058483
```>> rnorm(1)
```

> [1] 0.8864227
```>> rnorm(1)
```

> [1] -0.619243
```>> rnorm(1)
```

> [1] 2.206102
```>> rnorm(1)
```

> [1] -0.2550270
```>> rnorm(1)
```

> [1] -1.424495
```>> rnorm(1)
```

> [1] -0.1443996
```>> rnorm(1)
```

> [1] 0.2075383
```>> rnorm(1)
```

> [1] 2.307978
```>> rnorm(1)
```

> [1] 0.1058024
```>
>
```

> Dimitris Rizopoulos wrote:
```>>
>> look at ?set.seed, e.g.,
>>
>> rnorm. <- function(seed, ...){
>>     set.seed(seed)
>>     rnorm(...)
>> }
>> #########
>> rnorm.(100, 1, 2)
>>
>> I hope it helps.
>>
>> Best,
>> Dimitris
>>
>> ----
>> Dimitris Rizopoulos
>> Ph.D. Student
>> Biostatistical Centre
>> School of Public Health
>> Catholic University of Leuven
>>
>> Address: Kapucijnenvoer 35, Leuven, Belgium
>> Tel: +32/16/336899
>> Fax: +32/16/337015
>> Web: http://www.med.kuleuven.ac.be/biostat/
>>      http://www.student.kuleuven.ac.be/~m0390867/dimitris.htm
>>
>> ----- Original Message -----
>> From: "Clark Allan" <Allan@stats.uct.ac.za>
>> To: <r-help@stat.math.ethz.ch>
>> Sent: Friday, March 04, 2005 12:07 PM
>> Subject: [R] R: simulation
>>
>> > hi all
>> >
>> > a simple question
>> >
>> > i want to run simulations in r. i however want the experiments to
>> > be
>> > repeated at a later time with exactly the same numbers by other
>> > users.
>> > can i set the random number seed for rnorm in some way?
>> >
>> > e.g. is there some arguement that goes with rnorm?
>> >
>> > please supply an example
>> >
>> > regards
>> > Allan
>>
>> --------------------------------------------------------------------------------
>>
>> > ______________________________________________
>> > R-help@stat.math.ethz.ch mailing list
>> > https://stat.ethz.ch/mailman/listinfo/r-help