[R] how to remove the 'promise' attribute of an R object (.Random.seed)?

[luke-tierney at uiowa.edu]

On Tue, 22 May 2012, Yihui Xie wrote:

> Hi,
>
> The problem arises when I lazyLoad() the .Random.seed from a
> previously saved database. To simplify the process of reproducing the
> problem, see the example below:
>
> ## this assignment may not really make sense, but illustrates the problem
> delayedAssign('.Random.seed', 1L)
>
> typeof(.Random.seed)
> # [1] "integer"
>
> rnorm(1)
> # Error in rnorm(1) :
> #  .Random.seed is not an integer vector but of type 'promise'
>
> typeof(.Random.seed)
> # [1] "integer"
>
> So there must be an "attribute" "promise" somewhere attached to
> .Random.seed, and I cannot find it. The R function typeof() does not
> reveal it, but the TYPEOF() function in src/main/RNG.c says it is a
> 'promise'.
>
> My question is, how to make R use the real value of .Random.seed
> instead of complaining about the promise? Thanks!

Siple answer: Don't creat the promise in the first place, i.e. don't
use delayedAssign.

What is the real context where this arises? Knowing that may help us
decide whether the internals should address this possibility.

Best,

luke

>
> Regards,
> Yihui
> --
> Yihui Xie <xieyihui at gmail.com>
> Phone: 515-294-2465 Web: http://yihui.name
> Department of Statistics, Iowa State University
> 2215 Snedecor Hall, Ames, IA
>
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> and provide commented, minimal, self-contained, reproducible code.
>

-- 
Luke Tierney
Chair, Statistics and Actuarial Science
Ralph E. Wareham Professor of Mathematical Sciences
University of Iowa                  Phone:             319-335-3386
Department of Statistics and        Fax:               319-335-3017
    Actuarial Science
241 Schaeffer Hall                  email:   luke-tierney at uiowa.edu
Iowa City, IA 52242                 WWW:  http://www.stat.uiowa.edu