[R] [External] Unexplained behaviour of .Last.value

[iuke-tier@ey m@iii@g oii uiow@@edu]

Thanks for the report. Fixed in R-devel in r80530; will port to
R-patched soon.

Best,

luke

On Fri, 18 Jun 2021, Bickis, Mikelis wrote:

> Hello:
>
> Here is a bit of R-code:
>
>> mvr
> [1] 2.2658
>> (sin(.Last.value)+sin(2*.Last.value))
> [1] -0.2156507
>> acos((-sqrt(17)-1)/8)
> [1] 2.2658
>> (sin(.Last.value)+sin(2*.Last.value))
> [1] 1.76745
>> (sin(mvr)+sin(2*mvr))
> [1] -0.2156507
>>
>
> Note that my variable mvr is the value of acos((-sqrt(17)-1)/8).   However, if I use .Last.value after invoking the acos function in a further calculation, I get a nonsensical result.   What is going on?
>
> I am running R version 4.0.0 (2020-04-24) on an iMac, operating system MacOS 11.4 “Big Sur”.
>
> Mik Bickis
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-- 
Luke Tierney
Ralph E. Wareham Professor of Mathematical Sciences
University of Iowa                  Phone:             319-335-3386
Department of Statistics and        Fax:               319-335-3017
    Actuarial Science
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