R help - Sep 2024 - BUG: atan(1i) / 5 = NaN+Infi ?

Dear R Users,

Is this desired behaviour?
I presume it's a bug.

atan(1i)
# 0+Infi

tan(atan(1i))
# 0+1i

atan(1i) / 5
# NaN+Infi

There were some changes in handling of complex numbers. But it looks like a bug.

Sincerely,

Leonard


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What version of R are you using and on what platform?

I get:
> atan(1i)
[1] 0.7853982+Infi
> atan(1i)/5
[1] NaN+Infi

on:
R version 4.4.1 (2024-06-14)
Platform: aarch64-apple-darwin20
Running under: macOS Sonoma 14.6.1

-- Bert

On Thu, Sep 5, 2024 at 1:23?PM Leo Mada via R-help <r-help at
r-project.org>
wrote:
> Dear R Users,
>
> Is this desired behaviour?
> I presume it's a bug.
>
> atan(1i)
> # 0+Infi
>
> tan(atan(1i))
> # 0+1i
>
> atan(1i) / 5
> # NaN+Infi
>
> There were some changes in handling of complex numbers. But it looks like
> a bug.
>
> Sincerely,
>
> Leonard
>
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> https://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
	[[alternative HTML version deleted]]

On 2024-09-05 4:23 p.m., Leo Mada via R-help wrote:
> Dear R Users,
> 
> Is this desired behaviour?
> I presume it's a bug.
> 
> atan(1i)
> # 0+Infi
> 
> tan(atan(1i))
> # 0+1i
> 
> atan(1i) / 5
> # NaN+Infi
There's no need to involve atan() and tan() in this:

 > (0+Inf*1i)/5
[1] NaN+Infi

Why do you think this is a bug?

Duncan Murdoch