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While working on the printing code, my colleague Zbyn?k ?lajchrt noticed that complex matrixes are sometimes misaligned: > { matrix(1i,2,13) } [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12] [,13] [1,] 0+1i 0+1i 0+1i 0+1i 0+1i 0+1i 0+1i 0+1i 0+1i 0+1i 0+1i 0+1i 0+1i [2,] 0+1i 0+1i 0+1i 0+1i 0+1i 0+1i 0+1i 0+1i 0+1i 0+1i 0+1i 0+1i 0+1i (the values in the last four columns should be prefixed by two spaces instea...

...> instead of NA_complex_? > My opinions: > (1) No. The imaginary part of the result of parsing the strings "<b>i", > "<a>+<b>i", and "<a>-<b>i" can be nonzero. > Consider, e.g., Im(eval(str2lang("0+1i"))) and Im(as.complex("0+1i")). > If NA_character_ means "a string with unknown content", then we should > not assume that the string is parsed as a real number. > (2) Yes. I'd very much like to preserve the identity of c(Im(NA), Im(x)) > a...

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

...real_, i=0) instead of NA_complex_? My opinions: (1) No. The imaginary part of the result of parsing the strings "<b>i", "<a>+<b>i", and "<a>-<b>i" can be nonzero. Consider, e.g., Im(eval(str2lang("0+1i"))) and Im(as.complex("0+1i")). If NA_character_ means "a string with unknown content", then we should not assume that the string is parsed as a real number. (2) Yes. I'd very much like to preserve the identity of c(Im(NA), Im(x)) and I...

...gression test is failing in the following manner: =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= > ## log > stopifnot(all.equal(log(1:10), log(1:10, exp(1)))) > stopifnot(all.equal(log10(30), log(30, 10))) > stopifnot(all.equal(log2(2^pi), 2^log2(pi))) > stopifnot(Mod(pi - log(exp(pi*1i)) / 1i) < .Machine$double.eps) Error: Mod(pi - log(exp(pi * (0+1i)))/(0+1i)) < .Machine$double.eps is not TRUE Execution halted =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= I'm compiling on Tru64UNIX 5.1A using DECs C and Fortran compilers and perl 5.6.0. I found the above error in a f...

This is another follow-up to the thread from September "Recent changes to as.complex(NA_real_)". A test in data.table was broken by the changes for NA coercion to complex; the breakage essentially comes from c(NA, 0+1i) # vs c(as.complex(NA), 0+1i) The former is the output we tested against; the latter is essentially (via coerceVector() in C) what's generated by our data.table::shift() However, these are now (r85472) different: Im(c(NA, 0+1i)) # [1] NA 1 Im(c(as.complex(NA), 0+1i)) # [1] 0 1 The former m...

...23 09:41:42 -0800 writes: > This is another follow-up to the thread from September > "Recent changes to as.complex(NA_real_)". > A test in data.table was broken by the changes for NA > coercion to complex; the breakage essentially comes from > c(NA, 0+1i) > # vs > c(as.complex(NA), 0+1i) > The former is the output we tested against; the latter is essentially (via > coerceVector() in C) what's generated by our data.table::shift() > However, these are now (r85472) different: > Im(c(NA, 0+1i)) >...

Perhaps > Inf*1i [1] NaN+Infi clarifies why it is *not* a bug. (Boy, did that jog some long dusty math memories :-) ) -- Bert On Thu, Sep 5, 2024 at 2:48?PM Duncan Murdoch <murdoch.duncan at gmail.com> wrote: > On 2024-09-05 4:23 p.m., Leo Mada via R-help wrote: > > Dear R Users, > > >...

...ercion works different that it used to, so that as.complex(NA) == as.complex(NA_real) == NA_real_+0i) which now differs from NA_complex although both print as NA. I haven't been quite alert when this change was discussed, but it does look a bit unfortunate that usage patterns like c(NA, 0+1i) does not give complex NA for the 1st component, effectively changing the interpretation from "I don't know what this is" to "I don't know what this is but I'm sure it is on the real line". Also, notice that things like > Im(scan(text= "NA 0+1i", what...

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]]

Hi If I have a <- Inf + 1i then Re(a) is Inf, and Im(a) is 1, as expected. But if b <- 1 + Inf * 1i, then Im(b) = Inf , as expected, but Re(b) = NaN, which I didn't expect. Why this asymmetry? How to define an object with Re(b)=1, Im(b)=Inf? -- Robin Hankin Uncertainty Analyst Southampton Oceanography C...

...> This is another follow-up to the thread from September > > "Recent changes to as.complex(NA_real_)". > > > A test in data.table was broken by the changes for NA > > coercion to complex; the breakage essentially comes from > > > c(NA, 0+1i) > > # vs > > c(as.complex(NA), 0+1i) > > > The former is the output we tested against; the latter is > essentially (via > > coerceVector() in C) what's generated by our data.table::shift() > > > However, these are now (r85472) differen...

On 2024-09-05 6:12 p.m., Leo Mada wrote: > Dear Duncan, > > Here is also the missing information: > R version 4.4.1 (2024-06-14 ucrt) > Platform: x86_64-w64-mingw32/x64 > Running under: Windows 10 x64 (build 19045) > > Regarding the results: > atan(1i) > #?0+Infi > Re(atan(1i)) > # 0 > Im(atan(1i)) > #? Inf > > 0 + Inf i is a valid complex number: > tan(atan(1i)) > # 0+1i > > Inf / 5 > # Inf > > Note: atan(1i) / 5 should have generated 0 + Inf * 1i; even the explicit > complex number fails: > c...

Prof Brian Ripley wrote: > This is intentional: it aligns the numbers. E.g. > > >options(width=12) > >print(c(1+1i, 1-10i, 1+100i)) > [1] 1+ 1i > [2] 1- 10i > [3] 1+100i > > Neat, eh? > > What made you think this was a bug? Ah ok, I've misunderstood this feature probably perhaps because, at first sight, I found the display looks "strange" when some of the numbers have lar...

It seems to me that the documentation of R's complex class & R's atan function do not tell us what to expect, so (as others have suggested), some additional notes are needed. I think that mathematically atan(1i) should be NA_complex_, but R seems not to use any mathematically standard compactification of the complex plane (and I'm not sure that IEEE does either). Incidentally, the signature of the complex constructor is confusing. complex(1L) returns zero, but complex(1L, argument=theta) is an elemen...

> complex(real = 0, imaginary = Inf) [1] 0+Infi > Inf*1i [1] NaN+Infi >> complex(real = 0, imaginary = Inf)/5 [1] NaN+Infi See the Note in ?complex for the explanation, I think. Duncan can correct if I'm wrong. -- Bert On Thu, Sep 5, 2024 at 3:20?PM Leo Mada <leo.mada at syonic.eu> wrote: > Dear Bert, > > These behave like...

..._________________________ From: Bert Gunter <bgunter.4567 at gmail.com> Sent: Friday, September 6, 2024 1:12 AM To: Duncan Murdoch <murdoch.duncan at gmail.com> Cc: Leo Mada <leo.mada at syonic.eu>; r-help at r-project.org <r-help at r-project.org> Subject: Re: [R] BUG: atan(1i) / 5 = NaN+Infi ? Perhaps > Inf*1i [1] NaN+Infi clarifies why it is *not* a bug. (Boy, did that jog some long dusty math memories :-) ) -- Bert On Thu, Sep 5, 2024 at 2:48?PM Duncan Murdoch <murdoch.duncan at gmail.com<mailto:murdoch.duncan at gmail.com>> wrote: On 2024-09-05 4...

atan(1i) -> 0 + Inf i complex(1/5) -> 0.2 + 0i atan(1i) -> (0 + Inf i) * (0.2 + 0i) -> 0*0.2 + 0*0i + Inf i * 0.2 + Inf i * 0i infinity times zero is undefined -> 0 + 0i + Inf i + NaN * i^2 -> 0 + 0i + Inf i - NaN -> NaN + Inf i I am not sure how complex arithmetic could arrive at ano...

I expect that atan(1i) = (0 + infinity i) and that atan(1i)/5 = (0 + infinity i)/5 = (0 + infinity i). Here's what I get in C: (0,1) = (0, 1) atan((0,1)) = (0, inf) atan((0,1))/5 = (0, inf) Note the difference between I*infinity = (0,1)*infinity = (0*infinity,1*infinity) = (NaN,infinity) and (0,infinity)/5 = (0/5,i...

Hi When using Sweave, most of my functions get called with complex arguments. They get typeset in with additions that I don't want; "1+1i" appears as "1 + (0 + 1i)" and I would rather have plain old "1+1i". Example follows: \documentclass[a4paper]{article} \title{A Test File} \author{Robin Hankin} \usepackage{a4wide} \begin{document} \maketitle A simple example: <<print=TRUE>>= f <-...