similar to: branch cuts of atan()

Hello, Once again, I posted a message without a subject line. Sorry.... here is the question again. Is there a simple way to modify the circ.mean function in the CircStats package to include a vector of weights to obtain a weighted average angle? Thanks! Martin -- Martin Biuw Sea Mammal Research Unit Gatty Marine Laboratory, University of St Andrews St Andrews, Fife KY16 8PA Scotland Ph:

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 another answer. I advise against messing with infinities... use atan2() if you don't

On 4/3/23 14:07, Michael Milton wrote: > Hi all, > > There seems to have been a breaking change in the R trunk caused by a fix > to bug 18430 <https://bugs.r-project.org/show_bug.cgi?id=18430> that > relates to the layout of the Rcomplex typedef. Previously it was a struct, > but now it's a union by default >

Hello, I am trying to call the BLAS Level1 function zdotc from R via a .C call like this: #include "R.h" #include "R_ext/BLAS.h" void testzdotc() { Rcomplex zx[3], zy[3], ret_val; zx[0].r = 1.0; zx[0].i = 0.0; zx[1].r = 2.0; zx[0].i = 0.0; zx[2].r = 3.0; zx[0].i = 0.0; zy[0].r = 1.0; zy[0].i = 0.0; zy[1].r = 2.0; zy[0].i = 0.0; zy[2].r = 3.0;

On 4/3/23 15:50, Michael Milton wrote: > Okay, but I'm afraid this will only mean something to Rust users. The > reason being that we encountered this issue in extendr: a Rust > extension library for R. The specific compiler errors we encounter > happen because bindgen (the Rust code generation library) read the > changed R header files, and generated a new type definition

Hi Tomas, Thanks for this explanation. As you can probably tell I'm not much of a C person, so I didn't realise this change would be invisible to C users. I suppose R's stability contract only applies to C, and therefore changes that break other languages such as Rust are out of scope. You are right that this error is confused by bindgen's inability to handle anonymous types, but

Hi anyone coded up Stirling numbers in R? [I need unsigned Stirling numbers of the first kind] cheers Robin -- Robin Hankin Uncertainty Analyst National Oceanography Centre, Southampton European Way, Southampton SO14 3ZH, UK tel 023-8059-7743

o `Rcomplex' is preferred to `complex' (a future reserved word in C) for R complex objects passed to C. I'm a bit confused here. Is "complex" or "Rcomplex" the future reserved word in C (I thought "complex" already was, but I'm not a C programmer) and is this because R storage modes should or should not have names corresponding to C reserved

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

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]]

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

The thing is that real*complex, complex*real, and complex/real are not "complex arithmetic" in the requisite sense. The complex numbers are a vector space over the reals, and complex*real and real*complex are vector*scalar and scalar*vector. For example, in the Ada programming language, we have function "*" (Left, Right : Complex) return Complex; function "*" (Left :

Dear R experts. 'D()' function recognizes some of the analitical functions, such as sin, cos, etc. But I'd like to take analytical derivatives from asin, atan etc. functions. Are there any R packages providing that features? Thanks. -- Timur.

I don't think an auto-generated name (along the lines of u or u2) for the anonymous structs would be helpful here. You can see that bindgen is already generating a placeholder name ("__bindgen_anon_1"). A meaningful name might be nice instead, but I get the impression that isn't an option here since that would break the C API. Can I ask, would it make sense for us to hard code

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,infinity/5) = (0,infinity). The former involves multiplying 0 by infinity, which

> 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 real divisions/multiplications: >

Dear Bert, These behave like real divisions/multiplications: complex(re=Inf, im = Inf) * 5 # Inf+Infi complex(re=-Inf, im = Inf) * 5 # -Inf+Infi The real division / multiplication should be faster and also is well behaved. I was expecting R to do the real division/multiplication on a complex number. Which R actually does for these very particular cases; but not when only Im(x) is Inf.

If you set the "digits17" control option in deparse, you get a lot of unnecessary space in the representation of complex numbers. > deparse(0 + 0i) [1] "0+0i" > deparse(0 + 0i, control = "digits17") [1] "0 + 0i" As far as I can tell, the logic for this comes from this piece of /src/main/deparse.c: if (TYPEOF(vector) == CPLXSXP

>>>>> Richard O'Keefe >>>>> on Fri, 6 Sep 2024 17:24:07 +1200 writes: > The thing is that real*complex, complex*real, and complex/real are not > "complex arithmetic" in the requisite sense. > The complex numbers are a vector space over the reals, Yes, but they _also_ are field (and as others have argued mathematically only

Full_Name: Christian Marquardt Version: 2.2.1 OS: Linux Submission from: (NULL) (84.167.229.240) Hello, I believe this is a bug in the configuration / installation: When configuring R-2.2.1 using the Intel v9 Fortran compiler as default Fortran compiler and g++ as C++ compiler on a Suse 9.3 Linux, the configuration script finds that the C and Fortran idea of double comples disagree. I have