similar to: Strange behavior of atan2

Hi ?atan2 says that atan2(y,x)=atan(y/x) for x and y numeric or complex vectors. Well, I would expect atan2(1,1i) to be equal to atan(-1i), but > atan2(1,1i) Error in atan2(y, x) : Non-numeric argument to mathematical function > R.version _ platform powerpc-apple-darwin8.5.0 arch powerpc os darwin8.5.0 system powerpc, darwin8.5.0

Hi ?atan2 says that atan2(y,x)=atan(y/x) for x and y numeric or complex vectors. Well, I would expect atan2(1,1i) to be equal to atan(-1i), but > atan2(1,1i) Error in atan2(y, x) : Non-numeric argument to mathematical function > R.version _ platform powerpc-apple-darwin8.5.0 arch powerpc os darwin8.5.0 system powerpc, darwin8.5.0

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

> > Do you have plans to add other intrinsics? I'm curious as to why there > > is an llvm.sin intrinsic and an llvm.cos intrinsic, but no llvm.atan > > intrinsic. Why is there an llvm.pow intrinsic but no llvm.log > > intrinsic? > > Intrinsics get added on demand. Generally there has to be a good reason > to add them. llvm.sin was implemented (for

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 :

> 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: >

On Tue, Nov 27, 2007 at 10:50:03AM -0700, Jon Sargeant wrote: > > > Do you have plans to add other intrinsics? I'm curious as to why there > > > is an llvm.sin intrinsic and an llvm.cos intrinsic, but no llvm.atan > > > intrinsic. Why is there an llvm.pow intrinsic but no llvm.log > > > intrinsic? > > > > Intrinsics get added on demand.

I inherited a function written either for an older version of R or SPlus to draw a brace, "{", in a graph. It uses par("uin") to determine the scaling of the quarter circles that make up segments of the brace, but that setting doesn't exist in current R. I'm guessing that, in the function below, ux, uy can be defined from par("usr") and

>>>>> 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

Dear all, I have just uploaded to CRAN the version 1.4 of the package 'adehabitat'. Significant changes are listed below: - The eigenanalysis of selection ratios (Calenge and Dufour, 2006, Ecology) can now be performed using the function eisera(). It can be used for the analysis of habitat selection when habitat can be considered to consist of several habitat types (e.g.

Dear all, I have just uploaded to CRAN the version 1.4 of the package 'adehabitat'. Significant changes are listed below: - The eigenanalysis of selection ratios (Calenge and Dufour, 2006, Ecology) can now be performed using the function eisera(). It can be used for the analysis of habitat selection when habitat can be considered to consist of several habitat types (e.g.

Dear, I am trying to visualise a time-progressing line (it's supposed to represent spread patterns) using brew package and Google Earth. The idea is to have a function which takes start and end point geographic coordinates, as well as number of intervals to chop the path up, and returns the collection of points segmenting this line. Unfortunately my calculations fail for large distances,

Dear all, I have just uploaded to CRAN the version 1.2 of the package 'adehabitat'. This package now contains new functions for the estimation of home ranges (Nearest neighbour convex hull, brownian bridge approach for kernel estimation), estimation of schoener's ratio. This package now allows a better management of objects of class "area" (see plot.area, perarea, ararea).

Dear all, I have just uploaded to CRAN the version 1.3 of the package 'adehabitat'. Significant changes are listed below: - Several functions allowing the conversion from and to classes of the package sp have been added. Maps of class "asc", "kasc", "area", as well as radio-monitoring of class "traj" can now be converted to the spatial

Dear all, I have just uploaded to CRAN the version 1.3 of the package 'adehabitat'. Significant changes are listed below: - Several functions allowing the conversion from and to classes of the package sp have been added. Maps of class "asc", "kasc", "area", as well as radio-monitoring of class "traj" can now be converted to the spatial

Dear all, I have uploaded to CRAN the version 1.7 of the package 'adehabitat'. Significant changes are listed below: * The Brownian bridge kernel estimation algorithm has been greatly improved. It now takes more than 80% less time than the previous version. A new function "liker" has also been added, which estimates the one of the two smoothing parameters of the bridge

Dear all, I have uploaded to CRAN the version 1.7 of the package 'adehabitat'. Significant changes are listed below: * The Brownian bridge kernel estimation algorithm has been greatly improved. It now takes more than 80% less time than the previous version. A new function "liker" has also been added, which estimates the one of the two smoothing parameters of the bridge

Dear all, I have just uploaded to CRAN the version 1.2 of the package 'adehabitat'. This package now contains new functions for the estimation of home ranges (Nearest neighbour convex hull, brownian bridge approach for kernel estimation), estimation of schoener's ratio. This package now allows a better management of objects of class "area" (see plot.area, perarea, ararea).

G.5.1 para 2 can be found in the C17 standard -- I actually have the final draft not the published standard. It's in earlier standards, I just didn't check earlier standards. Complex arithmetic was not in the first C standard (C89) but was in C99. The complex numbers do indeed form a field, and Z*W invokes an operation in that field when Z and W are both complex numbers. Z*R and R*Z,

I am having problems with the 'if' syntax. I have an n x 4 matrix, X say. The first two columns hold x, y values and I am attempting to fill the second two columns with the quadrant in which the datapoint (x, y) is and with the heading angle. So I have two problems 1) how to do this elegantly (at which I've failed as I can't seem to vectorize the problem) and 2) how to