search for: qhull

Hi, does anyone know if there is an implementation of qhull (http://www.qhull.org/) in R? anyone is planning on it? "Qhull computes convex hulls, Delaunay triangulations, halfspace intersections about a point, Voronoi diagrams, furthest-site Delaunay triangulations, and furthest-site Voronoi diagrams. It runs in 2-d, 3-d, 4-d, and higher dimension...

I maintain the geometry package, which integrates the Qhull C library (http://qhull.org) into R. The Qhull function I hook into requires an open FILE handle as one of its arguments. I had set this file handle to stdout, but now R check NOTEs the presence of stdout, and the CRAN maintainers asked me to get rid of these NOTEs. Including the following defines...

...sage : > coord=matrix(ncol=2,byrow=TRUE,c(622633,7073452, + 621228,7073517, + 621879,7071762, + 621065,7073331)) > library(geometry) > > test=delaunayn(coord,options="Qbb") qhull precision warning: The initial hull is narrow (cosine of min. angle is 0.9999999999999999). Is the input lower dimensional (e.g., on a plane in 3-d)? Qhull may produce a wide facet. Options 'QbB' (scale to unit box) or 'Qbb' (scale last coordinate) may remove this warning. Use &...

Does anyone know of a R package that will determine the convex hull of a high-dimensional dataset (say 4-10 dimensions). I know chull works for 2D data. I'm neophyte to R and convex hulls so please keep it simple. Many thanks Ben -- Ben Stapley. Biomolecular Sciences, UMIST, PO Box 88, Manchester M60 1QD. Tel 0161 200 5818 Fax 0161 236 0409

...#compute hull > (hull1 = t(convhulln(points, options="QJ"))) [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [1,] 6 6 8 8 7 7 5 5 5 5 [2,] 9 9 6 6 9 8 9 8 7 7 [3,] 1 3 1 3 1 1 3 3 9 8 qhull warning: joggle ('QJ') always produces simplicial output. Triangulated output ('Qt') does nothing. Convex hull of 10 points in 3-d: Number of vertices: 7 Number of facets: 10 Statistics for: | qhull s Qt Tcv QJ Number of points processed: 7 Number of hyperplanes...

Hi, I've been looking for functions that can do delaunay tesselation and generate voronoi cells. I came across deldir and tripack but both seem to be restricted to 2D points. Are there any packages that can do a tesselation in N dimensions? I know that Matlab and Mathematica use the qhull package to provide functions for this. Does anybody know of any R packages that do this (maybe by calling on qhull)? Thanks, ------------------------------------------------------------------- Rajarshi Guha <rxg218 at psu.edu> <http://jijo.cjb.net> GPG Fingerprint: 0CCA 8EE2 2EEB 25E2...

...Func.div?dbFD ( trait_data, abundance_data, calc.FRic = T, corr="cailliez", w.abun = T, CWM.type = "all" ) FRic: Dimensionality reduction was required. The last PCoA axis (out of 6 in total) was removed. FRic: Quality of the reduced-space representation = 0.9402678 QH6114 qhull precision error: initial simplex is not convex. Distance=-2.7e-15 Error in convhulln(tr.FRic, "FA") : Received error code 2 from qhull. Best, Elisae [[alternative HTML version deleted]]

...well-founded. I have a (user-supplied) black-box function which takes R^n -> R^3 and a defined domain for each of the input reals. I want to send some samples through the box to determine an approximation of the convex hull of the function's range. (I'll use the library from http://www.qhull.org to compute the convex hull from the function's outputs.) My plan is to use the permutation of the min and max values for the n inputs along with k-1 samples w/in [min,max], but I want the adjust the k samples a bit to avoid sampling bias. To make it simpler, let's set the domain to [0...

Dear List Members, I'm presently carrying out morphological analysis of a data set of neuronal structures. These are essentially 3D binary trees. In due course I will be trying to use discriminant analysis or other methods to classify these neurons based on morphological variables such as total tree length, segment number etc. I would like to calculate a 3D convex hull for a set of X,Y,Z

...t;- norm( df[,ii] - df[,jj]) > } > } This is both inefficient and ugly, I'll welcome any suggestion. In particular: - the location of the points on the sphere is not ideal (understand: not uniformly distributed over the area): i looked into delaunayn from the geometry package and qhull.com but at best I obtained a random set of points on the sphere. It must be a most classical problem ?? generating a uniform distribution of points on a sphere??, but i've set that problem aside for the moment. - the double for loop over all the points cries out for a vectorized soluti...

...require(geometry) library(rgl) x<-rnorm(100) k<-runif(100)*20+5 y<-rnorm(100) z<-sin(x)+cos(y)^2 my.data.3d<-data.frame(cbind(x,y,z)) my.data.3d = sqrt(3) * my.data.3d / drop(sqrt((my.data.3d^2) %*% rep(1,3))) data.ts.surf = t( convhulln(my.data.3d,"QJ") ) # see the qhull documentations for the options ## Not run: rgl.triangles(my.data.3d[data.ts.surf,1],my.data.3d[data.ts.surf,2],my.data.3d[data.ts.surf,3],col="blue",alpha=.2) for(i in 1:(8*360)) rgl.viewpoint(i/8) [[alternative HTML version deleted]]

...ckage: octave --> Processing Dependency: gnuplot for package: octave --> Processing Dependency: libcxsparse.so.2 for package: octave --> Processing Dependency: libhdf5.so.0 for package: octave --> Processing Dependency: liblapack.so.3 for package: octave --> Processing Dependency: libqhull.so.5 for package: octave --> Running transaction check ---> Package glpk.i386 0:4.20-2.el5 set to be updated ---> Package octave.i386 6:3.0.1-2.el5 set to be updated --> Processing Dependency: libhdf5.so.0 for package: octave ---> Package qhull.i386 0:2003.1-7.el5 set to be updated -...

Dear friends, Do you know how to calculate the CONCAVE hull of a set of points (2- dimensional or n-dimensional)? is that possible in R? (With a "smoothing" parameter of course). Best, -- Corrado Topi Global Climate Change & Biodiversity Indicators Area 18,Department of Biology University of York, York, YO10 5YW, UK Phone: + 44 (0) 1904 328645, E-mail: ct529 at york.ac.uk

...when i stop with crtl-C a command running as root, # root prompt change in $ user prompt (with wheezy) Removed tag(s) sid and jessie. Removed tag(s) sid and jessie. Removed tag(s) sid and jessie. > tags 556302 - jessie sid wheezy Bug #556302 {Done: bap at debian.org (Barak A. Pearlmutter)} [src:qhull] FTBFS with binutils-gold Removed tag(s) sid, wheezy, and jessie. > tags 556870 - jessie sid wheezy Bug #556870 {Done: Debian FTP Masters <ftpmaster at ftp-master.debian.org>} [src:wzdftpd] FTBFS with binutils-gold Removed tag(s) sid, wheezy, and jessie. > tags 384372 - jessie sid squee...

...Bug #676277 [src:speedy-cgi-perl] speedy-cgi-perl: FTBFS with perl 5.16: memory link test Added tag(s) jessie. > tags 617094 + jessie Bug #617094 [src:sugar-hulahop] sugar-hulahop: deprecation of dh_pycentral, please use dh_python2 Added tag(s) jessie. > tags 556302 + jessie Bug #556302 [src:qhull] FTBFS with binutils-gold Added tag(s) jessie. > tags 578083 + jessie Bug #578083 [libqtgui4] libqtgui4: non-KDE Qt apps do not use style engine Added tag(s) jessie. > tags 579235 + jessie Bug #579235 [libgtksourceview2.0-0] libgtksourceview2.0-0: Missing debug package Added tag(s) jessie. &g...