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Questions tagged [qhull]

Qhull is a library for C and C++ which implements Quickhull algorithm for computing the convex hull.

Qhull is a library for C and C++ which implements Quickhull algorithm for computing the convex hull.

Homepage: http://www.qhull.org/html

Qhull computes the convex hull, Delaunay triangulation, Voronoi diagram, halfspace intersection about a point, furthest-site Delaunay triangulation, and furthest-site Voronoi diagram. The source code runs in 2-d, 3-d, 4-d, and higher dimensions.

Qhull handles roundoff errors from floating point arithmetic. It computes volumes, surface areas, and approximations to the convex hull.

Qhull does not support triangulation of non-convex surfaces, mesh generation of non-convex objects, medium-sized inputs in 9-D and higher, alpha shapes, weighted Voronoi diagrams, Voronoi volumes, or constrained Delaunay triangulations,

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Use fill_value outside boundaries with scipy.interpolate.griddata and method=nearest

Function scipy.interpolate.griddata allows to specify the keyword fill_value, for which the doc states: Value used to fill in for requested points outside of the convex hull of the input points. If not provided, then the default is nan. This…
Arcturus B
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How can I interpolate data represented in (r,spherical harmonic) space to a regular cartesian grid (F90)?

I'm trying to interpolate spherical harmonics to a cubic, Cartesian grid. The output data of my spherical, pseudo-spectral simulation has Nr radial levels between rMin and rMax, each containing a set of finite-order spherical harmonics for…
jvriesem
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Calculating a Voronoi diagram for planes in 3D

Is there a code/library that can calculate a Voronoi diagram for planes (parallelograms) in 3D? I checked Qhull and it seems it can only work with points, in its examples Voro++ works with different size of spheres but I couldn't find anything for…
zamazalotta
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Make qhull/qvoronoi limit Voronoi to convex hull or given polygon

A planar Voronoi tesselation will always have unbounded polygons (infinite regions). How do I tell qhull/qvoronoi to intersect the tesselation with either the original points' convex hull, or with a polygon I explicitly specify (probably a…
user354134
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Failure to link Qhull C++ interface in ROS catkin project

I'm having some trouble getting the QHull C++ interface working in a catkin project. My project compiles fine and I've specified the library to be used by the linker, however it fails to link with the following error…
PeteBlackerThe3rd
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Picture Convex hull in 3D Scatter Plot

I followed the tutorial about 3D visualization using the package "rgl" here So I was able to draw a 3D Scatter Plot with "iris" data and create an ellipsoid surrounding 95 % of the data points: library("rgl") data(iris) x <- sep.l <-…
ossesso
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How to disable console output on exception in scipy.spatial.qhull.Delaunay?

I have thousands of point sets which I feed to Scipy's Delaunay function to get a corresponding set of triangulations. If my input points are invalid, ex. all points on a line or for some other reason the Delaunay triangulation fails, it result in a…
Chau
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Integrating qdelaunay and qvoronoi function of qhull in c++

I know basics of visual studio and c++, but I am not an advanced user or programmer. What I want to do is to perform delaunay triangulation and generate voronoi grids using qhull library (using visual studio c++ in windows). I have no problem with…
changdong.yang
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provide qconvex's input in C++ Code

For my code I need to compute Convexhull of series of points and for some reasons I need to use qhull libraries. In this library there is a method qconvex that do exactly what I need. I can run this command in terminal and get what I want. for…
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scipy: Qhull error when using bilinear interpolation

I am interpolating data from satellite imagery. My initial data is not on a regular grid. The data e.g. ch1 refers to positions given by longitude and latitude. When I try nearest neighbour interpolation the result I get is good. from scipy import…
Kostas Kammenos
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how to plot non-convex surface from set of n x 3 data

Is there a straight forward way to plot a non-convex surface in R? I have used something like the following for convex surfaces and it works fine: xyz <- cbind(y,x,z) tbr <- t(surf.tri(xyz, delaunayn(xyz))) rgl.triangles(xyz[tbr,1], xyz[tbr,2],…
Graham G
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Regularly spaced orthogonal grid Delaunay triangulation (Computing the paraboloid coeficients)

I'm trying to construct a Delaunay triangulation for the very specific case where the input x and y coordinates are orthogonal and relatively equidistant. Given the data size is relatively large (1000x1200 triangulation points) and that the Qhull…
pelson
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convexHull in 3D Perl

I have a Set of points in 3D with x y z coordinates. i would lik eto calculate the convex Hull of these points. I haf gone through algorithms available but i couldnt do it in Perl. Perl Math:ConvextHull module also i have checked but i didnt get how…
gthm
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Issue in qhull.cpython-38-darwin.so while importing sklearn

I have tried uninstalling and reinstalling sklearn, scipy, numpy, anaconda3 and nothing resolved this issue. Provided the code and Error message below Code : from sklearn import svm,datasets Error Summary ImportError:…
Vishnu Ram
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Scipy.spatial does not contain 'qhull'

This is my first question on this site. Let's cut right to it: I'm trying to create Voronoi diagrams with scipy in Python 3.8 on Kubuntu 20.04, however the problem seems to be that I cannot access the Voronoi class in scipy.spatial because it does…
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