kdtree Questions
5
Solved
I am using CGAL's (the latest) KD-tree implementation for searching nearest neighbors in point sets. And also Wikipedia and other resources seem to suggest that KD-trees are the way to go. But some...
Limoges asked 27/2, 2013 at 23:53
2
Solved
I have a code, which calculates the nearest voxel (which is unassigned) to a voxel ( which is assigned). That is i have an array of voxels, few voxels already have a scalar (1,2,3,4....etc) values ...
Subzero asked 23/9, 2016 at 12:38
2
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For someone who is new to python, I don't understand how to remove an instance of a class from inside a recursive function.
Consider this code of a k-d Tree:
def remove(self, bin, targetAxis=0, p...
1
Solved
This post builds upon this one.
I got a Pandas dataframe containing cities with their geo-coordinates (geodetic) as longitude and latitude.
import pandas as pd
df = pd.DataFrame([{'city':"Berl...
Angarsk asked 25/3, 2017 at 19:25
5
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Let this coordinates class with the Euclidean distance,
case class coord(x: Double, y: Double) {
def dist(c: coord) = Math.sqrt( Math.pow(x-c.x, 2) + Math.pow(y-c.y, 2) )
}
and let a grid of c...
Bowerbird asked 6/9, 2014 at 5:9
2
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I try to create a KD tree of WGS84 coordinates and find neighbors within a certain radius
from sklearn.neighbors.dist_metrics import DistanceMetric
from sklearn.neighbors.kd_tree import KDTree
T ...
Variorum asked 4/7, 2016 at 16:22
2
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On the wikipedia entry for k-d trees, an algorithm is presented for doing a nearest neighbor search on a k-d tree. What I don't understand is the explanation of step 3.2. How do you know there isn'...
Iceni asked 26/10, 2009 at 20:58
1
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Given a list of points, how can I get their indices in a KDTree?
from scipy import spatial
import numpy as np
#some data
x, y = np.mgrid[0:3, 0:3]
data = zip(x.ravel(), y.ravel())
points = [[0,1...
1
I need to partition a large set of 3D points (using C++). The points are stored on the HDD as binary float array, and the files are usually larger than 10GB.
I need to divide the set into smaller ...
2
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I'm working on a kd-tree implementation and I'm currently using std::nth_element for partition a vector of elements by their median. However std::nth_element takes 90% of the time of tree construct...
1
I have two 2d arrays, obs1 and obs2. They represent two independent measurement series, and both have dim0 = 2, and slightly different dim1, say obs1.shape = (2, 250000), and obs2.shape = (2, 25005...
1
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I have a doubt regarding the parameter search_radius in nanoflann's radiusSearch function. My code is this:
#include <iostream>
#include <vector>
#include <map>
#include "nanofl...
Abampere asked 30/9, 2014 at 10:37
1
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I have a catalogue of data and I want to use it in my MCMC code. What is crucial is the speed of implementation, in order to avoid slowing down my Markov chain monte carlo sampling.
The problem:
I...
1
I am using Point Cloud Library (PCL) based C++ implementation of kd-tree nearest neighbour(NN) searching. The data set contains about 2.2 million points. I am searching NN points for every other po...
Litalitany asked 22/8, 2014 at 18:24
3
I am having huge set of 2D line segments. So, I know; Line number,
Begin (X,Y,Z) and End (x,Y,Z) of each line segment. I want to get
proximity line segments for a given line segment. Likewise for ...
Flareup asked 18/3, 2013 at 12:12
2
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After writing this article I decided to put my money where my mouth is and started to convert a previous project of mine to use recursion-schemes.
The data structure in question is a lazy kdtree....
Bangweulu asked 14/5, 2014 at 20:9
3
Solved
I'm trying to balance a set of (Million +) 3D points using a KD-tree and I have two ways of doing it.
Way 1:
Use an O(n) algorithm to find the arraysize/2-th largest element along a given axis a...
Laster asked 10/6, 2013 at 10:7
2
Solved
I am currently writing a KDTree for a physics engine (Hobby project).
The KDTree does not contain points.
Instead it contains Axis Aligned bounding boxes which bound the different objects in the e...
Kauslick asked 8/1, 2011 at 7:41
1
I have large 2D arrays with unsorted (X,Y) points, for which I need to know which points are in close proximity to each other (nearest-neighbor lookup). I have used cKDTree and query_ball_tree with...
0
I have about 80 million spatial points(3D) and I want to find all the nearest neighbors of a query point which lie under a sphere of a certain radius(can be given as input) with the query point as ...
Karlsbad asked 11/6, 2013 at 6:49
1
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I'm currently looking for a way to build a couple of kd trees for quickly querying some n-dimensional data. However, I'm having some issue with the scipy KD tree algorithm
My data consists of id -...
1
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I am trying to implement a Kd tree to perform the nearest neighbor and approximate nearest neighbor search in C++. So far I came across 2 versions of the most basic Kd tree.
The one, where data i...
Krauss asked 12/1, 2013 at 10:49
3
I know kd-trees are traditionally used to store points, but I want to store lines instead. Would it be best to split the line at every intersection with the splitting of the kd-tree? or would stori...
Wormwood asked 28/10, 2010 at 23:20
4
I'm currently attempting to find K Nearest Neighbor of all nodes of a balanced KD-Tree (with K=2).
My implementation is a variation of the code from the Wikipedia article and it's decently fast to...
Ought asked 26/3, 2010 at 14:3
3
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This is my understanding of it:
1. Recurse down the tree, taking the left or right subtree according as whether ELEMENT would lie in the left or the right subtree, if it existed.
2. Set CURRENT_BES...
Tannenwald asked 22/11, 2012 at 5:8
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