nearest-neighbor Questions

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As part of my high school thesis I am describing the heuristics for the Traveling Salesman Problem. I was reading this sort of case study (Page 8) but I cannot unserstand what these sentences mean:...

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Suppose that we have the following look up table | 1.23 2.63 4.74 6.43 5.64 -------|-------------------------------------- -------|-------------------------------------- 2.56 | 0 0 1 0 1 4.79...
Vaios asked 30/7, 2015 at 21:35

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I have a csv file, where each row is a vector of numbers representing a data point. I want to use weka from the command line to calculate the nearest neighbor of each data point in the csv file. I ...
Devon asked 10/7, 2015 at 21:24

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This is a question related to https://stats.stackexchange.com/questions/21572/how-to-plot-decision-boundary-of-a-k-nearest-neighbor-classifier-from-elements-o For completeness, here's the original...
Esposito asked 5/7, 2015 at 20:20

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For my current input data, which is points in 3D, I'm using Morton code to improve the cache coherence when accessing the point list. I have some other data that is 6D and 7D. Is Morton code still...

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I need an algorithm for the following problem: I'm given a set of 2D points P = { (x_1, y_1), (x_2, y_2), ..., (x_n, y_n) } on a plane. I need to group them in pairs in the following manner: Fin...
Objectify asked 27/5, 2015 at 17:7

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I have a dict that takes integer keys: a = {} a[1] = 100 a[55] = 101 a[127] = 102 I would like to be able to take the nearest neighbour when asking : a[20] # should return a[1] = 100 a[58] # sh...
Unaffected asked 17/3, 2015 at 8:34

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I am looking a efficient way to find the 1st order neighbors of a given polygon. My data are in shapefile format. My first idea was to calculate the x and y coordinates of the polygons' centroids ...
Itching asked 21/11, 2012 at 11:16

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Ever since Joshua Katz published these dialect maps that you can find all over the web using harvard's dialect survey, I have been trying to copy and generalize his methods.. but much of this is ov...
Mcquillin asked 27/4, 2014 at 1:6

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I have 2 sets: A and B. Both sets contain the same number of high dimensional points. How do I find the nearest neighbour in Set A for every point in Set B? I thought about using a Voronoi diagram...
Gambia asked 29/10, 2014 at 22:44

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I have a large corpus of data (text) that I have converted to a sparse term-document matrix (I am using scipy.sparse.csr.csr_matrix to store sparse matrix). I want to find, for every document, top ...
Ahrens asked 10/8, 2013 at 17:7

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Given n points in d-dimensional space, there are several data structures, such as Kd-Trees, Quadtrees, etc. to index the points. On these data structures it is possible to implement straight-forwar...
Simonetta asked 7/10, 2014 at 13:48

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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

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I currently have a reddit-clone type website. I'm trying to recommend posts based on the posts that my users have previously liked. It seems like K nearest neighbor or k means are the best way to ...

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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

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Is anyone aware of a nearest neighbor algorithm implemented in Python that can be updated incrementally? All the ones I've found, such as this one, appear to be batch processes. Is it possibl...
Jeannajeanne asked 25/11, 2010 at 6:10

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I working on a project at the moment, where I have a point feature -- the point feature includes a 142 points -- and multiple polygon (around 10). I want to calculate the distance between every sin...
Leonialeonid asked 8/5, 2013 at 19:10

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In an extract from my textbook it says that reducing the value of K when running this algorithm actually increases the complexity as it has to run more “smoothing”. Can anyone explain this to me? ...

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Suppose we have two sets of points A, B, and we want to find for every point in set A its nearest neighbor in set B. There are many good algorithms to find the nearest neighbor for one point. Is ...
Multiphase asked 21/10, 2012 at 17:34

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I have a set of circles with given locations and radii on a two dimensional plane. I want to determine for every circle if it is intersecting with any other circle and the distance that is needed t...
Mcspadden asked 31/1, 2011 at 3:2

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I am trying to use scikit's Nearest Neighbor implementation to find the closest column vectors to a given column vector, out of a matrix of random values. This code is supposed to find the nearest...

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Given a quaternion value, I would like to find its nearest neighbour in a set of quaternions. To do this, I clearly need a way to compare the "distance" between two quaternions. What distance repre...
Bassoon asked 7/2, 2011 at 1:10

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I need to find "near" neighbors among a set of points. There are 10 points in the above image. Red lines are edges from the Delaunay Triangulation, black stars mark the mid-lines of the edges, b...

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I have implemented a quadtree structure for n points as well as a method for returning an array of points within a given rectangle. I can't seem to find an algorithm to efficiently find the point t...
Pursuance asked 30/12, 2013 at 10:21

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If I have a set of N points in 2D space, defined by vectors X and Y of their locations. What is an efficient algorithm that will Select a fixed number (M) points to remove so as to maximize the s...
Katharinakatharine asked 12/11, 2013 at 17:27

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