nearest-neighbor Questions

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Description :- I am trying to rotate an image without using OpenCV functions in C++. The rotation center need not be the center of the image. It could be a different point (offset from the image ce...
Finke asked 11/7, 2019 at 3:5

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I am trying to join 2 SpatialPointsDataFrames by nearest neighbour analysis using sf::st_join(). Both files have been converted using st_as_sf() but when I try the join I get the error Error in ...
Incomplete asked 9/7, 2019 at 10:15

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I noticed that LSH seems a good way to find similar items with high-dimension properties. After reading the paper http://www.slaney.org/malcolm/yahoo/Slaney2008-LSHTutorial.pdf, I'm still co...

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I have a problem with getting nearest values for some rows in pandas dataframe and fill another column with values from those rows. data sample I have: id su_id r_value match_v A A1 0 1 A A2 0 1...
Balaton asked 30/5, 2019 at 12:47

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I'm new to machine learning and would like to setup a little sample using the k-nearest-Neighbor-method with the Python library Scikit. Transforming and fitting the data works fine but I can't fig...
Doering asked 15/5, 2019 at 16:20

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I have a numpy.ndarray of 3d-points, i.e. the np.shape of it is (4350,3) and such a second numpy.ndarray of 3d-points of np.shape (10510,3). Now I am trying to find the right python-package to cal...
Illegible asked 9/1, 2019 at 16:42

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I need to generate K nearest neighbours given a datapoint. I read up the sklearn.neighbours module of sklearn but it generates neighbours between two sets of data. What I want is probably a list of...
Humeral asked 21/12, 2018 at 13:14

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I am using the following Nearest Neighbor Query in PostGIS : SELECT g1.gid g2.gid FROM points as g1, polygons g2 WHERE g1.gid <> g2.gid ORDER BY g1.gid, ST_Distance(g1.the_geom,g2.the_geom)...
Portuguese asked 5/5, 2012 at 11:1

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I have a 2D list of only 1's and 0's: Boundaries = [ [0,0,0,0,0], [0,1,1,1,0], [0,1,1,1,1], [0,1,1,1,0], [0,0,1,0,0]] I need to test this list to check if there are any 1's surrounded by 8 other...
Anserine asked 14/10, 2014 at 14:39

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I'm having trouble coming up with an efficient SQL query to handle the following situation: Assume we have a table with two columns groupId : int value : float The table is huge (several milli...
Soil asked 6/4, 2009 at 9:25

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I am looking at the Wikipedia page for KD trees. As an example, I implemented, in python, the algorithm for building a kd tree listed. The algorithm for doing KNN search with a KD tree, however, ...
Koodoo asked 11/12, 2010 at 19:14

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I am looking for a performant algorithm to match a large number of people by location, gender and age according to this data structure: Longitude (denotes the persons location) Latitude (denotes ...

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As Spark's mllib doesn't have nearest-neighbors functionality, I'm trying to use Annoy for approximate Nearest Neighbors. I try to broadcast the Annoy object and pass it to workers; however, it doe...
Lylalyle asked 3/2, 2016 at 22:51

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I am working on a study that is trying to assign particulate matter exposure to specific individuals based on their addresses. I have two data sets with longitude and latitude coordinates. One if...
Frederiksen asked 5/12, 2017 at 21:51

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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 ...

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I have two vectors with a few thousand points, but generalized here: A <- c(10, 20, 30, 40, 50) b <- c(13, 17, 20) How can I get the indicies of A that are nearest to b? The expected outco...
Emelia asked 15/4, 2012 at 7:54

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I am trying to find a fast algorithm for finding the (approximate, if need be) nearest neighbours of a given point in a two-dimensional space where points are frequently removed from the dataset an...

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I have a collection of n dimensional points and I want to find which 2 are the closest. The best I could come up for 2 dimensions is: from numpy import * myArr = array( [[1, 2], [3, 4], [5, 6], ...
Jessikajessup asked 25/2, 2011 at 16:17

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So I have about 16,000 75-dimensional data points, and for each point I want to find its k nearest neighbours (using euclidean distance, currently k=2 if this makes it easiser) My first thought wa...

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I am trying to find all the nearest neighbors which are within 1 KM radius. Here is my script to construct tree and search the nearest points, from pysal.cg.kdtree import KDTree def construct_tre...
Carny asked 31/7, 2017 at 4:12

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I have 300 million addresses in my PostgreSQL 9.3 DB and I want to use pg_trgm to fuzzy search the rows. The final purpose is to implement a search function just like Google Map search. When I use...

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I have implemented a simple L1 distance calculator using Haskell. Since I am interested in performance I used unboxed vectors to store the images to compare. calculateL1Distance :: LabeledImage -&...

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I'm beginning to learn Python coming from a C++ background. What I am looking for is a quick and easy way to find the closest (nearest neighbor) of some multidimensional query point in an 2D (numpy...
Rori asked 15/12, 2011 at 23:16

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I am trying to find the k-nearest neighbor on a sphere using R. As I deal with million of points brute force is not an option. Does anyone know how I could do? Thank you
Meg asked 23/11, 2016 at 14:41

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I am trying to scale the "matching_to_many_images.cpp" for large set of images. (20K+ images) https://github.com/kipr/opencv/blob/master/samples/cpp/matching_to_many_images.cpp I use FLANN based m...
Interposition asked 24/10, 2016 at 6:15

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