# Questions tagged [clustering]

Clustering is grouping (partitioning) a set of objects so that items in the same group are more similar to each other than to items in different groups, where the notion of similarity may be variously defined.

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### Clustering of directed graphs satisfying priority constraints

I recently ran into a problem related to directed graph clustering, but don't know how to solve it. There is a directed acyclic graph $G = (V,E)$, where $V$ is the set of vertices, and $E$ is the set ...
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### Understanding academic paper methodology (clustering trajectories with Bezier curves)

I'm currently doing my Master's dissertation project using football (soccer) tracking data, and am looking to cluster player run paths of various lengths in Python. I have found a relevant paper ...
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### Get Maximum value of a cluster as a constraint in a MILP

I am facing the following problem: I have same kind of a clustering Problem \begin{alignat}{4} \text{min }\quad& \sum_{c \in C} \sum_{s \in S} - y_{c,s}\\[2ex] \text{s.t. }\quad& \sum_{c \in ...
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### Why does spectral clustering work?

Relevant Background I've recently learnt about the spectral clustering algorithm and had a hard time understanding why we do what we do. Trying to undetstand, I stumbled upon this great post, that ...
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### Find in which face lie a point on a hyper polytope, inscribed in an hyper unit-sphere (and how to generate this hyper polytope)

I am working on clustering normalized point in a k dimension space. At first i used Spherical LSH strategy where i used random planes to cut the hyper-sphere but it induces a lot of random (because i ...
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### Grouping/Clustering surface mesh triangles by function values

I have the following problem. I have triangular surface meshs of three dimensional bodies. For each triangle exists an associated function value. This value varies over the whole mesh, but there are ...
1 vote
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### Calculating Mahalanobis distance

I am slightly confused as to how you calculate Mahalanobis distance given a set of data. I have tried asking my tutor for help but he does not seem interested in helping what so ever and I am ...
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### Selecting N evenly spaced nodes in the plane

Given a set of nodes $P$, making up a completely disconnected graph, I am looking for a method of selecting $N$ of them such that the graph can be partitioned into approximately equally sized clusters ...
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### Sampling vertices from a graph to maximize the spread

Given a graph with N vertices, I want to sample K of them such that I have the maximum possible spread. A possible application of this is to build shelters in a road network so that they cover the ...
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### How RatioCut leads to unnormalized spectral clustering?

I have understood the underlying concepts of spectral clustering and how inter cluster distance equation is mapped to a matrix form and how it is optimized using lagrange multiplier. But unable to ...
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### Best order to allocate services in graph using custom comparator

Good day! I have a lot of graphs with different properties: structure, number of nodes & edges, etc. All of them are undirected, "weighted" (edges have width, in other words capacity). ...
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### Colorblind test -- finding and classifying lines in 3-D space

I am creating a color blind test that uses RGB colors. RGB ranges [0-255] in all three colors to determine the final color. I would like to test the user to find which colors they struggle with. For ...
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### Clustering Similarity Measurement Based on Mutual Information

I have a question when learning the measures based on mutual information to the similarity between two clusterings. See this paper. Say the labels can be permuted. For example, "both a and b ...
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### Approximate maximization of a function

I am trying to find $s$ and $\eta=(\eta_0,\eta_1)$, that maximizes the following function. $$\max_{s,\eta} <x, \eta(s)>-n_0(s)log(1+e^{\eta_0})-n_1(s)log(1+e^{\eta_1})$$ where $x$ is a vector ...
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### How to mathematically formulate this clustering optimization problem?

I need to perform clustering of two different entities (as seen in the attached image, red square and blue balls are two different entities) under the following constraints Lets say, red square: ...
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### Maximize colors within a circle

I have a set of $m$ points $P$ over a large bidimensional space, each point having a color. Every color belongs to one of $n$ disjunct sets $S_i$ of colors. Given a circle $c$ we define $C_c$ as the ...
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### Indexing The Nodes of a Dendrogram

Suppose I have a dataset $\{x_i\}_{i=1}^n$ that I have implemented some hierarchical clustering algorithm (e.g., Single-Linkage Clustering) on. This gives me a dendrogram, which we can use to ...
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### Is vector quantization belonging to the extention of K-means clustering

In unsupervised learning, vector quantization belongs to the extension of K-means clustering? since K-means tries to develop clusters with corresponding chose optimized centers to represent and find ...
1 vote