# Questions tagged [graphs]

For the nodes and links sense of graph; use the visualization tag for the charting sense.

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### Use cases for graph algorithms and graph data structures in finance and banking

I work in a bank and most data is in tabular format in relational databases. I have been reading about graph algorithms (page rank), graph libraries (spark graphx) and graph databases (neo4j). I would ...
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1 vote
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### Identify social users using graph embeddings

I have a social network and I want to identify the most social people in the graph. In a typical graph experiments this could have done using different network features. However, I recently came ...
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### How do you set sigma for the Gaussian similarity kernel?

Let's say we have $n$ two-dimensional vectors: $$\mathbf{x}_1,\dots,\mathbf{x}_i,\dots,\mathbf{x}_n=(x_{1_1},x_{1_2})^T,\dots,(x_{i_1},x_{i_2})^T,\dots,(x_{n_1},x_{n_2})^T$$ How do you set $\sigma$ ...
16k views

### What are graph embedding?

I recently came across graph embedding such as DeepWalk and LINE. However, I still do not have a clear idea as what is meant by graph embeddings and when to use it (applications)? Any suggestions are ...
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1 vote
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### Graph to display differences (or lack of) in multilevel categorical data

I am trying to find an interesting way to interpret and display a set of data for the research I'm working on. Columns 2-4 show the net change from time 1 to time 2 in antibiotic coverage for ...
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### Viterbi-like algorithm suggesting top-N probable state sequences implementation

Traditional Viterbi algorithm (say, for hidden Markov models) provides the most probable hidden state sequence given a sequence of observations. There probably is an algorithm for decoding top-N ...
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### In a directed graph, how to measure whether a node is more "upstream" or "downstream"?

Let's say that I have a directed graph, and for each node I want to have some measure of whether it is more of an "upstream" node (that lies at the beginning of many paths), or a "downstream" node (to ...
1 vote
53 views

### System to provide guide to students about getting admissions to universities of their choice or some specific courses [closed]

I basically want to build a system which will provide a student step by step guide or you can say a full route about what courses he/she should take currently or what examinations they need to clear ...
166 views

### Neo4j graph to cypher conversion

Is there a way or tools available to generate or retrieve cypher query from a Neo4j database ? Should we need to store cypher quries along with the graph data for regeneration ?
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### Clustering Multiple Networks

I'm looking for methods of Community Detection in networks. For example if I have a network of 100 people (each node is a person), how can I cluster nodes? What would be the best approach for grouping ...
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1 vote
65 views

### Why do we do citation analysis?

Pardon my question if it seems too general... I'm new to networks in general, but recently I came across a type of network called citations network. However, I couldn't figure out why we do citation ...
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### What is the best algorithm for deterministic belief propagation?

Here is a simple example: In a 3D space, if point A is the geocenter of a planet, point B is its north pole, and point C has a fixed latitude/longitude on the planet surface. Then the position of ...
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### Weighted degree in Multidimensional networks

Does there exist a definition for weighted degrees of multidimensional networks? I understand that the basic definition would be: Let $v\in V$ be a node of a network $G=(N,V,L)$. The function ...
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### Organize TSNE data into grid

I have some data reduced by TSNE into a 2D representation, which shows clear spatial features. However, I'd like to format this into a grid – not just snapping data to the nearest grid square but ...
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### Predict a tree structure out of nodes with different features

The Problem Suppose we have a representation of a document's text layout as in the image below: Here, each rectangle represents a chunk of text (one word, an expression or even part of a sentence). ...
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### How to create full graph from vertex data frame with igraph?

Here is a DF which I take as a representation of my future vertices: Id Name 01 Alpha 02 Beta 03 Delta 04 Epsilon I want to get an igraph ...
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### How to approach graphed data for a binary classification system?

I'm looking for articles and other reading material on handling and modeling graph-shaped data for classification systems. As I've never working with graphed base machine learning anything from novice ...
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### Which algorithms should I use for recommendation system using a graph database?

Basically I'm developing a recommendation system using a graph database (specifically neo4j), and I want to apply recommendation algorithms. Since i'm using a graph database, I can see the ...
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### Large Graphs: NetworkX distributed alternative

I have built some implementations using NetworkX(graph Python module) native algorithms in which I output some attributes which I use them for classification ...
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1 vote
317 views

### Kernel on graphs and SVM : a weird interaction.

I have a collection of 80k graphs, half of them are labeled 1 (they represent the cities of France) and the other half is labeled 0 (representing cities in the USA). My goal is to create a classifier ...
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### Finding groups of friends in social network data

I have some social network data in which I'd like to identify people who belong to a group of 5 friends. These are users who are friends with 4 other people who all are also friends with each other. ...
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1 vote
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### Multi Model data set Visualization Python

I have a data-set with two variable frequency values as given below ...
1 vote
22 views

### Network analysis applied on terms

I am dealing with textual data. Imagine a certain number of statements (they could be descriptions), each one referring to a certain process, where each process ends in one f three categories: A, B, C....
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### Is it ideally correct to benchmark neo4j as graph processing platform?

I would like to know if neo4j can be considered a graph processing platform, even though i know that: neo4j: is a graph database management system developed by Neo Technology, Inc. Described by its ...
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I'd like to test a new algorithm for link prediction on graphs. I'm interested in both weighted/unweighted and directed/undirected graphs. What are some common benchmark datasets that researchers ...
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### Application of ideas from graph theory in machine learning [closed]

I work with neural networks (ConvNNs, DeepNNs, RNNs/LSTMs) for image segmentation and recognition and Genetic Algorithms for some optimization problems. Recently I started to learn some deep graph ...
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### Visualize graph network with more than 30k edges

I have a dataset with users connection and I want to create a directed network graph. Nodes: ~20.000 Edges: ~33.000 I used to work before on NodeXL and Gephi, but now I am on Mac and I don't have ...
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### source and target functions in igraph package in R

What are the source and target functions in igraph package in R? so that source(s->t) = s and target(s->t) = t I am working on this directed graph example: ...
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### How to predict Estimated Time for Arrival given only trajectory data and time?

I have data of latitude, longitude and timestamp. I am trying to build a graph based on pincodes (in India) (equivalent to zipcode). Based on this graph and trajectory data that I have, I want to ...
44 views

### How to apply K-Medoids in many CFG?

I am having around 1000 DAG(Directed Acyclic Graph) of different files showing java.io.BufferedReader usage. Following is representation of one of the graphs ...
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### Visualizing a big number of polynomials as atlas of graphs?

Suppose you have a big number of polynomials such as xyz+xy+z where xyz, xy and ...
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### What is a Recurrent Heavy Subgraph?

I recently came across this term recurrent heavy subgraph in a talk. I don't seem to understand what it means and Google doesn't seem to show any good results. Can ...
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### How to make edges appear in a graph when adjacency matrix value is beyond a particular threshold?

I've created a graph from an adjacency matrix using the igraph package but I want edges to appear in the graph only when the value in the adjacency matrix is beyond a particular threshold. Using the ...
4k views

### How to convert a 2D matrix into a graph object in R

set.seed(42) iris_matrix <- as.matrix(iris[,1:4]) image(iris_matrix) g<-cor(iris_matrix) g library(igraph) independent.vertex.sets(g, min=NULL, max=NULL) ...
1 vote
101 views

### Algorithm to construct similarity structure from hash lookup table

I have constructed a lookup table using locality-sensitive hashing for comparing nearly similar documents/records. If two records (columns) have the same hash value in a row, they are considered to be ...
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### What is the difference between affinity matrix eigenvectors and graph Laplacian eigenvectors in the context of spectral clustering?

In spectral clustering, it's standard practice to solve the eigenvector problem $$L v = \lambda v$$ where $L$ is the graph Laplacian, $v$ is the eigenvector related to eigenvalue $\lambda$. My ...
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### Hub removal from graphs

I have a graph with vertices that represent some entities and the edges are weighted as the correlation between two such entities. I would like to break this graph into several subgraphs with high ...
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### collaborative filtering using graph and machine learning

What are the advantages and disadvantages of using Collaborative filtering based recommendation using machine learning approach and graph based approach ? Say I have user purchase data (user_name, ...
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1 vote
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### Designing an (RL) agent for a graph-based music improvisation system

I am trying to implement a simple agent that creates sounds by building up signal building blocks (e.g. sound generators, filters etc.) that can generally be connected in the form of a directed ...
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76 views

### Estimating destination according to previous data

I need an advice. I can resume my problem like that : I have some travels in a database, for example : ...
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1 vote
539 views

### Website navigation path using graph theory

In web analytics, one of the main issues is to find the optimal path of navigation. Question: Is there any literature in graph theory area, which is focused on studying optimal website navigation path?...
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### Cluster directed graph into DAG

I am looking for an algorithm that clusters a directed graph into a set of clusters that form a directed acyclic graph. For example, given: nodes: {A, B, C, D} with edges: {(A,B), (B,A), (A,C), (C,D),...
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### What makes a graph algorithm a good candidate for concurrency?

GraphX is the Apache Spark library for handling graph data. I was able to find a list of 'graph-parallel' algorithms on these slides (see slide 23). However, I am curious what characteristics of these ...
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### Is there any working alternatives to Netvizz? [closed]

I'd like to download my friends data as a graph/network from Facebook. In Feb 2015, Facebook banned the awesome application Netvizz. Do you know any alternative application for my purpose?
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### Traversing trees in SQL: JOINs vs imperative algorithm

I have a table representing posts on a message board. Posts may or may not have parents. What is the most common way to get all posts starting from a given post, or to find the root post of any given ...
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### Learning time of arrival (ETA) from historical location data of vehicle

I have location data of taxis moving around the city sourced from: Microsoft Research Overall it has around 17million data points. I have converted the data to JSON and filled up mongo. A sample ...
183 views

### Why are HMMs called linear-chain?

I found in many sources that Hidden Markov Models are linear-chain networks(e.g. in Predicting Structured Data book by MIT). However, as I understand it, HMMs can have any edges in its graph. Even ...
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### Canonical VS Graph Isomorphism [closed]

I'm having a having a hard time understanding the difference between an isomorphism in graphs and canonical graphs. I have read through the Wikipedia articles, but it still isn't clicking. Can ...
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I want to generate an $N\times N$ matrix $A$ so as to target an $N$ vector of row sums and simultaneously all column sums should sum to 1. In addition to this, I have a prefixed number of elements ...