a mathematical structure that contains a collection of vertices or 'nodes' and a collection of edges that connect pairs of vertices
0
votes
0answers
53 views
Evaluating code for a graph [on hold]
This is relatively long code. Please take a look at this code if you are still willing to do so. I will appreciate your feedback.
I have spent two days trying to come up with code to represent a ...
3
votes
1answer
115 views
How to solve binary labeling with graph cut?
Many literature references suggest that the binary labeling problem can be converted into a graph cut problem and solved with the max flow/min cut algorithm. I'm trying to understand the formulation ...
1
vote
1answer
47 views
How can I find all connections in a mesh network/graph?
Suppose I have a mesh of relationships, such as
Friends who trust some friends and not others
A IPv6 router that needs to locate peers across the Internet
A PGP Web Of Trust that needs two people ...
3
votes
1answer
163 views
Breadth-first graph search problem
I thought I was doing breadth-first graph search correctly, but my instructor's grading script is telling me that my answer is incorrect.
From the instructions:
Consider a breadth-first graph ...
2
votes
3answers
87 views
Storing a drawn graph information in database for web application
Well while developing a web application that allow users to draw graphs (flow charts, ER diagram , UML, .... etc) the information of drawn items and their relation to each other and position on canvas ...
1
vote
2answers
110 views
Is it possible to represent mutation of object-graph efficiently with immutable states?
I am practicing using of immutable object in C++. My personal goal is representing generic object graph (in heap) with sequence of immutable graphs.
Building the multi-version graph itself isn't that ...
1
vote
1answer
89 views
Data structure theory based on graph rewriting
First of all, I'm looking for a book, publication, project or any kind of information that should probably exceed the limits normally imposed on answers in this kind of forum. I know the rules about ...
2
votes
1answer
85 views
Class instance clustering in object reference graph for multi-entries serialization
My question is on the best way to cluster a graph of class instances around specifically marked objects (objects are the graph nodes and the references to each other are the directed edges of the ...
1
vote
1answer
85 views
Connected components of a graph using Prolog
Given a corner x of an undirected Graph G I would like to ask for the connected component of x, but my first try does not work as desired. Here it is:
edge( a,b ).
edge( b,a ).
edge( b,c ).
edge( ...
2
votes
1answer
146 views
Algorithm in undirected BFS graph
I'm trying to put together an algorithm that will display the node degree for every node in a breadth first tree graph (assume BFS was called). Assume it's an undirected graph. I'm not sure how to ...
4
votes
2answers
91 views
Placing elements in graph with a streaming/online algorthm
We have a stream of points with about 1000 points per second. For each point, we have a complex vector (hundreds of dimensions). Our goal, for each point is to link it to the 5 closest points that ...
4
votes
1answer
232 views
Where to learn graph theory applications [closed]
I am completely new to designing algorithms with graphs. I am following CLRS and other video lectures in Youtube, notably from IIT/MIT. They are pretty good, and I currently have decent idea about ...
4
votes
1answer
432 views
Building a Graph Editor - How to create a data driven graph
I am developing a graph-editor that uses drag and drop to build hierarchical graphs (containing nodes and links). Each node in the graph should be linked to a table in our database (SQL Server). I did ...
1
vote
1answer
207 views
Languages with graph data structures and algorithms in standard library
I am trying to improve my knowledge and ability with graphs and graph algorithms and have noticed something curious: as far as I can tell no "mainstream" language contains support for graphs in its ...
2
votes
3answers
321 views
How can you prove an acyclic graph has n-1 edges? [closed]
I'm not so hot on the maths for this but for what I understand...
A graph g exists with v vertices and edges. g = (V,E);
The spanning graph for this is an acyclic copy of this where all the vertices ...
6
votes
1answer
96 views
Detecting areas of isotropic vs anisotropic diffusion in a flood-fill (or similar) operation
Hello fellow programmers!
I have a 2D graph which is best described as a Cartesian grid with traversible and non-traversible cells. I'd like to be able to detect subsets of this graph where the ...
6
votes
3answers
836 views
What algorithm should I use to find the shortest path in this graph?
I have a graph with about a billion vertices, each of which is connected to about 100 other vertices at random.
I want to find the length of the shortest path between two points. I don't care about ...
-2
votes
1answer
372 views
using ant colony algorithm to create cross word game [closed]
I have difficulty to learn about ant colony algorithm (ACO), I have read about generating crossword game using (genetic algorithm) GA.I Know both of GA ant ACO usually used for optimization, but my ...
0
votes
1answer
218 views
How to turn a website into an offline usable directed graph for searching shortest ways between pages [closed]
I am an advanced-intermediate level student focused on the .NET and C#. I know all the basics as well as classes, methods, objects, inheritance, OOP principles and all that. Problem is we haven't ...
18
votes
6answers
545 views
Visiting points on a number line while minimizing a cost not related to distance
I need some help on this ACM ICPC problem. My current idea is to model this as a shortest path problem, which is described under the problem statement.
Problem
There are N = 1000 nuclear waste ...
2
votes
1answer
205 views
Finding subtree in a tree
I have a tree:
a
/ \
b c
/ \
d f
/ \
g h
And the pattern:
x
/ \
y z
/ \
q p
As output I would like to have:
x: a
y: b
z: c
q: d
p: f
and
x: b
y: f
z: c
q: ...
5
votes
2answers
108 views
spotting graph cycles - simple explanation
could some please help me understand how to find cycles in graphs in laymans terms?
I have read other questions, such as This one and also some of the wikipedia pages, but they seem to descend rather ...
1
vote
2answers
453 views
What is the best way to plot 3D/2D plots with real time data? [closed]
First of all, I like to use Python, because it is easy to work with. I am not a programmer, so I prefer anything that is easy to use and understand. I understand that it might be faster to program 3D ...
1
vote
1answer
126 views
Implementing a sort of navigation system
So I am undertaking a project which does navigation sort of thing. So here is how the problem statement looks like.
Say, given a map of a floor, with different rooms, now somehow, this information is ...
6
votes
3answers
720 views
Cyclomatic complexity with two IFs - why it is 3?
I have read an article with following example:
void func()
{
if (condition1)
a = a + 1;
if (condition2)
a = a - 1;
}
It says the CC is 3 as there are three possible paths. How come? Why not 4? I ...
3
votes
2answers
200 views
Chambers In A Castle Algorithm
Problem Statement -
Given a NxM grid of 1s & 0s (1s mark walls, while 0s indicate empty chambers), the task is to identify the number of chambers & the size of the largest. And just to ...
1
vote
2answers
494 views
Tree vs Graphs in search
Could anyone give a clear and concise explanation for when you use graphs vs when to use trees for data structures?
30
votes
7answers
3k views
When to use DAG (Directed Acyclic Graph) in programming?
I recently found a framework named ecto.
In this framework, a basic component named "plasm", which is the ecto Directed Acyclic Graph.In ecto, plasm can be operated by ecto scheduler.
I am ...
5
votes
4answers
828 views
What are graphs in laymen's terms
What are graphs, in computer science, and what are they used for? In laymen's terms preferably.
I have read the definition on Wikipedia:
In computer science, a graph is an abstract data type ...
5
votes
1answer
415 views
Nearest color algorithm using Hex Triplet
Following page list colors with names http://en.wikipedia.org/wiki/List_of_colors.
For example #5D8AA8 Hex Triplet is "Air Force Blue". This information will be stored in a databse table (tbl_Color ...
3
votes
1answer
188 views
Graph/diagram editor that works with pseudographics
Is there a graph/diagram editing tool that can output (or even better also parse) pseudographics, that can be easily inserted into source code comments? Like this:
+---------------+
| ...
6
votes
1answer
2k views
Am I right about the differences between Floyd-Warshall, Dijkstra's and Bellman-Ford algorithms?
I've been studying the three and I'm stating my inferences from them below. Could someone tell me if I have understood them accurately enough or not? Thank you.
Dijkstra's algorithm is used only ...
0
votes
3answers
517 views
Reasonable Number of Directed Graph Nodes and Edges
How many directed graph nodes are typically represented in the browser? I'm working with some large data-sets with nodes and edges more then 400,000. I'm wondering if I am going down a fruitless path ...
3
votes
2answers
161 views
Custom graph comparison?
I'm trying to compare two graphs using hash value ( i.e, at the time of comparison, try to avoid traversing the graph )
Is there a way to make a function such that the hash values compared can also ...
4
votes
1answer
307 views
Merging similar graphs based solely on the graph structure?
I am looking for (or attempting to design) a technique for matching nodes from very similar graphs based on the structure of the graph*. In the examples below, the top graph has 5 nodes, and the ...
5
votes
1answer
396 views
Algorithm for perfect non-binary graph layout
I have a complex non-binary graph model.
Each tree node can have multiple children&parents (a node can also have a connection to it's "brother").
A node is represented as square on screen with ...
1
vote
1answer
639 views
Networkx / Python : Is using a class for a node better practice than defining multiple attributes?
I've read through the NetworkX tutorial and documentation, but was unable to find real world answers for this question.
Usually when using NetworkX, I might use strings to define nodes, then set ...
8
votes
3answers
3k views
Efficient graph clustering algorithm
I'm looking for an efficient algorithm to find clusters on a large graph (It has approximately 5000 vertices and 10000 edges).
So far I am using the Girvan–Newman algorithm implemented in the JUNG ...
11
votes
3answers
686 views
Randomly generate directed graph on a grid
I am trying to randomly generate a directed graph for the purpose of making a puzzle game similar to the ice sliding puzzles from Pokemon.
This is essentially what I want to be able to randomly ...
4
votes
4answers
404 views
Building a route creator
Ok, already up front, I'm going to tell you, that this is a bonus task for Data structure course I'm taking. That should take care of all the questions whether or not this is for a homework.
Route ...
4
votes
3answers
1k views
What is an algorithm to find simple cycles?
I have a graph with an Eulerian cycle and no Hamiltonian cycles. I would like to divide this graph into simple cycles.
Edges may not be repeated in simple cycles.
How can this be done?
1
vote
2answers
232 views
Tool for large scale graph analysis
What are the best tools / frameworks / libraries available to implement and run algorithms on graphs?
In particular I need a tool that can load a set of nodes, edges and values assigned to these ...
16
votes
5answers
1k views
Algorithm to determine fastest route?
Let's say we're going from 1 to 5. The shortest route will be 1-4-3-5 (total: 60 km).
We can use Dijkstra's algorithm to do that.
Now the problem is, the shortest route is not always the fastest ...
2
votes
5answers
552 views
Programming language with native concurrency support for large graphs?
I'm currently looking for a new programming language to learn (currently working through some C++, know some C and Python), specifically one that has built-in concurrency support? I want to try to ...
0
votes
1answer
2k views
Are questions on graphs common in programming interviews?
Despite saying that graphs are very important, none of my friends have got any graph related questions in interviews in Google and Amazon. I am preparing for these companies right now.
Should I ...
5
votes
2answers
724 views
Algorithm for an exact solution to the Travelling Purchaser Problem
do you know of any algorithms which give an exact solution for the Traveling Purchaser Problem. I can only find heuristic and probabilistic approaches.
I do have implemented a genetic algorithm so ...
3
votes
2answers
593 views
When can I be sure a directed graph is acyclic?
The definition for directed acyclic graph is this: "there is no way to start at some vertex v and follow a sequence of edges that eventually loops back to v again."
So far so good, but I am trying to ...
