Questions tagged [heuristics]

Questions about algorithmic strategies that quickly solve a problem well most of the time, but give no guarantees.

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900 views

Can heuristic methods and machine learning approaches be considered alternate methods to solve NP-Complete problems?

I was watching the videos from Skiena's Computational Biology Lectures, which is also available at youtube. In those videos, the professor made a statement that, most of the problems posed to computer ...
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1answer
41 views

Quickly pruning edges below average weight for a membership-based weighting

I have points represented as sparse high-dimensional binary vectors, or put another way, I have a list of groups that each point belongs to. For two points, the edge weight between them is $\sum_i 1/|...
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1answer
305 views

How to perform local search on simple paths?

I have a local search problem. The set of valid solutions are all the simple paths (i.e. without repeated nodes) from a node $S$ to a node $T$ in a directed graph. The question is: given a current ...
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0answers
367 views

Trying to understand the Gilmore-Lawler lower bound

For a class project we're developing a software that solves a common optimisation problem. After some research we've found out that our problem is called QAP (Quadratic Asssignment Problem) and the ...
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1answer
809 views

Genetic algorithm fitness function [closed]

I'm trying to write some little code (POC for the selection/mutation operators) that uses a genetic algorithm to solve a global maximum for a function. ...
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2answers
4k views

What is the no free lunch theorem?

I've been reading about the No Free Lunch Theorem, but I can't quite understand what it is about. I've heard this theorem described elsewhere as the claim that "no general purpose universal optimiser ...
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1answer
1k views

Where is the recursion, in the minimax-decision algorithm?

The below is from an article titled: Minimax: Recursive Implementation To be a recursive function, you need to call yourself. What part of this pseudo code is calling itself? How does depth-...
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1answer
244 views

How do I compute this non terminal positions evaluation, for tic-tac-toe?

Looking at this solution on page 3 but having trouble understanding the evaluation function specifically. For non terminal positions, we use a linear evaluation function defined as Eval (...
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1answer
200 views

Neighbourhood in local search metaheuristic

I cannot seem to find an answer to this question with Google, so I am going to ask here: is it required for a good neighbourhood function that it in principle (i. e. by recursively considering all ...
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1answer
226 views

Solving AlienTiles with an A* heuristic

Hello I am trying to solve the AlienTiles problem described at alientiles.com using the A* algorithm but I cannot find any good heuristic function so far. In AlienTiles you have a board with $N \...
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1answer
3k views

Creating admissible heuristics from functions?

I'm having trouble figuring out how to create admissible heuristics from cost functions. For example, if I was trying to create an admissible heuristic from a cost function that takes in starting ...
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1answer
320 views

Local search: Problem with neighborhood definition

I have question on understanding the following neighborhood relation within a local-search approximation scheme. Let $M$ be a legal matching on any bipartite graph. Let $U_k$ be the neighborhood ...
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1answer
451 views

Algorithm to use for a TSP variant

What type of algorithm would you suggest me to use for this problem? I want to implement an algorithm that minimize the total distance in a graph (TSP) but for only X nodes. Also, we can go as many ...
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2answers
863 views

Heuristics & Constrain Satisfaction Problem Differences

I'm currently taking an Algorithms course, and we are covering Backtracking, CSP, and heuristics. However, I'm getting confused on exactly the differences between these terms and their applications. ...
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2answers
3k views

When does the nearest neighbor heuristic fail for the Traveling Salesperson?

Can you provide an example of NN algorithm failure on the Euclidean traveling salesman problem? I was trying to construct a specific example of this for my friends and was failing.
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2answers
17k views

Trying to improve minimax heuristic function for connect four game in JS

I have made a connect four game in JS and currently have a functioning minimax algorithm. The problem I'm having is that it is very, very easy to beat, even with a large depth. This is leading me to ...
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1answer
674 views

How approximate are “approximate” nearest neighbor (ANN) search algorithms?

Starting to use nanoflann to do some point cloud nearest neighbor searching and it got me thinking about just how "approximate" ANN methods are. If I have a (more or less) randomly distributed point ...
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2answers
14k views

Initial temperature in simulated annealing algorithm

I've done some testing of different initial temperatures in my simulating annealing algorithm and noticed the starting temperature has an affect on the performance of the algorithm. Is there any way ...
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0answers
1k views

Time complexity 2-opt method

I'm doing a practice test for a course on routing problems. There's a question asking to infere the time complexity of the 2-opt method. I can see that the complexity per iteration is in $O(n^2)$ ...
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1answer
4k views

A Good Resource for Christofides' Heuristic

Is there an explanation Christofides's Heuristic for solving TSP which does not simply state the algorithm and go ahead to prove the bound? To be specific: (Disclaimer : I am an engineer who knows ...
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0answers
174 views

Experimental Survey on Different Heuristics for Knapsack Problem

I am looking for a good survey/study of experimental results of heuristics for Knapsack problem (or implemented libraries in java/c++). Any help is appreciated!
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0answers
119 views

Heuristics for tree decomposition into k shortest paths

What kind of heuristics are useful in a tree decomposition of a graph to find the k shortest paths from a given source to a vertex? Moreover, the local shortest paths at each node in a tree are ...
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1answer
834 views

'Texas Hold Em Poker' Agent Heuristics to help decide whether to fold or bet?

I am designing a poker agent with different heuristics to decide whether to raise, fold or pass (in Texas holdem poker). I am planning to have 4 heuristics with the agent biased to one of them. The ...
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1answer
4k views

Why is Uniform cost search called “uniform” cost search?

By this possibly good attempt to explain this, the "uniformity" in the Uniform cost search is actually the uniformity of the heuristic function. Is this explanation correct ? If yes, then don't all <...
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3answers
57 views

Heuristically determine a value f such that a probability d/f approaches 1/2

We have a set X of N elements. We want to get a new set X' having a size M < N. ...
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1answer
457 views

Problem similar to set packing

Call a family of sets $\mathcal{F} = \{S_1, \dotsc, S_k\}$ "diverse" if each set $S_i \in \mathcal{F}$ has at least one unique element. What are possible approaches for finding the largest diverse ...
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1answer
1k views

How to implement the details of shotgun hill climbing to make it effective?

I am currently working on a solution to a problem for which (after a bit of research) the use of a hill climbing, and more specificly a shotgun (or random-restart) hill climbing algorithmic idea seems ...
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1answer
871 views

Heuristics for an Artificial Intelligence problem

Problem : Given a (one dimensional) row containing $2N$ tiles arranged in $2N + 1$ spaces. There are $N$ black tiles (B), $N$ white tiles (W), and a single empty space. The tiles are initially in an ...
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1answer
3k views

Nilsson's sequence score for 8-puzzle problem in A* algorithm

I am learning the A* search algorithm on an 8-puzzle problem. I don't have questions about A*, but I have some for the heuristic score - Nilsson's sequence score. Justin Heyes-Jones web pages - A* ...