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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49 views

How to perform local search to find maximal induced subgraphs?

I'm looking for efficient ways to perform local search to find maximal induced subgraphs that satisfy certain properties : a tree, a forest or a bipartite subgraph for example. What I mean by local ...
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30 views

Relevance of the ZeroSum game to Heuristic search?

A question was posed to me as to the relevance of the ZeroSum game to Heuristic search algorithms. I know that the zero sun game is a theory in which one persons gain is exactly balanced to another ...
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47 views

can someone provide a good resource for understanding 2 opt heuristic?

I have looked into wikipedia and this MIT slide. A step by step iteration of the algorithm with a clear example would be appreciated.
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557 views

8 puzzle admissible heuristic where tiles are in correct position

For the 8 puzzle problem, it has been proved that if h(n) = number of tiles on wrong place. h(n) is an admissible heuristic as every tile which is in wrong place must be moved out at least once. But ...
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41 views

How many states are examined in the most wins heuristic for tic-tac-toe (9-grid)?

I'm new to AI, and have a hard time to understanding how to count the total states are examined in the most wins heuristic for tic-tac-toe two plys deeper(9-grid)? Need help
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1answer
170 views

How to prove if a heuristic function is admissible or not

Can somebody tell me how to solve this problem?
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1answer
569 views

Nearest Insertion Traveling Salesman Heuristic: is it faster to insert nearest nodes first?

I am trying to implement the nearest insertion TSP heuristic. However, I am wondering if it matters which node I insert into the subgraph first. For example, should I start with one node; calculate ...
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1answer
802 views

A* Search Algorithm Implementation with Priority Queue

I've got a question regarding the A* search algorithm's implementation. According to Wikipedia, one has to use a priority queue for retrieving the next node with the lowest f value, is it possible to ...
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1answer
222 views

Does domination rule apply for inadmissible heuristics?

Let's say $h_1(n) \geq h_2(n)$ so that dominance is established even if $h_1$ and $h_2$ are both inadmissible/non-optimal heuristics -in whichever given search space. Is $h_1$ still faster/better ...
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1answer
527 views

Does this A-Star heuristic already exist?

I've been thinking about the A* algorithm recently. For context, A* is a graph-navigating algorithm most often used to solve problems that go "What is the shortest path from point A to point B?". It's ...
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2answers
52 views

Optimization Problem when calculating fitness is expensive

I need to solve an optimization problem, maximizing fitness in a set of around 1 million solutions. Calculating the fitness of any solution is very time consuming, taking around 5 minutes. Therefore, ...
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1answer
87 views

Steps to create a heuristic for solving a problem

I am completely new to AI and doing self-learning to acquire this knowledge. I went through the different available search algorithm like BFS, DFS and A* but something that I can't understand is a ...
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1answer
24 views

Justification behind this heuristic in SMA*+

I'm reading the paper Enhanced Simplified Memory-bounded A Star (SMA*+). In short, the authors propose a limited-memory version of A* where we cull nodes if we are out of memory, to re-expand them ...
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1answer
42 views

What is the peak in fitness landscape

I have just started reading about fitness landscapes and I couldn't understand what the peak means. What does the peak mean?
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302 views

SAT Solving + Turing Machines

I have a couple of questions based on how SAT solvers work. I understand that SAT solvers may employ any/all of the following techniques: Randomness Heuristics Backtracking SAT is just one example ...
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1answer
175 views

Improvement Heuristics for Asymmetric TSP

i have been solving the Time-Dependent Traveling Salesman Problem using an Ant Colony Optimization. Upon reading the ACO papers, there are several reminders which state that ACO performs best with ...
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1answer
358 views

Consistent heuristic and A*

The following graph has consistent heuristic. An A* algorithm will alter its first guess ACD to the correct shortest path ABD... if it has consistent heuristic, doesnt it mean, that AB should be ...
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1answer
20 views

How to get initial flow for TSP with missing edges

I need to solve a version of the traveling salesman problem with missing edges. I've decided to use simulated annealing. How do I generate a valid initial path effectively? I would use a greedy ...
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0answers
84 views

Comparison of time-dependent traveling salesman heuristics

I'm looking into implementing a heuristic for the time-dependent traveling traveling salesman problem (TDTSP) that completes in a certain amount of time. There are a wide range of possible ways to ...
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1answer
238 views

consistent heuristic - does it always exist?

I am studying for an artificial inteligence class, and i have to classify the following sentence "For any search space, there is always an admissable and consistent A* heuristic". Well, i know that ...
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277 views

What is the best heuristic function for evaluating the state in game of sprouts?

We are developing game of sprouts bot using min-max algorithm. We need a good heuristic function for evaluating the state of the game/player. Can someone please suggest?
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1answer
366 views

Comparing A* search to Simulated Annealing

Good Afternoon, I am comparing A* search to Simulated Annealing for an assignment, mainly the algorithms, memory complexity, choice of next actions, and optimality. Now, I am not 100% sure about my ...
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2answers
101 views

Greedy Heuristic for the Traveling Salesperson Problem

We're studying Heuristic in my Theoretical CS class, more specifically Greedy-Algorithms for the Traveling Salesperson Problem. The first one is the "next neighbor heuristic", where you start at any ...
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42 views

Defining preferred paths makes $A^*$ heuristic lose admissibility

In a geographical graph, where each edge's cost is equal to the physical distance between its nodes, one can be tempted to manipulate the cost of some of the edges, to make it a bit lower, in order to ...
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1answer
329 views

If $h(s)$ is an admissible heuristic, is $\sqrt{h(s)}$ admissible?

I was thinking yes because $0 \leq \sqrt{h(s)} < h(s)$ but I'm not entirely sure.
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509 views

Creating admissible and consistent Heuristic function Help

I am trying to create a heuristic function for use in an A* algorithm. The problem to be solved is a single row tile puzzle with 3 total w tiles and 3 b tiles and one "_" tile as shown below WWW_BBB ...
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1answer
378 views

Are there practical methods for solving ILP?

Recently I encountered some papers in which the most important part seems to be writing an Integer Linear Program for a problem for which there exist some exact or heuristic algorithms! Is solving an ...
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76 views

Table of incompatible turns in an intersection (steps to writing a program)

I just began reading Data Structures and Algorithms (Aho, Hopcraft, and Ullman). At the beginning, there is an example that discusses designing a traffic light for a complicated intersection of roads. ...
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1answer
65 views

Hueristic Algorithm to find the maximum clique

Let the algorithm be defined as follows: Consider the following heuristic algorithm for finding the maximum size clique in a graph. (1). Delete from the graph a vertex that is not connected to every ...
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1answer
983 views

AI: Heuristic function A* search

I have an assignment in my university where I have to implement Uniform Cost Search and A* Search. We have an input which includes a map and queries. The map is weighted, directed graph, represented ...
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1answer
3k views

Best heuristic for A*? [closed]

I'm trying to build a maze solver using A* algorithm. The maze is a grid with movement allowed in 4 directions (up, down, left, right). If there's a starting cell (x1, y1) and a destination (x2, y2), ...
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3answers
23k views

Why is the A* search heuristic optimal even if it underestimates costs?

A* search finds optimal solution to problems as long as the heuristic is admissible which means it never overestimates the cost of the path to the from any given node (and consistent but let us focus ...
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108 views

A* heuristic for the game Blockage

There is a flash game that you can very easily find on Google called Blockage. Rules & Goal of the game : Get all coloured blocks from their initial position to a corresponding target spot ...
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1answer
638 views

If h(n) is a perfect heuristic (that is, h(n) = h*(n)), then does it imply that A* will always take linear time complexity?

That is, if h(n) = h*(n), then A* only expands nodes that lie on an optimal path to the goal. But does this imply that A* will always take a linear time in the solution length to find an optimal ...
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3answers
13k views

Why is 'Manhattan distance' a better heuristic for 15 puzzle than 'number of tiles misplaced'?

Consider two heuristics $h_1$ and $h_2$ defined for the 15 puzzle problem as: $h_1(n)$ = number of misplaced tiles $h_2(n)$ = total Manhatten distance Could anyone tell why $h_2$ is a better ...
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0answers
760 views

A good heuristic for 2D Rubik's cube

I am looking for a good heuristic function for solving a 2D $n\times n$ Rubik's cube using A* search. There is a game already in the play store. The rules of the game: Swiping LEFT means the ...
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2answers
149 views

What is the importance of disjoint edges in k-opt algorithms?

I'm trying to implement a k-opt algorithm and I'm bogged down on a detail: the importance of choosing disjoint edges. My question: Is there any benefit to considering adjacent edges, or is the full ...
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222 views

Prove that a convex combination of admissible heuristics is admissible

I got this question that's been troubling me for some time. If $h_1$ and $h_2$ are admissible heuristic functions, prove that $h_3 = (c-1)\,h_1 + c\,h_2$, $0 < c < 1$, is also an admissible ...
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98 views

Was the “cuckoo search” independently discovered before 2009? If so, what was the name given to it?

Background: I would like to experiment with evolutionary algorithms to generate the "optimal" poem, according to a fitness function to be determined later. However, I cannot think of a good way of ...
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0answers
66 views

Are there many empirical results about which metaheuristics are well-suited for which problem domains?

One of the nice things about genetic algorithms is that they can easily be used for a diverse array of problem domains, whereas PSO for example seems best-suited for candidates of real-valued vectors (...
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1answer
75 views

Movement on Labyrinth with Best First Search

I have the following labyrinth where R is the robot(the parent node), red blocks are the obstacles where the R cannot move and <...
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1answer
471 views

How to proof a heuristic?

I am not very familiar with "heuristic", so please correct me if anything said by me is wrong. Per my understanding, Algorithm is an automatic steps which guarantee to give a correct solution ...
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1answer
1k views

Sort array with minimum swaps

Given an array, I need to sort the array (if not already sorted) in either decreasing or increasing order so that number of swaps are minimized. I was thinking of first determining whether it is ...
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56 views

Algorithms or specific approaches for maximum independent set problem in triangle free graphs

And obviously there will be no trivial vertex which has only 2 edges. I think triangle free graphs are (subjectively) easier than complicated graphs, i wonder if you know some heuristic approaches/...
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2answers
8k views

Is using a more informed heuristic guaranteed to expand fewer nodes of the search space?

I'm reading through the RMIT course notes on state space search. Consider a state space $S$, a set of nodes in which we look for an element having a certain property. A heuristic function $h:S\to\...
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1answer
774 views

Is a two-opt move guaranteed to produce a non-worse tour?

I have a little doubt with respect to the two-opt improvement heuristic for TSP. I understand how it works, from the Wikipedia article on 2-opt and "Heuristics for the Traveling Salesman Problem". ...
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1answer
1k views

Implement multi-fragment heuristics for the traveling salesman problem

I would like to implement the multi-fragment heuristics algorithm for finding a solution to the traveling salesman problem. The algorithm is described here as follows: This seriation method re-...
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1answer
2k views

How to verify that a heuristic is consistent?

A heuristic function is said to be consistent, or monotone, if its estimate is always less than or equal to the estimated distance from any neighboring vertex to the goal, plus the step cost of ...
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1answer
65 views

Distribution of beans in jars to k members

Here is the problem. We have N jars. Each jar can have any number of beans. These beans have to be distributed among C children. The resulting distribution should serve two goals Now the number of ...
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3answers
8k views

Difference between heuristic and approximation algorithm?

i have a problem regarding the following situation. I have two arrays of numbers like this: ...