Questions tagged [heuristics]
Questions about algorithmic strategies that quickly solve a problem well most of the time, but give no guarantees.
174 questions
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Morphing Hypercubes, Token Sliding and Odd Permutations
A month ago, I asked the following question math.exchange (https://math.stackexchange.com/questions/3127874/morphing-hypercubes-and-odd-permutations), but for completeness, I will include the details ...
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67 views
How can an A* algorithm visit all nodes?
Is it possible to find the shortest path and visit all the nodes in a graph by A* algorithm? If yes, how?
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1answer
16 views
Term for an A*-like pathfinding strategy where only the heuristic goal distance matters
I am trying to find a proper term for the A*-like best-first pathfinding strategy where the node to expand next is the one with the least estimated distance from the goal, regardless of its distance ...
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1answer
37 views
Ant Colony optimisation for finding subsets with ~0 sum
I have a set A = [x1, x2...xn] where xi in R (real). I need to find all non intersecting subsets with subset sum ~0 (approximately equal to zero).
Since the set can have non zero real numbers, I have ...
2
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2answers
42 views
Does an optimal path imply the heuristic is admissible?
If we are given an A$^*$ path search with some heuristic $h$ that yields an optimal path, without knowing that the heuristic is admissible beforehand, would this imply that $h$ is admissible?
2
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1answer
41 views
Overall time complexity of Heuristical Algorithm for travelling salesman problem [TSP]
I am trying to figure out the time complexity of a heuristical algorithm used to solve the Travelling Salesman Problem in a more efficient way than by brute force, ($\theta(n!)$ or similar)
The ...
3
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1answer
25 views
Longest simple walk below a certain weight
Given a directed graph G and a starting vertex $v$ and a cutoff weight $w$, I want to find a simple walk with net weight < $w$ that visits as many nodes as possible. Currently, I have a recursive ...
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64 views
Travelling Salesman problem using Guided Local Search
I am doing Week_4 of https://www.coursera.org/learn/discrete-optimization/
stuck in solving TSP.
As there are a lot of methods to solve this problem, I am currently coding
Guided Local Search as ...
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1answer
19 views
Defining Local Search stopping criteria
When performing a local search, for example, a 2-node exchange in a metaheuristic (like GRASP), what is the usual stopping criteria for that procedure?
Some bibliography says that the local search ...
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0answers
19 views
MAC-AC3 algorithm puts arcs in queue
I am studying Csp and I don't understand the line no 1.1 .
Does queue contains all arcs or not?Explain with me 4-queens please.
...
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0answers
62 views
How MAC-3(maintaining arc consistency-3) algorithm works?
I am studying CSP problems in artificial intelligence. I don't understand the MAC-3 algorithm especially line number 10. Could you tell me with step by step?
...
6
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1answer
125 views
Optimal partitioning of n-tuples
Motivation
Recently I was trying to optimize some API calls and reduced the problem to optimization of a cumulative number of identifiers across all the requests. I put some considerable effort into ...
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2answers
50 views
Choosing heuristic for A* algorithm where cost is less than absolute distance
Looking for information on choosing a heuristic for instances where the cost of traversing an edge can be less than one.
For example, say movement is allowed in the cardinal directions. Should all ...
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0answers
20 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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1answer
42 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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0answers
16 views
Can Heuristic repair algorithm be applied to TSP?
Can Heuristic repair algorithm (or it's modification) be applied to Traveling Sales Person problem ? My gut feeling is that it can. But I have no idea - what cost(s)/conflicts should be minimized. ...
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0answers
25 views
Heuristics vs meta-heuristics vs hyper-heuristics?
The wikipedia page on meta-heuristics states that they are "heuristics designed to find, generate, or select a heuristic".
The wikipedia page on hyper-heuristics states that they are "heuristic ...
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0answers
24 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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0answers
78 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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22 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
24 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
166 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 ...
1
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1answer
131 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 ...
2
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1answer
51 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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2answers
49 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
321 views
Aren’t most constraining variable and least constraining value the exact opposite?
So aren’t MCV and LCV the exact opposite?MCV tries to choose the variable with the most constraints on
remaining variables but LCV is opposite: it tries to rule out as least values for other variables ...
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1answer
29 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
29 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?
2
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1answer
83 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 ...
1
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1answer
22 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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0answers
10 views
Techniques used in customizing Task Scheduling
I am just learning about Scheduling, in particular the Completely Fair Scheduler.
In thinking of specific cases of the types of things that would need to be "prioritized" against each other, there ...
0
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1answer
108 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 ...
1
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1answer
17 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
68 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
69 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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0answers
195 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
1k views
How does the nearest insertion heuristic for TSP work?
In my theoretical computer science class and we were covering "Heuristics". In it we covered "Greedy Heuristics" for the "Vertex Cover Problem", "Interval Scheduling" and the "Traveling Salesperson ...
3
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0answers
40 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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2answers
81 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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1answer
245 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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337 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
...
3
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1answer
249 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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0answers
34 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
48 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 ...
1
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1answer
152 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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1answer
923 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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0answers
94 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 ...
1
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1answer
272 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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0answers
517 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 ...
4
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1answer
222 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 ...
