The salesman is shocked, but manages to say, "Excuse me, is your dad home?"
The kid responds, "What the hell do you think?"
Hello,
Iβm doing a project on the travelling salesman problem. I found the upper and lower bounds and used the Christofides Algorithm. However my solution from the Christofides algorithm is 0.9 times my lower bound (I expected it to be 1-1.5 times my lower bound which I assume to be the optimal solution). I have checked my lower bound calculations using both Kruskalβs and Primβs algorithm however itβs still the same. Can anyone explain why this is happening? Any advice regarding how to improve my lower bound or better explain the reason for this would be much appreciated :)
Thanks
Hey guys, can someone please let me visit their teapot so I can do travelling salesman. UID 849937440.
iβve been trying to understand this formula since a very long time. If anyone would be kind enough to send me a solved example or point me to one i would be eternally grateful.
This website says
The greedy algorithm goes as follows:
- Sort all of the edges in the network.
- Select the shortest edge and add it to our tour if it does not violate any of the following conditions: there are no cycles in our tour with less than n edges or increase the degree of any node (city) to more than 2.
- If we have n edges in our tour stop, if not repeat step 2.
What does "there are no cycles in our tour with less than n edges" mean exactly? To my understanding, it simply means that the cycle has to have less than n edges? So basically when I reach n edges, I stop, which is what rule 3 says
I'm new to this and never really use reddit so be gentle, i'm doing my best to explain this.
Skill: Archaeology
Problem: I have a bunch of partially completed collections, and like 60-80 bank spaces of artefacts etc. Some damaged some repaired. I want to take repair said artefacts and take them to the collector, but whenever I start looking at doing this, I just get drowned in tables, cross referencing, names and locations.
Suggested solution: A higher level overview of status within the game interface that helps indicate what you have in bank, what status its in, what mats you have to repair them, and if you have all the items needed to complete a collection.
Discussion/example: I understand that I can click a single item to see what collections in belongs to, and I can go to a collection and see what items it contains. So now I need to check the bank to see if I have all the items, but i've forgotten most of the names of the items so it takes about 10 minutes to check if I have everything. But then I also know that some of those artefacts go in multiple collections so I need to work out if I have enough of the artefacts for all the collections, and what other items are needed in those other collections to see if could complete them to make this worth doing. I also have to find if I have the mats to repair all the artefacts I would need to do those collections. Of course I don't have enough artefacts so then need decide which collection I'm going to try and complete with what I have. Decision made, I get all the artefacts and visit the collector and hand them all in, only to realise I missed one, and need another 10 levels to get it. Time wasted. Ultimately, I like the idea of completing collectors collections after finding and repairing the artefacts, but I find it a cross-reference nightmare. I end up in a situation where I end up trying to brute force it by having too much of everything and then it feels like I'm a travelling salesman not a skilled archaeologist.
I am currently working on a college project with a partner (both industrial engineers). We were planning on doing a travelling salesman problem using Lingo, but our professor recommended checking out python and gurobi. I am fairly new to python, having only seen Mosh's tutorial around halfway. I have programmed with VBA before. Do you guys know if doing the TSP with python is viable? Or would it be extremely out of our level (given we use online resources as a base and then adapt those to our specific needs)? I am moderately confident in my abilities to learn quickly and adapt in terms of coding, even though I don't have much experience. We have around 5 weeks. Any guidance is appreciated.
Considering he is a limited time vendor he should have a random assortment of furnishings from the realm depot shop (and have them cost half their normal price). Because as it stands, the furnishings are quite expensive and you're obviously limited to how many you can purchase per day.
The Travelling Salesman Problem (TSP) is known to be NP-Hard. However for a problem to be NP-Hard, it should be in the NP Class in the first place. According to these slides made by a Stanford professor, the NP class consists of all decision problems of which a "yes" answer can be efficiently verified and a decision problem is any problem that has a yes/no answer (Page 10 of the pdf).
How is the TSP a decision problem and how is a "yes" answer efficiently verified for the decision problem version of the TSP?
I want to create an algorithm to optimise the route a delivery car should follow in order to minimise time.
Basically the travelling salesman problem but the weights of the edges change over time depending on traffic (I already know the weights of the edges at all times).
Does anyone know what has already been done to solve this problem?
Hi, just finished a coding interview online. Absolutely failed it! Hard problem, and they barely give you any time to solve it (30mins). This is the problem. Do you know what this is called, in the general sense? I thought I might be a weighted longest path problem
You are given n integers. Each integer represents a city, and the number times you can travel TO that city.
How many times can a traveling salesman travel, starting from the first city, before he cannot travel to any more cities?
example: for the input 7 2 3, the salesman can travel to the first city 7 times, the 2nd city 2 times, and the 3rd city 3 times.
I didn't think this was a very good interview question. Certainly not only at 30mins
EDIT - I am receiving a lot of criticism for misleading people with my title. I would like to clarify. With my initial testing I found than when the points were ******NON-randomised i.e in a circle. I am able to solve the problem every time to the best solution (you can try this for yourself... I have tested this up to 400 points and it completes every run and in a pretty quickly time considering the amount of possible routes). I determine the solution is found when the route is in sequential order from 0 to the total points or the reverse of this.
******non randomised does not imply that the algorithm has any prior knowledge of the best route and all initial routes are populated at random.
https://reddit.com/link/k8c3jd/video/8eo0j76xdq361/player
If you don't know, The travelling salesman problem is an optimisation problem. Given a list of n points, you need to calculate the shortest distance between them all. Which route will you take?
Real world applications involve solving problems for delivery drivers most efficient delivery route etc.
Imagine a world with 100 cities and you need to go to them all.. Which route will you take?
100 points to choose from has (N-1)! / 2 possibilities (divided by two because each route can also be done in reverse)
How many possibilities is that? Its big... (correct me if i'm wrong)
466,631,077,219,720,768,248,848,888,576,312,920,744,944,336,736,344,592,320,432,120,192,648,432,664,448,048,464,160,152,768,040,368,600,128,056,864,248,176,200,472,360,208,208,680,872,472,888,184,392,032,568.
What is a genetic algorithm then? Random routes are populated into a group of what I see as "workers", the best of the bunch are "mated" together to get a new set of directions and this is then passed onto the rest of the workers (simulated breeding), then add a dash of "mutation" to their routes and were good to go.
Only problem I found is with my implementation on some configurations of points it gets stuck. It gets close but then it can go no further - it probably would get there eventually, but I haven't got time.
So I've added another layer. Groups of "workers" which I call "families". The workers are bred incestuously every generation and then between families less frequently.
I'm my testing it appears to perform much better on harder tasks.
Code:
I am currently working on a college project with a partner (both industrial engineers). We were planning on doing a travelling salesman problem using Lingo, but our professor recommended checking out python and gurobi. I am fairly new to python, having only seen Mosh's tutorial around halfway. I have programmed with VBA before. Do you guys know if doing the TSP with python is viable? Or would it be extremely out of our level (given we use online resources as a base and then adapt those to our specific needs)? I am moderately confident in my abilities to learn quickly and adapt in terms of coding, even though I don't have much experience. Any guidance is appreciated.
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