Comments on: A* Search Algorithm in JavaScript http://www.briangrinstead.com/blog/astar-search-algorithm-in-javascript Sat, 06 Mar 2010 08:57:33 -0700 http://wordpress.org/?v=2.9.2 hourly 1 By: Harvey Wasyliszyn http://www.briangrinstead.com/blog/astar-search-algorithm-in-javascript/comment-page-1#comment-3599 Harvey Wasyliszyn Fri, 05 Mar 2010 01:39:44 +0000 http://www.briangrinstead.com/?p=178#comment-3599 Hi, I found this article while searching for help with JavaScript. I've recently changed browsers from Chrome to Internet Explorer 7. Now I seem to have a issue with loading JavaScript. Everytime I browse website that requires Javascript, the page does not load and I get a "runtime error javascript.JSException: Unknown name". I cannot seem to find out how to fix the problem. Any aid is greatly appreciated! Thanks Hi, I found this article while searching for help with JavaScript. I’ve recently changed browsers from Chrome to Internet Explorer 7. Now I seem to have a issue with loading JavaScript. Everytime I browse website that requires Javascript, the page does not load and I get a “runtime error javascript.JSException: Unknown name”. I cannot seem to find out how to fix the problem. Any aid is greatly appreciated! Thanks

]]> By: Justin http://www.briangrinstead.com/blog/astar-search-algorithm-in-javascript/comment-page-1#comment-15 Justin Fri, 12 Jun 2009 22:14:51 +0000 http://www.briangrinstead.com/?p=178#comment-15 That's neat! I have a tutorial and C++ implementation of A* which uses an STL priority queue and has various optimisations. http://code.google.com/p/a-star-algorithm-implementation/ www.heyes-jones.com/astar.html That’s neat!

I have a tutorial and C++ implementation of A* which uses an STL priority queue and has various optimisations.

http://code.google.com/p/a-star-algorithm-implementation/
http://www.heyes-jones.com/astar.html

]]> By: Zack J. http://www.briangrinstead.com/blog/astar-search-algorithm-in-javascript/comment-page-1#comment-14 Zack J. Fri, 12 Jun 2009 19:44:49 +0000 http://www.briangrinstead.com/?p=178#comment-14 Here's an example running. I haven't posted it on the site or posted the source because I'm not sure what we're going to do with it yet: http://pixelwelders.com/experiments/Pathfinder2/ It could obviously be optimized even further, but this example shows the search process (yellow), and then the final path (blue line). It eliminates the stairstep and wall-hugging, as well as some other strange-looking paths that you sometimes get with A*. Here’s an example running. I haven’t posted it on the site or posted the source because I’m not sure what we’re going to do with it yet:

http://pixelwelders.com/experiments/Pathfinder2/

It could obviously be optimized even further, but this example shows the search process (yellow), and then the final path (blue line). It eliminates the stairstep and wall-hugging, as well as some other strange-looking paths that you sometimes get with A*.

]]> By: brian http://www.briangrinstead.com/blog/astar-search-algorithm-in-javascript/comment-page-1#comment-13 brian Fri, 12 Jun 2009 19:33:56 +0000 http://www.briangrinstead.com/?p=178#comment-13 Zack, could you go into a little more detail about removing the unnecessary nodes or provide a link to your code so I can look at it? By the way, <a href="http://www.policyalmanac.org/games/aStarTutorial.htm" rel="nofollow">A* Pathfinding for Beginners</a>, which you linked to from your site, is a great resource for anyone looking for more information about the algorithm. Zack, could you go into a little more detail about removing the unnecessary nodes or provide a link to your code so I can look at it?

By the way, A* Pathfinding for Beginners, which you linked to from your site, is a great resource for anyone looking for more information about the algorithm.

]]> By: Zack J. http://www.briangrinstead.com/blog/astar-search-algorithm-in-javascript/comment-page-1#comment-12 Zack J. Fri, 12 Jun 2009 19:26:36 +0000 http://www.briangrinstead.com/?p=178#comment-12 I've got an Actionscript implementation of A* that I've been cleaning up recently. I also added a smoothing step at the end to remove unnecessary nodes at the end; it makes it much more useful for game AI. I’ve got an Actionscript implementation of A* that I’ve been cleaning up recently. I also added a smoothing step at the end to remove unnecessary nodes at the end; it makes it much more useful for game AI.

]]> By: brian http://www.briangrinstead.com/blog/astar-search-algorithm-in-javascript/comment-page-1#comment-11 brian Fri, 12 Jun 2009 19:12:59 +0000 http://www.briangrinstead.com/?p=178#comment-11 Jelle, thanks for the feedback. I built it using a linked list because it was the most straightforward way to understand the code. This was more of a learning exercise for myself with the hope of being useful to anyone else. However, I would be interested in optimizations. I am not aware of a JavaScript heap object that is provided from the standard library, but I found a <a href="http://tide4javascript.com/?s=Heapsort" rel="nofollow">couple</a> of <a href="http://eloquentjavascript.net/appendix2.html" rel="nofollow">examples</a> online in case anyone is interested. It would be interesting to implement that and compare the performance between the two. Jelle, thanks for the feedback. I built it using a linked list because it was the most straightforward way to understand the code. This was more of a learning exercise for myself with the hope of being useful to anyone else.

However, I would be interested in optimizations. I am not aware of a JavaScript heap object that is provided from the standard library, but I found a couple of examples online in case anyone is interested.

It would be interesting to implement that and compare the performance between the two.

]]> By: Jelle http://www.briangrinstead.com/blog/astar-search-algorithm-in-javascript/comment-page-1#comment-10 Jelle Fri, 12 Jun 2009 18:25:31 +0000 http://www.briangrinstead.com/?p=178#comment-10 You're using A* instead of Dijkstra for some reason, I assume speed. So why do you loop through the open list instead of using a heap? Boom, N^2 instead of NlgN. You’re using A* instead of Dijkstra for some reason, I assume speed. So why do you loop through the open list instead of using a heap? Boom, N^2 instead of NlgN.

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