A* Algorithm - A Quick Guide to the A* Algorithm

In this tutorial I will overview the A* algorithm. The A* algorithm is a very helpful and easy to learn tool that will help you with your path finding. You will be shown what steps the A* algorithm takes to find a path to your target. Remember this is just a basic guide to the A* algorithm.

[daveau]

By having your heuristic mere add the number of rows and columns to the target, ignoring the possibility of diagonal movement, you are making the heuristic inadmissible. This means that the heuristic may overestimate the path cost from a node to the target, which can cause the algorithm to select a sub-optimal path. A much better heuristic would be to use Pythagoras to determine a straight-line distance to the target, or better still, to account for diagonal movement like this:

H = min(rows_away, cols_away)*14+(max(rows_away, cols_away)-min(rows_away, cols_away))*10
H = min(rows_away, cols_away)*4+max(rows_away, cols_away)*10

[daspifster]

I thought his explanation was very good, he kept it as simple as possible and spoke slowly.  Sometimes when explaining a complex subject it helps to repeat yourself a little.  

[UgotXpressUrSelf]

Have you ever tryed to use the Lee algorithm in a matrix??? ... to explain myself if you haven t heard about Lee Algorithm ... Lee Algorithm : fill in a queue with the nodes that u can visit and chose the best one by filling your matrix with numbers ... like if u were in (1, 1) and best way is to go in 1, 2 you fill the matrix[1][2] with matrix[1][1] + 1;.... i think is same efficiency ... with less memory .. btw i apreciate your work ... you are a very good programmer .. sorry for my bad english.

[Teedee]

You can optimize A* with bi-directional A*, using overdo Faktor for shortest distance, beam search (not too good), ALT precalulation or considering only fast routest( like motorways : for navi usefull)

[anilmawji]

Why in the world was this guy's account suspended? He provides us with wonderful tutorials!

[spsproos]

I know some are critizising it, but I appreciate your effort a lot and understand A* finally. Thanks! :)

[siddharthagrawal]

u could make ur explanation better imho.

[ramaken]

thank you for your explanation, it was really perfect and easy to understand

[HardcoreMontages]

You talk like Walter Jr off of Breaking Bad,

[Fromage_chaud]

Nice guide, the role of both lists is clearly exlained and I feel completely ready to code that ! However I still ignore what to do if the 1st path built with this method isn't the shortest (like if the wall was longer), but thanks anyway for that quick explanation !

[egan]

cleared some things up for me! on a side note i did have to play at atleast 1.5 times speed so i would suggest making some sort of script out to make things clearer and some way of getting rid of the static in the audio (prob a simple program u could find to do this)

[sidharthsinghal]

Great video. Very well explained. Thanks a lot!

[octaviocuervo]

Awesome, this really helped me understand the A* thanks a lot. I will be implementing this immediately :)

[GPaCrewify]

Hey, just wanted to say you fking rock. You beat "Hello World" down with a gigantic pwn hammer. Thank you.

[warjogr]

appreciate the time and effort you've put in this but really, what others are saying is correct. Organize yourself better on the given subject before you go on about making something like this. I guess some rehearsing would do. It's hard to follow this way.

[BrfTuck]

Very helpful, thank you for taking the time to do this :)

[fadsmfawopefaw]

Thank you so much! This actually makes sense!

[sfgman]

Your link for the A* algorithm in your description seems to be broken.

[yanyankelevich]

I'm pretty sur you could explain this in 5 minits if you prepare your video before talking.
Like doing the demo, recording it, and then adding your voice

[tyuo]

What if the wall wrapped around the top and bottom of the start point? Since you're ignoring the walls in the H cost you won't be able to find the optimal path.