A-star obstacles

Hello, I'm trying to my a-star program working. I need to plot the path between 2 points while avoiding obstacles. I have already got the path part done, but I'm having some issues with the obstacles.

The user is selecting point one and two, as well as obstacles on a GUI grid.

So far I have c(c==o] = []; to remove the obstacles(o) from the the parent/child numbers(c)

this works with one obstacle as the o value is just one number so it simply deletes it, but for multiple obstacles, o has many numbers inside of it(array) so it just errors and says

" Error using == Matrix dimensions must agree."

I'm guessing this is because, the code above is trying to remove numbers which are in o from c, but they aren't even in c yet, so it can't do it.

How can I resolve this problem?

Answer 1

[Geoff]

The problem is you can only compare matrices with the same dimensions, or a matrix with a scalar. You want to compare a matrix with multiple scalars.

You could just loop through each obstacle:

for ob = o
  c(c==ob) = [];
end

Edit: this does the same thing (didn't know about this function before). It ought to be more efficient.

c(ismember(c,o)) = [];

[marc buckle]

Thanks for the answer, however this doesn't solve the problem.

http://i41.tinypic.com/dvlpn6.png

When I try this, the plot just goes of the screen and doesn't error :/

[Geoff]

Well I can't vouch for the correctness of the rest of your algorithm, but I think I answered your question on how to fix the error message and remove multiple obstacles from your candidates.