Need help with finding distances in a matrix program

I have an A matrix, in which I need to find the distances between the points. I have the formulas, but I need help to translate this into matlab.

Lets say that a is equal to:

A=

0 1 0 0 1 0

1 0 0 0 0 0

0 0 0 0 1 0

I have a program to create a new matrix called B,finding this points in which the first column is the number of point, the second column is the x coordinate of the point and the third column is the y coordinate. In this case will be:

B=

1 2 1

2 5 1

3 1 2

4 5 3

Here is the code for this program:

clear z

p=1;

[row,col] = size(A);

for i = 1:row

    for j=1:col

        if(A(i,j)>0)

            z(p,:)=[j,i];

            p=p+1;

        end

    end

end

B=[(1:p-1)',z] %B matrix 1 col is #of point, 2 col is xcoord,3 col is ycoord

I need to find the distances between these points, in this case will be dijx(x distance) and dijy (y distance). For this matrix these will be the distances(absolute value from one point to another point):

dijx=

0 3 1 3

3 0 4 0

1 4 0 4

3 0 4 0

dijy=

0 0 1 2

0 0 1 2

1 1 0 1

2 2 1 0

Can you help me to create a for loop code to find those distances? Thank you!!

Answer 1

[Andrei Bobrov]

[r,c]=find(A');
dij = dist([r,c]'); % dist from Neural Network Toolbox

or

[r,c]=find(A');
dijx = bsxfun(@minus,r,r');
dijy = bsxfun(@minus,c,c');
dij = hypot(dijx,dijy);

[Sebastian]

This was exactly what I was trying to do, but if insted of a matrix with zeros and ones, I have a matrix with different numbers, and lets say I want all the numbers>than 8. How can I change this to make this happen?

A=

1 3 4 8 4

9 8 9 2 3

7 7 5 8 7

[Andrei Bobrov]

l = A > 8;
[r,c]=find(l');
dij = dist([r,c]');

[Sebastian]

Thank you!!

Answer 2

[Image Analyst]

You can get B in two lines of code:

[rows, columns] = find(A)
B = [[1:length(rows)]', rows, columns]

Now I'm not sure what distances you are after are you wanting every distance from N points to the other N-1 points? So you'll have every possible pairing and N*(N-1) distance?

[Sebastian]

I tried to get B like you said before, but the thing is that I need them to be in order, I have created a file this will explain it more

[Sebastian]

example file

[Image Analyst]

Well, you can flip the order with

[rows, columns] = find(A')