Best way to create a matrix of points?

Hello

I have a matrix that contains rectangles(squares in this case), for example:

A=[-5 -4.5 1.5 2; -5 -4.5 2 2.5; -5 -4.5 2.5 3; -4.5 -4 1.5 2; -4.5 -4 2 2.5; -4.5 -4 2.5 3];
for i=1:6
    rectangle('Position',[A(i,1) A(i,3) 0.5 0.5]);
    hold on;
end
hold on;
axis([-10 10 -10 10])

Each row contains ( ) coordinates.

So in this case the result matrix should contain 12 rows, each represents 1 point, like:

-5 1.5
-5 2
-5 2.5
-5 3
-4.5 1.5
-4.5 2
-4.5 2.5
-4.5 3
-4 1.5
-4 2
-4 2.5
-4 3

The rectangles are not guranteed to form another rectangle, a more realistic set of rectangles:

[Richárd Tóth]

I think I will simply iterate through the rectangles and add all 4 of their points to the result matrix, then select unique rows from the result. If you have a more efficient solution, let me know

Answer 1

[Guillaume]

A=[-5 -4.5 1.5 2; -5 -4.5 2 2.5; -5 -4.5 2.5 3; -4.5 -4 1.5 2; -4.5 -4 2 2.5; -4.5 -4 2.5 3];

points = unique([A(:, [1, 3]); A(:, [1, 4]); A(:, [2, 3]); A(:, [2, 4])], 'rows')

is the simplest though posibly not the most efficient.

edit: this may be marginally more efficient, though more obscure:

points = unique(reshape(A(:, [1 1 2 2 3 4 3 4])), 'rows')

[Richárd Tóth]

the second misses a parameter of the reshape function, the first one works nicely

[Guillaume]

Oops! How did that happen, should have been:

points = unique(reshape(A(:, [1 1 2 2 3 4 3 4]), [], 2), 'rows')

[Bruno Luong]

I don't know how A is generated but you might cautious to replace UNIQUE with UNIQUETOL in case two adjacent rectangles do not have the exact match of coordinates due to round-off.