# Removing Points Along a Diagonal Line

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### Answers (1)

infinity
on 30 Jul 2019

Hello,

I would suggest you a solution,

Since you have known two points of slope, which are (40,35) and (74.4, 15), you can easily get a segment passing to these points. Let say, y = ax + b.

Then, you can define a function, for example phi(x,y) = ax + b - y. As it can seen that phi(x,y) > 0 if (x,y) is in the left of the slope and phi(x,y) < 0 if (x,y) is in the right of the slope and phi(x,y) = 0 if (x,y) is in the slope. This technique is called "levelset method".

Now, what you can do is to use the phi funtion to check a point is in the left or the right of the slope. If it is in the right, you just eleminate it.

##### 5 Comments

infinity
on 31 Jul 2019

Edited: infinity
on 31 Jul 2019

Hello,

So, you could use for loop (or even don't need for loop) to check wheather a nodes in A is in B or not. If it is not, you store it into a new variable. For example,

clear

A = [1 2; 3 4; 5 6];

B = [3 4; 5 6];

C = [];

for i = 1:size(A,1)

if ~ismember(A(i,1),B(:,1)) || ~ismember(A(i,2),B(:,2))

C = [C; A(i,:)];

end

end

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