"how to create a matrix of coordinates and how to calculate the distance b/w different coordinates of the same matrix w.r.t the any single coordinate element?"

I want to create a matrix as given below for any input, and suppose the input is "4".

a = (-10.0) (0,0) (10,0) (20,0)

(-10,5) (0,5) (10,5) (20,5)

(-10,10) (0,10) (10,10) (20,10)

(-15,10) (0,15) (10,15) (20,15)

But i dont know how to do and also i want to calculate the distance of a single element say (0,0) w.r. t the rest of the elements?

Please help me with this problem

[Bob Thompson]

How are the matrix and the input related?

Do you have any code getting you started? If so, please post it.

Answer 1

[KALYAN ACHARJYA]

You may look at cell array

a={[-10,0],[0,0],[10,0],[20,0];[-10,5],[0,5],[10,5],[20,5];[-10,10],[0,10],[10,10],[20,10];[-15,10],[0,15],[10,15],[20,15]};
x1=[0,0]; % Single element as you said
distance_result=zeros(1,16);
for i=1:16
        x2=a{i};
        data1=x2(1)-x1(1);
        data2=x2(2)-x1(2);
        distance_result(i)=sqrt(data1^2+data2^2);
end
distance_result

Commad window:

>> whos a
  Name      Size            Bytes  Class    Attributes

  a         4x4              2048  cell      

Result:

distance_result =
  Columns 1 through 12
   10.0000   11.1803   14.1421   18.0278         0    5.0000   10.0000   15.0000   10.0000   11.1803   14.1421   18.0278
  Columns 13 through 16
   20.0000   20.6155   22.3607   25.0000

Hope it helps!

[Sonia Goyal]

Thank you for your response.

But is there any way to generate the above said matrix instead of entering it manually in cell array??

And also, i have to calculate the distance in matrix form and the expected output shall be in matrix too,

[KALYAN ACHARJYA]

But is there any way to generate the above said matrix instead of entering it manually in cell array??

sorry, I didnot find any relation of inputs to create that mat.

And also, i have to calculate the distance in matrix form and the expected output shall be in matrix too,

a={[-10,0],[0,0],[10,0],[20,0];[-10,5],[0,5],[10,5],[20,5];[-10,10],[0,10],[10,10],[20,10];[-15,10],[0,15],[10,15],[20,15]};
x1=[0,0]; % Single element as you said
distance_result=zeros(4,4);
for i=1:4
    for j=1:4
        x2=a{i,j};
        data1=x2(1)-x1(1);
        data2=x2(2)-x1(2);
        distance_result(i,j)=sqrt(data1^2+data2^2);
    end
end
distance_result

Result:

distance_result =

           10            0           10           20
        11.18            5        11.18       20.616
       14.142           10       14.142       22.361
       18.028           15       18.028           25

Note: If you could avoid multiple loops, it would be better.

Good Luck!

Answer 2

[Guillaume]

It's not clear where your X and Y come from and it's also not clear how you want the points to be stored since you don't use valid matlab syntax for your example

%maybe
X = -10:10:20;
Y = 0:5:15;

%create cartesian product of X and Y
[Xall, Yall] = ndgrid(X, Y);
points = [Xall(:), Yall(:)];

Here I've stored them as Nx2 matrix with column 1 the X, and column 2 the Y.

To calculate the distance of all points from another point:

source = [5, 7];  %whatever you want. A 1x2 vector
distances = sqrt(sum((points - source).^2, 2);

or

source = [5, 7];
distances = hypot(points(:, 1) - source(1), points(:, 2) - source(2));