Find the position index of vector array

Hi I am trying to find the position of a vector array. After I have found the maximum value in the first and third row, and the minimum value in the second row, how can I get the position index to be applied on the other variable as they correspond to the same position?

Answer 1

[Stephan]

Hi,

you can use the code from the following example for your purpose:

A = [1 2 3 10 6 0.999 -3 -5;...
     -3 -4 -10 1 2 0.003 -8 10;...
     2 3 6 7 9 10 0.2 0.0006];

indices = [find(A(1,:) == max(A(1,:)));...
           find(A(2,:) == min(A(2,:)));...
           find(A(3,:) == max(A(3,:)))];

this gives you:

A =

    Columns 1 through 4

      1.0000    2.0000    3.0000   10.0000
     -3.0000   -4.0000  -10.0000    1.0000
      2.0000    3.0000    6.0000    7.0000

    Columns 5 through 8

      6.0000    0.9990   -3.0000   -5.0000
      2.0000    0.0030   -8.0000   10.0000
      9.0000   10.0000    0.2000    0.0006

indices =

       4
       3
       6

Keep in mind that these indexes only reflect the column of the desired row. For further use, the first mentioned index must be addressed as follows:

Value_Row_1 = A(1, indices(1))
Value_Row_3 = A(2, indices(2))

which delivers:

Value_Row_1 =

      10

Value_Row_3 =

     -10

to make it a little easier use:

values = [max(A(1,:)); min(A(2,:)); max(A(3,:))];

which gives:

values =

      10
     -10
      10

these values you can directly access with:

values(2) % Accessing the minimum value from row 2

ans =

     -10

Best regards

Stephan

[Brendan Chou]

Thanks a lot Stephan! I have another variable with the same size of vector array. Once I have found the maximum and minimum index, I want to reflect it on the same position of the other variable, as they correspond to each other. Therefore may I know how can I correspond the position index on the other variable?

[Stephan]

Hi,

other_variable (1, indices (1)) = A (1, indices (1));
other_variable (2, indices (2)) = A (2, indices (2));
other_variable (3, indices (3)) = A (3, indices (3));

Best regards

Stephan