MATLAB: Find the position index of vector array

position index

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?

Best Answer

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
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