MATLAB: HOW TO SELECT ELEMENTS FROM DIFFERENT MATRIX

select elements from different matrices

Hello every one an trying to select elements from three different matrices which is stored in a template but the output is not correct. Following is my requirment.

harmony.Sol %template consisting of three 1×6 matrices as shown below:

[1 2 3 4 5 6]

[7 8 9 1 2 3]

[ 4 5 6 7 8 9]

i need to select random elements from above three matrices and create a new 1×6 matrix. probably named harmony.new. Ex: ans= [7 5 3 1 5 9]

Please help me on this, my codes are not giving the correct output. Thank u…

Best Answer

val = vertcat(harmony.Sol);
nchoice = size(val,1);
ncol = size(val,2);
ridx = randi(nchoice, 1, ncol);
harmony(173).new = val((0:ncol-1)*nchoice + ridx);

Related Solutions

MATLAB: How can i position the minimum value in the first cell for each column, without changing the sequence

This should do what you want:

M = randi(9,6,4);                               % Create Matrix
for k1 = 1:size(M,2)
    [~,idx] = min(M(:,k1));                     % Index Of Minimum In Column ‘k1’
    Mr(:,k1) = circshift(M(:,k1), 1-idx, 1);    % Rotate To Put First Minimum In First Row
end
M =
     1     6     9     5
     6     4     3     3
     9     5     7     4
     3     9     3     2
     1     4     9     4
     4     7     3     4
Mr =
     1     4     3     2
     6     5     7     4
     9     9     3     4
     3     4     9     5
     1     7     3     3
     4     6     9     4

Here ‘M’ is the original matrix, ‘Mr’ is the ‘rotated’ matrix. The circshift function will do what you want.

Note that the min (and max) functions only return the index of the first value of the minimum in a vector, if there are duplicates.

MATLAB: How to Put These Vectors in a Matrix

Here is one way:

>> A.B.G = [1 2 3];
>> A.C.G = [4 5 6];
>> A.D.G = [7 8 9];
>> A.E.G = [10 11 12];
>> A.F.G = [13 14 15];
>> cell2mat(structfun(@(s){s.G},A))
ans =
     1     2     3
     4     5     6
     7     8     9
    10    11    12
    13    14    15

Although to be honest your code would be much faster and simpler if you used a non-scalar structure, because then you can simply do this:

>> S(1).G = [1 2 3];
>> S(2).G = [4 5 6];
>> S(3).G = [7 8 9];
>> S(4).G = [10 11 12];
>> S(5).G = [13 14 15];
>> vertcat(S.G)
ans =
   1     2     3
   4     5     6
   7     8     9
  10    11    12
  13    14    15

Using indices will be much simpler than trying to access fieldnames, and woudl allow you to very simply solve your other question by using indices to select the parts of the structur that you want:

>> vertcat(S([1,3,4]).G)
ans =
     1     2     3
     7     8     9
    10    11    12

Do not make your code more complicated than it needs to be. Good data storage makes your code simpler and neater too.

Best Answer

Related Solutions

MATLAB: How can i position the minimum value in the first cell for each column, without changing the sequence

MATLAB: How to Put These Vectors in a Matrix

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