How to add a row vector for indexing

How to add a row vector for indexing C by M when my M is 4 dimensional ? any help will be thankful.

F=random('exp',1,3,3,4);
C=F*100
M=bsxfun(@times,  C./cumsum(C,3) , reshape(1:4,1,1,[])   );
[vec,idx] = max(M,[],1);      % value and row index of max in each column.
 S = size(M);                 % size of input array.
idx = idx + S(1)*(0:S(2)-1); % convert row index into linear index !
 C(idx);                % use linear index to get elements of C.

[Jan]

What exactly is your question? What do you want to add to what? Does the posted code do what you expect? If not, what do you want to change?

[Ashraf Sherif]

thank you Jan for inquires, well I have a matrix C is a 3 by 3 random variables with 4 iterations, at each iterate each element devided by it is average and collected at matrix M which done by below code

M=bsxfun(@times,  C./cumsum(C,3) , reshape(1:4,1,1,[])   );

I want to index C by the maximum values in each column of matrix M, by this code

[vec,idx] = max(M,[],1); 

so far all are OK but to continue the indexing by using the below code

idx = idx + S(1)*(0:S(2)-1); 

which to convert row index into linear index, an error appears

Error using +

Matrix dimensions must agree.

Error in Untitled5 (line 26)

idx = idx + S(1)*(0:S(2)-1);

some told me I have to add a row because different dimensions but i couldn't do that, and I am looking for some hlep or if there are an other methode to do whole this operation.

Answer 1

[Matt J]

I would do it this way,

idx=bsxfun(@eq, M,  max(M,[],1)  );
C(idx),

[Matt J]

I would also recommend that you learn how to use BSXFUN since you are running into it again and again, and since apparently you cannot upgrade to a more recent Matlab version where it is less required.

[Ashraf Sherif]

Thank you very much Matt J for you advice and help