Calculate t maximums in single vector

I have an iterative program for linear block codes (k,n), and at some point, I add code-words base10

The addition result in a vector of size (1,n)

I need to find the maximum (t) elements in this vector without going into loops operations, as the time of program execution is very important.

Example: if my Vector is (V)=(1,n)

V=[68 61 35 37 18 80 50 36 78 24 85 82 85 38 39 87 47 58 70 97 55 64 58 93 87 17 18 25 76 20 99 71]

I want a direct command that can calculate the maximum 5 elements of the Vector (V).

Kindly help.

Answer 1

[Star Strider]

You can always create your won function file from this code to produce your ‘direct command’:

V=[68 61 35 37 18 80 50 36 78 24 85 82 85 38 39 87 47 58 70 97 55 64 58 93 87 17 18 25 76 20 99 71];
Vs = sort(V,'descend');
Out = Vs(1:5)

Out =
    99    97    93    87    87

[Moe Joe]

But, I still need to return their locations (positions), that is, I want to return a vector of (1,n) with ONES in the position of those maximum elements.

[bio lim]

ismember(V,Out)

ans =

       0     0     0     0     0     0     0     0     0     0     0     0     0     0     0     1     0     0     0     1     0     0     0     1     1     0     0     0     0     0     1     0

[Moe Joe]

Perfect, thanks a lot.

[Star Strider]

My apologies for the delay. The other option would be to ask for two outputs from the sort function. The second will give you the indices of the sorted elements in the original vector.

From the documentation:

• [B,I] = sort(_) also returns a collection of index vectors for any of the previous syntaxes. I is the same size as A and describes the arrangement of the elements of A into B along the sorted dimension. For example, if A is a numeric vector, B = A(I).

Answer 2

[John D'Errico]

Sort them. Then take the first 5 elements from the sort. WTP?

No. It is not ONE single command. Not an option. Of course, nothing stops you from writing a function that does exactly that, in which case it will be one line.

[Moe Joe]

Already did this function:

% This is a function locates the positions of maximum (t) numbers in a

 function [v]=maxvic(X,t);
 vector V(1,n).
    n=length(X);
    v=zeros(1,n);       
    for i = 1:t;
        [y j]=max(X,[],2);
        v(j)=1;
        X(j)=0;
    end
    end

But thought the more expert than I could advice a better solution.