How to find the the most value index of N index from matrix M MATLAB

Question

Suppose I have a matrix M 500x500

and I want to find first 100 index that have the most value in M

my idea was sort the data M in descending order and use find to compare

[x,y] = find(M == sort(M(:),'descend'), 100, 'first');

But when I run the program I found error

I think it probably M == sort(M(:),'descend') this part

Can you help me please?

Answer 1

You don't need find . Just use the second output of sort :

[~, iSorted] = sort(M(:),'descend');
[x y] = ind2sub(size(M), iSorted(1:100));