Hi Maria, Because you cannot expect the number of peaks in the rows of A to be the same in each row, you can use a cell array to capture the number of peaks in each row.
A=[1 2 3 1 2; 1 15 2 5 2;1 2 1 2 1];
[x y]=size(A);
for i=1:x
a{i}=findpeaks(A(i,:));
end
