Francesco, with xlsread you read the entire spreadsheet. Which means, that you can read an entire matrix as is, at once. E.g., from the MathWorks documentation:
values = {1, 2, 3; 4, 5, 6; 7, 8, 9}; % write matrix to .xlsx file
headers = {'First','Second','Third'};
xlswrite('myExample.xlsx', [headers; values]);
and then
filename = 'myExample.xlsx'; % read matrix from file
A = xlsread(filename)
1 2 3
4 5 6
7 8 9
as expected, A is read as a 3-by-3 matrix.
