An important programming method is to avoid the inclusion of indices in the names of the variables. While it is rather tedious to access "output1, output2, ..." in is much easier to use an index as index(!):
output(1), output(2), ...
Btw, Do you mean "output2(1:419)" or should the zeros of output2 start at the 2nd element? Such typos frequently happen, when huge blocks of code with almost repeated names are written. So this is much easier:
output = rand(10, 1000);
for k = 1:10
output(k, k:419) = 0;
end
