MATLAB: Putting column vector in a matrix

Question

for i = 1:N
    for row = 1 : n
        for col = 1:m
           grad(row,col)= .... %%%% I get a n x m matrix %%%%
        end
     end
        gradv = grad(:);  %%% Now I convert the matrix in a column vector %%%
        
%%%% For the outer loop "for i = 1:N", I get a coulmn vector gradv on every iteration. I want to put it in a matrix N x (nxm).
gradmatrix = gradv (1); gradv(2);... gradv(N) %%% How do I do this?

Answer 1

gradv=cell(1,N);
for i = 1:N
    for row = 1 : n
        for col = 1:m
           grad(row,col)= .... %%%% I get a n x m matrix %%%%
        end
     end
        gradv{i} = grad(:); 
    end
    celldisp(gradv)
    matrix=[gradv{:}]