function [ok] = blkbidiag_mul_t_ok()
    ok = true;
    % -------------------------------------------------------------
    % You can change these parameters
    m    = 2;
    n    = 3;
    N    = 4;
    p   = 3;
    % -------------------------------------------------------------
    % Define the problem
    rand('seed', 123);
    v     = rand(n * N, 3);

    rand('seed', 123);
    a = rand(n, n, N);
    r = rand(n * N, m);
    Hdia  = rand(n, n, N);
    Hlow  = rand(n, n, N);
    Hcheck = zeros(n*N);

    blk_n = 1 : n;
    for k = 1 : N
        Hcheck(blk_n, blk_n) = Hdia(:,:, k)';
        blk_n           = blk_n + n;
    end
    blk_n = 1:n;
    for k = 2:N;
        blk_minus       = blk_n;
        blk_n           = blk_n + n;
        Hcheck(blk_minus, blk_n) = Hlow(:,:, k)';
       end
    % -------------------------------------

    H = ckbs_blkbidiag_mul_t(Hdia, Hlow, eye(n*N));

    % -------------------------------------
    check = H - Hcheck;
    ok    = ok & ( max(max(abs(check))) < 1e-10 );
    return
end