p_o.method = "continuous";
    ##    p_o.method = "intermittent";
  endif
  

  ## Check w.
  [n_w,m_w] = size(w);
  if ( (n_w<>n_y) || (m_w<>1) )
  if ( (n_w!=n_y) || (m_w!=1) )
    error(sprintf("ppp_lin_run: w must a column vector with %i elements",n_y));
  endif
  
  ## Initialise
  x_est = p_o.x_0;

  ## Initilise simulation state

	  = ppp_lin_quad (A,B,C,D,tau,p_c.Q,p_c.R);
    else
      error(sprintf("Control method %s not recognised", p_c.Method));
    endif

    ##Sanity check A_u
    [p_c.n_U,M_u] = size(p_c.A_u);
    if (p_c.n_U<>M_u)
    if (p_c.n_U!=M_u)
      error("A_u must be square");
    endif
    
    
    U = K_w*w;			# Initial control U

    ## Checks

      error("U must be a column vector with n_u*n_U components");
    endif
  else
    n_u = length(U)/n_U;	# Deduce n_u from U if no system
  endif
  
  [n_x0,m_x0] = size(x_0);
  if n_x0<>n_x
  if n_x0!=n_x
    error(sprintf("x_0 must be a column with length %i", n_x));
  endif
  

  [n,m]=size(tau);
  if (n != 1 )
    error("tau must be a row vector of times");