///withoutPrompt
function [f,gg,ind]=cost(Ti,ind)
  xc=x0;
  dxdt=[];
  N=size(Ti,2)
  tc=0;
  for i=1:N
    U=(-1)^(i-1)*Umax;
    if Ti(i)>1d-9 then    
      XX=ode([xc,eye(4,4)],tc,tc+Ti(i),1d-11,1d-12,simul)
    else
      XX=[xc,eye(4,4)]
    end  
    xc=XX(:,1);tc=Ti(i)+Ti(i)
    Psi=XX(:,2:$);
    dxdt=[Psi*dxdt,full_model(xc)];
  end
  f=sum(Ti)+xc'*W*xc/2
  gg=ones(Ti)+xc'*W*dxdt
endfunction ///\withPrompt{}