clc
clear all
T=2;
Nt=50;%%%%%Nt+1
deltat=T/Nt;
t0=(0:deltat:T);%%%%
N=16;
L=2*N;
%%%%%%
X=1;
Nx=50;%%%%%%Nx+1
deltax=X/Nx;
x=0:deltax:X;
%%%%%%%%u0(x)=exp(2*pi*i*x)
k0=1;
%%%%c(0)
cL0=zeros(1,L);
cL0(1,k0+N+1)=1;%%%%
[T,C] = ode45(@(t,c)fun(t,c,L),t0,cL0);%[0 1]
u=zeros(Nx+1,Nt+1);%%%%%%，
%%%%u
for i=1:(Nx+1)
for j=1:(Nt+1)
for k=-N:(N-1)
k1=k+N+1;
u(i,j)=u(i,j)+C(j,k1)*exp(2*1i*k*pi*x(i));
end
end
end
% % % % for i=1:51
% % % % for j=1:51
% % % % u(i,j)=C(j,1)*exp(2*1i*(-2)*pi*x(i))+C(j,2)*exp(2*1i*(-1)*pi*x(i))+C(j,3)*exp(2*1i*0*pi*x(i))+C(j,4)*exp(2*1i*1*pi*x(i));
% % % % end
% % % % end
ur=real(u);
figure(1)
surf(ur)
figure(2)
plot(ur(:,51))
ul=imag(u)
figure(3)
surf(ul)