为什么我这个运行出来G2_si只有61个值而且全是0
```c#
T=8; %ns t_rt=2*pi/w_FSR
r_s=1;%MHz
t0=3.7;%ns
dT=0.165; %ns探测器分辨率
for t=-100:1:100 %ns
if t >= t0/2
G2_si(:,1)=exp(-1*r_s*T-4*(1*T-t).^2/(dT)^2);
for j=1:1:60
G2_si(:,j+1)=G2_si(:,j)+exp(-j*r_s*T-4*(j*T-t).^2/(dT)^2);
end
else
G2_si(:,1)=exp(-1*r_s*T-4*(1*T-t).^2/(dT)^2);
for j=1:1:60
G2_si(:,j+1)= G2_si(:,j)+exp(-j*r_s*T-4*(-j*T-t).^2/(dT)^2);
end
end
end
```