How to generate this function to a time vector instead of discrete value of Tn

function[u]=centraldiff(Tn,zeta,v1,u1,acc,dt)

%zeta is the damping ration

%Tn is the natural period

%acc is the ground acceleration

%dt is the time step

%u1=0; % displacement at point t=0 of SDOF

%v1=0; % velocity at point t=0 of SDOF

wn=2*pi/Tn;

an(1)=acc(1)-(2*zeta*wn)*v1-(wn^2)*u1;

up=u1-dt*v1+dt^2*an(1)/2;

u(2)=-acc(1)/(1/dt^2+wn*zeta/dt)+((-1/dt^2+wn*zeta/dt)/(1/dt^2+wn*zeta/dt))*up+((-wn^2+2/dt^2)/(1/dt^2+wn*zeta/dt))*u1;

u(3)=-acc(2)/(1/dt^2+wn*zeta/dt)+((-1/dt^2+wn*zeta/dt)/(1/dt^2+wn*zeta/dt))*u1+((-wn^2+2/dt^2)/(1/dt^2+wn*zeta/dt))*u(2);

for m=3:12000;

u(m+1)=-acc(m)/(1/dt^2+wn*zeta/dt)+((-1/dt^2+wn*zeta/dt)/(1/dt^2+wn*zeta/dt))*u(m-1)+((-wn^2+2/dt^2)/(1/dt^2+wn*zeta/dt))*u(m);

end

T=0:dt:60;

plot(T,u,'k');

xlabel('Time (t) in seconds')

ylabel('Response U(t) in units')

title('Response U(t)/Tn=2 , zeta=0.05')

end

[TT]

this shows the response u(t) of a given ground acceleration. I need to generate this code for a given 'time vector' instead of a discrete value of Tn. Thank you for helping