Yo can try, either first or second order of Pade Approximation.

Dear Francisco J. Sanchez Careaga

Thank you for your response . But my question is related to coding of time varying delay differential equation(which is added in file) using inbuilt function ddesd in MATLAB.

Hi, the calling sequence of ddesd is the following one:

sol=ddesd(ddefun,delays,history,tspan)

ddefun has the following form:

dydt=ddefun(t,y,Z)

where t and y are classical entries while Z(:,j) approximates y(d(j)) where the delay d(j) is component j of delays(t,y).

You can simply refer to the MATLAB help for more details.

In brief, the delays (possibly multiple) have to be defined in parameter delays.

Hi, do you solve this problem? Than you

Xiao Guo Yes, first create a function for time-varying delays then call it in ddesd solver. For example,

d = delays(t,y)

d = 1- e^{t}/(1+e^{t})

now, call it in ddesd

sol = ddesd(@ddefun, @delays, @history, tspan)

Hope this will help you...

Rakesh Kumar Thank you ! I also utilized ddesd to solve this problem but finds that it faces another numerical accuracy issue. (I guess it's a stiff differential equation issue)

Anyway, thank you for your reply very much!