What function in Matlab is equivalent to the block in Simulink "Transport Delay"?

I want to use a delay function that does exactly what the block in Simulink "Transport Delay" does. I tried to use the function "delayseq" but that requires sampling frequency along the time delay. Any idea? Thanks in advance

[Walter Roberson]

What is the input that is to be delayed? What does your code use as its clock?

[Ismaeel]

Hi Walter, thanks for your reply. I use ode15s for solving DAEs system. I have one of the states (only one of them, the rest of states don't include any delay) needs to be delayed by a certain amount of time. The clock is the time that ode15s handles as an output, so I am not using the time variable directly but the states in DAEs are functions of time.

Answer 1

[Walter Roberson]

ode15s is the wrong function for solving delay differential equations. Have a look at https://www.mathworks.com/help/matlab/delay-differential-equations.html

[Ismaeel]

Thanks Walter, I have been working on the problem using the function you suggested (dde23 or ddesd) but I realized that these solvers can not solve stiff delay DAEs problems even when I give a very small amount of delay (1e-15). The problem can be solved easily without delay using ode15s function. I hope Mathworks works on stiff delay DE for the future versions of Matlab.