This is my notebook, the function is in this form . but, I get the error: NDSolve::idelay: Initial history needs to be specified for all variables for delay-differential equations. My code is not very beautiful, sorry! Is there anybody that can help me? Thank you very much,

ok, i know where the problem is. I used Norm[] to a vector, then derivative of this with the elements of the vector. then derivative of the result with the elements fo the vector again. Conjugation occurs in this process. the problem is solved when I add //ComplexExpand behind Norm[]. thank you very much

The error message states that your equations are not resulting in numbers. This clue suggests that you need to evaluate the equations at the start to find a syntax error. By setting time to zero and substituting in all the initial conditions, you can evaluate the first step manually to see what is wrong. (cpdae /. t -> 0) /. (cpinit /. Equal -> Rule) This should result in equations with only the lowest derivatives and numbers, however, I get terms that have expressions like this: +(1/2) Sqrt[3] Derivative[1][Conjugate][Sqrt[3]/2] You have the derivative of Conjugate[] applied to constants. You need to fix your equations before trying to run NDSolve so these terms are not there. I have not looked in detail at what you are doing but is it safe to set those terms to zero? -- I'm not sure what the derivative of the Conjugate function really means. It likely results from the chain rule applied to Conjugate[function[t]]. If you fix this, your equations should evaluate. I hope this helps. Regards, Neil

Thanks for your help, I think your suggestion is feasible.

A problem about NDSolve:idelay