One last question hopefully for now (I am using one of the scripts by Hermine Maes that uses umx to test the general assumptions of the twin design: oneSATu.pdf [6]
For a given phenotype I've gotten this error:
> All fit attempts resulted in errors - check starting values or model specification
> Error in if (rfu == "r'Wr") { : argument is of length zero
In addition:
> Warning messages:
> 1: In model 'oneSATcu' Optimizer returned a non-zero status code 6. The model does not satisfy the first-order optimality conditions to the required accuracy, and no improved point for the merit function could be found during the final linesearch (Mx status RED)
My thought is maybe to do something with mxTryHard (increase the amount of attempts in some manner), but I am wondering now if there is also a way to alter the starting values for umx or just a general potential solution (albeit, I am not sure how that works with the umxEquate()/umxSuperModel()/umxRAM() aspects (as compared to the ACE model)).
Thanks as always!