About Lyson

Lyson · ‎10-13-2024

Hi @FreelanceReinh Thanks for the advice. I finally Got hold of the author (Piepho) and got his algorithm that I must submit first before accessing the %mult macro functions. I am sorted now. Thank you.

Lyson · ‎09-25-2024

Hi Jiltao Thanks for the response and advice, I am busy trying that one. Convergence is what I really want to achieve, with reasonable standard errors reflecting on the output. My model is trying to combine all random effects into one model, that is the main objective. So I am not quite sure if there is another approach of forcing this model to behave well without necessarily simplifying it (excluding other random effects).

SteveDenham · ‎07-23-2024

From experience, I think you may not have enough data to be able to distinguish and correctly estimate your RANDOM effects in these models, which would lead to the G matrix issues. Covariance parameter = 0 means you will get the non-positive definite message in the output. So, except in certain regulatory situations, you should simplify the RANDOM statement. SteveDenham

Rick_SAS · ‎07-19-2024

Dup of Solved: How do i get a block diagonal covariance matrix, V, in SAS Proc Mixed ... - SAS Support Communities

Lyson · ‎12-14-2022

Dear Rick I will definitely follow the discussion. Thank you so much.

SteveDenham · ‎04-06-2022

Specifying TYPE=HF in the REPEATED statement can accomplish this. However, I suspect you missed the point I was trying to make. Consider other covariance structures - I really doubt that HF will lead to the smallest corrected AIC - it will probably not be the best fit for your model. This avoids making a sphericity assumption, which is really not necessary (see the chapter on Repeated Measures in any edition of SAS for Mixed Models for a discussion). SteveDenham

Lyson · ‎04-05-2022

@SASKiwi Thank you for the clarity. I have adopted @Sajid01's answer as well.

Lyson · ‎04-03-2022

Hi Colleagues. I got a question from someone who saw my SAS Proc Mixed code that I used to fit a linear mixed model in SAS Studio (SAS on Demand). They asked me: "In what software environment is the procedure implemented?" I am confused with this environment term. How do I answer that one?

Lyson · ‎02-16-2022

Dear Rick Thank you for the reading by Gibbs and Kiernan (2020), "Simulating Data for Complex Linear Models." I see its full of wonderful sample simulation programs for linear models that I need time to grasp on. I appreciate the assistance.

Lyson · ‎02-14-2022

Yes I got it. Thanks Steve.

Lyson · ‎02-13-2022

Thank you. I got it like that and it works perfectly well.

Lyson · ‎02-12-2022

@PaigeMiller Yes indeed!! Thank you so much.

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