Hi,

(I post it on R-help list but I just realize I may get more help from
this email list)

 

I have coding question on mixed model in R. I am using R2.11.0 in
windows. I have an experiment with 2 fixed effect factors - A and B. The
levels of B are within the levels of A factor. The model is very similar
to a split plot design except the nesting relationship between the 2
fixed effect factors. For example: there are 2 levels for A - GM and ZM.
There are 7 levels of B in total (G1-G4 and Z1 - Z3) - but G1, G2, G3,
G4 only appear in GM while Z1, Z2 and Z3 only appear in ZM. The SAS code
is like the following:

Proc Mixed data = a;

Class A B rep;

Model y = A B(A);

Random rep rep*A;

Run;

 

I tried to code this model in R using lmer(). It turned out that R has
some issues with nesting levels with fixed effect. I changed and tried a
few models just for diagnostic purpose. And I found whenever I included
the nesting fixed effects, I got the following error message: "Problem
in .C("mixed_EM",: Singularity in backsolve, while calling subroutine
mixed_EM". I am wondering whether someone can help me set up this mixed
model in R. 

Thanks 

 

Huiyan Zhao

 


---------------------------------------------------------------------------------------------------------
This e-mail message may contain privileged and/or confidential information, and is intended to be received only by persons entitled to receive such information. If you have received this e-mail in error, please notify the sender immediately. Please delete it and all attachments from any servers, hard drives or any other media. Other use of this e-mail by you is strictly prohibited.


All e-mails and attachments sent and received are subject to monitoring, reading and archival by Monsanto, including its subsidiaries. The recipient of this e-mail is solely responsible for checking for the presence of "Viruses" or other "Malware". Monsanto, along with its subsidiaries, accepts no liability for any damage caused by any such code transmitted by or accompanying this e-mail or any attachment.
---------------------------------------------------------------------------------------------------------


	[[alternative HTML version deleted]]


