Re: LogL Converged, Parameter Not Converged

Dear subash
I am trying to fit a linear mixed model for a Group Unbalanced Block
design, and I get a warning message in the .ASR file as ?LogL Converged,
Parameters Not converged?. I increased the number of iterations from 30 to
100 and still got the same warning message. Then, I changed it to 300 and
the model converged. So I thought it is safe to use a big number for
!MAXIT and changed it to 500. I got the same warning message which, I
thought, doesn?t make any sense for parameters to converge at 300
iterations but, not with 500 iterations. What could be the reason? The
other question I had is, Should I use !CONTINUE option instead of
increasing the number of iterations. How is it different from increasing
the number of iterations using !MAXIT? What impact does it have on the run
time?

1. This message prints out in some situations when a parameter may be
small or poorly estimated - in the sense that the data may not support the
model you are fitting. If you would like to sanitise the data for
confidentiality reasons I would be most happy to try to run it for you to
see what I can make of it
2. continue is often a more reasonable way to achieve convergence as some
parameters may get fixed at boundary values etc

warm regards

Brian Cullis|Research Leader, Biometrics &
Senior Principal Research Scientist |
Industry & Investment NSW | Wagga Wagga Agricultural Institute | Pine
Gully Road | Wagga Wagga NSW 2650 |
PMB | Wagga Wagga NSW 2650
T: 02 6938 1855 | M: 0439 448 591 | F: 02 6938 1809 | E:
brian.cullis_at_industry.nsw.gov,au
W: www.industry.nsw.gov.au |

Visiting Professorial Fellow
School of Mathematics and Applied Statistics
Faculty of Informatics
University of Wollongong

Professor,
Faculty of Agriculture, Food & Natural Resources
The University of Sydney

Adjunct Professor
School of Computing and Mathematics
Charles Sturt University
 
Received on Mon Oct 11 2009 - 20:43:40 EST