Updating Factor Analytic loadings
!AILOADINGS i
!AILOADINGS i
relates to the fitting of eXtended Factor Analytic models.
After ASReml calculates updates for variance parameters, it
checks whether the updates are reasonable and sometimes reduces them
over and above any !STEPSIZE shrinkage. The extra shrinkage
has two levels. Loadings that change sign are restricted to
doubling in magnitude, and if the average change in
magnitude of loadings is greater than 10-fold, they are all shrunk back.
When the user does not provide constraits, ASReml rotates the
loadings each iteration. When
!AILOADINGS i
is specified,
it also prevents AI updates of some loadings during the first
i iterations.
For f
(>1) factors, only the last factor
is estimated (conditional on the earlier ones) in the first f-1
iterations. Then pairs including the last are estimated until
iteration i.
If !AILOADINGS is not specified and
!CONTINUE is used and ASReml initializes the
XFA model from a lower order model,
the i parameter is set internally.
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