# Best Linear Unbiased Prediction

## !BLUP

!BLUP `n`

restricts ASReml
to performing only part of the first iteration.
The estimation routine is aborted after

` n` = 1: forming the estimates of the vector of fixed and
random effects,

` n` = 2: forming the estimates of the vector of fixed and
random effects, REML log-likelihood and residuals (this is the default),

` n` = 3: forming the estimates of the vector of fixed and
random effects, REML log-likelihood, residuals and
inverse coefficient matrix.

` n` = 4: forming the estimates of the vector of fixed and
random effects by solving the mixed model equations using

the preconditioned gradient method,
` n` = 10:19 forming the estimates of the vector of fixed and
random effects by solving the mixed model equations by

Gauss-Seidal iteration with relaxation factor `n/10`.
Use the !MAXIT `i` where ` i` > 100 to set the maximum
number of iterations used when $4 <= i <= 19.
ASReml prints its standard reports as if it had completed the
iteration normally, but since it has not completed it, some of the
information printed will be incorrect. In particular, variance information
on the variance parameters will always be wrong. Standard errors on
the estimates will be wrong unless ` n`=3. Residuals are not available if
` n`=1.
Use of ` n`=3
or ` n`=2 will halve the processing
time when compared to the alternative of using
!MAXIT 1.
However, !MAXIT 1 does result in a complete and correct
output report.
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