Putting *
as the first character in `s`
indicates that numbers are repeat counts,
A-Z are equality codes
and only . is unconstrained.
Thus !=*.3A2.
is equivalent to !=0AAA00
or !=0aaa00)
#### Examples

4 0 US !=ABACBA0CBA

constrains all parameters corresponding to A to be equal,
similarly for B and
C. The 7th parameter would be left unconstrained.
This sequence applied to an unstructured 4 x 4 matrix would make it banded, that is

A

B A

C B A

0 C B A

site.gen 2 # G header line
site 0 US .3 !=0A0AA0 !GPUPUUP
.1 .4 .1 .1 .3
gen

defines a structure for the genotype
by site interaction effects in a MET in which the genotypes are
independent random effects within sites but are correlated
across sites with equal covariance.

site 0 FA2 !G4PZ3P4P !=00000000VVVV
4*.9 # initial values for 1st factor
0 3*.1 # initial values for 2nd factor, first fixed at 0
4*.2 # initial values for site variances

defines a 2 factor Factor Analytic model for 4 sites with equal
variance. The first loading in the second factor is
constrained equal to 0 for identifiability. P places
restrictions on the magnitude of the loadings and the variances to be positive.

xfa(site,2) 0 XFA2 !=VVVV0 !4P4PZ3P
4*.2 # initial specific variances
4*1.2 # initial loadings for 1st factor
0 3*.3 # initial loadings for 2nd factor

defines a 2 factor Factor analytic model in which the
specific variances are all equal.
#### Parameters between and within variance models

More general relationships between variance parameters can be
defined using the
!VCC ` c`
qualifier placed on the data file definition line.