Description Usage Arguments Value Author(s) References See Also Examples
This function is a constructor for the corSymm
class,
representing a general correlation structure. The internal
representation of this structure, in terms of unconstrained
parameters, uses the spherical parametrization defined in Pinheiro and
Bates (1996). Objects created using this constructor must later be
initialized using the appropriate Initialize
method.
1  corSymm(value, form, fixed)

value 
an optional vector with the parameter values. Default is

form 
a one sided formula of the form 
fixed 
an optional logical value indicating whether the
coefficients should be allowed to vary in the optimization, or kept
fixed at their initial value. Defaults to 
an object of class corSymm
representing a general correlation
structure.
José Pinheiro and Douglas Bates [email protected]
Pinheiro, J.C. and Bates., D.M. (1996) "Unconstrained Parametrizations for VarianceCovariance Matrices", Statistics and Computing, 6, 289296.
Pinheiro, J.C., and Bates, D.M. (2000) "MixedEffects Models in S and SPLUS", Springer.
Initialize.corSymm
,
summary.corSymm
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28  ## covariate is observation order and grouping factor is Subject
cs1 < corSymm(form = ~ 1  Subject)
# Pinheiro and Bates, p. 225
cs1CompSymm < corCompSymm(value = 0.3, form = ~ 1  Subject)
cs1CompSymm < Initialize(cs1CompSymm, data = Orthodont)
corMatrix(cs1CompSymm)
# Pinheiro and Bates, p. 226
cs1Symm < corSymm(value =
c(0.2, 0.1, 0.1, 0, 0.2, 0),
form = ~ 1  Subject)
cs1Symm < Initialize(cs1Symm, data = Orthodont)
corMatrix(cs1Symm)
# example gls(..., corSpher ...)
# Pinheiro and Bates, pp. 261, 263
fm1Wheat2 < gls(yield ~ variety  1, Wheat2)
# p. 262
fm2Wheat2 < update(fm1Wheat2, corr =
corSpher(c(28, 0.2),
form = ~ latitude + longitude, nugget = TRUE))
# example gls(..., corSymm ... )
# Pinheiro and Bates, p. 251
fm1Orth.gls < gls(distance ~ Sex * I(age  11), Orthodont,
correlation = corSymm(form = ~ 1  Subject),
weights = varIdent(form = ~ 1  age))

Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.