Control Function for rrvglm()
Algorithmic constants and parameters for running rrvglm
are set
using this function.
rrvglm.control(Rank = 1, Algorithm = c("alternating", "derivative"), Corner = TRUE, Uncorrelated.latvar = FALSE, Wmat = NULL, Svd.arg = FALSE, Index.corner = if (length(str0)) head((1:1000)[-str0], Rank) else 1:Rank, Ainit = NULL, Alpha = 0.5, Bestof = 1, Cinit = NULL, Etamat.colmax = 10, sd.Ainit = 0.02, sd.Cinit = 0.02, str0 = NULL, noRRR = ~1, Norrr = NA, noWarning = FALSE, trace = FALSE, Use.Init.Poisson.QO = FALSE, checkwz = TRUE, Check.rank = TRUE, Check.cm.rank = TRUE, wzepsilon = .Machine$double.eps^0.75, ...)
Rank |
The numerical rank R of the model.
Must be an element from the set {1,2,...,min(M,p2)}.
Here, the vector of explanatory variables x is partitioned into
(x1,x2), which is of dimension p1+p2.
The variables making up x1 are given by the terms in
|
Algorithm |
Character string indicating what algorithm is to be used. The default is the first one. |
Corner |
Logical indicating whether corner constraints are
to be used. This is one method for ensuring a unique solution.
If |
Uncorrelated.latvar |
Logical indicating whether uncorrelated latent variables are to be used.
This is normalization forces the variance-covariance
matrix of the latent variables to be |
Wmat |
Yet to be done. |
Svd.arg |
Logical indicating whether a singular value decomposition
of the outer product is to computed. This is another normalization
which ensures uniqueness. See the argument |
Index.corner |
Specifies the R rows of the constraint matrices that are used for the corner constraints, i.e., they hold an order-R identity matrix. |
Alpha |
The exponent in the singular value decomposition that is used in
the first part: if the SVD is
U %*% D %*% t(V) then the
first and second parts are
U %*% D^Alpha
and
D^(1-Alpha) %*% t(V) respectively.
A value of 0.5 is ‘symmetrical’.
This argument is used only when |
Bestof |
Integer. The best of |
Ainit, Cinit |
Initial A and C matrices which may speed up convergence. They must be of the correct dimension. |
Etamat.colmax |
Positive integer, no smaller than |
str0 |
Integer vector specifying which rows
of the estimated constraint matrices (A) are
to be all zeros.
These are called structural zeros.
Must not have any common value with |
sd.Ainit, sd.Cinit |
Standard deviation of the initial values for the elements
of A and C.
These are normally distributed with mean zero.
This argument is used only if |
noRRR |
Formula giving terms that are not to be included
in the reduced-rank regression.
That is, |
Norrr |
Defunct. Please use |
trace |
Logical indicating if output should be produced for each iteration. |
Use.Init.Poisson.QO |
Logical indicating whether the |
checkwz |
logical indicating whether the diagonal elements of
the working weight matrices should be checked whether they are
sufficiently positive, i.e., greater than |
noWarning, Check.rank, Check.cm.rank |
Same as |
wzepsilon |
Small positive number used to test whether the diagonals of the working weight matrices are sufficiently positive. |
... |
Variables in ... are passed into
|
In the above, R is the Rank
and
M is the number of linear predictors.
VGAM supports three normalizations to ensure a unique
solution. Of these, only corner constraints will work with
summary
of RR-VGLM objects.
A list with components matching the input names. Some error checking is done, but not much.
The arguments in this function begin with an upper case letter to help
avoid interference with those of vglm.control
.
In the example below a rank-1 stereotype model (Anderson, 1984) is fitted.
Thomas W. Yee
Yee, T. W. and Hastie, T. J. (2003). Reduced-rank vector generalized linear models. Statistical Modelling, 3, 15–41.
## Not run: set.seed(111) pneumo <- transform(pneumo, let = log(exposure.time), x3 = runif(nrow(pneumo))) # x3 is random noise fit <- rrvglm(cbind(normal, mild, severe) ~ let + x3, multinomial, data = pneumo, Rank = 1, Index.corner = 2) constraints(fit) vcov(fit) summary(fit) ## End(Not run)
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