Taste of R
2010-Nov-24 22:49 UTC
[R] Seeking advice on dynamic linear models with matrix state variable.
Hello, fellow R users,
I recently need to estimate a dynamic linear model in the following form:
For the measurement equation:
Y_t = F_t * a_t + v_t
where Y_t is the observation. It is a 1 by q row vector for each t.
F_t is my forecasting variable. It is a 1 by p row vector.
a_t is my state variable. It is a p by q MATRIX of parameters with each column
of the matrix being regression coefficient of a random variable in Y_t. And v is
a multivariate normal noise.
The state equation is:
a_t = a_(t-1) + Omega_t
So a_t is a matrix random walk process. The distribution of Omega_t is a
matrix-normal distribution.
This model is very well discussed on page 579 of West and Harrison's book on
DLM. The key feature being that the state variable is a matrix. I have spent
quiet some time with package dlm and even bought the book written by the authors
from Amazon. But all the models disussed in the R book for dlm package has the
state variable being vectors. (For various reasons, I do not want to stack up
the columns of the matrix into a vector.) So I am wondering any body can offer
me some hints on how I could proceed? If anybody can show me an example in R
that would be fantastic.
Happy thanksgiving.
Wei
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