lotri | R Documentation |
Easily Specify block-diagonal matrices with lower triangular info
lotri(x, ..., envir = parent.frame(), default = "id")
x |
list, matrix or expression, see details |
... |
Other arguments treated as a list that will be concatenated then reapplied to this function. |
envir |
the |
default |
Is the default factor when no conditioning is implemented. |
This can take an R matrix, a list including matrices or expressions, or expressions
Expressions can take the form
name ~ estimate
Or the lower triangular matrix when "adding" the names
name1 + name2 ~ c(est1, est2, est3)
The matrices are concatenated into a block diagonal matrix, like
bdiag
, but allows expressions to specify
matrices easier.
named symmetric matrix useful in 'rxode2()' simulations (and perhaps elsewhere)
Matthew L Fidler
## A few ways to specify the same matrix lotri({et2 + et3 + et4 ~ c(40, 0.1, 20, 0.1, 0.1, 30)}) ## You do not need to enclose in {} lotri(et2 + et3 + et4 ~ c(40, 0.1, 20, 0.1, 0.1, 30), et5 ~ 6) ## But if you do enclose in {}, you can use ## multi-line matrix specifications: lotri({et2 + et3 + et4 ~ c(40, 0.1, 20, 0.1, 0.1, 30) et5 ~ 6 }) ## You can also add lists or actual R matrices as in this example: lotri(list(et2 + et3 + et4 ~ c(40, 0.1, 20, 0.1, 0.1, 30), matrix(1,dimnames=list("et5","et5")))) ## Overall this is a flexible way to specify symmetric block ## diagonal matrices. ## For rxode2, you may also condition based on different levels of ## nesting with lotri; Here is an example: mat <- lotri(lotri(iov.Ka ~ 0.5, iov.Cl ~ 0.6), lotri(occ.Ka ~ 0.5, occ.Cl ~ 0.6) | occ(lower=4,nu=3)) mat ## you may access features of the matrix simply by `$` that is mat$lower # Shows the lower bound for each condition mat$lower$occ # shows the lower bound for the occasion variable ## Note that `lower` fills in defaults for parameters. This is true ## for `upper` true; In fact when accessing this the defaults ## are put into the list mat$upper ## However all other values return NULL if they are not present like mat$lotri ## And values that are specified once are only returned on one list: mat$nu mat$nu$occ mat$nu$id ## You can also change the default condition with `as.lotri` mat <- as.lotri(mat, default="id") mat
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