Constructing lookup tables for time-varying covariates.
# S4 method for numeric
covariate_table(..., order = c("linear", "constant"), times)# S4 method for character
covariate_table(..., order = c("linear", "constant"), times)
numeric vectors or data frames containing time-varying covariates. It must be possible to bind these into a data frame.
the order of interpolation to be used.
Options are “linear” (the default) and “constant”.
Setting order="linear" treats the covariates as piecewise linear functions of time;
order="constant" treats them as right-continuous piecewise constant functions.
the times corresponding to the covariates. This may be given as a vector of (non-decreasing, finite) numerical values. Alternatively, one can specify by name which of the given variables is the time variable.
If the ‘pomp’ object contains covariates (specified via the covar argument), then interpolated values of the covariates will be available to each of the model components whenever it is called.
In particular, variables with names as they appear in the covar covariate table will be available to any C snippet.
When a basic component is defined using an R function, that function will be called with an extra argument, covars, which will be a named numeric vector containing the interpolated values from the covariate table.
An exception to this rule is the prior (rprior and dprior):
covariate-dependent priors are not allowed.
Nor are parameter transformations permitted to depend upon covariates.
lookup
More on implementing POMP models:
Csnippet,
accumulators,
basic_components,
distributions,
dmeasure_spec,
dprocess_spec,
parameter_trans(),
pomp-package,
prior_spec,
rinit_spec,
rmeasure_spec,
rprocess_spec,
skeleton_spec,
transformations,
userdata