A temporal interaction function for use in
can be constructed via the
It checks the supplied function elements, assigns defaults for
missing arguments, and returns all checked arguments in a list.
However, for standard applications it is much easier to use one of the
pre-defined temporal interaction functions, e.g.,
tiaf(g, G, deriv, Deriv, npars, validpars = NULL)
the temporal interaction function. It must accept
two arguments, the first one being a vector of time points, the
second one a parameter vector. For marked
twinstim, it must
accept the type of the event (integer code) as its third argument
(either a single type for all locations or separate types for each
a primitive of \(g(t)\) (with respect to time). It must
accept the same arguments as
g, for instance a vector
of time points (not just a single one).
optional derivative of \(g(t)\) with respect to
the parameters. It takes the same arguments as
returns a matrix with as many rows as there were time points in the
npars columns. This derivative is necessary for the
calculation of the score function in
twinstim(), which is
advantageous for the numerical log-likelihood maximization.
optional primitive of
deriv (with respect to
time). It must accept the same arguments as
G and returns a matrix with as many rows as there were time
points in the input and
npars columns. The integrated
derivative is necessary for the score function in
the number of parameters of the temporal interaction
g (i.e. the length of its second argument).
optional function taking one argument, the parameter vector, indicating if it
is valid. This approach to specify parameter constraints is rarely
needed, because usual box-constrained parameters can be taken into
account by using L-BFGS-B as the optimization method in
twinstim (with arguments
positivity constraints by using log-parametrizations.
This component is not necessary (and ignored) if
npars == 0.
list of checked arguments.