Wraps binary ergm terms for use in valued models, with formula specifying which terms
are to be wrapped and form specifying how they are to be
used and how the binary network they are evaluated on is to be constructed.
# valued: B(formula, form)a one-sided ergm()-style formula whose RHS contains the
binary ergm terms to be evaluated. Which terms may be used
depends on the argument form
One of three values:
"sum": see section "Generalizations of
binary terms" in ergmTerm help; all terms in formula must
be dyad-independent.
"nonzero": section "Generalizations of
binary terms" in ergmTerm help; any binary ergm terms
may be used in formula .
a one-sided formula value-dependent
network. form must contain one "valued" ergm term, with
the following properties:
dyadic independence;
dyadwise contribution of either 0 or 1; and
dyadwise contribution of 0 for a 0-valued dyad.
Formally, this means that it is expressable as $$g(y) = \sum_{i,j} f_{i,j}(y_{i,j}),$$ where for all \(i\), \(j\), and \(y\), \(f_{i,j}(y_{i,j})\) is either 0 or 1 and, in particular, \(f_{i,j}(0)=0\).
Examples of such terms include nonzero ,
ininterval() , atleast() , atmost() ,
greaterthan() , lessthen() , and equalto() .
Then, the value of the statistic will be the value of the
statistics in formula evaluated on a binary network that is
defined to have an edge if and only if the corresponding
dyad of the valued network adds 1 to the valued term in
form .
For example, B(~nodecov("a"), form="sum") is equivalent to
nodecov("a", form="sum") and similarly with
form="nonzero" .
When a valued implementation is available, it should be preferred, as it is likely to be faster.
ergmTerm for index of model terms currently visible to the package.
ergm:::.formatTermKeywords("ergmTerm", "B", "subsection")