An edgelist matrix. Each row is assumed to be of the form (from_node_id
to_node_id
time_stamp
). For a directed network ,from_node_id
is the id of the source node and to_node_id
is the id of the destination node. For an undirected network, the order is ignored and from_node_id
and to_node_id
are the ids of two ends. time_stamp
is the arrival time of the edge. from_node_id
and to_node_id
are assumed to be integers that are at least \(0\). The whole ids need not to be contiguous.
To register a new node \(i\) at time \(t\) without any edge, add a row with format (i -1 t
). This works for both undirected and directed networks.
time_stamp
can be either numeric or string. The value of a time-stamp can be arbitrary, but we assume that a smaller time_stamp (regarded so by the sort
function in R
) represents an earlier arrival time. Examples of time-stamps that satisfy this assumption are the integer 0:T
, the string format `yyyy-mm-dd', and the POSIX time.