rpa_control_preference {wdnet}

Set preference function(s). Defined for rpanet.

Description

Set preference function(s). Defined for rpanet.

Usage

rpa_control_preference(
  ftype = c("default", "customized"),
  sparams = c(1, 1, 0, 0, 1),
  tparams = c(0, 0, 1, 1, 1),
  params = c(1, 1),
  spref = "outs + 1",
  tpref = "ins + 1",
  pref = "s + 1"
)

Arguments

ftype

Preference function type. Either "default" or "customized". "customized" preference functions require "binary" or "linear" generation methods. If using default preference functions, sparams, tparams and params must be specified. If using customized preference functions, spref, tpref and pref must be specified.

sparams

A numerical vector of length 5 giving the parameters of the default source preference function. Defined for directed networks. Probability of choosing an existing node as the source node is proportional to sparams[1] * out-strength^sparams[2] + sparams[3] * in-strength^sparams[4] + sparams[5].

tparams

A numerical vector of length 5 giving the parameters of the default target preference function. Defined for directed networks. Probability of choosing an existing node as the target node is proportional to tparams[1] * out-strength^tparams[2] + tparams[3] * in-strength^tparams[4] + tparams[5].

params

A numerical vector of length 2 giving the parameters of the default preference function. Defined for undirected networks. Probability of choosing an existing node is proportional to strength^params[1] + params[2].

spref

Character expression or an object of class XPtr giving the customized source preference function. Defined for directed networks. Default value is "outs + 1", i.e., node out-strength + 1. See Details and Examples for more information.

tpref

Character expression or an object of class XPtr giving the customized target preference function. Defined for directed networks. Default value is "ins + 1", i.e., node in-strength + 1.

pref

Character expression or an object of class XPtr giving the customized preference function. Defined for undirected networks. Default value is "s + 1", i.e, node strength + 1.

Details

If choosing customized preference functions, spref, tpref and pref will be used and the network generation method must be "binary" or "linear". spref (tpref) defines the source (target) preference function, it can be a character expression or an object of class XPtr.

• Character expression; it must be a one-line C++ style expression of outs (node out-strength) and ins (node in-strength). For example, "pow(outs, 2) + 1", "pow(outs, 2) + pow(ins, 2) + 1", etc. The expression will be used to define an XPtr via RcppXPtrUtils::cppXPtr. The XPtr will be passed to the network generation function. The expression must not have variables other than outs and ins.

• 'XPtr' an external pointer wrapped in an object of class XPtr defined via RcppXPtrUtils::cppXPtr. An example for defining an XPtr with C++ source code is included in Examples. For more information about passing function pointers, see https://gallery.rcpp.org/articles/passing-cpp-function-pointers-rcppxptrutils/. Please note the supplied C++ function accepts two double arguments and returns a double. The first and second arguments represent node out- and in-strength, respectively. Note that the XPtr will be invalid and cannot be used to control network generation in another separate R session. Therefore, we recommend preserving the source code of your preference function for future use.

pref is defined analogously. If using character expression, it must be a one-line C++ style expression of s (node strength). If using XPtr, the supplied C++ function accepts only one double argument and returns a double.

Value

A list of class rpacontrol with components ftype, sparams, tparams, params or ftype, spref, tpref, pref with function pointers spref.pointer, tpref.pointer, pref.pointer.

Examples

# Set source preference as out-strength^2 + in-strength + 1,
# target preference as out-strength + in-strength^2 + 1.
# 1. use default preference functions
ctr1 <- rpa_control_preference(
  ftype = "default",
  sparams = c(1, 2, 1, 1, 1), tparams = c(1, 1, 1, 2, 1)
)
# 2. use character expressions
ctr2 <- rpa_control_preference(
  ftype = "customized",
  spref = "pow(outs, 2) + ins + 1", tpref = "outs + pow(ins, 2) + 1"
)
# 3. define XPtr's with C++ source code
spref.pointer <- RcppXPtrUtils::cppXPtr(
  code =
    "double spref(double outs, double ins) {return pow(outs, 2) + ins + 1;}"
)
tpref.pointer <- RcppXPtrUtils::cppXPtr(
  code =
    "double tpref(double outs, double ins) {return outs + pow(ins, 2) + 1;}"
)
ctr3 <- rpa_control_preference(
  ftype = "customized",
  spref = spref.pointer,
  tpref = tpref.pointer
)
ret <- rpanet(1e5, control = ctr3)