cross_basis: Build crossbasis
In dlim: Distributed Lag Interaction Model

cross_basis

R Documentation

Build crossbasis

Creates cross-basis using natural splines for regression in DLIM

cross_basis(
  x,
  M,
  L = NULL,
  argmod = list(),
  arglag = list(),
  model_type = "standard"
)

`x`	a numeric time series vector of length n or matrix of lagged exposures (columns) for n individuals (rows)
`M`	vector of length n containing modifier values
`L`	a numeric vector of length 1 containing the number of lag terms. This is required if `x` is vector, and is not used if `x` is a matrix.
`argmod`	a list: $fun is the spline function for the modifier ("ps" or "cr" to penalize), $arg is a list of arguments for the spline function (must be named by argument), $df is the degrees of freedom, $sp is optional smoothing parameter
`arglag`	a list: $fun is the spline function for the lag ("ps" or "cr" to penalize), $arg is a list of arguments for the spline function (must be named by argument), $df is the degrees of freedom, $sp is optional smoothing parameter
`model_type`	"linear" for a DLIM with linear interaction, "quadratic" for a DLIM with quadratic interaction, "standard" for a DLIM with splines

This function returns a list of 5 or 6 elements:

`cb`	cross-basis (matrix)
`B_lag`	lag basis (basis matrix)
`B_mod`	modifier basis (basis matrix)
`df_l`	lag degrees of freedom (numeric)
`df_m`	modifier degrees of freedom (numeric)
`L`	number of lags (numeric)
`Slist`	lag and modifier penalty matrices, if penalizing (list)