lin: Generate a Basis Matrix with a Variable as Linear
In gasparrini/dlnm: Distributed Lag Non-Linear Models

Description Usage Arguments Details Value Note Author(s) See Also Examples

The function generates a basis matrix including a linear un-transformed variable. It is meant to be used internally by onebasis and crossbasis and not directly run by the users.

1	lin(x, intercept=FALSE)

`x`	the predictor variable. Missing values are allowed.
`intercept`	logical. If `TRUE`, an intercept is included in the basis matrix, namely a vector of 1's.

The function returns a basis matrix with the un-transformed variable, optionally with an intercept if intercept=TRUE.

A matrix object of class "lin". It contains the attribute intercept.

This function is mainly used internally thorugh onebasis to create basis matrices. It is not exported in the namespace, and can be accessed through the triple colon operator ':::' (see Examples below).

Antonio Gasparrini <antonio.gasparrini@lshtm.ac.uk>

onebasis to generate basis matrices and crossbasis to generate cross-basis matrices.

See dlnm-package for an introduction to the package and for links to package vignettes providing more detailed information.

### simple use (accessing non-exported function through ':::')
dlnm:::lin(1:5)
dlnm:::lin(1:5, intercept=TRUE)

### use as an internal function in onebasis (note the centering)
b <- onebasis(chicagoNMMAPS$pm10, "lin")
summary(b)
model <- glm(death ~ b, family=quasipoisson(), chicagoNMMAPS)
pred <- crosspred(b, model, at=0:60)
plot(pred, xlab="PM10", ylab="RR", main="RR for PM10")