detrend {Epi} | R Documentation |
The columns of a model matrix M
is projected on the
orthogonal complement to the matrix (1,t)
,
resp. (1,t,t^2)
.
Orthogonality is defined w.r.t. an inner product defined by the
matrix diag(weight)
.
detrend( M, t, weight = rep(1, nrow(M)) ) decurve( M, t, weight = rep(1, nrow(M)) )
M |
A model matrix. |
t |
The trend defining a subspace. A numerical vector of length
|
weight |
Weights defining the inner product of vectors |
The functions are intended to be used in parametrization of age-period-cohort models.
A full-rank matrix with columns orthogonal to (1,t)
, for
decurv
, (1,t,t^2)
.
Bendix Carstensen, Steno Diabetes Center, http://BendixCarstensen.com, with essential help from Peter Dalgaard.