detrend: Projection of a model matrix on to the orthogonal complement...

Description Usage Arguments Details Value Author(s) See Also

View source: R/detrend.R

Description

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).

Usage

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  detrend( M, t, weight = rep(1, nrow(M)) )
  decurve( M, t, weight = rep(1, nrow(M)) )

Arguments

M

A model matrix.

t

The trend defining a subspace. A numerical vector of length nrow(M)

weight

Weights defining the inner product of vectors x and y as sum(x*w*y). A numerical vector of length nrow(M), defaults to a vector of 1s. Must be all non-negative.

Details

The functions are intended to be used in parametrization of age-period-cohort models.

Value

A full-rank matrix with columns orthogonal to (1,t), for decurv, (1,t,t^2).

Author(s)

Bendix Carstensen, Steno Diabetes Center, http://BendixCarstensen.com, with essential help from Peter Dalgaard.

See Also

projection.ip


Epi documentation built on May 15, 2018, 3 p.m.

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