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rms (version 6.8-2)

Xcontrast: Xcontrast

Description

Produce Design Matrices for Contrasts

Usage

Xcontrast(
  fit,
  a,
  b = NULL,
  a2 = NULL,
  b2 = NULL,
  ycut = NULL,
  weights = "equal",
  expand = TRUE,
  Zmatrix = TRUE
)

Value

numeric matrix

Arguments

fit

an `rms` or `rmsb` fit object, not necessarily complete

a

see [rms::contrast.rms()]

b

see [rms::contrast.rms()]

a2

see [rms::contrast.rms()]

b2

see [rms::contrast.rms()]

ycut

see [rms::contrast.rms()]

weights

see [rms::contrast.rms()]

expand

see [rms::contrast.rms()]

Zmatrix

set to `FALSE` for a partial PO model in which you do not want to include the Z matrix in the returned contrast matrix

Author

Frank Harrell

Details

This is a simpler version of `contrast.rms` that creates design matrices or differences of them and does not require the fit object to be complete (i.e., to have coefficients). This is used for the `pcontrast` option in [rmsb::blrm()].