Xcontrast function

Xcontrast

Xcontrast

Produce Design Matrices for Contrasts

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

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

Returns

numeric matrix

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()].

Author(s)

Frank Harrell

  • Maintainer: Frank E Harrell Jr
  • License: GPL (>= 2)
  • Last published: 2025-01-17