rotmat: rotmat

In cbmodels: Collection of "combined" models: PCA-LDA, PLS-LDA, etc.

Description

Calculate a rotation matrix

Usage

  rotmat(alpha = 0, ndim = 2, dim1 = 1, dim2 = 2)

Arguments

alpha	rotation angle (in rad)
ndim	number of dimensions
dim1,dim2	the plane in which the rotation should take place

Details

The rotation will take place in the plane spanned by dimensions dim1, dim2. All other directions are left untouched.

Matrix-multiplying ndim-dimensional points with the rotation matrix rotates the points alpha radians clockwise, see the example.

Value

matrix of size (ndim x ndim),

Author(s)

Claudia Beleites

Examples

rotmat (alpha = pi/2)
rotmat (alpha = 1)

point <- t (c (1, 1))
R <- rotmat (pi/20)
R
plot (point, ylim = c (0, 1.2), xlim = c (0, 1.2), pch = 19)
## clockwise rotation
points (point %*% R)
## counterclockwise rotation
points (point %*% t (R), col = 2)

cbmodels documentation built on May 31, 2017, 2:11 a.m.