changesOfSign {gyro}

Changes of sign

Description

Sometimes, the coordinates of the vertices of a polyhedron are given with changes of sign (with a symbol +/-). This function performs the changes of sign.

Usage

changesOfSign(M, changes = "all")

Arguments

M

a numeric matrix of coordinates of some points (one point per row)

changes

either the indices of the columns of M where the changes of sign must be done, or "all" to select all the indices

Value

A numeric matrix, M transformed by the changes of sign.

Examples

library(gyro)
library(rgl)
## ~~ rhombicosidodecahedron ~~##
phi <- (1 + sqrt(5)) / 2
vs1 <- rbind(
  c(1, 1, phi^3),
  c(phi^2, phi, 2 * phi),
  c(2 + phi, 0, phi^2)
)
vs2 <- rbind(vs1, vs1[, c(2, 3, 1)], vs1[, c(3, 1, 2)]) # even permutations
vs <- changesOfSign(vs2)
open3d(windowRect = c(50, 50, 562, 562), zoom = 0.65)
plotGyrohull3d(vs)