splitDegenerateConic {RConics}

Split degenerate conic

Description

Split a degenerate conic into two lines.

Usage

splitDegenerateConic(C)

Arguments

C

a (3 \times 3) matrix representation of a degenerate conic.

Value

A (3 \times 2) matrix whose columns correspond to the homongeneous representation of two lines (real or complex).

Source

Richter-Gebert, Jürgen (2011). Perspectives on Projective Geometry - A Guided Tour Through Real and Complex Geometry, Springer, Berlin, ISBN: 978-3-642-17285-4

Examples

# tw0 lines
g <- c(0.75,0.25,3)
h <- c(0.5,-0.25,2)

# a degenerate conic 
D <- g %*% t(h) + h %*% t(g)

# split the degenerate conic into 2 lines
L <- splitDegenerateConic(D)

# plot
plot(0,0,xlim=c(-10,5),ylim=c(-10,10),type="n")
addLine(L[,1],col="red")
addLine(L[,2],col="green")