left {tripack}

Determines whether given points are left of a directed edge.

Description

This function returns a logical vector indicating which elements of the given points P0 are left of the directed edge P1->P2.

Usage

left(x0, y0, x1, y1, x2, y2)

Arguments

x0

Numeric vector, 'x' coordinates of points P0 to check

y0

Numeric vector, 'y' coordinates of points P0 to check, same length as 'x'.

x1

'x' coordinate of point P1

y1

'y' coordinate of point P1

x2

'x' coordinate of point P2

y2

'y' coordinate of point P2

Value

Logical vector.

Note

This is an interface to the Fortran function VLEFT, wich is modeled after TRIPACKs LEFT function but accepts more than one point P0.

Author(s)

A. Gebhardt

See Also

in.convex.hull

Examples

left(c(0,0,1,1),c(0,1,0,1),0,0,1,1)