tripack: left – R documentation

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left

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

Examples

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

tripack

Triangulation of Irregularly Spaced Data

v1.3-9.1

ACM | file LICENSE

Authors

Fortran code by R. J. Renka. R functions by Albrecht Gebhardt <albrecht.gebhardt@aau.at>. With contributions from Stephen Eglen <stephen@anc.ed.ac.uk>, Sergei Zuyev <sergei@stams.strath.ac.uk> and Denis White <white.denis@epamail.epa.gov>

Initial release

2020-03-06