# circum: Determine the circumcircle of a triangle In tripack: Triangulation of Irregularly Spaced Data

## Description

This function returns the circumcircle of a triangle.

## Usage

 `1` ```circum(x, y) ```

## Arguments

 `x` Vector of three elements, giving the x coordinatres of the triangle nodes. `y` Vector of three elements, giving the y coordinatres of the triangle nodes.

## Details

This is an interface to the Fortran function CIRCUM found in TRIPACK.

## Value

 ` x ` 'x' coordinate of center ` y ` 'y' coordinate of center ` radius ` circumcircle radius ` signed.area ` signed area of riangle (positive iff nodes are numbered counter clock wise) ` aspect.ratio ` ratio "radius of inscribed circle"/"radius of circumcircle", varies between 0 and 0.5 0 means collinear points, 0.5 equilateral trangle.

## Note

This function is mainly intended to be used by `circumcircle`.

## Author(s)

Fortran code: R. J. Renka, R code: A. Gebhardt

## References

R. J. Renka (1996). Algorithm 751: TRIPACK: a constrained two-dimensional Delaunay triangulation package. ACM Transactions on Mathematical Software. 22, 1-8.

## See Also

`circumcircle`

## Examples

 `1` ```circum(c(0,1,0),c(0,0,1)) ```

tripack documentation built on May 29, 2017, 9:52 p.m.