This library contains an R implementation of some triangulation routines.  

It is based on Fortran code from R. J. Renka in the ACM Collected 
Algorithms archive under

  http://www.netlib.org/toms/751

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

Currently it contains the following R functions which provide acces to the 
Fortran subroutines of TRIPACK and implement a new triangulation object:

  tri.mesh
  triangles
  plot.tri
  print.tri
  summary.tri
  tri.find
  neighbours
  identify.tri
  convex.hull
  add.constraint

Future versions will contain more functions to get access to all subroutines of 
TRIPACK, but at the moment my main interest was to have a convex.hull and 
basic triangulation functions (with plot and print methods).

The help pages are based on the Fortran comments. 

This library was intended by the akima library, which also contains some (but 
not all) of the TRIPACK functions. If it would be possible (in future R 
versions) to call subroutiunes of other shared object directly from C or
Fortran, it would not be necessary to include TRIPACK functions in library
akima at all but use this triangulation library instead.

------------------------------------------------------------------
Albrecht Gebhardt           email: albrecht.gebhardt@uni-klu.ac.at
Institut fuer Mathematik    Tel. : (++43 463) 2700/837
Universitaet Klagenfurt     Fax  : (++43 463) 2700/834
Villacher Str. 161
A-9020 Klagenfurt, Austria
------------------------------------------------------------------

The abstract of the original article at ACM follows:
##############################################################################
                 TRIPACK is a Fortran 77 software package that employs
                 an incremental algorithm to construct a constrained
                 Delaunay triangulation of a set of points in the plane
                 (nodes). The triangulation covers the convex hull of
                 the nodes but may include polygonal constraint regions
                 whose triangles are distinguishable from those in the
                 remainder of the triangulation. This effectively allows
                 for a nonconvex or multiply connected triangulation
                 (the complement of the union of constraint regions)
                 while retaining the efficiency of searching and
                 updating a convex triangulation. The package provides a
                 wide range of capabilities including an efficient means
                 of updating the triangulation with nodal additions or
                 deletions. For N  nodes, the storage requirement is
                 13N integer storage locations in addition to the 2N 
                 nodal coordinates.

