Added triangulation routine

lib/triangle/README

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+Triangle
+A Two-Dimensional Quality Mesh Generator and Delaunay Triangulator.
+Version 1.6
+
+Show Me
+A Display Program for Meshes and More.
+Version 1.6
+
+Copyright 1993, 1995, 1997, 1998, 2002, 2005 Jonathan Richard Shewchuk
+2360 Woolsey #H
+Berkeley, California  94705-1927
+Please send bugs and comments to jrs@cs.berkeley.edu
+
+Created as part of the Quake project (tools for earthquake simulation).
+Supported in part by NSF Grant CMS-9318163 and an NSERC 1967 Scholarship.
+There is no warranty whatsoever.  Use at your own risk.
+
+
+Triangle generates exact Delaunay triangulations, constrained Delaunay
+triangulations, conforming Delaunay triangulations, Voronoi diagrams, and
+high-quality triangular meshes.  The latter can be generated with no small
+or large angles, and are thus suitable for finite element analysis.
+Show Me graphically displays the contents of the geometric files used by
+Triangle.  Show Me can also write images in PostScript form.
+
+Information on the algorithms used by Triangle, including complete
+references, can be found in the comments at the beginning of the triangle.c
+source file.  Another listing of these references, with PostScript copies
+of some of the papers, is available from the Web page
+
+    http://www.cs.cmu.edu/~quake/triangle.research.html
+
+------------------------------------------------------------------------------
+
+These programs may be freely redistributed under the condition that the
+copyright notices (including the copy of this notice in the code comments
+and the copyright notice printed when the `-h' switch is selected) are
+not removed, and no compensation is received.  Private, research, and
+institutional use is free.  You may distribute modified versions of this
+code UNDER THE CONDITION THAT THIS CODE AND ANY MODIFICATIONS MADE TO IT
+IN THE SAME FILE REMAIN UNDER COPYRIGHT OF THE ORIGINAL AUTHOR, BOTH
+SOURCE AND OBJECT CODE ARE MADE FREELY AVAILABLE WITHOUT CHARGE, AND
+CLEAR NOTICE IS GIVEN OF THE MODIFICATIONS.  Distribution of this code as
+part of a commercial system is permissible ONLY BY DIRECT ARRANGEMENT
+WITH THE AUTHOR.  (If you are not directly supplying this code to a
+customer, and you are instead telling them how they can obtain it for
+free, then you are not required to make any arrangement with me.)
+
+------------------------------------------------------------------------------
+
+The files included in this distribution are:
+
+  README           The file you're reading now.
+  triangle.c       Complete C source code for Triangle.
+  showme.c         Complete C source code for Show Me.
+  triangle.h       Include file for calling Triangle from another program.
+  tricall.c        Sample program that calls Triangle.
+  makefile         Makefile for compiling Triangle and Show Me.
+  A.poly           A sample input file.
+
+Each of Triangle and Show Me is a single portable C file.  The easiest way
+to compile them is to edit and use the included makefile.  Before
+compiling, read the makefile, which describes your options, and edit it
+accordingly.  You should specify:
+
+  The source and binary directories.
+
+  The C compiler and level of optimization.
+
+  The "correct" directories for include files (especially X include files),
+  if necessary.
+
+  Do you want single precision or double?  (The default is double.)  Do you
+  want to leave out some of Triangle's features to reduce the size of the
+  executable file?  Investigate the SINGLE, REDUCED, and CDT_ONLY symbols.
+
+  If yours is not a Unix system, define the NO_TIMER symbol to remove the
+  Unix-specific timing code.  Also, don't try to compile Show Me; it only
+  works with X Windows.
+
+  If you are compiling on an Intel x86 CPU and using gcc w/Linux or
+  Microsoft C, be sure to define the LINUX or CPU86 (for Microsoft) symbol
+  during compilation so that the exact arithmetic works right.
+
+Once you've done this, type "make" to compile the programs.  Alternatively,
+the files are usually easy to compile without a makefile:
+
+  cc -O -o triangle triangle.c -lm
+  cc -O -o showme showme.c -lX11
+
+On some systems, the C compiler won't be able to find the X include files
+or libraries, and you'll need to specify an include path or library path:
+
+  cc -O -I/usr/local/include -o showme showme.c -L/usr/local/lib -lX11
+
+Some processors, including Intel x86 family and possibly Motorola 68xxx
+family chips, are IEEE conformant but have extended length internal
+floating-point registers that may defeat Triangle's exact arithmetic
+routines by failing to cause enough roundoff error!  Typically, there is a
+way to set these internal registers so that they are rounded off to IEEE
+single or double precision format.  I believe (but I'm not certain) that
+Triangle has the right incantations for x86 chips, if you have gcc running
+under Linux (define the LINUX compiler symbol) or Microsoft C (define the
+CPU86 compiler symbol).
+
+If you have a different processor or operating system, or if I got the
+incantations wrong, you should check your C compiler or system manuals to
+find out how to configure these internal registers to the precision you are
+using.  Otherwise, the exact arithmetic routines won't be exact at all.
+See http://www.cs.cmu.edu/~quake/robust.pc.html for details.  Triangle's
+exact arithmetic hasn't a hope of working on machines like the Cray C90 or
+Y-MP, which are not IEEE conformant and have inaccurate rounding.
+
+Triangle and Show Me have both text and HTML documentation.  The latter is
+illustrated.  Find it on the Web at
+
+  http://www.cs.cmu.edu/~quake/triangle.html
+  http://www.cs.cmu.edu/~quake/showme.html
+
+Complete text instructions are printed by invoking each program with the
+`-h' switch:
+
+  triangle -h
+  showme -h
+
+The instructions are long; you'll probably want to pipe the output to
+`more' or `lpr' or redirect it to a file.
+
+Both programs give a short list of command line options if they are invoked
+without arguments (that is, just type `triangle' or `showme').
+
+Try out Triangle on the enclosed sample file, A.poly:
+
+  triangle -p A
+  showme A.poly &
+
+Triangle will read the Planar Straight Line Graph defined by A.poly, and
+write its constrained Delaunay triangulation to A.1.node and A.1.ele.
+Show Me will display the figure defined by A.poly.  There are two buttons
+marked "ele" in the Show Me window; click on the top one.  This will cause
+Show Me to load and display the triangulation.
+
+For contrast, try running
+
+  triangle -pq A
+
+Now, click on the same "ele" button.  A new triangulation will be loaded;
+this one having no angles smaller than 20 degrees.
+
+To see a Voronoi diagram, try this:
+
+  cp A.poly A.node
+  triangle -v A
+
+Click the "ele" button again.  You will see the Delaunay triangulation of
+the points in A.poly, without the segments.  Now click the top "voro" button.
+You will see the Voronoi diagram corresponding to that Delaunay triangulation.
+Click the "Reset" button to see the full extent of the diagram.
+
+------------------------------------------------------------------------------
+
+If you wish to call Triangle from another program, instructions for doing
+so are contained in the file `triangle.h' (but read Triangle's regular
+instructions first!).  Also look at `tricall.c', which provides an example
+of how to call Triangle.
+
+Type "make trilibrary" to create triangle.o, a callable object file.
+Alternatively, the object file is usually easy to compile without a
+makefile:
+
+  cc -DTRILIBRARY -O -c triangle.c
+
+Type "make distclean" to remove all the object and executable files created
+by make.
+
+------------------------------------------------------------------------------
+
+If you use Triangle, and especially if you use it to accomplish real work,
+I would like very much to hear from you.  A short letter or email (to
+jrs@cs.berkeley.edu) describing how you use Triangle will mean a lot to me.
+The more people I know are using this program, the more easily I can
+justify spending time on improvements and on the three-dimensional
+successor to Triangle, which in turn will benefit you.  Also, I can put you
+on a list to receive email whenever a new version of Triangle is available.
+
+If you use a mesh generated by Triangle or plotted by Show Me in a
+publication, please include an acknowledgment as well.  And please spell
+Triangle with a capital `T'!  If you want to include a citation, use
+`Jonathan Richard Shewchuk, ``Triangle:  Engineering a 2D Quality Mesh
+Generator and Delaunay Triangulator,'' in Applied Computational Geometry:
+Towards Geometric Engineering (Ming C. Lin and Dinesh Manocha, editors),
+volume 1148 of Lecture Notes in Computer Science, pages 203-222,
+Springer-Verlag, Berlin, May 1996.  (From the First ACM Workshop on Applied
+Computational Geometry.)'
+
+
+Jonathan Richard Shewchuk
+July 27, 2005