__delaunayn__.cc

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/*
  16. July 2000 - Kai Habel: first release
 
  25. September 2002 - Changes by Rafael Laboissiere <rafael@laboissiere.net>
 
  * Added Qbb option to normalize the input and avoid crashes in Octave.
  * delaunayn accepts now a second (optional) argument that must be a string
  containing extra options to the qhull command.
  * Fixed doc string.  The dimension of the result matrix is [m, dim+1], and
  not [n, dim-1].
 
  6. June 2006: Changes by Alexander Barth <abarth@marine.usf.edu>
 
  * triangulate non-simplicial facets
  * allow options to be specified as cell array of strings
  * change the default options (for compatibility with matlab)
*/
 
#if defined (HAVE_CONFIG_H)
#  include "config.h"
#endif
 
#include <cstdio>
 
#include <limits>
#include <string>
 
#include "Array.h"
#include "dMatrix.h"
#include "dRowVector.h"
#include "oct-locbuf.h"
#include "unwind-prot.h"
 
#include "defun-dld.h"
#include "error.h"
#include "errwarn.h"
#include "ovl.h"
 
#if defined (HAVE_QHULL)
 
#  include "oct-qhull.h"
 
#  if defined (NEED_QHULL_VERSION)
char qh_version[] = "__delaunayn__.oct 2007-08-21";
#  endif
 
static void
close_fcn (FILE *f)
{
  std::fclose (f);
}
 
static void
free_qhull_memory ()
{
  qh_freeqhull (! qh_ALL);
 
  int curlong, totlong;
  qh_memfreeshort (&curlong, &totlong);
 
  if (curlong || totlong)
    warning ("__delaunayn__: did not free %d bytes of long memory (%d pieces)",
             totlong, curlong);
}
 
static bool
octave_qhull_dims_ok (octave_idx_type dim, octave_idx_type n, const char *who)
{
  if (sizeof (octave_idx_type) > sizeof (int))
    {
      int maxval = std::numeric_limits<int>::max ();
 
      if (dim > maxval || n > maxval)
        error ("%s: dimension too large for Qhull", who);
    }
 
  return true;
}
 
#endif
 
DEFUN_DLD (__delaunayn__, args, ,
           doc: /* -*- texinfo -*-
@deftypefn  {} {@var{T} =} __delaunayn__ (@var{pts})
@deftypefnx {} {@var{T} =} __delaunayn__ (@var{pts}, @var{options})
Undocumented internal function.
@end deftypefn */)
 
{
#if defined (HAVE_QHULL)
 
  int nargin = args.length ();
 
  if (nargin < 1 || nargin > 2)
    print_usage ();
 
  octave_value_list retval;
 
  retval(0) = 0.0;
 
  Matrix p (args(0).matrix_value ());
  const octave_idx_type dim = p.columns ();
  const octave_idx_type n = p.rows ();
 
  if (! octave_qhull_dims_ok (dim, n, "__delaynayn__"))
    return retval;
 
  // Default options
  std::string options;
  if (dim <= 3)
    options = "Qt Qbb Qc";
  else
    options = "Qt Qbb Qc Qx";
 
  if (nargin == 2)
    {
      if (args(1).is_string ())
        options = args(1).string_value ();
      else if (args(1).isempty ())
        ;  // Use default options
      else if (args(1).iscellstr ())
        {
          options = "";
          Array<std::string> tmp = args(1).cellstr_value ();
 
          for (octave_idx_type i = 0; i < tmp.numel (); i++)
            options += tmp(i) + ' ';
        }
      else
        error ("__delaunayn__: OPTIONS argument must be a string, cell array of strings, or empty");
    }
 
  if (n > dim + 1)
    {
      p = p.transpose ();
      double *pt_array = p.fortran_vec ();
      boolT ismalloc = false;
 
      // Qhull flags argument is not const char*
      OCTAVE_LOCAL_BUFFER (char, flags, 9 + options.length ());
 
      sprintf (flags, "qhull d %s", options.c_str ());
 
      octave::unwind_protect frame;
 
      // Replace the outfile pointer with stdout for debugging information.
#if defined (OCTAVE_HAVE_WINDOWS_FILESYSTEM) && ! defined (OCTAVE_HAVE_POSIX_FILESYSTEM)
      FILE *outfile = std::fopen ("NUL", "w");
#else
      FILE *outfile = std::fopen ("/dev/null", "w");
#endif
      FILE *errfile = stderr;
 
      if (! outfile)
        error ("__delaunayn__: unable to create temporary file for output");
 
      frame.add_fcn (close_fcn, outfile);
 
      int exitcode = qh_new_qhull (dim, n, pt_array,
                                   ismalloc, flags, outfile, errfile);
 
      frame.add_fcn (free_qhull_memory);
 
      if (exitcode)
        error ("__delaunayn__: qhull failed");
 
      // triangulate non-simplicial facets
      qh_triangulate ();
 
      facetT *facet;
      vertexT *vertex, **vertexp;
      octave_idx_type nf = 0;
      octave_idx_type i = 0;
 
      FORALLfacets
        {
          if (! facet->upperdelaunay)
            nf++;
 
          // Double check.  Non-simplicial facets will cause segfault below
          if (! facet->simplicial)
            error ("__delaunayn__: Qhull returned non-simplicial facets -- try delaunayn with different options");
        }
 
      Matrix simpl (nf, dim+1);
 
      FORALLfacets
        {
          if (! facet->upperdelaunay)
            {
              octave_idx_type j = 0;
 
              FOREACHvertex_ (facet->vertices)
                {
                  simpl(i, j++) = 1 + qh_pointid(vertex->point);
                }
              i++;
            }
        }
 
      retval(0) = simpl;
    }
  else if (n == dim + 1)
    {
      // FIXME: One should check if nx points span a simplex.
      //        I will look at this later.
      RowVector vec (n);
      for (octave_idx_type i = 0; i < n; i++)
        vec(i) = i + 1.0;
 
      retval(0) = vec;
    }
 
  return retval;
 
#else
 
  octave_unused_parameter (args);
 
  err_disabled_feature ("__delaunayn__", "Qhull");
 
#endif
}
 
/*
## No test needed for internal helper function.
%!assert (1)
*/