Re: qhull6 and octave

[Tatsuro MATSUOKA]

Hello

On MinGW，qhull2011 gives errors.
(The qhull library was created using GCC-4.6.1)

For example,   
src\DLD-FUNCTIONS\convhulln.cc ......................... PASS    0/3    FAIL 3

  ***** testif HAVE_QHULL cube = [0 0 0;1 0 0;1 1 0;0 1 0;0 0 1;1 0 1;1 1 1;0 1 
1]; [h, v] = convhulln (cube); assert (size (h), [6 4]);  h = sortrows (sort 
(h, 2), [1:4]); assert (h, [1 2 3 4; 1 2 5 6; 1 4 5 8; 2 3 6 7; 3 4 7 8; 5 6 7 
8]); assert (v, 1, 10*eps);!!!!! test failedassert (size (h),[6, 4]) expected   
6   4but got   0   3values do not match  ***** testif HAVE_QHULL cube = [0 0 
0;1 0 0;1 1 0;0 1 0;0 0 1;1 0 1;1 1 1;0 1 1]; [h, v] = convhulln (cube, "QJ"); 
assert (size (h), [12 3]);  assert (sortrows (sort (h, 2), [1:3]), [1 2 4; 1 2 
5; 1 4 5; 2 3 4; 2 3 6; 2 5 6; 3 4 8; 3 6 7; 3 7 8; 4 5 8; 5 6 8; 6 7 8]); 
assert (v, 1.0, 1e6*eps);!!!!! test failedassert (size (h),[12, 3]) expected   
12    3but got   0   3values do not match  ***** testif HAVE_QHULL tetrahedron 
= [1 1 1;-1 -1 1;-1 1 -1;1 -1 -1]; [h, v] = convhulln (tetrahedron); h = 
sortrows (sort (h, 2), [1 2 3]); assert (h, [1 2 3;1 2 4; 1 3 4; 2 3
 4]); assert (v, 8/3, 10*eps);!!!!! test failedassert (h,[1, 2, 3; 1, 2, 4; 1, 
3, 4; 2, 3, 4]) expected   1   2   3   1   2   4   1   3   4   2   3   4but 
got[](0x3)Dimensions don't match
This error did not occur on qull2010.

Regards

Tatsuro--- On Thu, 2011/12/1, Brad Barber wrote:

> Hi Petr,
> 
> Glad it worked.   Without seeing the whole build system that was used, here's 
> my guess from what you showed me.
> 
> Some news first.  I've released qhull 2011.2 with several changes, mostly 
> minor.   Octave may be interested in the fix to qh_new_qhull (call 
> qh_prepare_output if !outfile).  qh_prepare_output handles options that are 
> processed after building the convex hull (e.g., compute area and volume).  
> There's a new, simple Makefile for static builds (in src/libqhull).   
> 
> Please let me know when the Debian builds are available.  The qhull download 
> page is rather out-of-date.  Can someone produce a rpm build?  I've also lost 
> my archive/mirror site for old Qhull downloads.  Let me know if someone would 
> like to host it.
>     http://www.qhull.org/download/
> 
> qhull5 was apparently built with qh_QHpointer=0  [user.h].  The global data 
> structure for qhull is defined as a static array qh_qh [libqhull.h].  qhull6 
> was built with qh_QHpointer=1.  The global data structure for qhull is 
> allocated on the heap with a pointer from the global variable qh_qh.   This 
> allows for multiple global data structures that can be swapped by updating 
> qh_qh.   Two other pointers/static structures are similarly defined (qh_qhmem 
> for the memory allocator and qh_qhstat for statistics).  
> 
> The extra flexibility comes at some cost.  The last time I measured it, the 
> cost was 4% overhead in space and 4% in time.  The C++ interface for qhull 
> uses qh_QHpointer=1.    The same effect could be achieved by copying data 
> from  statically defined structures to/from the heap.
> 
> The code references these representations with the 'qh', 'qhmem', and 
> 'qhstat' macros.  That's why the code has an odd appearance.  These macros 
> allow the data structures to be allocated elsewhere (e.g., thread-local 
> storage or an extra function parameter).
> 
> Many thanks for keeping Qhull part of Octave.
> 
>                                 --Brad
> 
> At 06:09 AM 11/30/2011, Petr Gajdos wrote:
> >Hi Brad,
> >
> >very well, defining qh_QHpointer to 1, i. e.
> >
> >#include <stdio.h>
> >#if defined QHULL5
> >#include <qhull/qhull_a.h>
> >#warning qhull5
> >#else
> >#define qh_QHpointer 1
> >#include <libqhull/qhull_a.h>
> >#warning qhull6
> >#endif
> >...
> >
> >gives same results for qhull6 as for qhull5.
> >
> >When you find time, could you please give me 
> >an explanation (maybe cc octave-help@ too)?
> >
> >Have a nice day & thanks a lot,
> >Petr
> >
> >
> 
>