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qhalf_r.c
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/*<html><pre> -<a href="../libqhull/qh-qhull.htm"
>-------------------------------</a><a name="TOP">-</a>
qhalf.c
compute the intersection of halfspaces about a point
see unix.c for full interface
Copyright (c) 1993-2015, The Geometry Center
*/
#include "libqhull_r/libqhull_r.h"
#include "libqhull_r/mem_r.h"
#include "libqhull_r/qset_r.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <math.h>
#if __cplusplus
extern "C" {
int isatty(int);
}
#elif _MSC_VER
#include <io.h>
#define isatty _isatty
/* int _isatty(int); */
#else
int isatty(int); /* returns 1 if stdin is a tty
if "Undefined symbol" this can be deleted along with call in main() */
#endif
/*-<a href="../libqhull/qh-qhull.htm#TOC"
>-------------------------------</a><a name="prompt">-</a>
qh_prompt
long prompt for qhull
notes:
restricted version of libqhull.c
see:
concise prompt below
*/
/* duplicated in qhalf.htm */
char hidden_options[]=" d n v Qbb QbB Qf Qg Qm Qr QR Qv Qx Qz TR E V Fa FA FC FD FS Ft FV Gt Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Q9 ";
char qh_prompta[]= "\n\
qhalf- compute the intersection of halfspaces about a point\n\
http://www.qhull.org %s\n\
\n\
input (stdin):\n\
optional interior point: dimension, 1, coordinates\n\
first lines: dimension+1 and number of halfspaces\n\
other lines: halfspace coefficients followed by offset\n\
comments: start with a non-numeric character\n\
\n\
options:\n\
Hn,n - specify coordinates of interior point\n\
Qt - triangulated output\n\
QJ - joggled input instead of merged facets\n\
Qc - keep coplanar halfspaces\n\
Qi - keep other redundant halfspaces\n\
\n\
Qhull control options:\n\
QJn - randomly joggle input in range [-n,n]\n\
%s%s%s%s"; /* split up qh_prompt for Visual C++ */
char qh_promptb[]= "\
Qbk:0Bk:0 - remove k-th coordinate from input\n\
Qs - search all halfspaces for the initial simplex\n\
QGn - print intersection if visible to halfspace n, -n for not\n\
QVn - print intersections for halfspace n, -n if not\n\
\n\
";
char qh_promptc[]= "\
Trace options:\n\
T4 - trace at level n, 4=all, 5=mem/gauss, -1= events\n\
Tc - check frequently during execution\n\
Ts - print statistics\n\
Tv - verify result: structure, convexity, and redundancy\n\
Tz - send all output to stdout\n\
TFn - report summary when n or more facets created\n\
TI file - input data from file, no spaces or single quotes\n\
TO file - output results to file, may be enclosed in single quotes\n\
TPn - turn on tracing when halfspace n added to intersection\n\
TMn - turn on tracing at merge n\n\
TWn - trace merge facets when width > n\n\
TVn - stop qhull after adding halfspace n, -n for before (see TCn)\n\
TCn - stop qhull after building cone for halfspace n (see TVn)\n\
\n\
Precision options:\n\
Cn - radius of centrum (roundoff added). Merge facets if non-convex\n\
An - cosine of maximum angle. Merge facets if cosine > n or non-convex\n\
C-0 roundoff, A-0.99/C-0.01 pre-merge, A0.99/C0.01 post-merge\n\
Rn - randomly perturb computations by a factor of [1-n,1+n]\n\
Un - max distance below plane for a new, coplanar halfspace\n\
Wn - min facet width for outside halfspace (before roundoff)\n\
\n\
Output formats (may be combined; if none, produces a summary to stdout):\n\
f - facet dump\n\
G - Geomview output (dual convex hull)\n\
i - non-redundant halfspaces incident to each intersection\n\
m - Mathematica output (dual convex hull)\n\
o - OFF format (dual convex hull: dimension, points, and facets)\n\
p - vertex coordinates of dual convex hull (coplanars if 'Qc' or 'Qi')\n\
s - summary (stderr)\n\
\n\
";
char qh_promptd[]= "\
More formats:\n\
Fc - count plus redundant halfspaces for each intersection\n\
- Qc (default) for coplanar and Qi for other redundant\n\
Fd - use cdd format for input (homogeneous with offset first)\n\
FF - facet dump without ridges\n\
FI - ID of each intersection\n\
Fm - merge count for each intersection (511 max)\n\
FM - Maple output (dual convex hull)\n\
Fn - count plus neighboring intersections for each intersection\n\
FN - count plus intersections for each non-redundant halfspace\n\
FO - options and precision constants\n\
Fp - dim, count, and intersection coordinates\n\
FP - nearest halfspace and distance for each redundant halfspace\n\
FQ - command used for qhalf\n\
Fs - summary: #int (8), dim, #halfspaces, #non-redundant, #intersections\n\
for output: #non-redundant, #intersections, #coplanar\n\
halfspaces, #non-simplicial intersections\n\
#real (2), max outer plane, min vertex\n\
Fv - count plus non-redundant halfspaces for each intersection\n\
Fx - non-redundant halfspaces\n\
\n\
";
char qh_prompte[]= "\
Geomview output (2-d, 3-d and 4-d; dual convex hull)\n\
Ga - all points (i.e., transformed halfspaces) as dots\n\
Gp - coplanar points and vertices as radii\n\
Gv - vertices (i.e., non-redundant halfspaces) as spheres\n\
Gi - inner planes (i.e., halfspace intersections) only\n\
Gn - no planes\n\
Go - outer planes only\n\
Gc - centrums\n\
Gh - hyperplane intersections\n\
Gr - ridges\n\
GDn - drop dimension n in 3-d and 4-d output\n\
\n\
Print options:\n\
PAn - keep n largest facets (i.e., intersections) by area\n\
Pdk:n- drop facet if normal[k] <= n (default 0.0)\n\
PDk:n- drop facet if normal[k] >= n\n\
Pg - print good facets (needs 'QGn' or 'QVn')\n\
PFn - keep facets whose area is at least n\n\
PG - print neighbors of good facets\n\
PMn - keep n facets with most merges\n\
Po - force output. If error, output neighborhood of facet\n\
Pp - do not report precision problems\n\
\n\
. - list of all options\n\
- - one line descriptions of all options\n\
-V - version\n\
";
/* for opts, don't assign 'e' or 'E' to a flag (already used for exponent) */
/*-<a href="../libqhull/qh-qhull.htm#TOC"
>-------------------------------</a><a name="prompt2">-</a>
qh_prompt2
synopsis for qhull
*/
char qh_prompt2[]= "\n\
qhalf- halfspace intersection about a point. Qhull %s\n\
input (stdin): [dim, 1, interior point], dim+1, n, coefficients+offset\n\
comments start with a non-numeric character\n\
\n\
options (qhalf.htm):\n\
Hn,n - specify coordinates of interior point\n\
Qt - triangulated output\n\
QJ - joggled input instead of merged facets\n\
Tv - verify result: structure, convexity, and redundancy\n\
. - concise list of all options\n\
- - one-line description of all options\n\
-V - version\n\
\n\
output options (subset):\n\
s - summary of results (default)\n\
Fp - intersection coordinates\n\
Fv - non-redundant halfspaces incident to each intersection\n\
Fx - non-redundant halfspaces\n\
o - OFF file format (dual convex hull)\n\
G - Geomview output (dual convex hull)\n\
m - Mathematica output (dual convex hull)\n\
QVn - print intersections for halfspace n, -n if not\n\
TO file - output results to file, may be enclosed in single quotes\n\
\n\
examples:\n\
rbox d | qconvex FQ n | qhalf s H0,0,0 Fp\n\
rbox c | qconvex FQ FV n | qhalf s i\n\
rbox c | qconvex FQ FV n | qhalf s o\n\
\n\
";
/* for opts, don't assign 'e' or 'E' to a flag (already used for exponent) */
/*-<a href="../libqhull/qh-qhull.htm#TOC"
>-------------------------------</a><a name="prompt3">-</a>
qh_prompt3
concise prompt for qhull
*/
char qh_prompt3[]= "\n\
Qhull %s.\n\
Except for 'F.' and 'PG', upper_case options take an argument.\n\
\n\
incidences Geomview mathematica OFF_format point_dual\n\
summary facet_dump\n\
\n\
Fc_redundant Fd_cdd_in FF_dump_xridge FIDs Fmerges\n\
Fneighbors FN_intersect FOptions Fp_coordinates FP_nearest\n\
FQhalf Fsummary Fv_halfspace FMaple Fx_non_redundant\n\
\n\
Gvertices Gpoints Gall_points Gno_planes Ginner\n\
Gcentrums Ghyperplanes Gridges Gouter GDrop_dim\n\
\n\
PArea_keep Pdrop d0:0D0 Pgood PFacet_area_keep\n\
PGood_neighbors PMerge_keep Poutput_forced Pprecision_not\n\
\n\
Qbk:0Bk:0_drop Qcoplanar QG_half_good Qi_redundant QJoggle\n\
Qsearch_1st Qtriangulate QVertex_good\n\
\n\
T4_trace Tcheck_often Tstatistics Tverify Tz_stdout\n\
TFacet_log TInput_file TPoint_trace TMerge_trace TOutput_file\n\
TWide_trace TVertex_stop TCone_stop\n\
\n\
Angle_max Centrum_size Random_dist Ucoplanar_max Wide_outside\n\
";
/*-<a href="../libqhull/qh-qhull.htm#TOC"
>-------------------------------</a><a name="main">-</a>
main( argc, argv )
processes the command line, calls qhull() to do the work, and exits
design:
initializes data structures
reads points
finishes initialization
computes convex hull and other structures
checks the result
writes the output
frees memory
*/
int main(int argc, char *argv[]) {
int curlong, totlong; /* used !qh_NOmem */
int exitcode, numpoints, dim;
coordT *points;
boolT ismalloc;
qhT qh_qh;
qhT *qh= &qh_qh;
QHULL_LIB_CHECK /* Check for compatible library */
if ((argc == 1) && isatty( 0 /*stdin*/)) {
fprintf(stdout, qh_prompt2, qh_version);
exit(qh_ERRnone);
}
if (argc > 1 && *argv[1] == '-' && !*(argv[1]+1)) {
fprintf(stdout, qh_prompta, qh_version,
qh_promptb, qh_promptc, qh_promptd, qh_prompte);
exit(qh_ERRnone);
}
if (argc > 1 && *argv[1] == '.' && !*(argv[1]+1)) {
fprintf(stdout, qh_prompt3, qh_version);
exit(qh_ERRnone);
}
if (argc > 1 && *argv[1] == '-' && *(argv[1]+1)=='V') {
fprintf(stdout, "%s\n", qh_version2);
exit(qh_ERRnone);
}
qh_init_A(qh, stdin, stdout, stderr, argc, argv); /* sets qh->qhull_command */
exitcode= setjmp(qh->errexit); /* simple statement for CRAY J916 */
if (!exitcode) {
qh->NOerrexit = False;
qh_option(qh, "Halfspace", NULL, NULL);
qh->HALFspace= True; /* 'H' */
qh_checkflags(qh, qh->qhull_command, hidden_options);
qh_initflags(qh, qh->qhull_command);
if (qh->SCALEinput) {
fprintf(qh->ferr, "\
qhull error: options 'Qbk:n' and 'QBk:n' are not used with qhalf.\n\
Use 'Qbk:0Bk:0 to drop dimension k.\n");
qh_errexit(qh, qh_ERRinput, NULL, NULL);
}
points= qh_readpoints(qh, &numpoints, &dim, &ismalloc);
if (dim >= 5) {
qh_option(qh, "Qxact_merge", NULL, NULL);
qh->MERGEexact= True; /* 'Qx' always */
}
qh_init_B(qh, points, numpoints, dim, ismalloc);
qh_qhull(qh);
qh_check_output(qh);
qh_produce_output(qh);
if (qh->VERIFYoutput && !qh->FORCEoutput && !qh->STOPpoint && !qh->STOPcone)
qh_check_points(qh);
exitcode= qh_ERRnone;
}
qh->NOerrexit= True; /* no more setjmp */
#ifdef qh_NOmem
qh_freeqhull(qh, True);
#else
qh_freeqhull(qh, False);
qh_memfreeshort(qh, &curlong, &totlong);
if (curlong || totlong)
qh_fprintf_stderr(6263, "qhull internal warning (main): did not free %d bytes of long memory(%d pieces)\n",
totlong, curlong);
#endif
return exitcode;
} /* main */

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