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/*<html><pre> -<a href="qh-poly.htm"
>-------------------------------</a><a name="TOP">-</a>
poly.c
implements polygons and simplices
see qh-poly.htm, poly.h and qhull.h
infrequent code is in poly2.c
(all but top 50 and their callers 12/3/95)
copyright (c) 1993-2002, The Geometry Center
*/
#include "qhull_a.h"
/*======== functions in alphabetical order ==========*/
/*-<a href="qh-poly.htm#TOC"
>-------------------------------</a><a name="appendfacet">-</a>
qh_appendfacet( facet )
appends facet to end of qh.facet_list,
returns:
updates qh.newfacet_list, facet_next, facet_list
increments qh.numfacets
notes:
assumes qh.facet_list/facet_tail is defined (createsimplex)
see:
qh_removefacet()
*/
void qh_appendfacet(facetT *facet) {
facetT *tail= qh facet_tail;
if (tail == qh newfacet_list)
qh newfacet_list= facet;
if (tail == qh facet_next)
qh facet_next= facet;
facet->previous= tail->previous;
facet->next= tail;
if (tail->previous)
tail->previous->next= facet;
else
qh facet_list= facet;
tail->previous= facet;
qh num_facets++;
trace4((qh ferr, "qh_appendfacet: append f%d to facet_list\n", facet->id));
} /* appendfacet */
/*-<a href="qh-poly.htm#TOC"
>-------------------------------</a><a name="appendvertex">-</a>
qh_appendvertex( vertex )
appends vertex to end of qh.vertex_list,
returns:
sets vertex->newlist
updates qh.vertex_list, newvertex_list
increments qh.num_vertices
notes:
assumes qh.vertex_list/vertex_tail is defined (createsimplex)
*/
void qh_appendvertex (vertexT *vertex) {
vertexT *tail= qh vertex_tail;
if (tail == qh newvertex_list)
qh newvertex_list= vertex;
vertex->newlist= True;
vertex->previous= tail->previous;
vertex->next= tail;
if (tail->previous)
tail->previous->next= vertex;
else
qh vertex_list= vertex;
tail->previous= vertex;
qh num_vertices++;
trace4((qh ferr, "qh_appendvertex: append v%d to vertex_list\n", vertex->id));
} /* appendvertex */
/*-<a href="qh-poly.htm#TOC"
>-------------------------------</a><a name="attachnewfacets">-</a>
qh_attachnewfacets( )
attach horizon facets to new facets in qh.newfacet_list
newfacets have neighbor and ridge links to horizon but not vice versa
only needed for qh.ONLYgood
returns:
set qh.NEWfacets
horizon facets linked to new facets
ridges changed from visible facets to new facets
simplicial ridges deleted
qh.visible_list, no ridges valid
facet->f.replace is a newfacet (if any)
design:
delete interior ridges and neighbor sets by
for each visible, non-simplicial facet
for each ridge
if last visit or if neighbor is simplicial
if horizon neighbor
delete ridge for horizon's ridge set
delete ridge
erase neighbor set
attach horizon facets and new facets by
for all new facets
if corresponding horizon facet is simplicial
locate corresponding visible facet {may be more than one}
link visible facet to new facet
replace visible facet with new facet in horizon
else it's non-simplicial
for all visible neighbors of the horizon facet
link visible neighbor to new facet
delete visible neighbor from horizon facet
append new facet to horizon's neighbors
the first ridge of the new facet is the horizon ridge
link the new facet into the horizon ridge
*/
void qh_attachnewfacets (void ) {
facetT *newfacet= NULL, *neighbor, **neighborp, *horizon, *visible;
ridgeT *ridge, **ridgep;
qh NEWfacets= True;
trace3((qh ferr, "qh_attachnewfacets: delete interior ridges\n"));
qh visit_id++;
FORALLvisible_facets {
visible->visitid= qh visit_id;
if (visible->ridges) {
FOREACHridge_(visible->ridges) {
neighbor= otherfacet_(ridge, visible);
if (neighbor->visitid == qh visit_id
|| (!neighbor->visible && neighbor->simplicial)) {
if (!neighbor->visible) /* delete ridge for simplicial horizon */
qh_setdel (neighbor->ridges, ridge);
qh_setfree (&(ridge->vertices)); /* delete on 2nd visit */
qh_memfree (ridge, sizeof(ridgeT));
}
}
SETfirst_(visible->ridges)= NULL;
}
SETfirst_(visible->neighbors)= NULL;
}
trace1((qh ferr, "qh_attachnewfacets: attach horizon facets to new facets\n"));
FORALLnew_facets {
horizon= SETfirstt_(newfacet->neighbors, facetT);
if (horizon->simplicial) {
visible= NULL;
FOREACHneighbor_(horizon) { /* may have more than one horizon ridge */
if (neighbor->visible) {
if (visible) {
if (qh_setequal_skip (newfacet->vertices, 0, horizon->vertices,
SETindex_(horizon->neighbors, neighbor))) {
visible= neighbor;
break;
}
}else
visible= neighbor;
}
}
if (visible) {
visible->f.replace= newfacet;
qh_setreplace (horizon->neighbors, visible, newfacet);
}else {
fprintf (qh ferr, "qhull internal error (qh_attachnewfacets): couldn't find visible facet for horizon f%d of newfacet f%d\n",
horizon->id, newfacet->id);
qh_errexit2 (qh_ERRqhull, horizon, newfacet);
}
}else { /* non-simplicial, with a ridge for newfacet */
FOREACHneighbor_(horizon) { /* may hold for many new facets */
if (neighbor->visible) {
neighbor->f.replace= newfacet;
qh_setdelnth (horizon->neighbors,
SETindex_(horizon->neighbors, neighbor));
neighborp--; /* repeat */
}
}
qh_setappend (&horizon->neighbors, newfacet);
ridge= SETfirstt_(newfacet->ridges, ridgeT);
if (ridge->top == horizon)
ridge->bottom= newfacet;
else
ridge->top= newfacet;
}
} /* newfacets */
if (qh PRINTstatistics) {
FORALLvisible_facets {
if (!visible->f.replace)
zinc_(Zinsidevisible);
}
}
} /* attachnewfacets */
/*-<a href="qh-poly.htm#TOC"
>-------------------------------</a><a name="checkflipped">-</a>
qh_checkflipped( facet, dist, allerror )
checks facet orientation to interior point
if allerror set,
tests against qh.DISTround
else
tests against 0 since tested against DISTround before
returns:
False if it flipped orientation (sets facet->flipped)
distance if non-NULL
*/
boolT qh_checkflipped (facetT *facet, realT *distp, boolT allerror) {
realT dist;
if (facet->flipped && !distp)
return False;
zzinc_(Zdistcheck);
qh_distplane(qh interior_point, facet, &dist);
if (distp)
*distp= dist;
if ((allerror && dist > -qh DISTround)|| (!allerror && dist >= 0.0)) {
facet->flipped= True;
zzinc_(Zflippedfacets);
trace0((qh ferr, "qh_checkflipped: facet f%d is flipped, distance= %6.12g during p%d\n",
facet->id, dist, qh furthest_id));
qh_precision ("flipped facet");
return False;
}
return True;
} /* checkflipped */
/*-<a href="qh-poly.htm#TOC"
>-------------------------------</a><a name="delfacet">-</a>
qh_delfacet( facet )
removes facet from facet_list and frees up its memory
notes:
assumes vertices and ridges already freed
*/
void qh_delfacet(facetT *facet) {
void **freelistp; /* used !qh_NOmem */
trace4((qh ferr, "qh_delfacet: delete f%d\n", facet->id));
if (facet == qh tracefacet)
qh tracefacet= NULL;
if (facet == qh GOODclosest)
qh GOODclosest= NULL;
qh_removefacet(facet);
if (!facet->tricoplanar || facet->keepcentrum) {
qh_memfree_(facet->normal, qh normal_size, freelistp);
if (qh CENTERtype == qh_ASvoronoi) { /* uses macro calls */
qh_memfree_(facet->center, qh center_size, freelistp);
}else /* AScentrum */ {
qh_memfree_(facet->center, qh normal_size, freelistp);
}
}
qh_setfree(&(facet->neighbors));
if (facet->ridges)
qh_setfree(&(facet->ridges));
qh_setfree(&(facet->vertices));
if (facet->outsideset)
qh_setfree(&(facet->outsideset));
if (facet->coplanarset)
qh_setfree(&(facet->coplanarset));
qh_memfree_(facet, sizeof(facetT), freelistp);
} /* delfacet */
/*-<a href="qh-poly.htm#TOC"
>-------------------------------</a><a name="deletevisible">-</a>
qh_deletevisible()
delete visible facets and vertices
returns:
deletes each facet and removes from facetlist
at exit, qh.visible_list empty (== qh.newfacet_list)
notes:
ridges already deleted
horizon facets do not reference facets on qh.visible_list
new facets in qh.newfacet_list
uses qh.visit_id;
*/
void qh_deletevisible (void /*qh visible_list*/) {
facetT *visible, *nextfacet;
vertexT *vertex, **vertexp;
int numvisible= 0, numdel= qh_setsize(qh del_vertices);
trace1((qh ferr, "qh_deletevisible: delete %d visible facets and %d vertices\n",
qh num_visible, numdel));
for (visible= qh visible_list; visible && visible->visible;
visible= nextfacet) { /* deleting current */
nextfacet= visible->next;
numvisible++;
qh_delfacet(visible);
}
if (numvisible != qh num_visible) {
fprintf (qh ferr, "qhull internal error (qh_deletevisible): qh num_visible %d is not number of visible facets %d\n",
qh num_visible, numvisible);
qh_errexit (qh_ERRqhull, NULL, NULL);
}
qh num_visible= 0;
zadd_(Zvisfacettot, numvisible);
zmax_(Zvisfacetmax, numvisible);
zzadd_(Zdelvertextot, numdel);
zmax_(Zdelvertexmax, numdel);
FOREACHvertex_(qh del_vertices)
qh_delvertex (vertex);
qh_settruncate (qh del_vertices, 0);
} /* deletevisible */
/*-<a href="qh-poly.htm#TOC"
>-------------------------------</a><a name="facetintersect">-</a>
qh_facetintersect( facetA, facetB, skipa, skipB, prepend )
return vertices for intersection of two simplicial facets
may include 1 prepended entry (if more, need to settemppush)
returns:
returns set of qh.hull_dim-1 + prepend vertices
returns skipped index for each test and checks for exactly one
notes:
does not need settemp since set in quick memory
see also:
qh_vertexintersect and qh_vertexintersect_new
use qh_setnew_delnthsorted to get nth ridge (no skip information)
design:
locate skipped vertex by scanning facet A's neighbors
locate skipped vertex by scanning facet B's neighbors
intersect the vertex sets
*/
setT *qh_facetintersect (facetT *facetA, facetT *facetB,
int *skipA,int *skipB, int prepend) {
setT *intersect;
int dim= qh hull_dim, i, j;
facetT **neighborsA, **neighborsB;
neighborsA= SETaddr_(facetA->neighbors, facetT);
neighborsB= SETaddr_(facetB->neighbors, facetT);
i= j= 0;
if (facetB == *neighborsA++)
*skipA= 0;
else if (facetB == *neighborsA++)
*skipA= 1;
else if (facetB == *neighborsA++)
*skipA= 2;
else {
for (i= 3; i < dim; i++) {
if (facetB == *neighborsA++) {
*skipA= i;
break;
}
}
}
if (facetA == *neighborsB++)
*skipB= 0;
else if (facetA == *neighborsB++)
*skipB= 1;
else if (facetA == *neighborsB++)
*skipB= 2;
else {
for (j= 3; j < dim; j++) {
if (facetA == *neighborsB++) {
*skipB= j;
break;
}
}
}
if (i >= dim || j >= dim) {
fprintf (qh ferr, "qhull internal error (qh_facetintersect): f%d or f%d not in others neighbors\n",
facetA->id, facetB->id);
qh_errexit2 (qh_ERRqhull, facetA, facetB);
}
intersect= qh_setnew_delnthsorted (facetA->vertices, qh hull_dim, *skipA, prepend);
trace4((qh ferr, "qh_facetintersect: f%d skip %d matches f%d skip %d\n",
facetA->id, *skipA, facetB->id, *skipB));
return(intersect);
} /* facetintersect */
/*-<a href="qh-poly.htm#TOC"
>-------------------------------</a><a name="gethash">-</a>
qh_gethash( hashsize, set, size, firstindex, skipelem )
return hashvalue for a set with firstindex and skipelem
notes:
assumes at least firstindex+1 elements
assumes skipelem is NULL, in set, or part of hash
hashes memory addresses which may change over different runs of the same data
using sum for hash does badly in high d
*/
unsigned qh_gethash (int hashsize, setT *set, int size, int firstindex, void *skipelem) {
void **elemp= SETelemaddr_(set, firstindex, void);
ptr_intT hash = 0, elem;
int i;
switch (size-firstindex) {
case 1:
hash= (ptr_intT)(*elemp) - (ptr_intT) skipelem;
break;
case 2:
hash= (ptr_intT)(*elemp) + (ptr_intT)elemp[1] - (ptr_intT) skipelem;
break;
case 3:
hash= (ptr_intT)(*elemp) + (ptr_intT)elemp[1] + (ptr_intT)elemp[2]
- (ptr_intT) skipelem;
break;
case 4:
hash= (ptr_intT)(*elemp) + (ptr_intT)elemp[1] + (ptr_intT)elemp[2]
+ (ptr_intT)elemp[3] - (ptr_intT) skipelem;
break;
case 5:
hash= (ptr_intT)(*elemp) + (ptr_intT)elemp[1] + (ptr_intT)elemp[2]
+ (ptr_intT)elemp[3] + (ptr_intT)elemp[4] - (ptr_intT) skipelem;
break;
case 6:
hash= (ptr_intT)(*elemp) + (ptr_intT)elemp[1] + (ptr_intT)elemp[2]
+ (ptr_intT)elemp[3] + (ptr_intT)elemp[4]+ (ptr_intT)elemp[5]
- (ptr_intT) skipelem;
break;
default:
hash= 0;
i= 3;
do { /* this is about 10% in 10-d */
if ((elem= (ptr_intT)*elemp++) != (ptr_intT)skipelem) {
hash ^= (elem << i) + (elem >> (32-i));
i += 3;
if (i >= 32)
i -= 32;
}
}while(*elemp);
break;
}
hash %= (ptr_intT) hashsize;
/* hash= 0; for debugging purposes */
return hash;
} /* gethash */
/*-<a href="qh-poly.htm#TOC"
>-------------------------------</a><a name="makenewfacet">-</a>
qh_makenewfacet( vertices, toporient, horizon )
creates a toporient? facet from vertices
returns:
returns newfacet
adds newfacet to qh.facet_list
newfacet->vertices= vertices
if horizon
newfacet->neighbor= horizon, but not vice versa
newvertex_list updated with vertices
*/
facetT *qh_makenewfacet(setT *vertices, boolT toporient,facetT *horizon) {
facetT *newfacet;
vertexT *vertex, **vertexp;
FOREACHvertex_(vertices) {
if (!vertex->newlist) {
qh_removevertex (vertex);
qh_appendvertex (vertex);
}
}
newfacet= qh_newfacet();
newfacet->vertices= vertices;
newfacet->toporient= toporient;
if (horizon)
qh_setappend(&(newfacet->neighbors), horizon);
qh_appendfacet(newfacet);
return(newfacet);
} /* makenewfacet */
/*-<a href="qh-poly.htm#TOC"
>-------------------------------</a><a name="makenewplanes">-</a>
qh_makenewplanes()
make new hyperplanes for facets on qh.newfacet_list
returns:
all facets have hyperplanes or are marked for merging
doesn't create hyperplane if horizon is coplanar (will merge)
updates qh.min_vertex if qh.JOGGLEmax
notes:
facet->f.samecycle is defined for facet->mergehorizon facets
*/
void qh_makenewplanes (void /* newfacet_list */) {
facetT *newfacet;
FORALLnew_facets {
if (!newfacet->mergehorizon)
qh_setfacetplane (newfacet);
}
if (qh JOGGLEmax < REALmax/2)
minimize_(qh min_vertex, -wwval_(Wnewvertexmax));
} /* makenewplanes */
/*-<a href="qh-poly.htm#TOC"
>-------------------------------</a><a name="makenew_nonsimplicial">-</a>
qh_makenew_nonsimplicial( visible, apex, numnew )
make new facets for ridges of a visible facet
returns:
first newfacet, bumps numnew as needed
attaches new facets if !qh.ONLYgood
marks ridge neighbors for simplicial visible
if (qh.ONLYgood)
ridges on newfacet, horizon, and visible
else
ridge and neighbors between newfacet and horizon
visible facet's ridges are deleted
notes:
qh.visit_id if visible has already been processed
sets neighbor->seen for building f.samecycle
assumes all 'seen' flags initially false
design:
for each ridge of visible facet
get neighbor of visible facet
if neighbor was already processed
delete the ridge (will delete all visible facets later)
if neighbor is a horizon facet
create a new facet
if neighbor coplanar
adds newfacet to f.samecycle for later merging
else
updates neighbor's neighbor set
(checks for non-simplicial facet with multiple ridges to visible facet)
updates neighbor's ridge set
(checks for simplicial neighbor to non-simplicial visible facet)
(deletes ridge if neighbor is simplicial)
*/
#ifndef qh_NOmerge
facetT *qh_makenew_nonsimplicial (facetT *visible, vertexT *apex, int *numnew) {
void **freelistp; /* used !qh_NOmem */
ridgeT *ridge, **ridgep;
facetT *neighbor, *newfacet= NULL, *samecycle;
setT *vertices;
boolT toporient;
int ridgeid;
FOREACHridge_(visible->ridges) {
ridgeid= ridge->id;
neighbor= otherfacet_(ridge, visible);
if (neighbor->visible) {
if (!qh ONLYgood) {
if (neighbor->visitid == qh visit_id) {
qh_setfree (&(ridge->vertices)); /* delete on 2nd visit */
qh_memfree_(ridge, sizeof(ridgeT), freelistp);
}
}
}else { /* neighbor is an horizon facet */
toporient= (ridge->top == visible);
vertices= qh_setnew (qh hull_dim); /* makes sure this is quick */
qh_setappend (&vertices, apex);
qh_setappend_set (&vertices, ridge->vertices);
newfacet= qh_makenewfacet(vertices, toporient, neighbor);
(*numnew)++;
if (neighbor->coplanar) {
newfacet->mergehorizon= True;
if (!neighbor->seen) {
newfacet->f.samecycle= newfacet;
neighbor->f.newcycle= newfacet;
}else {
samecycle= neighbor->f.newcycle;
newfacet->f.samecycle= samecycle->f.samecycle;
samecycle->f.samecycle= newfacet;
}
}
if (qh ONLYgood) {
if (!neighbor->simplicial)
qh_setappend(&(newfacet->ridges), ridge);
}else { /* qh_attachnewfacets */
if (neighbor->seen) {
if (neighbor->simplicial) {
fprintf (qh ferr, "qhull internal error (qh_makenew_nonsimplicial): simplicial f%d sharing two ridges with f%d\n",
neighbor->id, visible->id);
qh_errexit2 (qh_ERRqhull, neighbor, visible);
}
qh_setappend (&(neighbor->neighbors), newfacet);
}else
qh_setreplace (neighbor->neighbors, visible, newfacet);
if (neighbor->simplicial) {
qh_setdel (neighbor->ridges, ridge);
qh_setfree (&(ridge->vertices));
qh_memfree (ridge, sizeof(ridgeT));
}else {
qh_setappend(&(newfacet->ridges), ridge);
if (toporient)
ridge->top= newfacet;
else
ridge->bottom= newfacet;
}
trace4((qh ferr, "qh_makenew_nonsimplicial: created facet f%d from v%d and r%d of horizon f%d\n",
newfacet->id, apex->id, ridgeid, neighbor->id));
}
}
neighbor->seen= True;
} /* for each ridge */
if (!qh ONLYgood)
SETfirst_(visible->ridges)= NULL;
return newfacet;
} /* makenew_nonsimplicial */
#else /* qh_NOmerge */
facetT *qh_makenew_nonsimplicial (facetT *visible, vertexT *apex, int *numnew) {
return NULL;
}
#endif /* qh_NOmerge */
/*-<a href="qh-poly.htm#TOC"
>-------------------------------</a><a name="makenew_simplicial">-</a>
qh_makenew_simplicial( visible, apex, numnew )
make new facets for simplicial visible facet and apex
returns:
attaches new facets if (!qh.ONLYgood)
neighbors between newfacet and horizon
notes:
nop if neighbor->seen or neighbor->visible (see qh_makenew_nonsimplicial)
design:
locate neighboring horizon facet for visible facet
determine vertices and orientation
create new facet
if coplanar,
add new facet to f.samecycle
update horizon facet's neighbor list
*/
facetT *qh_makenew_simplicial (facetT *visible, vertexT *apex, int *numnew) {
facetT *neighbor, **neighborp, *newfacet= NULL;
setT *vertices;
boolT flip, toporient;
int horizonskip, visibleskip;
FOREACHneighbor_(visible) {
if (!neighbor->seen && !neighbor->visible) {
vertices= qh_facetintersect(neighbor,visible, &horizonskip, &visibleskip, 1);
SETfirst_(vertices)= apex;
flip= ((horizonskip & 0x1) ^ (visibleskip & 0x1));
if (neighbor->toporient)
toporient= horizonskip & 0x1;
else
toporient= (horizonskip & 0x1) ^ 0x1;
newfacet= qh_makenewfacet(vertices, toporient, neighbor);
(*numnew)++;
if (neighbor->coplanar && (qh PREmerge || qh MERGEexact)) {
#ifndef qh_NOmerge
newfacet->f.samecycle= newfacet;
newfacet->mergehorizon= True;
#endif
}
if (!qh ONLYgood)
SETelem_(neighbor->neighbors, horizonskip)= newfacet;
trace4((qh ferr, "qh_makenew_simplicial: create facet f%d top %d from v%d and horizon f%d skip %d top %d and visible f%d skip %d, flip? %d\n",
newfacet->id, toporient, apex->id, neighbor->id, horizonskip,
neighbor->toporient, visible->id, visibleskip, flip));
}
}
return newfacet;
} /* makenew_simplicial */
/*-<a href="qh-poly.htm#TOC"
>-------------------------------</a><a name="matchneighbor">-</a>
qh_matchneighbor( newfacet, newskip, hashsize, hashcount )
either match subridge of newfacet with neighbor or add to hash_table
returns:
duplicate ridges are unmatched and marked by qh_DUPLICATEridge
notes:
ridge is newfacet->vertices w/o newskip vertex
do not allocate memory (need to free hash_table cleanly)
uses linear hash chains
see also:
qh_matchduplicates
design:
for each possible matching facet in qh.hash_table
if vertices match
set ismatch, if facets have opposite orientation
if ismatch and matching facet doesn't have a match
match the facets by updating their neighbor sets
else
indicate a duplicate ridge
set facet hyperplane for later testing
add facet to hashtable
unless the other facet was already a duplicate ridge
mark both facets with a duplicate ridge
add other facet (if defined) to hash table
*/
void qh_matchneighbor (facetT *newfacet, int newskip, int hashsize, int *hashcount) {
boolT newfound= False; /* True, if new facet is already in hash chain */
boolT same, ismatch;
int hash, scan;
facetT *facet, *matchfacet;
int skip, matchskip;
hash= (int)qh_gethash (hashsize, newfacet->vertices, qh hull_dim, 1,
SETelem_(newfacet->vertices, newskip));
trace4((qh ferr, "qh_matchneighbor: newfacet f%d skip %d hash %d hashcount %d\n",
newfacet->id, newskip, hash, *hashcount));
zinc_(Zhashlookup);
for (scan= hash; (facet= SETelemt_(qh hash_table, scan, facetT));
scan= (++scan >= hashsize ? 0 : scan)) {
if (facet == newfacet) {
newfound= True;
continue;
}
zinc_(Zhashtests);
if (qh_matchvertices (1, newfacet->vertices, newskip, facet->vertices, &skip, &same)) {
if (SETelem_(newfacet->vertices, newskip) ==
SETelem_(facet->vertices, skip)) {
qh_precision ("two facets with the same vertices");
fprintf (qh ferr, "qhull precision error: Vertex sets are the same for f%d and f%d. Can not force output.\n",
facet->id, newfacet->id);
qh_errexit2 (qh_ERRprec, facet, newfacet);
}
ismatch= (same == (newfacet->toporient ^ facet->toporient));
matchfacet= SETelemt_(facet->neighbors, skip, facetT);
if (ismatch && !matchfacet) {
SETelem_(facet->neighbors, skip)= newfacet;
SETelem_(newfacet->neighbors, newskip)= facet;
(*hashcount)--;
trace4((qh ferr, "qh_matchneighbor: f%d skip %d matched with new f%d skip %d\n",
facet->id, skip, newfacet->id, newskip));
return;
}
if (!qh PREmerge && !qh MERGEexact) {
qh_precision ("a ridge with more than two neighbors");
fprintf (qh ferr, "qhull precision error: facets f%d, f%d and f%d meet at a ridge with more than 2 neighbors. Can not continue.\n",
facet->id, newfacet->id, getid_(matchfacet));
qh_errexit2 (qh_ERRprec, facet, newfacet);
}
SETelem_(newfacet->neighbors, newskip)= qh_DUPLICATEridge;
newfacet->dupridge= True;
if (!newfacet->normal)
qh_setfacetplane (newfacet);
qh_addhash (newfacet, qh hash_table, hashsize, hash);
(*hashcount)++;
if (!facet->normal)
qh_setfacetplane (facet);
if (matchfacet != qh_DUPLICATEridge) {
SETelem_(facet->neighbors, skip)= qh_DUPLICATEridge;
facet->dupridge= True;
if (!facet->normal)
qh_setfacetplane (facet);
if (matchfacet) {
matchskip= qh_setindex (matchfacet->neighbors, facet);
SETelem_(matchfacet->neighbors, matchskip)= qh_DUPLICATEridge;
matchfacet->dupridge= True;
if (!matchfacet->normal)
qh_setfacetplane (matchfacet);
qh_addhash (matchfacet, qh hash_table, hashsize, hash);
*hashcount += 2;
}
}
trace4((qh ferr, "qh_matchneighbor: new f%d skip %d duplicates ridge for f%d skip %d matching f%d ismatch %d at hash %d\n",
newfacet->id, newskip, facet->id, skip,
(matchfacet == qh_DUPLICATEridge ? -2 : getid_(matchfacet)),
ismatch, hash));
return; /* end of duplicate ridge */
}
}
if (!newfound)
SETelem_(qh hash_table, scan)= newfacet; /* same as qh_addhash */
(*hashcount)++;
trace4((qh ferr, "qh_matchneighbor: no match for f%d skip %d at hash %d\n",
newfacet->id, newskip, hash));
} /* matchneighbor */
/*-<a href="qh-poly.htm#TOC"
>-------------------------------</a><a name="matchnewfacets">-</a>
qh_matchnewfacets()
match newfacets in qh.newfacet_list to their newfacet neighbors
returns:
qh.newfacet_list with full neighbor sets
get vertices with nth neighbor by deleting nth vertex
if qh.PREmerge/MERGEexact or qh.FORCEoutput
sets facet->flippped if flipped normal (also prevents point partitioning)
if duplicate ridges and qh.PREmerge/MERGEexact
sets facet->dupridge
missing neighbor links identifies extra ridges to be merging (qh_MERGEridge)
notes:
newfacets already have neighbor[0] (horizon facet)
assumes qh.hash_table is NULL
vertex->neighbors has not been updated yet
do not allocate memory after qh.hash_table (need to free it cleanly)
design:
delete neighbor sets for all new facets
initialize a hash table
for all new facets
match facet with neighbors
if unmatched facets (due to duplicate ridges)
for each new facet with a duplicate ridge
match it with a facet
check for flipped facets
*/
void qh_matchnewfacets (void /* qh newfacet_list */) {
int numnew=0, hashcount=0, newskip;
facetT *newfacet, *neighbor;
int dim= qh hull_dim, hashsize, neighbor_i, neighbor_n;
setT *neighbors;
#ifndef qh_NOtrace
int facet_i, facet_n, numfree= 0;
facetT *facet;
#endif
trace1((qh ferr, "qh_matchnewfacets: match neighbors for new facets.\n"));
FORALLnew_facets {
numnew++;
{ /* inline qh_setzero (newfacet->neighbors, 1, qh hull_dim); */
neighbors= newfacet->neighbors;
neighbors->e[neighbors->maxsize].i= dim+1; /*may be overwritten*/
memset ((char *)SETelemaddr_(neighbors, 1, void), 0, dim * SETelemsize);
}
}
qh_newhashtable (numnew*(qh hull_dim-1)); /* twice what is normally needed,
but every ridge could be DUPLICATEridge */
hashsize= qh_setsize (qh hash_table);
FORALLnew_facets {
for (newskip=1; newskip<qh hull_dim; newskip++) /* furthest/horizon already matched */
qh_matchneighbor (newfacet, newskip, hashsize, &hashcount);
#if 0 /* use the following to trap hashcount errors */
{
int count= 0, k;
facetT *facet, *neighbor;
count= 0;
FORALLfacet_(qh newfacet_list) { /* newfacet already in use */
for (k=1; k < qh hull_dim; k++) {
neighbor= SETelemt_(facet->neighbors, k, facetT);
if (!neighbor || neighbor == qh_DUPLICATEridge)
count++;
}
if (facet == newfacet)
break;
}
if (count != hashcount) {
fprintf (qh ferr, "qh_matchnewfacets: after adding facet %d, hashcount %d != count %d\n",
newfacet->id, hashcount, count);
qh_errexit (qh_ERRqhull, newfacet, NULL);
}
}
#endif /* end of trap code */
}
if (hashcount) {
FORALLnew_facets {
if (newfacet->dupridge) {
FOREACHneighbor_i_(newfacet) {
if (neighbor == qh_DUPLICATEridge) {
qh_matchduplicates (newfacet, neighbor_i, hashsize, &hashcount);
/* this may report MERGEfacet */
}
}
}
}
}
if (hashcount) {
fprintf (qh ferr, "qhull internal error (qh_matchnewfacets): %d neighbors did not match up\n",
hashcount);
qh_printhashtable (qh ferr);
qh_errexit (qh_ERRqhull, NULL, NULL);
}
#ifndef qh_NOtrace
if (qh IStracing >= 2) {
FOREACHfacet_i_(qh hash_table) {
if (!facet)
numfree++;
}
fprintf (qh ferr, "qh_matchnewfacets: %d new facets, %d unused hash entries . hashsize %d\n",
numnew, numfree, qh_setsize (qh hash_table));
}
#endif /* !qh_NOtrace */
qh_setfree (&qh hash_table);
if (qh PREmerge || qh MERGEexact) {
if (qh IStracing >= 4)
qh_printfacetlist (qh newfacet_list, NULL, qh_ALL);
FORALLnew_facets {
if (newfacet->normal)
qh_checkflipped (newfacet, NULL, qh_ALL);
}
}else if (qh FORCEoutput)
qh_checkflipped_all (qh newfacet_list); /* prints warnings for flipped */
} /* matchnewfacets */
/*-<a href="qh-poly.htm#TOC"
>-------------------------------</a><a name="matchvertices">-</a>
qh_matchvertices( firstindex, verticesA, skipA, verticesB, skipB, same )
tests whether vertices match with a single skip
starts match at firstindex since all new facets have a common vertex
returns:
true if matched vertices
skip index for each set
sets same iff vertices have the same orientation
notes:
assumes skipA is in A and both sets are the same size
design:
set up pointers
scan both sets checking for a match
test orientation
*/
boolT qh_matchvertices (int firstindex, setT *verticesA, int skipA,
setT *verticesB, int *skipB, boolT *same) {
vertexT **elemAp, **elemBp, **skipBp=NULL, **skipAp;
elemAp= SETelemaddr_(verticesA, firstindex, vertexT);
elemBp= SETelemaddr_(verticesB, firstindex, vertexT);
skipAp= SETelemaddr_(verticesA, skipA, vertexT);
do if (elemAp != skipAp) {
while (*elemAp != *elemBp++) {
if (skipBp)
return False;
skipBp= elemBp; /* one extra like FOREACH */
}
}while(*(++elemAp));
if (!skipBp)
skipBp= ++elemBp;
*skipB= SETindex_(verticesB, skipB);
*same= !(((ptr_intT)skipA & 0x1) ^ ((ptr_intT)*skipB & 0x1));
trace4((qh ferr, "qh_matchvertices: matched by skip %d (v%d) and skip %d (v%d) same? %d\n",
skipA, (*skipAp)->id, *skipB, (*(skipBp-1))->id, *same));
return (True);
} /* matchvertices */
/*-<a href="qh-poly.htm#TOC"
>-------------------------------</a><a name="newfacet">-</a>
qh_newfacet()
return a new facet
returns:
all fields initialized or cleared (NULL)
preallocates neighbors set
*/
facetT *qh_newfacet(void) {
facetT *facet;
void **freelistp; /* used !qh_NOmem */
qh_memalloc_(sizeof(facetT), freelistp, facet, facetT);
memset ((char *)facet, 0, sizeof(facetT));
if (qh facet_id == qh tracefacet_id)
qh tracefacet= facet;
facet->id= qh facet_id++;
facet->neighbors= qh_setnew(qh hull_dim);
#if !qh_COMPUTEfurthest
facet->furthestdist= 0.0;
#endif
#if qh_MAXoutside
if (qh FORCEoutput && qh APPROXhull)
facet->maxoutside= qh MINoutside;
else
facet->maxoutside= qh DISTround;
#endif
facet->simplicial= True;
facet->good= True;
facet->newfacet= True;
trace4((qh ferr, "qh_newfacet: created facet f%d\n", facet->id));
return (facet);
} /* newfacet */
/*-<a href="qh-poly.htm#TOC"
>-------------------------------</a><a name="newridge">-</a>
qh_newridge()
return a new ridge
*/
ridgeT *qh_newridge(void) {
ridgeT *ridge;
void **freelistp; /* used !qh_NOmem */
qh_memalloc_(sizeof(ridgeT), freelistp, ridge, ridgeT);
memset ((char *)ridge, 0, sizeof(ridgeT));
zinc_(Ztotridges);
if (qh ridge_id == 0xFFFFFF) {
fprintf(qh ferr, "\
qhull warning: more than %d ridges. ID field overflows and two ridges\n\
may have the same identifier. Otherwise output ok.\n", 0xFFFFFF);
}
ridge->id= qh ridge_id++;
trace4((qh ferr, "qh_newridge: created ridge r%d\n", ridge->id));
return (ridge);
} /* newridge */
/*-<a href="qh-poly.htm#TOC"
>-------------------------------</a><a name="pointid">-</a>
qh_pointid( )
return id for a point,
returns -3 if null, -2 if interior, or -1 if not known
alternative code:
unsigned long id;
id= ((unsigned long)point - (unsigned long)qh.first_point)/qh.normal_size;
notes:
if point not in point array
the code does a comparison of unrelated pointers.
*/
int qh_pointid (pointT *point) {
long offset, id;
if (!point)
id= -3;
else if (point == qh interior_point)
id= -2;
else if (point >= qh first_point
&& point < qh first_point + qh num_points * qh hull_dim) {
offset= point - qh first_point;
id= offset / qh hull_dim;
}else if ((id= qh_setindex (qh other_points, point)) != -1)
id += qh num_points;
else
id= -1;
return (int) id;
} /* pointid */
/*-<a href="qh-poly.htm#TOC"
>-------------------------------</a><a name="removefacet">-</a>
qh_removefacet( facet )
unlinks facet from qh.facet_list,
returns:
updates qh.facet_list .newfacet_list .facet_next visible_list
decrements qh.num_facets
see:
qh_appendfacet
*/
void qh_removefacet(facetT *facet) {
facetT *next= facet->next, *previous= facet->previous;
if (facet == qh newfacet_list)
qh newfacet_list= next;
if (facet == qh facet_next)
qh facet_next= next;
if (facet == qh visible_list)
qh visible_list= next;
if (previous) {
previous->next= next;
next->previous= previous;
}else { /* 1st facet in qh facet_list */
qh facet_list= next;
qh facet_list->previous= NULL;
}
qh num_facets--;
trace4((qh ferr, "qh_removefacet: remove f%d from facet_list\n", facet->id));
} /* removefacet */
/*-<a href="qh-poly.htm#TOC"
>-------------------------------</a><a name="removevertex">-</a>
qh_removevertex( vertex )
unlinks vertex from qh.vertex_list,
returns:
updates qh.vertex_list .newvertex_list
decrements qh.num_vertices
*/
void qh_removevertex(vertexT *vertex) {
vertexT *next= vertex->next, *previous= vertex->previous;
if (vertex == qh newvertex_list)
qh newvertex_list= next;
if (previous) {
previous->next= next;
next->previous= previous;
}else { /* 1st vertex in qh vertex_list */
qh vertex_list= vertex->next;
qh vertex_list->previous= NULL;
}
qh num_vertices--;
trace4((qh ferr, "qh_removevertex: remove v%d from vertex_list\n", vertex->id));
} /* removevertex */
/*-<a href="qh-poly.htm#TOC"
>-------------------------------</a><a name="updatevertices">-</a>
qh_updatevertices()
update vertex neighbors and delete interior vertices
returns:
if qh.VERTEXneighbors, updates neighbors for each vertex
if qh.newvertex_list,
removes visible neighbors from vertex neighbors
if qh.newfacet_list
adds new facets to vertex neighbors
if qh.visible_list
interior vertices added to qh.del_vertices for later partitioning
design:
if qh.VERTEXneighbors
deletes references to visible facets from vertex neighbors
appends new facets to the neighbor list for each vertex
checks all vertices of visible facets
removes visible facets from neighbor lists
marks unused vertices for deletion
*/
void qh_updatevertices (void /*qh newvertex_list, newfacet_list, visible_list*/) {
facetT *newfacet= NULL, *neighbor, **neighborp, *visible;
vertexT *vertex, **vertexp;
trace3((qh ferr, "qh_updatevertices: delete interior vertices and update vertex->neighbors\n"));
if (qh VERTEXneighbors) {
FORALLvertex_(qh newvertex_list) {
FOREACHneighbor_(vertex) {
if (neighbor->visible)
SETref_(neighbor)= NULL;
}
qh_setcompact (vertex->neighbors);
}
FORALLnew_facets {
FOREACHvertex_(newfacet->vertices)
qh_setappend (&vertex->neighbors, newfacet);
}
FORALLvisible_facets {
FOREACHvertex_(visible->vertices) {
if (!vertex->newlist && !vertex->deleted) {
FOREACHneighbor_(vertex) { /* this can happen under merging */
if (!neighbor->visible)
break;
}
if (neighbor)
qh_setdel (vertex->neighbors, visible);
else {
vertex->deleted= True;
qh_setappend (&qh del_vertices, vertex);
trace2((qh ferr, "qh_updatevertices: delete vertex p%d (v%d) in f%d\n",
qh_pointid(vertex->point), vertex->id, visible->id));
}
}
}
}
}else { /* !VERTEXneighbors */
FORALLvisible_facets {
FOREACHvertex_(visible->vertices) {
if (!vertex->newlist && !vertex->deleted) {
vertex->deleted= True;
qh_setappend (&qh del_vertices, vertex);
trace2((qh ferr, "qh_updatevertices: delete vertex p%d (v%d) in f%d\n",
qh_pointid(vertex->point), vertex->id, visible->id));
}
}
}
}
} /* updatevertices */
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