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merge.c
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3622 lines (3253 loc) · 119 KB
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/*<html><pre> -<a href="qh-merge.htm#TOC"
>-------------------------------</a><a name="TOP">-</a>
merge.c
merges non-convex facets
see qh-merge.htm and merge.h
other modules call qh_premerge() and qh_postmerge()
the user may call qh_postmerge() to perform additional merges.
To remove deleted facets and vertices (qhull() in libqhull.c):
qh_partitionvisible(!qh_ALL, &numoutside); // visible_list, newfacet_list
qh_deletevisible(); // qh.visible_list
qh_resetlists(False, qh_RESETvisible); // qh.visible_list newvertex_list newfacet_list
assumes qh.CENTERtype= centrum
merges occur in qh_mergefacet and in qh_mergecycle
vertex->neighbors not set until the first merge occurs
Copyright (c) 1993-2012 C.B. Barber.
$Id: //main/2011/qhull/src/libqhull/merge.c#4 $$Change: 1490 $
$DateTime: 2012/02/19 20:27:01 $$Author: bbarber $
*/
#include "qhull_a.h"
#ifndef qh_NOmerge
/*===== functions(alphabetical after premerge and postmerge) ======*/
/*-<a href="qh-merge.htm#TOC"
>-------------------------------</a><a name="premerge">-</a>
qh_premerge( apex, maxcentrum )
pre-merge nonconvex facets in qh.newfacet_list for apex
maxcentrum defines coplanar and concave (qh_test_appendmerge)
returns:
deleted facets added to qh.visible_list with facet->visible set
notes:
uses globals, qh.MERGEexact, qh.PREmerge
design:
mark duplicate ridges in qh.newfacet_list
merge facet cycles in qh.newfacet_list
merge duplicate ridges and concave facets in qh.newfacet_list
check merged facet cycles for degenerate and redundant facets
merge degenerate and redundant facets
collect coplanar and concave facets
merge concave, coplanar, degenerate, and redundant facets
*/
void qh_premerge(vertexT *apex, realT maxcentrum, realT maxangle) {
boolT othermerge= False;
facetT *newfacet;
if (qh ZEROcentrum && qh_checkzero(!qh_ALL))
return;
trace2((qh ferr, 2008, "qh_premerge: premerge centrum %2.2g angle %2.2g for apex v%d facetlist f%d\n",
maxcentrum, maxangle, apex->id, getid_(qh newfacet_list)));
if (qh IStracing >= 4 && qh num_facets < 50)
qh_printlists();
qh centrum_radius= maxcentrum;
qh cos_max= maxangle;
qh degen_mergeset= qh_settemp(qh TEMPsize);
qh facet_mergeset= qh_settemp(qh TEMPsize);
if (qh hull_dim >=3) {
qh_mark_dupridges(qh newfacet_list); /* facet_mergeset */
qh_mergecycle_all(qh newfacet_list, &othermerge);
qh_forcedmerges(&othermerge /* qh facet_mergeset */);
FORALLnew_facets { /* test samecycle merges */
if (!newfacet->simplicial && !newfacet->mergeridge)
qh_degen_redundant_neighbors(newfacet, NULL);
}
if (qh_merge_degenredundant())
othermerge= True;
}else /* qh hull_dim == 2 */
qh_mergecycle_all(qh newfacet_list, &othermerge);
qh_flippedmerges(qh newfacet_list, &othermerge);
if (!qh MERGEexact || zzval_(Ztotmerge)) {
zinc_(Zpremergetot);
qh POSTmerging= False;
qh_getmergeset_initial(qh newfacet_list);
qh_all_merges(othermerge, False);
}
qh_settempfree(&qh facet_mergeset);
qh_settempfree(&qh degen_mergeset);
} /* premerge */
/*-<a href="qh-merge.htm#TOC"
>-------------------------------</a><a name="postmerge">-</a>
qh_postmerge( reason, maxcentrum, maxangle, vneighbors )
post-merge nonconvex facets as defined by maxcentrum and maxangle
'reason' is for reporting progress
if vneighbors,
calls qh_test_vneighbors at end of qh_all_merge
if firstmerge,
calls qh_reducevertices before qh_getmergeset
returns:
if first call (qh.visible_list != qh.facet_list),
builds qh.facet_newlist, qh.newvertex_list
deleted facets added to qh.visible_list with facet->visible
qh.visible_list == qh.facet_list
notes:
design:
if first call
set qh.visible_list and qh.newfacet_list to qh.facet_list
add all facets to qh.newfacet_list
mark non-simplicial facets, facet->newmerge
set qh.newvertext_list to qh.vertex_list
add all vertices to qh.newvertex_list
if a pre-merge occured
set vertex->delridge {will retest the ridge}
if qh.MERGEexact
call qh_reducevertices()
if no pre-merging
merge flipped facets
determine non-convex facets
merge all non-convex facets
*/
void qh_postmerge(const char *reason, realT maxcentrum, realT maxangle,
boolT vneighbors) {
facetT *newfacet;
boolT othermerges= False;
vertexT *vertex;
if (qh REPORTfreq || qh IStracing) {
qh_buildtracing(NULL, NULL);
qh_printsummary(qh ferr);
if (qh PRINTstatistics)
qh_printallstatistics(qh ferr, "reason");
qh_fprintf(qh ferr, 8062, "\n%s with 'C%.2g' and 'A%.2g'\n",
reason, maxcentrum, maxangle);
}
trace2((qh ferr, 2009, "qh_postmerge: postmerge. test vneighbors? %d\n",
vneighbors));
qh centrum_radius= maxcentrum;
qh cos_max= maxangle;
qh POSTmerging= True;
qh degen_mergeset= qh_settemp(qh TEMPsize);
qh facet_mergeset= qh_settemp(qh TEMPsize);
if (qh visible_list != qh facet_list) { /* first call */
qh NEWfacets= True;
qh visible_list= qh newfacet_list= qh facet_list;
FORALLnew_facets {
newfacet->newfacet= True;
if (!newfacet->simplicial)
newfacet->newmerge= True;
zinc_(Zpostfacets);
}
qh newvertex_list= qh vertex_list;
FORALLvertices
vertex->newlist= True;
if (qh VERTEXneighbors) { /* a merge has occurred */
FORALLvertices
vertex->delridge= True; /* test for redundant, needed? */
if (qh MERGEexact) {
if (qh hull_dim <= qh_DIMreduceBuild)
qh_reducevertices(); /* was skipped during pre-merging */
}
}
if (!qh PREmerge && !qh MERGEexact)
qh_flippedmerges(qh newfacet_list, &othermerges);
}
qh_getmergeset_initial(qh newfacet_list);
qh_all_merges(False, vneighbors);
qh_settempfree(&qh facet_mergeset);
qh_settempfree(&qh degen_mergeset);
} /* post_merge */
/*-<a href="qh-merge.htm#TOC"
>-------------------------------</a><a name="all_merges">-</a>
qh_all_merges( othermerge, vneighbors )
merge all non-convex facets
set othermerge if already merged facets (for qh_reducevertices)
if vneighbors
tests vertex neighbors for convexity at end
qh.facet_mergeset lists the non-convex ridges in qh_newfacet_list
qh.degen_mergeset is defined
if qh.MERGEexact && !qh.POSTmerging,
does not merge coplanar facets
returns:
deleted facets added to qh.visible_list with facet->visible
deleted vertices added qh.delvertex_list with vertex->delvertex
notes:
unless !qh.MERGEindependent,
merges facets in independent sets
uses qh.newfacet_list as argument since merges call qh_removefacet()
design:
while merges occur
for each merge in qh.facet_mergeset
unless one of the facets was already merged in this pass
merge the facets
test merged facets for additional merges
add merges to qh.facet_mergeset
if vertices record neighboring facets
rename redundant vertices
update qh.facet_mergeset
if vneighbors ??
tests vertex neighbors for convexity at end
*/
void qh_all_merges(boolT othermerge, boolT vneighbors) {
facetT *facet1, *facet2;
mergeT *merge;
boolT wasmerge= True, isreduce;
void **freelistp; /* used !qh_NOmem */
vertexT *vertex;
mergeType mergetype;
int numcoplanar=0, numconcave=0, numdegenredun= 0, numnewmerges= 0;
trace2((qh ferr, 2010, "qh_all_merges: starting to merge facets beginning from f%d\n",
getid_(qh newfacet_list)));
while (True) {
wasmerge= False;
while (qh_setsize(qh facet_mergeset)) {
while ((merge= (mergeT*)qh_setdellast(qh facet_mergeset))) {
facet1= merge->facet1;
facet2= merge->facet2;
mergetype= merge->type;
qh_memfree_(merge, (int)sizeof(mergeT), freelistp);
if (facet1->visible || facet2->visible) /*deleted facet*/
continue;
if ((facet1->newfacet && !facet1->tested)
|| (facet2->newfacet && !facet2->tested)) {
if (qh MERGEindependent && mergetype <= MRGanglecoplanar)
continue; /* perform independent sets of merges */
}
qh_merge_nonconvex(facet1, facet2, mergetype);
numdegenredun += qh_merge_degenredundant();
numnewmerges++;
wasmerge= True;
if (mergetype == MRGconcave)
numconcave++;
else /* MRGcoplanar or MRGanglecoplanar */
numcoplanar++;
} /* while setdellast */
if (qh POSTmerging && qh hull_dim <= qh_DIMreduceBuild
&& numnewmerges > qh_MAXnewmerges) {
numnewmerges= 0;
qh_reducevertices(); /* otherwise large post merges too slow */
}
qh_getmergeset(qh newfacet_list); /* facet_mergeset */
} /* while mergeset */
if (qh VERTEXneighbors) {
isreduce= False;
if (qh hull_dim >=4 && qh POSTmerging) {
FORALLvertices
vertex->delridge= True;
isreduce= True;
}
if ((wasmerge || othermerge) && (!qh MERGEexact || qh POSTmerging)
&& qh hull_dim <= qh_DIMreduceBuild) {
othermerge= False;
isreduce= True;
}
if (isreduce) {
if (qh_reducevertices()) {
qh_getmergeset(qh newfacet_list); /* facet_mergeset */
continue;
}
}
}
if (vneighbors && qh_test_vneighbors(/* qh newfacet_list */))
continue;
break;
} /* while (True) */
if (qh CHECKfrequently && !qh MERGEexact) {
qh old_randomdist= qh RANDOMdist;
qh RANDOMdist= False;
qh_checkconvex(qh newfacet_list, qh_ALGORITHMfault);
/* qh_checkconnect(); [this is slow and it changes the facet order] */
qh RANDOMdist= qh old_randomdist;
}
trace1((qh ferr, 1009, "qh_all_merges: merged %d coplanar facets %d concave facets and %d degen or redundant facets.\n",
numcoplanar, numconcave, numdegenredun));
if (qh IStracing >= 4 && qh num_facets < 50)
qh_printlists();
} /* all_merges */
/*-<a href="qh-merge.htm#TOC"
>-------------------------------</a><a name="appendmergeset">-</a>
qh_appendmergeset( facet, neighbor, mergetype, angle )
appends an entry to qh.facet_mergeset or qh.degen_mergeset
angle ignored if NULL or !qh.ANGLEmerge
returns:
merge appended to facet_mergeset or degen_mergeset
sets ->degenerate or ->redundant if degen_mergeset
see:
qh_test_appendmerge()
design:
allocate merge entry
if regular merge
append to qh.facet_mergeset
else if degenerate merge and qh.facet_mergeset is all degenerate
append to qh.degen_mergeset
else if degenerate merge
prepend to qh.degen_mergeset
else if redundant merge
append to qh.degen_mergeset
*/
void qh_appendmergeset(facetT *facet, facetT *neighbor, mergeType mergetype, realT *angle) {
mergeT *merge, *lastmerge;
void **freelistp; /* used !qh_NOmem */
if (facet->redundant)
return;
if (facet->degenerate && mergetype == MRGdegen)
return;
qh_memalloc_((int)sizeof(mergeT), freelistp, merge, mergeT);
merge->facet1= facet;
merge->facet2= neighbor;
merge->type= mergetype;
if (angle && qh ANGLEmerge)
merge->angle= *angle;
if (mergetype < MRGdegen)
qh_setappend(&(qh facet_mergeset), merge);
else if (mergetype == MRGdegen) {
facet->degenerate= True;
if (!(lastmerge= (mergeT*)qh_setlast(qh degen_mergeset))
|| lastmerge->type == MRGdegen)
qh_setappend(&(qh degen_mergeset), merge);
else
qh_setaddnth(&(qh degen_mergeset), 0, merge);
}else if (mergetype == MRGredundant) {
facet->redundant= True;
qh_setappend(&(qh degen_mergeset), merge);
}else /* mergetype == MRGmirror */ {
if (facet->redundant || neighbor->redundant) {
qh_fprintf(qh ferr, 6092, "qhull error (qh_appendmergeset): facet f%d or f%d is already a mirrored facet\n",
facet->id, neighbor->id);
qh_errexit2 (qh_ERRqhull, facet, neighbor);
}
if (!qh_setequal(facet->vertices, neighbor->vertices)) {
qh_fprintf(qh ferr, 6093, "qhull error (qh_appendmergeset): mirrored facets f%d and f%d do not have the same vertices\n",
facet->id, neighbor->id);
qh_errexit2 (qh_ERRqhull, facet, neighbor);
}
facet->redundant= True;
neighbor->redundant= True;
qh_setappend(&(qh degen_mergeset), merge);
}
} /* appendmergeset */
/*-<a href="qh-merge.htm#TOC"
>-------------------------------</a><a name="basevertices">-</a>
qh_basevertices( samecycle )
return temporary set of base vertices for samecycle
samecycle is first facet in the cycle
assumes apex is SETfirst_( samecycle->vertices )
returns:
vertices(settemp)
all ->seen are cleared
notes:
uses qh_vertex_visit;
design:
for each facet in samecycle
for each unseen vertex in facet->vertices
append to result
*/
setT *qh_basevertices(facetT *samecycle) {
facetT *same;
vertexT *apex, *vertex, **vertexp;
setT *vertices= qh_settemp(qh TEMPsize);
apex= SETfirstt_(samecycle->vertices, vertexT);
apex->visitid= ++qh vertex_visit;
FORALLsame_cycle_(samecycle) {
if (same->mergeridge)
continue;
FOREACHvertex_(same->vertices) {
if (vertex->visitid != qh vertex_visit) {
qh_setappend(&vertices, vertex);
vertex->visitid= qh vertex_visit;
vertex->seen= False;
}
}
}
trace4((qh ferr, 4019, "qh_basevertices: found %d vertices\n",
qh_setsize(vertices)));
return vertices;
} /* basevertices */
/*-<a href="qh-merge.htm#TOC"
>-------------------------------</a><a name="checkconnect">-</a>
qh_checkconnect()
check that new facets are connected
new facets are on qh.newfacet_list
notes:
this is slow and it changes the order of the facets
uses qh.visit_id
design:
move first new facet to end of qh.facet_list
for all newly appended facets
append unvisited neighbors to end of qh.facet_list
for all new facets
report error if unvisited
*/
void qh_checkconnect(void /* qh newfacet_list */) {
facetT *facet, *newfacet, *errfacet= NULL, *neighbor, **neighborp;
facet= qh newfacet_list;
qh_removefacet(facet);
qh_appendfacet(facet);
facet->visitid= ++qh visit_id;
FORALLfacet_(facet) {
FOREACHneighbor_(facet) {
if (neighbor->visitid != qh visit_id) {
qh_removefacet(neighbor);
qh_appendfacet(neighbor);
neighbor->visitid= qh visit_id;
}
}
}
FORALLnew_facets {
if (newfacet->visitid == qh visit_id)
break;
qh_fprintf(qh ferr, 6094, "qhull error: f%d is not attached to the new facets\n",
newfacet->id);
errfacet= newfacet;
}
if (errfacet)
qh_errexit(qh_ERRqhull, errfacet, NULL);
} /* checkconnect */
/*-<a href="qh-merge.htm#TOC"
>-------------------------------</a><a name="checkzero">-</a>
qh_checkzero( testall )
check that facets are clearly convex for qh.DISTround with qh.MERGEexact
if testall,
test all facets for qh.MERGEexact post-merging
else
test qh.newfacet_list
if qh.MERGEexact,
allows coplanar ridges
skips convexity test while qh.ZEROall_ok
returns:
True if all facets !flipped, !dupridge, normal
if all horizon facets are simplicial
if all vertices are clearly below neighbor
if all opposite vertices of horizon are below
clears qh.ZEROall_ok if any problems or coplanar facets
notes:
uses qh.vertex_visit
horizon facets may define multiple new facets
design:
for all facets in qh.newfacet_list or qh.facet_list
check for flagged faults (flipped, etc.)
for all facets in qh.newfacet_list or qh.facet_list
for each neighbor of facet
skip horizon facets for qh.newfacet_list
test the opposite vertex
if qh.newfacet_list
test the other vertices in the facet's horizon facet
*/
boolT qh_checkzero(boolT testall) {
facetT *facet, *neighbor, **neighborp;
facetT *horizon, *facetlist;
int neighbor_i;
vertexT *vertex, **vertexp;
realT dist;
if (testall)
facetlist= qh facet_list;
else {
facetlist= qh newfacet_list;
FORALLfacet_(facetlist) {
horizon= SETfirstt_(facet->neighbors, facetT);
if (!horizon->simplicial)
goto LABELproblem;
if (facet->flipped || facet->dupridge || !facet->normal)
goto LABELproblem;
}
if (qh MERGEexact && qh ZEROall_ok) {
trace2((qh ferr, 2011, "qh_checkzero: skip convexity check until first pre-merge\n"));
return True;
}
}
FORALLfacet_(facetlist) {
qh vertex_visit++;
neighbor_i= 0;
horizon= NULL;
FOREACHneighbor_(facet) {
if (!neighbor_i && !testall) {
horizon= neighbor;
neighbor_i++;
continue; /* horizon facet tested in qh_findhorizon */
}
vertex= SETelemt_(facet->vertices, neighbor_i++, vertexT);
vertex->visitid= qh vertex_visit;
zzinc_(Zdistzero);
qh_distplane(vertex->point, neighbor, &dist);
if (dist >= -qh DISTround) {
qh ZEROall_ok= False;
if (!qh MERGEexact || testall || dist > qh DISTround)
goto LABELnonconvex;
}
}
if (!testall) {
FOREACHvertex_(horizon->vertices) {
if (vertex->visitid != qh vertex_visit) {
zzinc_(Zdistzero);
qh_distplane(vertex->point, facet, &dist);
if (dist >= -qh DISTround) {
qh ZEROall_ok= False;
if (!qh MERGEexact || dist > qh DISTround)
goto LABELnonconvex;
}
break;
}
}
}
}
trace2((qh ferr, 2012, "qh_checkzero: testall %d, facets are %s\n", testall,
(qh MERGEexact && !testall) ?
"not concave, flipped, or duplicate ridged" : "clearly convex"));
return True;
LABELproblem:
qh ZEROall_ok= False;
trace2((qh ferr, 2013, "qh_checkzero: facet f%d needs pre-merging\n",
facet->id));
return False;
LABELnonconvex:
trace2((qh ferr, 2014, "qh_checkzero: facet f%d and f%d are not clearly convex. v%d dist %.2g\n",
facet->id, neighbor->id, vertex->id, dist));
return False;
} /* checkzero */
/*-<a href="qh-merge.htm#TOC"
>-------------------------------</a><a name="compareangle">-</a>
qh_compareangle( angle1, angle2 )
used by qsort() to order merges by angle
*/
int qh_compareangle(const void *p1, const void *p2) {
const mergeT *a= *((mergeT *const*)p1), *b= *((mergeT *const*)p2);
return((a->angle > b->angle) ? 1 : -1);
} /* compareangle */
/*-<a href="qh-merge.htm#TOC"
>-------------------------------</a><a name="comparemerge">-</a>
qh_comparemerge( merge1, merge2 )
used by qsort() to order merges
*/
int qh_comparemerge(const void *p1, const void *p2) {
const mergeT *a= *((mergeT *const*)p1), *b= *((mergeT *const*)p2);
return(a->type - b->type);
} /* comparemerge */
/*-<a href="qh-merge.htm#TOC"
>-------------------------------</a><a name="comparevisit">-</a>
qh_comparevisit( vertex1, vertex2 )
used by qsort() to order vertices by their visitid
*/
int qh_comparevisit(const void *p1, const void *p2) {
const vertexT *a= *((vertexT *const*)p1), *b= *((vertexT *const*)p2);
return(a->visitid - b->visitid);
} /* comparevisit */
/*-<a href="qh-merge.htm#TOC"
>-------------------------------</a><a name="copynonconvex">-</a>
qh_copynonconvex( atridge )
set non-convex flag on other ridges (if any) between same neighbors
notes:
may be faster if use smaller ridge set
design:
for each ridge of atridge's top facet
if ridge shares the same neighbor
set nonconvex flag
*/
void qh_copynonconvex(ridgeT *atridge) {
facetT *facet, *otherfacet;
ridgeT *ridge, **ridgep;
facet= atridge->top;
otherfacet= atridge->bottom;
FOREACHridge_(facet->ridges) {
if (otherfacet == otherfacet_(ridge, facet) && ridge != atridge) {
ridge->nonconvex= True;
trace4((qh ferr, 4020, "qh_copynonconvex: moved nonconvex flag from r%d to r%d\n",
atridge->id, ridge->id));
break;
}
}
} /* copynonconvex */
/*-<a href="qh-merge.htm#TOC"
>-------------------------------</a><a name="degen_redundant_facet">-</a>
qh_degen_redundant_facet( facet )
check facet for degen. or redundancy
notes:
bumps vertex_visit
called if a facet was redundant but no longer is (qh_merge_degenredundant)
qh_appendmergeset() only appends first reference to facet (i.e., redundant)
see:
qh_degen_redundant_neighbors()
design:
test for redundant neighbor
test for degenerate facet
*/
void qh_degen_redundant_facet(facetT *facet) {
vertexT *vertex, **vertexp;
facetT *neighbor, **neighborp;
trace4((qh ferr, 4021, "qh_degen_redundant_facet: test facet f%d for degen/redundant\n",
facet->id));
FOREACHneighbor_(facet) {
qh vertex_visit++;
FOREACHvertex_(neighbor->vertices)
vertex->visitid= qh vertex_visit;
FOREACHvertex_(facet->vertices) {
if (vertex->visitid != qh vertex_visit)
break;
}
if (!vertex) {
qh_appendmergeset(facet, neighbor, MRGredundant, NULL);
trace2((qh ferr, 2015, "qh_degen_redundant_facet: f%d is contained in f%d. merge\n", facet->id, neighbor->id));
return;
}
}
if (qh_setsize(facet->neighbors) < qh hull_dim) {
qh_appendmergeset(facet, facet, MRGdegen, NULL);
trace2((qh ferr, 2016, "qh_degen_redundant_neighbors: f%d is degenerate.\n", facet->id));
}
} /* degen_redundant_facet */
/*-<a href="qh-merge.htm#TOC"
>-------------------------------</a><a name="degen_redundant_neighbors">-</a>
qh_degen_redundant_neighbors( facet, delfacet, )
append degenerate and redundant neighbors to facet_mergeset
if delfacet,
only checks neighbors of both delfacet and facet
also checks current facet for degeneracy
notes:
bumps vertex_visit
called for each qh_mergefacet() and qh_mergecycle()
merge and statistics occur in merge_nonconvex
qh_appendmergeset() only appends first reference to facet (i.e., redundant)
it appends redundant facets after degenerate ones
a degenerate facet has fewer than hull_dim neighbors
a redundant facet's vertices is a subset of its neighbor's vertices
tests for redundant merges first (appendmergeset is nop for others)
in a merge, only needs to test neighbors of merged facet
see:
qh_merge_degenredundant() and qh_degen_redundant_facet()
design:
test for degenerate facet
test for redundant neighbor
test for degenerate neighbor
*/
void qh_degen_redundant_neighbors(facetT *facet, facetT *delfacet) {
vertexT *vertex, **vertexp;
facetT *neighbor, **neighborp;
int size;
trace4((qh ferr, 4022, "qh_degen_redundant_neighbors: test neighbors of f%d with delfacet f%d\n",
facet->id, getid_(delfacet)));
if ((size= qh_setsize(facet->neighbors)) < qh hull_dim) {
qh_appendmergeset(facet, facet, MRGdegen, NULL);
trace2((qh ferr, 2017, "qh_degen_redundant_neighbors: f%d is degenerate with %d neighbors.\n", facet->id, size));
}
if (!delfacet)
delfacet= facet;
qh vertex_visit++;
FOREACHvertex_(facet->vertices)
vertex->visitid= qh vertex_visit;
FOREACHneighbor_(delfacet) {
/* uses early out instead of checking vertex count */
if (neighbor == facet)
continue;
FOREACHvertex_(neighbor->vertices) {
if (vertex->visitid != qh vertex_visit)
break;
}
if (!vertex) {
qh_appendmergeset(neighbor, facet, MRGredundant, NULL);
trace2((qh ferr, 2018, "qh_degen_redundant_neighbors: f%d is contained in f%d. merge\n", neighbor->id, facet->id));
}
}
FOREACHneighbor_(delfacet) { /* redundant merges occur first */
if (neighbor == facet)
continue;
if ((size= qh_setsize(neighbor->neighbors)) < qh hull_dim) {
qh_appendmergeset(neighbor, neighbor, MRGdegen, NULL);
trace2((qh ferr, 2019, "qh_degen_redundant_neighbors: f%d is degenerate with %d neighbors. Neighbor of f%d.\n", neighbor->id, size, facet->id));
}
}
} /* degen_redundant_neighbors */
/*-<a href="qh-merge.htm#TOC"
>-------------------------------</a><a name="find_newvertex">-</a>
qh_find_newvertex( oldvertex, vertices, ridges )
locate new vertex for renaming old vertex
vertices is a set of possible new vertices
vertices sorted by number of deleted ridges
returns:
newvertex or NULL
each ridge includes both vertex and oldvertex
vertices sorted by number of deleted ridges
notes:
modifies vertex->visitid
new vertex is in one of the ridges
renaming will not cause a duplicate ridge
renaming will minimize the number of deleted ridges
newvertex may not be adjacent in the dual (though unlikely)
design:
for each vertex in vertices
set vertex->visitid to number of references in ridges
remove unvisited vertices
set qh.vertex_visit above all possible values
sort vertices by number of references in ridges
add each ridge to qh.hash_table
for each vertex in vertices
look for a vertex that would not cause a duplicate ridge after a rename
*/
vertexT *qh_find_newvertex(vertexT *oldvertex, setT *vertices, setT *ridges) {
vertexT *vertex, **vertexp;
setT *newridges;
ridgeT *ridge, **ridgep;
int size, hashsize;
int hash;
#ifndef qh_NOtrace
if (qh IStracing >= 4) {
qh_fprintf(qh ferr, 8063, "qh_find_newvertex: find new vertex for v%d from ",
oldvertex->id);
FOREACHvertex_(vertices)
qh_fprintf(qh ferr, 8064, "v%d ", vertex->id);
FOREACHridge_(ridges)
qh_fprintf(qh ferr, 8065, "r%d ", ridge->id);
qh_fprintf(qh ferr, 8066, "\n");
}
#endif
FOREACHvertex_(vertices)
vertex->visitid= 0;
FOREACHridge_(ridges) {
FOREACHvertex_(ridge->vertices)
vertex->visitid++;
}
FOREACHvertex_(vertices) {
if (!vertex->visitid) {
qh_setdelnth(vertices, SETindex_(vertices,vertex));
vertexp--; /* repeat since deleted this vertex */
}
}
qh vertex_visit += (unsigned int)qh_setsize(ridges);
if (!qh_setsize(vertices)) {
trace4((qh ferr, 4023, "qh_find_newvertex: vertices not in ridges for v%d\n",
oldvertex->id));
return NULL;
}
qsort(SETaddr_(vertices, vertexT), (size_t)qh_setsize(vertices),
sizeof(vertexT *), qh_comparevisit);
/* can now use qh vertex_visit */
if (qh PRINTstatistics) {
size= qh_setsize(vertices);
zinc_(Zintersect);
zadd_(Zintersecttot, size);
zmax_(Zintersectmax, size);
}
hashsize= qh_newhashtable(qh_setsize(ridges));
FOREACHridge_(ridges)
qh_hashridge(qh hash_table, hashsize, ridge, oldvertex);
FOREACHvertex_(vertices) {
newridges= qh_vertexridges(vertex);
FOREACHridge_(newridges) {
if (qh_hashridge_find(qh hash_table, hashsize, ridge, vertex, oldvertex, &hash)) {
zinc_(Zdupridge);
break;
}
}
qh_settempfree(&newridges);
if (!ridge)
break; /* found a rename */
}
if (vertex) {
/* counted in qh_renamevertex */
trace2((qh ferr, 2020, "qh_find_newvertex: found v%d for old v%d from %d vertices and %d ridges.\n",
vertex->id, oldvertex->id, qh_setsize(vertices), qh_setsize(ridges)));
}else {
zinc_(Zfindfail);
trace0((qh ferr, 14, "qh_find_newvertex: no vertex for renaming v%d(all duplicated ridges) during p%d\n",
oldvertex->id, qh furthest_id));
}
qh_setfree(&qh hash_table);
return vertex;
} /* find_newvertex */
/*-<a href="qh-merge.htm#TOC"
>-------------------------------</a><a name="findbest_test">-</a>
qh_findbest_test( testcentrum, facet, neighbor, bestfacet, dist, mindist, maxdist )
test neighbor of facet for qh_findbestneighbor()
if testcentrum,
tests centrum (assumes it is defined)
else
tests vertices
returns:
if a better facet (i.e., vertices/centrum of facet closer to neighbor)
updates bestfacet, dist, mindist, and maxdist
*/
void qh_findbest_test(boolT testcentrum, facetT *facet, facetT *neighbor,
facetT **bestfacet, realT *distp, realT *mindistp, realT *maxdistp) {
realT dist, mindist, maxdist;
if (testcentrum) {
zzinc_(Zbestdist);
qh_distplane(facet->center, neighbor, &dist);
dist *= qh hull_dim; /* estimate furthest vertex */
if (dist < 0) {
maxdist= 0;
mindist= dist;
dist= -dist;
}else {
mindist= 0;
maxdist= dist;
}
}else
dist= qh_getdistance(facet, neighbor, &mindist, &maxdist);
if (dist < *distp) {
*bestfacet= neighbor;
*mindistp= mindist;
*maxdistp= maxdist;
*distp= dist;
}
} /* findbest_test */
/*-<a href="qh-merge.htm#TOC"
>-------------------------------</a><a name="findbestneighbor">-</a>
qh_findbestneighbor( facet, dist, mindist, maxdist )
finds best neighbor (least dist) of a facet for merging
returns:
returns min and max distances and their max absolute value
notes:
avoids merging old into new
assumes ridge->nonconvex only set on one ridge between a pair of facets
could use an early out predicate but not worth it
design:
if a large facet
will test centrum
else
will test vertices
if a large facet
test nonconvex neighbors for best merge
else
test all neighbors for the best merge
if testing centrum
get distance information
*/
facetT *qh_findbestneighbor(facetT *facet, realT *distp, realT *mindistp, realT *maxdistp) {
facetT *neighbor, **neighborp, *bestfacet= NULL;
ridgeT *ridge, **ridgep;
boolT nonconvex= True, testcentrum= False;
int size= qh_setsize(facet->vertices);
*distp= REALmax;
if (size > qh_BESTcentrum2 * qh hull_dim + qh_BESTcentrum) {
testcentrum= True;
zinc_(Zbestcentrum);
if (!facet->center)
facet->center= qh_getcentrum(facet);
}
if (size > qh hull_dim + qh_BESTnonconvex) {
FOREACHridge_(facet->ridges) {
if (ridge->nonconvex) {
neighbor= otherfacet_(ridge, facet);
qh_findbest_test(testcentrum, facet, neighbor,
&bestfacet, distp, mindistp, maxdistp);
}
}
}
if (!bestfacet) {
nonconvex= False;
FOREACHneighbor_(facet)
qh_findbest_test(testcentrum, facet, neighbor,
&bestfacet, distp, mindistp, maxdistp);
}
if (!bestfacet) {
qh_fprintf(qh ferr, 6095, "qhull internal error (qh_findbestneighbor): no neighbors for f%d\n", facet->id);
qh_errexit(qh_ERRqhull, facet, NULL);
}
if (testcentrum)
qh_getdistance(facet, bestfacet, mindistp, maxdistp);
trace3((qh ferr, 3002, "qh_findbestneighbor: f%d is best neighbor for f%d testcentrum? %d nonconvex? %d dist %2.2g min %2.2g max %2.2g\n",
bestfacet->id, facet->id, testcentrum, nonconvex, *distp, *mindistp, *maxdistp));
return(bestfacet);
} /* findbestneighbor */
/*-<a href="qh-merge.htm#TOC"
>-------------------------------</a><a name="flippedmerges">-</a>
qh_flippedmerges( facetlist, wasmerge )
merge flipped facets into best neighbor
assumes qh.facet_mergeset at top of temporary stack
returns:
no flipped facets on facetlist
sets wasmerge if merge occurred
degen/redundant merges passed through
notes:
othermerges not needed since qh.facet_mergeset is empty before & after
keep it in case of change
design:
append flipped facets to qh.facetmergeset
for each flipped merge
find best neighbor
merge facet into neighbor
merge degenerate and redundant facets
remove flipped merges from qh.facet_mergeset
*/
void qh_flippedmerges(facetT *facetlist, boolT *wasmerge) {
facetT *facet, *neighbor, *facet1;
realT dist, mindist, maxdist;
mergeT *merge, **mergep;
setT *othermerges;
int nummerge=0;
trace4((qh ferr, 4024, "qh_flippedmerges: begin\n"));
FORALLfacet_(facetlist) {
if (facet->flipped && !facet->visible)
qh_appendmergeset(facet, facet, MRGflip, NULL);
}
othermerges= qh_settemppop(); /* was facet_mergeset */
qh facet_mergeset= qh_settemp(qh TEMPsize);
qh_settemppush(othermerges);
FOREACHmerge_(othermerges) {
facet1= merge->facet1;
if (merge->type != MRGflip || facet1->visible)
continue;
if (qh TRACEmerge-1 == zzval_(Ztotmerge))
qhmem.IStracing= qh IStracing= qh TRACElevel;
neighbor= qh_findbestneighbor(facet1, &dist, &mindist, &maxdist);
trace0((qh ferr, 15, "qh_flippedmerges: merge flipped f%d into f%d dist %2.2g during p%d\n",
facet1->id, neighbor->id, dist, qh furthest_id));