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root/radiance/ray/src/cv/bsdfmesh.c
Revision: 2.39
Committed: Fri Oct 6 00:23:09 2017 UTC (6 years, 7 months ago) by greg
Content type: text/plain
Branch: MAIN
CVS Tags: rad5R2
Changes since 2.38: +6 -9 lines
Log Message:
Improved robustness of specular component estimation

File Contents

# User Rev Content
1 greg 2.1 #ifndef lint
2 greg 2.39 static const char RCSid[] = "$Id: bsdfmesh.c,v 2.38 2017/05/16 20:41:03 greg Exp $";
3 greg 2.1 #endif
4     /*
5     * Create BSDF advection mesh from radial basis functions.
6     *
7     * G. Ward
8     */
9    
10 schorsch 2.37 #if !defined(_WIN32) && !defined(_WIN64)
11 greg 2.1 #include <unistd.h>
12     #include <sys/wait.h>
13     #include <sys/mman.h>
14     #endif
15     #define _USE_MATH_DEFINES
16     #include <stdio.h>
17     #include <stdlib.h>
18     #include <string.h>
19     #include <math.h>
20     #include "bsdfrep.h"
21 greg 2.19
22     #ifndef NEIGH_FACT2
23 greg 2.21 #define NEIGH_FACT2 0.1 /* empirical neighborhood distance weight */
24 greg 2.19 #endif
25 greg 2.1 /* number of processes to run */
26     int nprocs = 1;
27     /* number of children (-1 in child) */
28     static int nchild = 0;
29    
30 greg 2.30 /* Compute average DSF value at the given radius from central vector */
31     static double
32     eval_DSFsurround(const RBFNODE *rbf, const FVECT outvec, const double rad)
33     {
34     const int ninc = 12;
35     const double phinc = 2.*M_PI/ninc;
36     double sum = 0;
37     int n = 0;
38     FVECT tvec;
39     int i;
40     /* compute initial vector */
41     if (output_orient*outvec[2] >= 1.-FTINY) {
42     tvec[0] = tvec[2] = 0;
43     tvec[1] = 1;
44     } else {
45     tvec[0] = tvec[1] = 0;
46     tvec[2] = 1;
47     }
48     geodesic(tvec, outvec, tvec, rad, GEOD_RAD);
49     /* average surrounding DSF */
50     for (i = 0; i < ninc; i++) {
51     if (i) spinvector(tvec, tvec, outvec, phinc);
52     if (tvec[2] > 0 ^ output_orient > 0)
53     continue;
54 greg 2.33 sum += eval_rbfrep(rbf, tvec) * COSF(tvec[2]);
55 greg 2.30 ++n;
56     }
57     if (n < 2) /* should never happen! */
58     return(sum);
59     return(sum/(double)n);
60     }
61    
62     /* Estimate single-lobe radius for DSF at the given outgoing angle */
63     static double
64     est_DSFrad(const RBFNODE *rbf, const FVECT outvec)
65     {
66 greg 2.39 const double rad_epsilon = 0.01;
67 greg 2.33 const double DSFtarget = 0.60653066 * eval_rbfrep(rbf,outvec) *
68     COSF(outvec[2]);
69 greg 2.30 double inside_rad = rad_epsilon;
70     double outside_rad = 0.5;
71     double DSFinside = eval_DSFsurround(rbf, outvec, inside_rad);
72     double DSFoutside = eval_DSFsurround(rbf, outvec, outside_rad);
73     #define interp_rad inside_rad + (outside_rad-inside_rad) * \
74     (DSFtarget-DSFinside) / (DSFoutside-DSFinside)
75 greg 2.32 /* Newton's method (sort of) */
76     do {
77 greg 2.30 double test_rad = interp_rad;
78 greg 2.32 double DSFtest;
79 greg 2.39 if ((test_rad >= outside_rad) | (test_rad <= inside_rad))
80     test_rad = .5*(inside_rad + outside_rad);
81 greg 2.32 DSFtest = eval_DSFsurround(rbf, outvec, test_rad);
82     if (DSFtest > DSFtarget) {
83 greg 2.30 inside_rad = test_rad;
84     DSFinside = DSFtest;
85     } else {
86     outside_rad = test_rad;
87     DSFoutside = DSFtest;
88     }
89 greg 2.32 } while (outside_rad-inside_rad > rad_epsilon);
90 greg 2.39
91     return(.5*(inside_rad + outside_rad));
92 greg 2.30 #undef interp_rad
93     }
94    
95 greg 2.35 static int
96     dbl_cmp(const void *p1, const void *p2)
97     {
98     double d1 = *(const double *)p1;
99     double d2 = *(const double *)p2;
100    
101     if (d1 > d2) return(1);
102     if (d1 < d2) return(-1);
103     return(0);
104     }
105    
106 greg 2.36 /* Conservative estimate of average BSDF value from current DSF's */
107 greg 2.30 static void
108     comp_bsdf_spec(void)
109     {
110 greg 2.35 double vmod_sum = 0;
111 greg 2.30 double rad_sum = 0;
112     int n = 0;
113 greg 2.35 double *cost_list = NULL;
114     double max_cost = 1.;
115 greg 2.30 RBFNODE *rbf;
116     FVECT sdv;
117 greg 2.36 /* sort by incident altitude */
118 greg 2.35 for (rbf = dsf_list; rbf != NULL; rbf = rbf->next)
119     n++;
120     if (n >= 10)
121     cost_list = (double *)malloc(sizeof(double)*n);
122     if (cost_list == NULL) {
123     bsdf_spec_val = 0;
124 greg 2.31 bsdf_spec_rad = 0;
125 greg 2.30 return;
126     }
127 greg 2.35 n = 0;
128     for (rbf = dsf_list; rbf != NULL; rbf = rbf->next)
129     cost_list[n++] = rbf->invec[2]*input_orient;
130     qsort(cost_list, n, sizeof(double), dbl_cmp);
131 greg 2.36 max_cost = cost_list[(n+3)/4]; /* accept 25% nearest grazing */
132 greg 2.35 free(cost_list);
133     n = 0;
134 greg 2.30 for (rbf = dsf_list; rbf != NULL; rbf = rbf->next) {
135 greg 2.35 double this_rad, cosfact, vest;
136     if (rbf->invec[2]*input_orient > max_cost)
137     continue;
138 greg 2.30 sdv[0] = -rbf->invec[0];
139     sdv[1] = -rbf->invec[1];
140     sdv[2] = rbf->invec[2]*(2*(input_orient==output_orient) - 1);
141 greg 2.36 cosfact = COSF(sdv[2]);
142 greg 2.35 this_rad = est_DSFrad(rbf, sdv);
143     vest = eval_rbfrep(rbf, sdv) * cosfact *
144 greg 2.36 (2.*M_PI) * this_rad*this_rad;
145     if (vest > rbf->vtotal) /* don't over-estimate energy */
146 greg 2.35 vest = rbf->vtotal;
147 greg 2.36 vmod_sum += vest / cosfact; /* remove cosine factor */
148 greg 2.35 rad_sum += this_rad;
149 greg 2.30 ++n;
150     }
151 greg 2.31 bsdf_spec_rad = rad_sum/(double)n;
152 greg 2.35 bsdf_spec_val = vmod_sum/(2.*M_PI*n*bsdf_spec_rad*bsdf_spec_rad);
153 greg 2.30 }
154    
155 greg 2.2 /* Create a new migration holder (sharing memory for multiprocessing) */
156     static MIGRATION *
157     new_migration(RBFNODE *from_rbf, RBFNODE *to_rbf)
158     {
159     size_t memlen = sizeof(MIGRATION) +
160     sizeof(float)*(from_rbf->nrbf*to_rbf->nrbf - 1);
161     MIGRATION *newmig;
162 schorsch 2.37 #if defined(_WIN32) || defined(_WIN64)
163 greg 2.2 if (nprocs > 1)
164     fprintf(stderr, "%s: warning - multiprocessing not supported\n",
165     progname);
166     nprocs = 1;
167     newmig = (MIGRATION *)malloc(memlen);
168     #else
169     if (nprocs <= 1) { /* single process? */
170     newmig = (MIGRATION *)malloc(memlen);
171     } else { /* else need to share memory */
172     newmig = (MIGRATION *)mmap(NULL, memlen, PROT_READ|PROT_WRITE,
173     MAP_ANON|MAP_SHARED, -1, 0);
174     if ((void *)newmig == MAP_FAILED)
175     newmig = NULL;
176     }
177     #endif
178     if (newmig == NULL) {
179     fprintf(stderr, "%s: cannot allocate new migration\n", progname);
180     exit(1);
181     }
182     newmig->rbfv[0] = from_rbf;
183     newmig->rbfv[1] = to_rbf;
184     /* insert in edge lists */
185     newmig->enxt[0] = from_rbf->ejl;
186     from_rbf->ejl = newmig;
187     newmig->enxt[1] = to_rbf->ejl;
188     to_rbf->ejl = newmig;
189     newmig->next = mig_list; /* push onto global list */
190     return(mig_list = newmig);
191     }
192    
193 schorsch 2.37 #if defined(_WIN32) || defined(_WIN64)
194 greg 2.2 #define await_children(n) (void)(n)
195     #define run_subprocess() 0
196     #define end_subprocess() (void)0
197     #else
198    
199     /* Wait for the specified number of child processes to complete */
200     static void
201     await_children(int n)
202     {
203     int exit_status = 0;
204    
205     if (n > nchild)
206     n = nchild;
207     while (n-- > 0) {
208     int status;
209     if (wait(&status) < 0) {
210     fprintf(stderr, "%s: missing child(ren)!\n", progname);
211     nchild = 0;
212     break;
213     }
214     --nchild;
215     if (status) { /* something wrong */
216     if ((status = WEXITSTATUS(status)))
217     exit_status = status;
218     else
219     exit_status += !exit_status;
220     fprintf(stderr, "%s: subprocess died\n", progname);
221     n = nchild; /* wait for the rest */
222     }
223     }
224     if (exit_status)
225     exit(exit_status);
226     }
227    
228     /* Start child process if multiprocessing selected */
229     static pid_t
230     run_subprocess(void)
231     {
232     int status;
233     pid_t pid;
234    
235     if (nprocs <= 1) /* any children requested? */
236     return(0);
237     await_children(nchild + 1 - nprocs); /* free up child process */
238     if ((pid = fork())) {
239     if (pid < 0) {
240     fprintf(stderr, "%s: cannot fork subprocess\n",
241     progname);
242 greg 2.6 await_children(nchild);
243 greg 2.2 exit(1);
244     }
245     ++nchild; /* subprocess started */
246     return(pid);
247     }
248     nchild = -1;
249     return(0); /* put child to work */
250     }
251    
252     /* If we are in subprocess, call exit */
253     #define end_subprocess() if (nchild < 0) _exit(0); else
254    
255     #endif /* ! _WIN32 */
256    
257 greg 2.19 /* Compute normalized distribution scattering functions for comparison */
258     static void
259     compute_nDSFs(const RBFNODE *rbf0, const RBFNODE *rbf1)
260     {
261     const double nf0 = (GRIDRES*GRIDRES) / rbf0->vtotal;
262     const double nf1 = (GRIDRES*GRIDRES) / rbf1->vtotal;
263     int x, y;
264     FVECT dv;
265    
266     for (x = GRIDRES; x--; )
267     for (y = GRIDRES; y--; ) {
268 greg 2.20 ovec_from_pos(dv, x, y); /* cube root (brightness) */
269     dsf_grid[x][y].val[0] = pow(nf0*eval_rbfrep(rbf0, dv), .3333);
270     dsf_grid[x][y].val[1] = pow(nf1*eval_rbfrep(rbf1, dv), .3333);
271 greg 2.19 }
272     }
273    
274     /* Compute neighborhood distance-squared (dissimilarity) */
275     static double
276     neighborhood_dist2(int x0, int y0, int x1, int y1)
277     {
278     int rad = GRIDRES>>5;
279     double sum2 = 0.;
280     double d;
281     int p[4];
282     int i, j;
283     /* check radius */
284     p[0] = x0; p[1] = y0; p[2] = x1; p[3] = y1;
285     for (i = 4; i--; ) {
286     if (p[i] < rad) rad = p[i];
287     if (GRIDRES-1-p[i] < rad) rad = GRIDRES-1-p[i];
288     }
289     for (i = -rad; i <= rad; i++)
290     for (j = -rad; j <= rad; j++) {
291     d = dsf_grid[x0+i][y0+j].val[0] -
292     dsf_grid[x1+i][y1+j].val[1];
293     sum2 += d*d;
294     }
295     return(sum2 / (4*rad*(rad+1) + 1));
296     }
297    
298 greg 2.27 /* Compute distance between two RBF lobes */
299     double
300     lobe_distance(RBFVAL *rbf1, RBFVAL *rbf2)
301     {
302     FVECT vfrom, vto;
303     double d, res;
304     /* quadratic cost function */
305     ovec_from_pos(vfrom, rbf1->gx, rbf1->gy);
306     ovec_from_pos(vto, rbf2->gx, rbf2->gy);
307     d = Acos(DOT(vfrom, vto));
308     res = d*d;
309     d = R2ANG(rbf2->crad) - R2ANG(rbf1->crad);
310     res += d*d;
311     /* neighborhood difference */
312     res += NEIGH_FACT2 * neighborhood_dist2( rbf1->gx, rbf1->gy,
313     rbf2->gx, rbf2->gy );
314     return(res);
315 greg 2.1 }
316    
317 greg 2.26
318 greg 2.1 /* Compute and insert migration along directed edge (may fork child) */
319     static MIGRATION *
320     create_migration(RBFNODE *from_rbf, RBFNODE *to_rbf)
321     {
322     MIGRATION *newmig;
323 greg 2.6 int i, j;
324 greg 2.1 /* check if exists already */
325     for (newmig = from_rbf->ejl; newmig != NULL;
326     newmig = nextedge(from_rbf,newmig))
327     if (newmig->rbfv[1] == to_rbf)
328     return(NULL);
329     /* else allocate */
330 greg 2.7 #ifdef DEBUG
331 greg 2.14 fprintf(stderr, "Building path from (theta,phi) (%.1f,%.1f) ",
332 greg 2.7 get_theta180(from_rbf->invec),
333     get_phi360(from_rbf->invec));
334 greg 2.14 fprintf(stderr, "to (%.1f,%.1f) with %d x %d matrix\n",
335 greg 2.7 get_theta180(to_rbf->invec),
336     get_phi360(to_rbf->invec),
337     from_rbf->nrbf, to_rbf->nrbf);
338     #endif
339 greg 2.1 newmig = new_migration(from_rbf, to_rbf);
340     if (run_subprocess())
341     return(newmig); /* child continues */
342 greg 2.27
343     /* compute transport plan */
344     compute_nDSFs(from_rbf, to_rbf);
345     plan_transport(newmig);
346 greg 2.6
347 greg 2.1 for (i = from_rbf->nrbf; i--; ) { /* normalize final matrix */
348 greg 2.6 double nf = rbf_volume(&from_rbf->rbfa[i]);
349 greg 2.1 if (nf <= FTINY) continue;
350     nf = from_rbf->vtotal / nf;
351     for (j = to_rbf->nrbf; j--; )
352 greg 2.6 mtx_coef(newmig,i,j) *= nf; /* row now sums to 1.0 */
353 greg 2.1 }
354     end_subprocess(); /* exit here if subprocess */
355     return(newmig);
356     }
357    
358     /* Check if prospective vertex would create overlapping triangle */
359     static int
360     overlaps_tri(const RBFNODE *bv0, const RBFNODE *bv1, const RBFNODE *pv)
361     {
362     const MIGRATION *ej;
363     RBFNODE *vother[2];
364     int im_rev;
365     /* find shared edge in mesh */
366     for (ej = pv->ejl; ej != NULL; ej = nextedge(pv,ej)) {
367     const RBFNODE *tv = opp_rbf(pv,ej);
368     if (tv == bv0) {
369     im_rev = is_rev_tri(ej->rbfv[0]->invec,
370     ej->rbfv[1]->invec, bv1->invec);
371     break;
372     }
373     if (tv == bv1) {
374     im_rev = is_rev_tri(ej->rbfv[0]->invec,
375     ej->rbfv[1]->invec, bv0->invec);
376     break;
377     }
378     }
379     if (!get_triangles(vother, ej)) /* triangle on same side? */
380     return(0);
381     return(vother[im_rev] != NULL);
382     }
383    
384 greg 2.14 /* Find convex hull vertex to complete triangle (oriented call) */
385 greg 2.1 static RBFNODE *
386     find_chull_vert(const RBFNODE *rbf0, const RBFNODE *rbf1)
387     {
388     FVECT vmid, vejn, vp;
389     RBFNODE *rbf, *rbfbest = NULL;
390     double dprod, area2, bestarea2 = FHUGE, bestdprod = -.5;
391    
392     VSUB(vejn, rbf1->invec, rbf0->invec);
393     VADD(vmid, rbf0->invec, rbf1->invec);
394     if (normalize(vejn) == 0 || normalize(vmid) == 0)
395     return(NULL);
396     /* XXX exhaustive search */
397     /* Find triangle with minimum rotation from perpendicular */
398     for (rbf = dsf_list; rbf != NULL; rbf = rbf->next) {
399     if ((rbf == rbf0) | (rbf == rbf1))
400     continue;
401     tri_orient(vp, rbf0->invec, rbf1->invec, rbf->invec);
402     if (DOT(vp, vmid) <= FTINY)
403     continue; /* wrong orientation */
404     area2 = .25*DOT(vp,vp);
405 greg 2.14 VSUB(vp, rbf->invec, vmid);
406 greg 2.1 dprod = -DOT(vp, vejn);
407     VSUM(vp, vp, vejn, dprod); /* above guarantees non-zero */
408     dprod = DOT(vp, vmid) / VLEN(vp);
409     if (dprod <= bestdprod + FTINY*(1 - 2*(area2 < bestarea2)))
410     continue; /* found better already */
411     if (overlaps_tri(rbf0, rbf1, rbf))
412     continue; /* overlaps another triangle */
413     rbfbest = rbf;
414     bestdprod = dprod; /* new one to beat */
415     bestarea2 = area2;
416     }
417     return(rbfbest);
418     }
419    
420     /* Create new migration edge and grow mesh recursively around it */
421     static void
422     mesh_from_edge(MIGRATION *edge)
423     {
424     MIGRATION *ej0, *ej1;
425     RBFNODE *tvert[2];
426    
427     if (edge == NULL)
428     return;
429     /* triangle on either side? */
430     get_triangles(tvert, edge);
431     if (tvert[0] == NULL) { /* grow mesh on right */
432     tvert[0] = find_chull_vert(edge->rbfv[0], edge->rbfv[1]);
433     if (tvert[0] != NULL) {
434     if (tvert[0]->ord > edge->rbfv[0]->ord)
435     ej0 = create_migration(edge->rbfv[0], tvert[0]);
436     else
437     ej0 = create_migration(tvert[0], edge->rbfv[0]);
438     if (tvert[0]->ord > edge->rbfv[1]->ord)
439     ej1 = create_migration(edge->rbfv[1], tvert[0]);
440     else
441     ej1 = create_migration(tvert[0], edge->rbfv[1]);
442     mesh_from_edge(ej0);
443     mesh_from_edge(ej1);
444 greg 2.28 return;
445 greg 2.1 }
446 greg 2.28 }
447     if (tvert[1] == NULL) { /* grow mesh on left */
448 greg 2.1 tvert[1] = find_chull_vert(edge->rbfv[1], edge->rbfv[0]);
449     if (tvert[1] != NULL) {
450     if (tvert[1]->ord > edge->rbfv[0]->ord)
451     ej0 = create_migration(edge->rbfv[0], tvert[1]);
452     else
453     ej0 = create_migration(tvert[1], edge->rbfv[0]);
454     if (tvert[1]->ord > edge->rbfv[1]->ord)
455     ej1 = create_migration(edge->rbfv[1], tvert[1]);
456     else
457     ej1 = create_migration(tvert[1], edge->rbfv[1]);
458     mesh_from_edge(ej0);
459     mesh_from_edge(ej1);
460     }
461     }
462     }
463 greg 2.15
464     /* Add normal direction if missing */
465     static void
466     check_normal_incidence(void)
467     {
468 greg 2.25 static FVECT norm_vec = {.0, .0, 1.};
469 greg 2.16 const int saved_nprocs = nprocs;
470     RBFNODE *near_rbf, *mir_rbf, *rbf;
471     double bestd;
472     int n;
473 greg 2.15
474     if (dsf_list == NULL)
475     return; /* XXX should be error? */
476     near_rbf = dsf_list;
477     bestd = input_orient*near_rbf->invec[2];
478     if (single_plane_incident) { /* ordered plane incidence? */
479     if (bestd >= 1.-2.*FTINY)
480     return; /* already have normal */
481     } else {
482     switch (inp_coverage) {
483     case INP_QUAD1:
484     case INP_QUAD2:
485     case INP_QUAD3:
486     case INP_QUAD4:
487     break; /* quadrilateral symmetry? */
488     default:
489     return; /* else we can interpolate */
490     }
491 greg 2.38 for (rbf = dsf_list; rbf != NULL; rbf = rbf->next) {
492 greg 2.15 const double d = input_orient*rbf->invec[2];
493     if (d >= 1.-2.*FTINY)
494     return; /* seems we have normal */
495     if (d > bestd) {
496     near_rbf = rbf;
497     bestd = d;
498     }
499     }
500     }
501     if (mig_list != NULL) { /* need to be called first */
502     fprintf(stderr, "%s: Late call to check_normal_incidence()\n",
503     progname);
504     exit(1);
505     }
506     #ifdef DEBUG
507     fprintf(stderr, "Interpolating normal incidence by mirroring (%.1f,%.1f)\n",
508     get_theta180(near_rbf->invec), get_phi360(near_rbf->invec));
509     #endif
510     /* mirror nearest incidence */
511     n = sizeof(RBFNODE) + sizeof(RBFVAL)*(near_rbf->nrbf-1);
512     mir_rbf = (RBFNODE *)malloc(n);
513     if (mir_rbf == NULL)
514     goto memerr;
515     memcpy(mir_rbf, near_rbf, n);
516     mir_rbf->ord = near_rbf->ord - 1; /* not used, I think */
517     mir_rbf->next = NULL;
518 greg 2.22 mir_rbf->ejl = NULL;
519 greg 2.15 rev_rbf_symmetry(mir_rbf, MIRROR_X|MIRROR_Y);
520     nprocs = 1; /* compute migration matrix */
521 greg 2.22 if (create_migration(mir_rbf, near_rbf) == NULL)
522 greg 2.15 exit(1); /* XXX should never happen! */
523 greg 2.25 norm_vec[2] = input_orient; /* interpolate normal dist. */
524 greg 2.29 rbf = e_advect_rbf(mig_list, norm_vec, 0);
525 greg 2.15 nprocs = saved_nprocs; /* final clean-up */
526     free(mir_rbf);
527     free(mig_list);
528     mig_list = near_rbf->ejl = NULL;
529     insert_dsf(rbf); /* insert interpolated normal */
530     return;
531     memerr:
532     fprintf(stderr, "%s: Out of memory in check_normal_incidence()\n",
533     progname);
534     exit(1);
535     }
536 greg 2.1
537     /* Build our triangle mesh from recorded RBFs */
538     void
539     build_mesh(void)
540     {
541     double best2 = M_PI*M_PI;
542     RBFNODE *shrt_edj[2];
543     RBFNODE *rbf0, *rbf1;
544 greg 2.30 /* average specular peak */
545     comp_bsdf_spec();
546 greg 2.15 /* add normal if needed */
547     check_normal_incidence();
548 greg 2.1 /* check if isotropic */
549     if (single_plane_incident) {
550     for (rbf0 = dsf_list; rbf0 != NULL; rbf0 = rbf0->next)
551     if (rbf0->next != NULL)
552     create_migration(rbf0, rbf0->next);
553     await_children(nchild);
554     return;
555     }
556     shrt_edj[0] = shrt_edj[1] = NULL; /* start w/ shortest edge */
557     for (rbf0 = dsf_list; rbf0 != NULL; rbf0 = rbf0->next)
558     for (rbf1 = rbf0->next; rbf1 != NULL; rbf1 = rbf1->next) {
559     double dist2 = 2. - 2.*DOT(rbf0->invec,rbf1->invec);
560     if (dist2 < best2) {
561     shrt_edj[0] = rbf0;
562     shrt_edj[1] = rbf1;
563     best2 = dist2;
564     }
565     }
566     if (shrt_edj[0] == NULL) {
567     fprintf(stderr, "%s: Cannot find shortest edge\n", progname);
568     exit(1);
569     }
570     /* build mesh from this edge */
571     if (shrt_edj[0]->ord < shrt_edj[1]->ord)
572     mesh_from_edge(create_migration(shrt_edj[0], shrt_edj[1]));
573     else
574     mesh_from_edge(create_migration(shrt_edj[1], shrt_edj[0]));
575     /* complete migrations */
576     await_children(nchild);
577     }