assign.cc 17.9 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
#include <LEDA/graph_alg.h>
#include <LEDA/graphwin.h>
#include <LEDA/dictionary.h>
#include <LEDA/map.h>
#include <LEDA/graph_iterator.h>
#include <iostream.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <sys/time.h>
#include <string.h>

#include "testbed.h"

16 17
#include "phys.h"
topology *topo = NULL;
18
tbgraph PG(1,1);
19 20 21 22 23
/* How can we chop things up? */
#define PARTITION_BY_ANNEALING 0

int nparts = 3;     /* DEFAULTS */
int intercap = 2;
David G Andersen's avatar
David G Andersen committed
24
int *nodecap = NULL;
25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42
int better_heuristic = 0;
int accepts = 0;
int nnodes = 0;
int partition_mechanism;
int on_line = 0;

float sensitivity = .1;

static const int initial_temperature = 100;
static const int temp_prob = 130;

int refreshed = 0;

tbgraph G(1, 1);
node_array<int> bestnodes, absnodes;
float                       bestscore, absbest;

float *interlinks;
43
int *numnodes;
44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70

/*
 * Basic simulated annealing parameters:
 *
 * Make changes proportional to T
 * Accept worse solution with p = e^(change/Temperature*sensitivity)
 *
 */

inline int accept(float change, float temperature)
{
	float p;
	int r;

	if (change == 0) {
		p = 1000 * temperature / temp_prob;
	} else {
		p = expf(change/(temperature*sensitivity)) * 1000;
	}
	r = random() % 1000;
	if (r < p) {
		accepts++;
		return 1;
	}
	return 0;
}

David G Andersen's avatar
David G Andersen committed
71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115
/*
 * score performs two functions at the moment.  First, it actually
 * performs an assignment of the virtual nodes in a switch to
 * physical nodes in that switch.  Then it returns a numeric evaluation
 * of the current mapping.
 *
 * There are several problems it solves:
 *
 *  a)  Assigning generic vnodes to nodes.
 *
 *      This is performed by searching a list of the nodes and assigning
 *      the virtual node to a node with the minimum necessary number
 *      of interfaces.
 *
 *  b)  Assigning delay vnodes to delay nodes:
 *
 *      Since a delay node may support many delay vnodes, this is a
 *      unit weight knapsack problem.  I take the easy out here
 *      by simply assigning the delay vnodes to nodes as they
 *      come along in the list.  This works for finding a feasible
 *      solution, but does not optimize the use of physical nodes.
 *
 *  c)  Scoring
 *
 *      Scoring is handled by:
 *       i)  add 1 for each unassigned node (excess nodes or too many
 *           interfaces
 *      ii)  Add 1 for each link across switches in excess of the
 *           capacity
 *     iii)  Add .1 for each switch used to try to minimize the number
 *           of switches involved
 *      iv)  Add .1 for each unit of bandwidth between switches to try
 *           to minimize interswitch bandwidth consumption
 *
 *
 *  The score function is the big bottleneck of the program right
 *  now.  Unlike the earlier versions in which only changed nodes
 *  were updated, score recomputes the entire solution each time
 *  it's called.  This is very inefficient and should be fixed
 *  by having the scupdate function update only the parts of the
 *  topology which changed.  This needs to be looked at more,
 *  but should probably be delayed until the rest of the features
 *  have been added.
 */

116 117 118 119 120 121
float score()
{

	float sc = 0;

	for (int i = 0; i < nparts; i++) {
David G Andersen's avatar
David G Andersen committed
122
		/* Have we violated bandwidth between switches? */
123 124 125
		if (interlinks[i] > intercap) {
			sc += (interlinks[i]-intercap);
		}
126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169
		/* XXX:  THIS MUST BE OPTIMIZED */
		
		/* Experimental:  Collapse delay nodes together
		 * and handle node fanout restrictions */

		/* Mark all nodes unused */
		for (int j = 0; j < topo->switches[i]->numnodes(); j++) {
			topo->switches[i]->nodes[j].used = 0;
		}
		
		int numdelays = 0;
		int assigned = 0;
		node n;
		forall_nodes(n, G) {
		    if (G[n].partition() == i) {
		        if (G[n].type() == testnode::TYPE_DELAY) {
				numdelays++;
			} else {
			    assigned = 0;
			    /* Assign to an available node */
			    for (int j = 0;
				 j < topo->switches[i]->numnodes();
				 j++) {
				    if (topo->switches[i]->nodes[j].used == 0 && (topo->switches[i]->nodes[j].ints >= G.degree(n))) {
					    topo->switches[i]->nodes[j].used = 1;
					    assigned = 1;
					    break;
				    }
			    }
			    if (!assigned) {
				    sc += 1;
			    }
			}
		    }
		}
		int numn = numnodes[i];

		numn -= numdelays;
		/* Now turn normal nodes into delay nodes as needed */
		/* XXX:  THIS IS NOT OPTIMAL.  We should improve on this
		 * so it uses the right size nodes a bit... but oh well */
		int maxnodes = topo->switches[i]->numnodes();
		int j = 0;
		while (numdelays > 0 && j < maxnodes) {
170
			if (topo->switches[i]->nodes[j].used) { j++; continue; }
171 172 173 174 175 176 177 178 179 180
			numdelays -= topo->switches[i]->nodes[j].ints/2;
			topo->switches[i]->nodes[j].used = 1;
			j++;
		}

		/* Add in the unsatisfied delay nodes */
		if (numdelays > 0) {
			sc += numdelays;
		}

David G Andersen's avatar
David G Andersen committed
181 182 183 184 185 186 187 188 189
		/* Try to minimize the number of switches used */
		/* This is likely NOT an effective way to do it! */
		if (numnodes[i] > 0) {
			sc += .1;
		}
		/* Try to minimize the bandwidth used... also probably
		   not effective */
		if (interlinks[i] > 0) {
			sc += .1 * interlinks[i];
190 191 192 193 194
		}
	}
	return sc;
}

David G Andersen's avatar
David G Andersen committed
195 196 197 198 199 200 201 202 203 204 205 206 207 208
/*
 * This is a completely bogus function.  It's a straight copy of the
 * score() function, but instead of incrementing a score counter,
 * it prints out a list of the constraints which are violated.
 *
 * In the future, this function should return something allowing us
 * to determine if a critical resource (nodes, interfaces, etc.) is
 * violated, or if a non-critical resource (interswitch bandwidth)
 * has been violated, so we can allow the user to proceed with a
 * potentially bad configuration if they so desire.
 *
 * ... and the "coding by copy" junk should be eliminated.  Jeez. :)
 */

209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259
void violated()
{
	for (int i = 0; i < nparts; i++) {
		/* Have we violated bandwidth between switches? */
		if (interlinks[i] > intercap) {
			cout << "violated:  switch " << i << " bandwidth"
			     << endl;
		}
		for (int j = 0; j < topo->switches[i]->numnodes(); j++) {
			topo->switches[i]->nodes[j].used = 0;
		}
		
		int numdelays = 0;
		int assigned = 0;
		int unassigned = 0;
		node n;
		forall_nodes(n, G) {
		    if (G[n].partition() == i) {
		        if (G[n].type() == testnode::TYPE_DELAY) {
				numdelays++;
			} else {
			    /* Assign to an available node */
			    assigned = 0;
			    for (int j = 0;
				 j < topo->switches[i]->numnodes();
				 j++) {
				    if ((topo->switches[i]->nodes[j].used == 0) && (topo->switches[i]->nodes[j].ints >= G.degree(n))) {
					    topo->switches[i]->nodes[j].used = 1;
					    assigned = 1;
					    break;
				    }
			    }
			    if (!assigned) {
				    unassigned++;
			    }
			}
		    }
		}
		if (unassigned > 0) {
			cout << "violated:  switch " << i << " had "
			     << unassigned << " unassigned nodes" << endl;
		}
		int numn = numnodes[i];

		numn -= numdelays;
		/* Now turn normal nodes into delay nodes as needed */
		/* XXX:  THIS IS NOT OPTIMAL.  We should improve on this
		 * so it uses the right size nodes a bit... but oh well */
		int maxnodes = topo->switches[i]->numnodes();
		int j = 0;
		while (numdelays > 0 && j < maxnodes) {
260
			if (topo->switches[i]->nodes[j].used) { j++; continue; }
261 262 263 264 265 266 267 268 269 270 271 272 273 274 275
			numdelays -= topo->switches[i]->nodes[j].ints/2;
			topo->switches[i]->nodes[j].used = 1;
			j++;
		}

		/* Add in the unsatisfied delay nodes */
		if (numdelays > 0) {
			cout << "violated:  switch " << i << " had "
			     << numdelays << " unassigned delay nodes"
			     << endl;
		}
	}
}


David G Andersen's avatar
David G Andersen committed
276 277 278 279 280
/*
 * Reset the interlinks and numnodes arrays to an accurate
 * value.  Requires an inspection of all nodes and edges.
 */

281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301
void screset() {
	edge e;
	node n;
	for (int i = 0; i < nparts; i++) {
		interlinks[i] = numnodes[i] = 0;
	}
    
	forall_nodes(n, G) {
		numnodes[G[n].partition()]++;
	}
	forall_edges(e, G) {
		node v = G.source(e);
		node w = G.target(e);
	
		if (G[v].partition() != G[w].partition()) {
			interlinks[G[v].partition()]++;
			interlinks[G[w].partition()]++;
		}
	}
}

David G Andersen's avatar
David G Andersen committed
302 303 304 305 306 307 308 309 310 311 312
/*
 * Move a node 'n' from its current switch to a new one, indicated by
 * newpos.
 *
 * Right now, this function performs the update logic to change the
 * node counts and the interswitch bandwidth, but does not cope
 * with the rest of the score.  In the future, it should perform
 * the incremental score update.  See the comments for the score()
 * function for more details.
 */

313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354
void scupdate(node n, int newpos)
{
	int prevpos;

	AdjIt it(G, n);
	prevpos = G[n].partition();
	if (newpos == prevpos) return;

	numnodes[prevpos]--;
	numnodes[newpos]++;

	while (it.eol() == false) {
		edge e = it.get_edge();
		node n1 = G.source(e);
		node n2 = G.target(e);
		/* Ensure that n2 points to the stationary node */
		if (n2 == n) n2 = n1;

		/* They were not in the same bucket to start with */
		/* So both contributed to their interlinks */
		if (G[n2].partition() != prevpos) {
			interlinks[prevpos]--;

			/* If they're together now, there's no interlink */
			if (G[n2].partition() == newpos) {
				interlinks[G[n2].partition()]--;
			} else { /* Otherwise, move the interlink */
				interlinks[newpos]++;
			}
		}
		else /* They were in the same bucket.  They aren't anymore,
		      * or we would have exited earlier */
		{
			interlinks[G[n2].partition()]++;
			interlinks[newpos]++;
		}
		++it;
	}

	G[n].partition(newpos);
}

David G Andersen's avatar
David G Andersen committed
355 356 357 358 359 360 361 362 363 364 365 366 367 368
/*
 * The workhorse of our program.
 *
 * Assign performs an assignment of the virtual nodes (vnodes) to
 * nodes in the physical topology.
 *
 * The input virtual topology is the graph G (global)
 * the input physical topology is the topology topo (global).
 *
 * The simulated annealing logic is contained herein,
 * except for the "accept a bad change" computation,
 * which is performed in accept().
 */

369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463
int assign()
{
	float newscore, bestscore, absbest;
	node n;
	int iters = 0;

	float timestart = used_time();
	float timeend;
	float scorediff;

	nnodes = G.number_of_nodes();
 
	float cycles = 120.0*(float)(nnodes + G.number_of_edges());

	int mintrans = (int)cycles;
	int trans;
	int naccepts = 40*nnodes;
	int accepts = 0;
	int oldpos;

	float temp = initial_temperature;
  
	/* Set up the initial counts */
	screset();

	bestscore = score();
	absbest = bestscore;

	if (bestscore == 0) {
#ifdef VERBOSE
		cout << "Problem started optimal\n";
#endif
		return 1;
	}
  
	while (temp >= 2) {
#ifdef VERBOSE
		cout << "Temperature:  " << temp << endl;
#endif
		trans = 0;
		accepts = 0;
      
		while (trans < mintrans && accepts < naccepts) {
			int newpos;
			trans++;
			iters++;
			n = G.choose_node();
			oldpos = G[n].partition();

			newpos = oldpos;
			/* XXX:  Room for improvement. :-) */
			while (newpos == oldpos)
				newpos = random() % nparts;
			scupdate(n, newpos);
			newscore = score();
			if (newscore < 0.1f) {
				timeend = used_time(timestart);
				cout << "OPTIMAL (0.0) in "
				     << iters << " iters, "
				     << timeend << " seconds" << endl;
				return 1;
			}
			/* So it's negative if bad */
			scorediff = bestscore - newscore;

			if (newscore < bestscore || accept(scorediff, temp)) {
				bestnodes[n] = G[n].partition();
				bestscore = newscore;
				accepts++;
				if (newscore < absbest) {
					node n2;
					forall_nodes(n2, G) {
						absnodes[n2] = G[n2].partition();
					}
					absbest = newscore;
				}
			} else { /* Reject this change */
				scupdate(n, oldpos);
			}
		}
      
		temp *= .9;
	}
	forall_nodes(n, G) {
		bestnodes[n] = absnodes[n];
	}
	bestscore = absbest;

	forall_nodes(n, G) {
		G[n].partition(absnodes[n]);
	}
	timeend = used_time(timestart);
	cout << "   BEST SCORE:  " << score() << " in "
	     << iters << " iters and " << timeend << " seconds" << endl;
	cout << "With " << accepts << " accepts of increases\n";
464
#if 0
465
	for (int i = 0; i < nparts; i++) {
David G Andersen's avatar
David G Andersen committed
466
		if (numnodes[i] > nodecap[i]) {
467 468 469 470 471 472 473 474 475 476 477 478 479
			cout << "node " << i << " has "
			     << numnodes[i] << " nodes" << endl;
		}
		if (interlinks[i] > intercap) {
			cout << "node " << i << " has "
			     << interlinks[i] << " links" << endl;
		}
	}
	if (score() < 0.0001) {
		return 1; /* Optimal enough */
	} else {
		return 0;
	}
480 481
#endif
	return 0;
482 483
}

David G Andersen's avatar
David G Andersen committed
484 485 486 487 488 489 490 491
/*
 * A legacy function from a less general version of the program.
 *
 * Now simply resets the node assignment, performs a new assignment,
 * and prints out the results.
 *
 */

492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507
void loopassign()
{
	node_array<int> nodestorage;
	int optimal = 0;
	int orig_nparts;
	int orig_cap;
	float timestart = used_time();
	float totaltime;

	nodestorage.init(G, 0);
	bestnodes.init(G, 0);
	absnodes.init(G, 0);
    
	nnodes = G.number_of_nodes();
	optimal = assign();
	totaltime = used_time(timestart);
508
	violated();
509 510
	cout << "Total time to find solution "
	     << totaltime << " seconds" << endl;
511
	node n;
512 513
}

David G Andersen's avatar
David G Andersen committed
514 515 516 517 518
/*
 * If we have more ways of partitioning the graph other than just
 * simulated annealing, throw them in here.
 */

519 520 521 522 523 524 525 526 527 528 529 530 531 532 533
void chopgraph(GraphWin& gw) {
	node n;
	forall_nodes(n, G) {
		G[n].partition(0);
	}
	switch(partition_mechanism) {
	case PARTITION_BY_ANNEALING:
		loopassign();
		break;
	default:
		cerr << "Unknown partition mechanism.  eeeek." << endl;
		exit(-1);
	}
}

David G Andersen's avatar
David G Andersen committed
534 535 536 537 538 539 540 541
/*
 * Something in the graph has changed!  Better redisplay.
 *
 * Performs the color assignment for whichever switch the
 * node belongs to and shows the inter-switch links as
 * dashed lines.
 */

542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610
void display_scc(GraphWin& gw)
{
	edge e;
	node n;
	
	if (!refreshed) {
		forall_nodes(n, G) {
			G[n].partition(0);
		}
		if (on_line)
			chopgraph(gw);
	}
	
	refreshed = 0;
	
	/* Now color them according to their partition */
	forall_nodes(n, G) {
		switch(G[n].partition()) {
		case 0:
			gw.set_color(n, black);
			break;
		case 1:
			gw.set_color(n, blue);
			break;
		case 2:
			gw.set_color(n, green);
			break;
		case 3:
			gw.set_color(n, red);
			break;
		case 4:
			gw.set_color(n, yellow);
			break;
		case 5:
			gw.set_color(n, violet);
			break;
		case 6:
			gw.set_color(n, cyan);
			break;
		case 7:
			gw.set_color(n, brown);
			break;
		case 8:
			gw.set_color(n, pink);
			break;
		case 9:
			gw.set_color(n, orange);
			break;
		case 10:
			gw.set_color(n, grey1);
			break;
		case 11:
			gw.set_color(n, grey3);
			break;
		}
	}
	
	forall_edges(e, G) {
		node v = G.source(e);
		node w = G.target(e);
		if (G[v].partition() == G[w].partition()) {
			gw.set_style(e, solid_edge);
		} else {
			gw.set_style(e, dashed_edge);
		}
	}
	gw.redraw();
}

David G Andersen's avatar
David G Andersen committed
611 612 613 614 615
/*
 * Someone clicked on the "reassign" button.
 * Reset and redisplay.
 */

616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636
void reassign(GraphWin& gw)
{
	node n;
	forall_nodes(n, G) {
		G[n].partition(0);
	}
	bestnodes.init(G, 0);
	absnodes.init(G, 0);
	chopgraph(gw);
	refreshed = 1;
	display_scc(gw);
}


void new_edge_handler(GraphWin& gw, edge)  { display_scc(gw); }
void del_edge_handler(GraphWin& gw)        { display_scc(gw); }
void new_node_handler(GraphWin& gw, node)  { display_scc(gw); }
void del_node_handler(GraphWin& gw)        { display_scc(gw); }

void usage() {
	fprintf(stderr,
637
		"usage:  assign [-h] [-ao] [-s <switches>] [-n nodes/switch] [-c cap] [file]\n"
638 639 640 641 642 643 644
		"           -h ...... brief help listing\n"
		"           -s #  ... number of switches in cluster\n"
		"           -n #  ... number of nodes per switch\n"
		"           -c #  ... inter-switch capacity (bw)\n"
		"                 (# of links which can go between switches\n"
		"           -a ...... Use simulated annealing (default)\n"
		"           -o ...... Update on-line (vs batch, default)\n"
645
		"           -t <file> Input topology desc. from <file>\n"
646 647 648 649 650 651 652 653
		);
}

int main(int argc, char **argv)
{
	int h_menu;
	extern char *optarg;
	extern int optind;
654
	char *topofile = NULL;
655 656 657 658 659
    
	int ch;

	partition_mechanism = PARTITION_BY_ANNEALING;
    
660
	while ((ch = getopt(argc, argv, "oas:n:c:t:h")) != -1)
661 662 663 664 665 666
		switch(ch) {
		case 'h': usage(); exit(0);
		case 's': nparts = atoi(optarg); break;
		case 'c': intercap = atoi(optarg); break;
		case 'a': partition_mechanism = PARTITION_BY_ANNEALING; break;
		case 'o': on_line = 1; break;
667
		case 't': topofile = optarg; break;
668 669 670 671 672 673 674
		default: usage(); exit(-1);
		}

	argc -= optind;
	argv += optind;
    
	interlinks = new float[nparts];
675
	numnodes = new int[nparts];
676 677 678 679 680 681
	for (int i = 0; i < nparts; i++) {
		interlinks[i] = 0;
		numnodes[i] = 0;
	}
    
	srandom(time(NULL) + getpid());
David G Andersen's avatar
David G Andersen committed
682 683 684 685 686 687 688

	/*
	 * Set up the LEDA graph window environment.  Whenever
	 * the user does anything to the graph, call the
	 * proper handler.
	 */
	
689 690 691 692 693 694 695 696 697 698 699
	GraphWin gw(G, "Flux Testbed:  Simulated Annealing");
    
	gw.set_init_graph_handler(del_edge_handler);
	gw.set_new_edge_handler(new_edge_handler);
	gw.set_del_edge_handler(del_edge_handler);
	gw.set_new_node_handler(new_node_handler);
	gw.set_del_node_handler(del_node_handler);
    
	gw.set_node_width(24);
	gw.set_node_height(24);
    
David G Andersen's avatar
David G Andersen committed
700 701 702 703
	/*
	 * Allow the user to specify a topology in ".top" format.
	 */

704 705 706
	if (argc == 1) {
		ifstream infile;
		infile.open(argv[0]);
707
		if (!infile || !infile.good()) {
708 709
		  cerr << "Error opening file: " << argv[0] << endl;
		  exit(-11);
710
		}
711 712 713 714
		parse_top(G, infile);
		gw.update_graph();
		node n;
		forall_nodes(n, G) {
David G Andersen's avatar
David G Andersen committed
715 716 717
			if (G[n].name() == NULL) {
				G[n].name("");
			}
718 719 720 721 722
			gw.set_label(n, G[n].name());
			gw.set_position(n,
					point(random() % 200, random() % 200));
		}
	}
723

David G Andersen's avatar
David G Andersen committed
724 725 726 727 728 729
	/*
	 * Allow the user to specify a physical topology
	 * in .phys format.  Fills in the "topo" global variable.
	 * Make no mistake:  This is actually mandatory now.
	 */
	
730
	if (topofile != NULL) {
731 732 733 734 735 736 737 738 739
		cout << "Parsing ptop\n";
		ifstream ptopfile;
		ptopfile.open(topofile);
		if (!ptopfile || !ptopfile.good()) {
		  cerr << "Error opening file: " << topofile << endl;
		  exit(-1);
		}
		parse_ptop(PG,ptopfile);
		topo=ptop_to_phys(PG);
740
		if (!topo) {
741
			cerr << "Could not convert ptop to phys: "
742 743 744 745
			     << topofile << endl;
			exit(-1);
		}
		nparts = topo->switchcount;
David G Andersen's avatar
David G Andersen committed
746 747 748 749 750
		cout << "Nparts: " << nparts << endl;
		nodecap = new int[nparts];
		for (int i = 0; i < nparts; i++) {
			nodecap[i] = topo->switches[i]->numnodes();
		}
751
		topo->print_topo();
752
	}
753 754 755 756 757 758 759 760 761 762
    
	gw.display();
    
	gw.set_directed(false);
    
	gw.set_node_shape(circle_node);
	gw.set_node_label_type(user_label);
    
	h_menu = gw.get_menu("Layout");
	gw_add_simple_call(gw, reassign, "Reassign", h_menu);
David G Andersen's avatar
David G Andersen committed
763 764 765 766

	/* Run until the user quits.  Everything is handled by callbacks
	 * from LEDA's event loop from here on.                           */
	
767 768 769 770
	gw.edit();
    
	return 0;
}