1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 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 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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 | /* asprgen.cppname: approximate single-peaked ranking generatorfunction: find ordering of candidates for which most voters are single-peakedinfo: branch and bound algorithm constructing partial axes in nodes, filteringparticipants according to single-peakdness consistency with partial axis,bounding when upper bound of participants less than lower bound found in leafimplementation: Alex Francois NienaberCopyright (c) 2012 University of Toronto. All rights reserved. */#include <cstring>#include <iostream>#include <sstream>#include <fstream>#include <algorithm>using namespace std;/*general functionality global variables*///name of input profile// candidates must be numbered from 1 to total number of candidates.// participants' rankings have to be sequences of (nonzero) integers// seperated by spaces, corresponding to their ordering of the// candidates. each individual profile has to be a total order.string input = "./sushi.data";//number of candidatesint candidates = 10;//number of participantsint participants = 5000;//verbosityint verbose = 0;//cpu time computationint timecheck = 0;//preferencesint** preferences;//best axis so farint* bestAxis = new int[candidates];//consistent prefs so farint* bestPref = new int[participants];//max lower boundint lowerBound = 0;//approximation method// 0 exact single-peakdness// 1 k-local candidate deletion approximate single-peakdnessint approx = 0;//k approximation parameter// k-local candidate deletion imposes: k < candidatesint k = 1;/*satellite functionality global variables*/// instead of tracking the best leaf, it is// possible to modify code at #leaf to track// leaves over a certain threshold//total number of leaves reachedint leaves = 0;//total number of distinct voters in leaves//since there may be overlapping in leavesint totalc = 0;//array to store distinct prefs of leavesstatic int* distinctParticipants = new int[participants];//tree data structure, nodes are distinguished by partial axesclass node{public: //parent node* parent; //children int totalChildren; //number of children int currentChild; //position in children node** children; //array of children ordered by upperBound //preferences int upperBound; //number of preference rankings int* consistentPref; //index of preferences consistent with partial axis //partial axis int* partialAxis; //constructor node(node* p, int ub, int* prefs, int* paxis) { parent = p; totalChildren = 0; currentChild = 0; children = NULL; upperBound = ub; consistentPref = prefs; partialAxis = paxis; } //deconstructor ~node() { delete[] consistentPref; delete[] partialAxis; delete[] children; }};//reversed sort comparator to sort pointer to nodes according to their induced ubbool ubcomp(const node* less, const node* greater){ return less->upperBound > greater->upperBound;}/*note to self: the reason you needed to overload sort with ubcomp instead ofof using regular 2 args sort and overriding bool operator < (const struct, const struct)is because the latter method will not work with pointers to structs but with structs.*///factorial functionint factorial(int n){ if (n > 1) { return n*factorial(n-1); } else { return 1; }}//helper prototypesvoid printUsage();void printPref(int** preferences);void printAxis(int* Axis);void printNode(node* node, int vp);node* lonelyChild(node* parent, int lastc);int fillConsistent(int* childAxis, int* parentArray, int parentSize, int* childArray, int approxMethod);int exactCons(int* childAxis, int* parentArray, int parentSize, int* childArray);int localCandidateCons(int* childAxis, int* parentArray, int parentSize, int* childArray);//find best ordering of candidates for given profileint main(int argc, const char * argv[]){ //parse parameters if(argc>1) { for(int p=1;p<argc;p++) { string param=argv[p]; if(param == "-i") {input=argv[p+1];} else if(param == "-a") {approx=atoi(argv[p+1]);} else if(param == "-c") {candidates=atoi(argv[p+1]);} else if(param == "-k") {k=atoi(argv[p+1]);} else if(param == "-p") {participants=atoi(argv[p+1]);} else if(param == "-v") {verbose=1;} else if(param == "-t") {timecheck=1;} else if(param == "-h") {printUsage(); exit(0);} } } //CPU time initialization clock_t start, end; double cputime; if(timecheck == 1) { start = clock(); } //check zero conditions if(candidates == 0 || participants == 0) { cout<<"error: candidates or participants cannot be zero"<<endl; return -1; } //create an array of individual preference profiles preferences = new int*[participants]; for(int i=0; i<participants; i++) { preferences[i]=new int[candidates]; } //fill the array from input ifstream in; in.open(input.c_str()); if(!in.is_open()) { cout<<"cannot open file"<<endl; return -1;} int temp; for(int i=0; i<participants; i++) { for(int j=0; j<candidates; j++) { in>>temp; preferences[i][j]=temp; } } in.close(); //temporary array to store consistent ids int* tempConsistent = new int[participants]; //create parent node (with all participants) int* parentArray = new int[participants]; for(int i=0; i<participants; i++) { parentArray[i] = i; } int* parentAxis = new int[candidates]; for(int j=0; j<candidates; j++) { parentAxis[j] = 0; } node* parent = new node(NULL, participants, parentArray, parentAxis); //create parents array of children pointers int firstgensize = factorial(candidates)/(2*factorial(candidates-2)); node** parentChildren = new node*[firstgensize]; //create first generation of tree node* child; int ubchild; int childpos = 0; for(int left=1; left<candidates; left++) { for(int right=left+1; right<=candidates; right++) { //create child axis int* axis = new int[candidates]; axis[0] = left; for(int j=1; j<candidates-1; j++) { axis[j] = 0; } axis[candidates-1] = right; //fill temporary array with consistent ids from parent array ubchild = fillConsistent(axis, parentArray, participants, tempConsistent, approx); //copy those ids to child's array int* array = new int[ubchild]; memcpy(array, tempConsistent, ubchild*sizeof(int)); //create the child child = new node(parent, ubchild, array, axis); //add child pointer to parent's array of children parentChildren[childpos] = child; childpos++; } } //sort array of children by upperbound and give it to parent sort(parentChildren, parentChildren+firstgensize, ubcomp); parent->children = parentChildren; parent->totalChildren = firstgensize;// //print first generation #print// for(int k=0; k<firstgensize; k++)// {// printNode(parentChildren[k], 0);// cout<<endl;// }// cout<<endl<<endl<<endl<<endl; //branch and bound algorithm //setup int traversed = 0; int gen, partial, remainingsize, newchildrensize; int remaining[candidates]; node** newchildren; //traverse the tree node* driver = parent; while(!traversed) { //climb down the tree (to the next child) if(driver->currentChild < driver->totalChildren) { driver = driver->children[driver->currentChild]; } //climb up the tree (if no child left) else if(driver->parent != NULL) {\ driver = driver->parent; delete driver->children[driver->currentChild]; driver->currentChild++; continue; } //done traversing the tree else { traversed = 1; //just making a point. break; } //get to a leaf, i.e. build a complete axis partial = 1; while(partial) { if(verbose == 1) { printAxis(driver->partialAxis); } //#print //check bounding condition if(driver->upperBound > lowerBound) //#bounding { //store remaining candidates remainingsize = 0; for(int j=1; j<=candidates; j++) { for(int jj=0; jj<candidates; jj++) { //already placed if(driver->partialAxis[jj] == j) { break; } //not yet placed else if(jj == candidates-1) { remaining[remainingsize] = j; remainingsize++; } } } //check for completion if(remainingsize == 0) { break; } else if(remainingsize == 1) { partial = 0; child = lonelyChild(driver, remaining[0]); newchildren = new node*[1]; newchildren[0] = child; driver->children = newchildren; driver->totalChildren = 1; driver = child; break; } else if(remainingsize == 2) { partial = 0; } //create children array newchildrensize = remainingsize*(remainingsize-1);//p=2 => n!/(n-p)! = n(n-1) newchildren = new node*[newchildrensize]; childpos = 0; //spawn children for(int left=0; left<remainingsize; left++) //#branching { for(int right=0; right<remainingsize; right++) { if(right != left) { //find generation for(int j=1; j<candidates; j++) { if(driver->partialAxis[j] == 0) { gen = j; break; } } //create child axis int* childaxis = new int[candidates]; memcpy(childaxis, driver->partialAxis, candidates*sizeof(int)); childaxis[gen] = remaining[left]; childaxis[candidates-1-gen] = remaining[right]; //fill temporary array with consistent ids from parent array ubchild = fillConsistent(childaxis, driver->consistentPref, driver->upperBound, tempConsistent, approx); //copy those ids to child's array int* childpref = new int[ubchild]; memcpy(childpref, tempConsistent, ubchild*sizeof(int)); //create the child child = new node(driver, ubchild, childpref, childaxis); //add child pointer to parent's array of children newchildren[childpos] = child; childpos++; } } } //sort array of children by upperbound and give it to parent sort(newchildren, newchildren+newchildrensize, ubcomp); driver->children = newchildren; driver->totalChildren = newchildrensize;// //print current driver's offspring #print// for(int k=0; k<newchildrensize; k++)// {// printNode(driver->children[k], 1);// cout<<endl;// } cout<<endl<<endl<<endl<<endl; //climb down the tree (to the best child) driver = driver->children[driver->currentChild]; } else { break; } } //get a new lowerbound #leaf //checking the bounding is useful only in cases with lonely children (odd number of participants) if(partial == 0 && driver->upperBound > lowerBound) { lowerBound = driver->upperBound; memcpy(bestAxis, driver->partialAxis, candidates*sizeof(int)); memcpy(bestPref, driver->consistentPref, driver->upperBound*sizeof(int)); /*the following code can be used to get a rough idea of how many participants can be covered after several iterations*/ //printNode(driver, 1); cout<<endl; //#print //for(int i=0; i<driver->upperBound; i++) { distinctParticipants[bestPref[i]] = 1; } //leaves++; } //climb up the tree (if leaf or bounded node) driver = driver->parent; delete driver->children[driver->currentChild]; driver->currentChild++; } //print results cout<<endl<<"Best ordering of candidates found: "; printAxis(bestAxis); cout<<" "<<lowerBound<<endl; cout<<"Consistent participants "<<lowerBound<<endl; cout<<"prefs "; for(int x=0; x<lowerBound; x++) { cout<<bestPref[x]<<" "; } cout<<endl; /*the following code can be used to get a rough idea of how many participants can be covered after several iterations*/ //cout<<"leaves traversed "<<leaves<<endl; //for(int i=0; i<participants; i++) { if (distinctParticipants[i] == 1) { totalc++; } } //cout<<"total distinct participants "<<totalc<<endl; /*the following code can be used to export all preference rankings excluding the ones consistent with the best axis found to stderr*/// int filterpos = 0;// int filter = bestPref[filterpos];// for(int i=0; i<participants; i++)// {// if(i != filter)// {// for(int j=0; j<candidates; j++)// {// cerr<<preferences[i][j]<<" ";// }// cerr<<endl;// }// else// {// if(filterpos < lowerBound-1)// {// filterpos++;// filter = bestPref[filterpos];// }// }// } //CPU time retrieval if(timecheck == 1) { end = clock(); cputime = ((double)(end - start))/CLOCKS_PER_SEC; cout<<endl<<"Processing time: "<<cputime<<endl; } return 0;}//print usagevoid printUsage(){ cout<<"Usage:"<<endl; cout<<"asprgen -a [arg] -i [arg] -c [arg] -k [arg] -v [arg] -t -h"<<endl; cout<<"-a: approximation"<<endl; cout<<" [0] exact single-peaked consistency (no approximation)"<<endl; cout<<" [1] k-local candidate deletion approximate sp consistency"<<endl; cout<<"-i: input profile"<<endl; cout<<"-c: number of candidates"<<endl; cout<<"-k: k parameter"<<endl; cout<<"-p: number of participants"<<endl; cout<<"-v: verbosity (nodes traversed)"<<endl; cout<<"-t: running time"<<endl; cout<<"-h: help"<<endl;}//print preferencesvoid printPref(int** preferences){ for(int i=0; i<participants; i++) { for(int j=0; j<candidates; j++) { cout<<preferences[i][j]<<" "; } cout<<endl; }}//print axisvoid printAxis(int* Axis){ for(int j=0; j<candidates; j++) { cout<<Axis[j]<<" "; }}//print node infovoid printNode(node* node, int vp){ cout<<"upper bound "<<node->upperBound<<endl<<"partial axis "; printAxis(node->partialAxis); if(vp == 1) { cout<<"consistent prefs "; for(int i=0; i<node->upperBound; i++) { cout<<node->consistentPref[i]<<" "; } cout<<endl; }}//creates a node for a single child and returns pointer to itnode* lonelyChild(node* parent, int lastc){ //setup int tempConsistent[parent->upperBound]; //create child axis int* childaxis = new int[candidates]; memcpy(childaxis, parent->partialAxis, candidates*sizeof(int)); for(int j=0; j<candidates; j++) { if(parent->partialAxis[j] == 0) { childaxis[j] = lastc; break; } } //fill temporary array with consistent ids from parent array //no proof has been given, but commented code below provides the same result //int ublonely = 0; //for(int i=0; i<parent->upperBound; i++) { tempConsistent[ublonely] = parent->consistentPref[i]; ublonely++; } int ublonely = fillConsistent(childaxis, parent->consistentPref, parent->upperBound, tempConsistent, approx); //copy those ids to child's array int* childpref = new int[ublonely]; memcpy(childpref, tempConsistent, ublonely*sizeof(int)); //create the child node* child = new node(parent, ublonely, childpref, childaxis); return child;}//fill childArray with parentArray's ids that are consistent with axis, return num of ids transferredint fillConsistent(int* childAxis, int* parentArray, int parentSize, int* childArray, int approxMethod){ int ubConsistent = 0; //exact single-peaked consistency if(approxMethod == 0) { ubConsistent = exactCons(childAxis, parentArray, parentSize, childArray); } //k-local candidate deletion approximate single-peaked consistency else if(approxMethod == 1) { ubConsistent = localCandidateCons(childAxis, parentArray, parentSize, childArray); } return ubConsistent;}//fill Array with ids exactly single-peaked consistentint exactCons(int* childAxis, int* parentArray, int parentSize, int* childArray){ //setup int left, right, posleft, posright; int pospart, pospref, skip, checkval; int poschild = 0; //loop through parentArray's ids for(int i=0; i<parentSize; i++) { //initialization posleft = 0; posright = candidates-1; left = childAxis[posleft]; right = childAxis[posright]; pospart = parentArray[i]; pospref = candidates-1; skip = 0; //check if lastpref is either left or right or undefined //(posleft <= posright) <=> (posleft < posright) because the last check is bound to be true while(pospref >= 0 && ((left != 0 || right != 0) || posleft <= posright)) { checkval = preferences[pospart][pospref]; //checkval is left if(checkval == left) { posleft++; left = childAxis[posleft]; pospref--; } //checkval is right else if(checkval == right) { posright--; right = childAxis[posright]; pospref--; } //checkval is undefined (left) else if(left == 0) { posleft++; left = childAxis[posleft]; pospref--; } //checkval is undefined (right) else if(right == 0) { posright--; right = childAxis[posright]; pospref--; } //the ranking is not consistent else { skip = 1; break; } } if(skip != 1) { //transfer id to child's array childArray[poschild] = pospart; poschild++; } } return poschild;}//fill Array with ids k-local candidate deletion approximate single-peaked consistentint localCandidateCons(int* childAxis, int* parentArray, int parentSize, int* childArray){ //setup int left, right, posleft, posright; int pospart, pospref, skip, checkval; int poschild = 0; int tempaxis[candidates]; memcpy(tempaxis, childAxis, candidates*sizeof(int)); int count = 0; //loop through parentArray's ids for(int i=0; i<parentSize; i++) { //axis reset if(count != 0) { memcpy(tempaxis, childAxis, candidates*sizeof(int)); count = 0; } //initialization posleft = 0; posright = candidates-1; left = tempaxis[posleft]; right = tempaxis[posright]; pospart = parentArray[i]; pospref = candidates-1; skip = 0; //check if lastpref is either left or right or undefined knowing that the axis can adapt k times while(pospref >= 0 && ((left != 0 || right != 0) || posleft < posright)) { checkval = preferences[pospart][pospref]; //checkval is left if(checkval == left) { posleft++; left = tempaxis[posleft]; pospref--; //skip correction if(left == -1) { posleft++; left = tempaxis[posleft]; } } //checkval is right else if(checkval == right) { posright--; right = tempaxis[posright]; pospref--; //skip correction if(right == -1) { posright--; right = tempaxis[posright]; } } //checkval is unplaced (left) else if(left == 0) { posleft++; left = tempaxis[posleft]; pospref--; //skip correction if(left == -1) { posleft++; left = tempaxis[posleft]; } } //checkval is unplaced (right) else if(right == 0) { posright--; right = tempaxis[posright]; pospref--; //skip correction if(right == -1) { posright--; right = tempaxis[posright]; } } else if(count < k) { //assign a skip value of -1 to the value of checkval if placed on the axis int placed = 0; for(int j=posleft+1; j<posright; j++) { if(tempaxis[j] == checkval) { tempaxis[j] = -1; placed = 1; } } //assign a skip value of -1 to a placeholder of checkval if not placed on the axis if(placed == 0) { for(int j=posleft+1; j<posright; j++) { if(tempaxis[j] == 0) { tempaxis[j] = -1; break; } } } //update count and pospref count++; pospref--; } //the ranking is not consistent else { skip = 1; break; } } if(skip != 1) { //transfer id to child's array childArray[poschild] = pospart; poschild++; } } return poschild;} |