ginac/expairseq.cpp

   1 /** @file expairseq.cpp
   2  *
   3  *  Implementation of sequences of expression pairs. */
   4
   5 /*
   6  *  GiNaC Copyright (C) 1999-2006 Johannes Gutenberg University Mainz, Germany
   7  *
   8  *  This program is free software; you can redistribute it and/or modify
   9  *  it under the terms of the GNU General Public License as published by
  10  *  the Free Software Foundation; either version 2 of the License, or
  11  *  (at your option) any later version.
  12  *
  13  *  This program is distributed in the hope that it will be useful,
  14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *  GNU General Public License for more details.
  17  *
  18  *  You should have received a copy of the GNU General Public License
  19  *  along with this program; if not, write to the Free Software
  20  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  21  */
  22
  23 #include <iostream>
  24 #include <algorithm>
  25 #include <string>
  26 #include <stdexcept>
  27
  28 #include "expairseq.h"
  29 #include "lst.h"
  30 #include "add.h"
  31 #include "mul.h"
  32 #include "power.h"
  33 #include "relational.h"
  34 #include "wildcard.h"
  35 #include "archive.h"
  36 #include "operators.h"
  37 #include "utils.h"
  38 #include "indexed.h"
  39
  40 #if EXPAIRSEQ_USE_HASHTAB
  41 #include <cmath>
  42 #endif // EXPAIRSEQ_USE_HASHTAB
  43
  44 namespace GiNaC {
  45
  46
  47 GINAC_IMPLEMENT_REGISTERED_CLASS_OPT(expairseq, basic,
  48   print_func<print_context>(&expairseq::do_print).
  49   print_func<print_tree>(&expairseq::do_print_tree))
  50
  51
  52 //////////
  53 // helper classes
  54 //////////
  55
  56 class epp_is_less
  57 {
  58 public:
  59         bool operator()(const epp &lh, const epp &rh) const
  60         {
  61                 return (*lh).is_less(*rh);
  62         }
  63 };
  64
  65 //////////
  66 // default constructor
  67 //////////
  68
  69 // public
  70
  71 expairseq::expairseq() : inherited(&expairseq::tinfo_static)
  72 #if EXPAIRSEQ_USE_HASHTAB
  73                                                    , hashtabsize(0)
  74 #endif // EXPAIRSEQ_USE_HASHTAB
  75 {}
  76
  77 // protected
  78
  79 #if 0
  80 /** For use by copy ctor and assignment operator. */
  81 void expairseq::copy(const expairseq &other)
  82 {
  83         seq = other.seq;
  84         overall_coeff = other.overall_coeff;
  85 #if EXPAIRSEQ_USE_HASHTAB
  86         // copy hashtab
  87         hashtabsize = other.hashtabsize;
  88         if (hashtabsize!=0) {
  89                 hashmask = other.hashmask;
  90                 hashtab.resize(hashtabsize);
  91                 epvector::const_iterator osb = other.seq.begin();
  92                 for (unsigned i=0; i<hashtabsize; ++i) {
  93                         hashtab[i].clear();
  94                         for (epplist::const_iterator cit=other.hashtab[i].begin();
  95                              cit!=other.hashtab[i].end(); ++cit) {
  96                                 hashtab[i].push_back(seq.begin()+((*cit)-osb));
  97                         }
  98                 }
  99         } else {
 100                 hashtab.clear();
 101         }
 102 #endif // EXPAIRSEQ_USE_HASHTAB
 103 }
 104 #endif
 105
 106 //////////
 107 // other constructors
 108 //////////
 109
 110 expairseq::expairseq(const ex &lh, const ex &rh) : inherited(&expairseq::tinfo_static)
 111 {
 112         construct_from_2_ex(lh,rh);
 113         GINAC_ASSERT(is_canonical());
 114 }
 115
 116 expairseq::expairseq(const exvector &v) : inherited(&expairseq::tinfo_static)
 117 {
 118         construct_from_exvector(v);
 119         GINAC_ASSERT(is_canonical());
 120 }
 121
 122 expairseq::expairseq(const epvector &v, const ex &oc, bool do_index_renaming)
 123   : inherited(&expairseq::tinfo_static), overall_coeff(oc)
 124 {
 125         GINAC_ASSERT(is_a<numeric>(oc));
 126         construct_from_epvector(v, do_index_renaming);
 127         GINAC_ASSERT(is_canonical());
 128 }
 129
 130 expairseq::expairseq(std::auto_ptr<epvector> vp, const ex &oc, bool do_index_renaming)
 131   : inherited(&expairseq::tinfo_static), overall_coeff(oc)
 132 {
 133         GINAC_ASSERT(vp.get()!=0);
 134         GINAC_ASSERT(is_a<numeric>(oc));
 135         construct_from_epvector(*vp, do_index_renaming);
 136         GINAC_ASSERT(is_canonical());
 137 }
 138
 139 //////////
 140 // archiving
 141 //////////
 142
 143 expairseq::expairseq(const archive_node &n, lst &sym_lst) : inherited(n, sym_lst)
 144 #if EXPAIRSEQ_USE_HASHTAB
 145         , hashtabsize(0)
 146 #endif
 147 {
 148         for (unsigned int i=0; true; i++) {
 149                 ex rest;
 150                 ex coeff;
 151                 if (n.find_ex("rest", rest, sym_lst, i) && n.find_ex("coeff", coeff, sym_lst, i))
 152                         seq.push_back(expair(rest, coeff));
 153                 else
 154                         break;
 155         }
 156
 157         n.find_ex("overall_coeff", overall_coeff, sym_lst);
 158
 159         canonicalize();
 160         GINAC_ASSERT(is_canonical());
 161 }
 162
 163 void expairseq::archive(archive_node &n) const
 164 {
 165         inherited::archive(n);
 166         epvector::const_iterator i = seq.begin(), iend = seq.end();
 167         while (i != iend) {
 168                 n.add_ex("rest", i->rest);
 169                 n.add_ex("coeff", i->coeff);
 170                 ++i;
 171         }
 172         n.add_ex("overall_coeff", overall_coeff);
 173 }
 174
 175 DEFAULT_UNARCHIVE(expairseq)
 176
 177 //////////
 178 // functions overriding virtual functions from base classes
 179 //////////
 180
 181 // public
 182
 183 void expairseq::do_print(const print_context & c, unsigned level) const
 184 {
 185         c.s << "[[";
 186         printseq(c, ',', precedence(), level);
 187         c.s << "]]";
 188 }
 189
 190 void expairseq::do_print_tree(const print_tree & c, unsigned level) const
 191 {
 192         c.s << std::string(level, ' ') << class_name() << " @" << this
 193             << std::hex << ", hash=0x" << hashvalue << ", flags=0x" << flags << std::dec
 194             << ", nops=" << nops()
 195             << std::endl;
 196         size_t num = seq.size();
 197         for (size_t i=0; i<num; ++i) {
 198                 seq[i].rest.print(c, level + c.delta_indent);
 199                 seq[i].coeff.print(c, level + c.delta_indent);
 200                 if (i != num - 1)
 201                         c.s << std::string(level + c.delta_indent, ' ') << "-----" << std::endl;
 202         }
 203         if (!overall_coeff.is_equal(default_overall_coeff())) {
 204                 c.s << std::string(level + c.delta_indent, ' ') << "-----" << std::endl
 205                     << std::string(level + c.delta_indent, ' ') << "overall_coeff" << std::endl;
 206                 overall_coeff.print(c, level + c.delta_indent);
 207         }
 208         c.s << std::string(level + c.delta_indent,' ') << "=====" << std::endl;
 209 #if EXPAIRSEQ_USE_HASHTAB
 210         c.s << std::string(level + c.delta_indent,' ')
 211             << "hashtab size " << hashtabsize << std::endl;
 212         if (hashtabsize == 0) return;
 213 #define MAXCOUNT 5
 214         unsigned count[MAXCOUNT+1];
 215         for (int i=0; i<MAXCOUNT+1; ++i)
 216                 count[i] = 0;
 217         unsigned this_bin_fill;
 218         unsigned cum_fill_sq = 0;
 219         unsigned cum_fill = 0;
 220         for (unsigned i=0; i<hashtabsize; ++i) {
 221                 this_bin_fill = 0;
 222                 if (hashtab[i].size() > 0) {
 223                         c.s << std::string(level + c.delta_indent, ' ')
 224                             << "bin " << i << " with entries ";
 225                         for (epplist::const_iterator it=hashtab[i].begin();
 226                              it!=hashtab[i].end(); ++it) {
 227                                 c.s << *it-seq.begin() << " ";
 228                                 ++this_bin_fill;
 229                         }
 230                         c.s << std::endl;
 231                         cum_fill += this_bin_fill;
 232                         cum_fill_sq += this_bin_fill*this_bin_fill;
 233                 }
 234                 if (this_bin_fill<MAXCOUNT)
 235                         ++count[this_bin_fill];
 236                 else
 237                         ++count[MAXCOUNT];
 238         }
 239         unsigned fact = 1;
 240         double cum_prob = 0;
 241         double lambda = (1.0*seq.size()) / hashtabsize;
 242         for (int k=0; k<MAXCOUNT; ++k) {
 243                 if (k>0)
 244                         fact *= k;
 245                 double prob = std::pow(lambda,k)/fact * std::exp(-lambda);
 246                 cum_prob += prob;
 247                 c.s << std::string(level + c.delta_indent, ' ') << "bins with " << k << " entries: "
 248                     << int(1000.0*count[k]/hashtabsize)/10.0 << "% (expected: "
 249                     << int(prob*1000)/10.0 << ")" << std::endl;
 250         }
 251         c.s << std::string(level + c.delta_indent, ' ') << "bins with more entries: "
 252             << int(1000.0*count[MAXCOUNT]/hashtabsize)/10.0 << "% (expected: "
 253             << int((1-cum_prob)*1000)/10.0 << ")" << std::endl;
 254
 255         c.s << std::string(level + c.delta_indent, ' ') << "variance: "
 256             << 1.0/hashtabsize*cum_fill_sq-(1.0/hashtabsize*cum_fill)*(1.0/hashtabsize*cum_fill)
 257             << std::endl;
 258         c.s << std::string(level + c.delta_indent, ' ') << "average fill: "
 259             << (1.0*cum_fill)/hashtabsize
 260             << " (should be equal to " << (1.0*seq.size())/hashtabsize << ")" << std::endl;
 261 #endif // EXPAIRSEQ_USE_HASHTAB
 262 }
 263
 264 bool expairseq::info(unsigned inf) const
 265 {
 266         return inherited::info(inf);
 267 }
 268
 269 size_t expairseq::nops() const
 270 {
 271         if (overall_coeff.is_equal(default_overall_coeff()))
 272                 return seq.size();
 273         else
 274                 return seq.size()+1;
 275 }
 276
 277 ex expairseq::op(size_t i) const
 278 {
 279         if (i < seq.size())
 280                 return recombine_pair_to_ex(seq[i]);
 281         GINAC_ASSERT(!overall_coeff.is_equal(default_overall_coeff()));
 282         return overall_coeff;
 283 }
 284
 285 ex expairseq::map(map_function &f) const
 286 {
 287         std::auto_ptr<epvector> v(new epvector);
 288         v->reserve(seq.size());
 289
 290         epvector::const_iterator cit = seq.begin(), last = seq.end();
 291         while (cit != last) {
 292                 v->push_back(split_ex_to_pair(f(recombine_pair_to_ex(*cit))));
 293                 ++cit;
 294         }
 295
 296         if (overall_coeff.is_equal(default_overall_coeff()))
 297                 return thisexpairseq(v, default_overall_coeff(), true);
 298         else
 299                 return thisexpairseq(v, f(overall_coeff), true);
 300 }
 301
 302 /** Perform coefficient-wise automatic term rewriting rules in this class. */
 303 ex expairseq::eval(int level) const
 304 {
 305         if ((level==1) && (flags &status_flags::evaluated))
 306                 return *this;
 307
 308         std::auto_ptr<epvector> vp = evalchildren(level);
 309         if (vp.get() == 0)
 310                 return this->hold();
 311
 312         return (new expairseq(vp, overall_coeff))->setflag(status_flags::dynallocated | status_flags::evaluated);
 313 }
 314
 315 epvector* conjugateepvector(const epvector&epv)
 316 {
 317         epvector *newepv = 0;
 318         for (epvector::const_iterator i=epv.begin(); i!=epv.end(); ++i) {
 319                 if(newepv) {
 320                         newepv->push_back(i->conjugate());
 321                         continue;
 322                 }
 323                 expair x = i->conjugate();
 324                 if (x.is_equal(*i)) {
 325                         continue;
 326                 }
 327                 newepv = new epvector;
 328                 newepv->reserve(epv.size());
 329                 for (epvector::const_iterator j=epv.begin(); j!=i; ++j) {
 330                         newepv->push_back(*j);
 331                 }
 332                 newepv->push_back(x);
 333         }
 334         return newepv;
 335 }
 336
 337 ex expairseq::conjugate() const
 338 {
 339         epvector* newepv = conjugateepvector(seq);
 340         ex x = overall_coeff.conjugate();
 341         if (!newepv && are_ex_trivially_equal(x, overall_coeff)) {
 342                 return *this;
 343         }
 344         ex result = thisexpairseq(newepv ? *newepv : seq, x);
 345         if (newepv) {
 346                 delete newepv;
 347         }
 348         return result;
 349 }
 350
 351 bool expairseq::is_polynomial(const ex & var) const
 352 {
 353         if (!is_exactly_a<add>(*this) && !is_exactly_a<mul>(*this))
 354                 return basic::is_polynomial(var);
 355         for (epvector::const_iterator i=seq.begin(); i!=seq.end(); ++i) {
 356                 if (!(i->rest).is_polynomial(var))
 357                         return false;
 358         }
 359         return true;
 360 }
 361
 362 bool expairseq::match(const ex & pattern, lst & repl_lst) const
 363 {
 364         // This differs from basic::match() because we want "a+b+c+d" to
 365         // match "d+*+b" with "*" being "a+c", and we want to honor commutativity
 366
 367         if (this->tinfo() == ex_to<basic>(pattern).tinfo()) {
 368
 369                 // Check whether global wildcard (one that matches the "rest of the
 370                 // expression", like "*" above) is present
 371                 bool has_global_wildcard = false;
 372                 ex global_wildcard;
 373                 for (size_t i=0; i<pattern.nops(); i++) {
 374                         if (is_exactly_a<wildcard>(pattern.op(i))) {
 375                                 has_global_wildcard = true;
 376                                 global_wildcard = pattern.op(i);
 377                                 break;
 378                         }
 379                 }
 380
 381                 // Unfortunately, this is an O(N^2) operation because we can't
 382                 // sort the pattern in a useful way...
 383
 384                 // Chop into terms
 385                 exvector ops;
 386                 ops.reserve(nops());
 387                 for (size_t i=0; i<nops(); i++)
 388                         ops.push_back(op(i));
 389
 390                 // Now, for every term of the pattern, look for a matching term in
 391                 // the expression and remove the match
 392                 for (size_t i=0; i<pattern.nops(); i++) {
 393                         ex p = pattern.op(i);
 394                         if (has_global_wildcard && p.is_equal(global_wildcard))
 395                                 continue;
 396                         exvector::iterator it = ops.begin(), itend = ops.end();
 397                         while (it != itend) {
 398                                 lst::const_iterator last_el = repl_lst.end();
 399                                 --last_el;
 400                                 if (it->match(p, repl_lst)) {
 401                                         ops.erase(it);
 402                                         goto found;
 403                                 }
 404                                 while(true) {
 405                                         lst::const_iterator next_el = last_el;
 406                                         ++next_el;
 407                                         if(next_el == repl_lst.end())
 408                                                 break;
 409                                         else
 410                                                 repl_lst.remove_last();
 411                                 }
 412                                 ++it;
 413                         }
 414                         return false; // no match found
 415 found:          ;
 416                 }
 417
 418                 if (has_global_wildcard) {
 419
 420                         // Assign all the remaining terms to the global wildcard (unless
 421                         // it has already been matched before, in which case the matches
 422                         // must be equal)
 423                         size_t num = ops.size();
 424                         std::auto_ptr<epvector> vp(new epvector);
 425                         vp->reserve(num);
 426                         for (size_t i=0; i<num; i++)
 427                                 vp->push_back(split_ex_to_pair(ops[i]));
 428                         ex rest = thisexpairseq(vp, default_overall_coeff());
 429                         for (lst::const_iterator it = repl_lst.begin(); it != repl_lst.end(); ++it) {
 430                                 if (it->op(0).is_equal(global_wildcard))
 431                                         return rest.is_equal(it->op(1));
 432                         }
 433                         repl_lst.append(global_wildcard == rest);
 434                         return true;
 435
 436                 } else {
 437
 438                         // No global wildcard, then the match fails if there are any
 439                         // unmatched terms left
 440                         return ops.empty();
 441                 }
 442         }
 443         return inherited::match(pattern, repl_lst);
 444 }
 445
 446 ex expairseq::subs(const exmap & m, unsigned options) const
 447 {
 448         std::auto_ptr<epvector> vp = subschildren(m, options);
 449         if (vp.get())
 450                 return ex_to<basic>(thisexpairseq(vp, overall_coeff, true));
 451         else if ((options & subs_options::algebraic) && is_exactly_a<mul>(*this))
 452                 return static_cast<const mul *>(this)->algebraic_subs_mul(m, options);
 453         else
 454                 return subs_one_level(m, options);
 455 }
 456
 457 // protected
 458
 459 int expairseq::compare_same_type(const basic &other) const
 460 {
 461         GINAC_ASSERT(is_a<expairseq>(other));
 462         const expairseq &o = static_cast<const expairseq &>(other);
 463
 464         int cmpval;
 465
 466         // compare number of elements
 467         if (seq.size() != o.seq.size())
 468                 return (seq.size()<o.seq.size()) ? -1 : 1;
 469
 470         // compare overall_coeff
 471         cmpval = overall_coeff.compare(o.overall_coeff);
 472         if (cmpval!=0)
 473                 return cmpval;
 474
 475 #if EXPAIRSEQ_USE_HASHTAB
 476         GINAC_ASSERT(hashtabsize==o.hashtabsize);
 477         if (hashtabsize==0) {
 478 #endif // EXPAIRSEQ_USE_HASHTAB
 479                 epvector::const_iterator cit1 = seq.begin();
 480                 epvector::const_iterator cit2 = o.seq.begin();
 481                 epvector::const_iterator last1 = seq.end();
 482                 epvector::const_iterator last2 = o.seq.end();
 483
 484                 for (; (cit1!=last1)&&(cit2!=last2); ++cit1, ++cit2) {
 485                         cmpval = (*cit1).compare(*cit2);
 486                         if (cmpval!=0) return cmpval;
 487                 }
 488
 489                 GINAC_ASSERT(cit1==last1);
 490                 GINAC_ASSERT(cit2==last2);
 491
 492                 return 0;
 493 #if EXPAIRSEQ_USE_HASHTAB
 494         }
 495
 496         // compare number of elements in each hashtab entry
 497         for (unsigned i=0; i<hashtabsize; ++i) {
 498                 unsigned cursize=hashtab[i].size();
 499                 if (cursize != o.hashtab[i].size())
 500                         return (cursize < o.hashtab[i].size()) ? -1 : 1;
 501         }
 502
 503         // compare individual (sorted) hashtab entries
 504         for (unsigned i=0; i<hashtabsize; ++i) {
 505                 unsigned sz = hashtab[i].size();
 506                 if (sz>0) {
 507                         const epplist &eppl1 = hashtab[i];
 508                         const epplist &eppl2 = o.hashtab[i];
 509                         epplist::const_iterator it1 = eppl1.begin();
 510                         epplist::const_iterator it2 = eppl2.begin();
 511                         while (it1!=eppl1.end()) {
 512                                 cmpval = (*(*it1)).compare(*(*it2));
 513                                 if (cmpval!=0)
 514                                         return cmpval;
 515                                 ++it1;
 516                                 ++it2;
 517                         }
 518                 }
 519         }
 520
 521         return 0; // equal
 522 #endif // EXPAIRSEQ_USE_HASHTAB
 523 }
 524
 525 bool expairseq::is_equal_same_type(const basic &other) const
 526 {
 527         const expairseq &o = static_cast<const expairseq &>(other);
 528
 529         // compare number of elements
 530         if (seq.size()!=o.seq.size())
 531                 return false;
 532
 533         // compare overall_coeff
 534         if (!overall_coeff.is_equal(o.overall_coeff))
 535                 return false;
 536
 537 #if EXPAIRSEQ_USE_HASHTAB
 538         // compare number of elements in each hashtab entry
 539         if (hashtabsize!=o.hashtabsize) {
 540                 std::cout << "this:" << std::endl;
 541                 print(print_tree(std::cout));
 542                 std::cout << "other:" << std::endl;
 543                 other.print(print_tree(std::cout));
 544         }
 545
 546         GINAC_ASSERT(hashtabsize==o.hashtabsize);
 547
 548         if (hashtabsize==0) {
 549 #endif // EXPAIRSEQ_USE_HASHTAB
 550                 epvector::const_iterator cit1 = seq.begin();
 551                 epvector::const_iterator cit2 = o.seq.begin();
 552                 epvector::const_iterator last1 = seq.end();
 553
 554                 while (cit1!=last1) {
 555                         if (!(*cit1).is_equal(*cit2)) return false;
 556                         ++cit1;
 557                         ++cit2;
 558                 }
 559
 560                 return true;
 561 #if EXPAIRSEQ_USE_HASHTAB
 562         }
 563
 564         for (unsigned i=0; i<hashtabsize; ++i) {
 565                 if (hashtab[i].size() != o.hashtab[i].size())
 566                         return false;
 567         }
 568
 569         // compare individual sorted hashtab entries
 570         for (unsigned i=0; i<hashtabsize; ++i) {
 571                 unsigned sz = hashtab[i].size();
 572                 if (sz>0) {
 573                         const epplist &eppl1 = hashtab[i];
 574                         const epplist &eppl2 = o.hashtab[i];
 575                         epplist::const_iterator it1 = eppl1.begin();
 576                         epplist::const_iterator it2 = eppl2.begin();
 577                         while (it1!=eppl1.end()) {
 578                                 if (!(*(*it1)).is_equal(*(*it2))) return false;
 579                                 ++it1;
 580                                 ++it2;
 581                         }
 582                 }
 583         }
 584
 585         return true;
 586 #endif // EXPAIRSEQ_USE_HASHTAB
 587 }
 588
 589 unsigned expairseq::return_type() const
 590 {
 591         return return_types::noncommutative_composite;
 592 }
 593
 594 unsigned expairseq::calchash() const
 595 {
 596         unsigned v = golden_ratio_hash((p_int)this->tinfo());
 597         epvector::const_iterator i = seq.begin();
 598         const epvector::const_iterator end = seq.end();
 599         while (i != end) {
 600                 v ^= i->rest.gethash();
 601 #if !EXPAIRSEQ_USE_HASHTAB
 602                 // rotation spoils commutativity!
 603                 v = rotate_left(v);
 604                 v ^= i->coeff.gethash();
 605 #endif // !EXPAIRSEQ_USE_HASHTAB
 606                 ++i;
 607         }
 608
 609         v ^= overall_coeff.gethash();
 610
 611         // store calculated hash value only if object is already evaluated
 612         if (flags &status_flags::evaluated) {
 613                 setflag(status_flags::hash_calculated);
 614                 hashvalue = v;
 615         }
 616
 617         return v;
 618 }
 619
 620 ex expairseq::expand(unsigned options) const
 621 {
 622         std::auto_ptr<epvector> vp = expandchildren(options);
 623         if (vp.get())
 624                 return thisexpairseq(vp, overall_coeff);
 625         else {
 626                 // The terms have not changed, so it is safe to declare this expanded
 627                 return (options == 0) ? setflag(status_flags::expanded) : *this;
 628         }
 629 }
 630
 631 //////////
 632 // new virtual functions which can be overridden by derived classes
 633 //////////
 634
 635 // protected
 636
 637 /** Create an object of this type.
 638  *  This method works similar to a constructor.  It is useful because expairseq
 639  *  has (at least) two possible different semantics but we want to inherit
 640  *  methods thus avoiding code duplication.  Sometimes a method in expairseq
 641  *  has to create a new one of the same semantics, which cannot be done by a
 642  *  ctor because the name (add, mul,...) is unknown on the expaiseq level.  In
 643  *  order for this trick to work a derived class must of course override this
 644  *  definition. */
 645 ex expairseq::thisexpairseq(const epvector &v, const ex &oc, bool do_index_renaming) const
 646 {
 647         return expairseq(v, oc, do_index_renaming);
 648 }
 649
 650 ex expairseq::thisexpairseq(std::auto_ptr<epvector> vp, const ex &oc, bool do_index_renaming) const
 651 {
 652         return expairseq(vp, oc, do_index_renaming);
 653 }
 654
 655 void expairseq::printpair(const print_context & c, const expair & p, unsigned upper_precedence) const
 656 {
 657         c.s << "[[";
 658         p.rest.print(c, precedence());
 659         c.s << ",";
 660         p.coeff.print(c, precedence());
 661         c.s << "]]";
 662 }
 663
 664 void expairseq::printseq(const print_context & c, char delim,
 665                          unsigned this_precedence,
 666                          unsigned upper_precedence) const
 667 {
 668         if (this_precedence <= upper_precedence)
 669                 c.s << "(";
 670         epvector::const_iterator it, it_last = seq.end() - 1;
 671         for (it=seq.begin(); it!=it_last; ++it) {
 672                 printpair(c, *it, this_precedence);
 673                 c.s << delim;
 674         }
 675         printpair(c, *it, this_precedence);
 676         if (!overall_coeff.is_equal(default_overall_coeff())) {
 677                 c.s << delim;
 678                 overall_coeff.print(c, this_precedence);
 679         }
 680
 681         if (this_precedence <= upper_precedence)
 682                 c.s << ")";
 683 }
 684
 685
 686 /** Form an expair from an ex, using the corresponding semantics.
 687  *  @see expairseq::recombine_pair_to_ex() */
 688 expair expairseq::split_ex_to_pair(const ex &e) const
 689 {
 690         return expair(e,_ex1);
 691 }
 692
 693
 694 expair expairseq::combine_ex_with_coeff_to_pair(const ex &e,
 695                                                 const ex &c) const
 696 {
 697         GINAC_ASSERT(is_exactly_a<numeric>(c));
 698
 699         return expair(e,c);
 700 }
 701
 702
 703 expair expairseq::combine_pair_with_coeff_to_pair(const expair &p,
 704                                                   const ex &c) const
 705 {
 706         GINAC_ASSERT(is_exactly_a<numeric>(p.coeff));
 707         GINAC_ASSERT(is_exactly_a<numeric>(c));
 708
 709         return expair(p.rest,ex_to<numeric>(p.coeff).mul_dyn(ex_to<numeric>(c)));
 710 }
 711
 712
 713 /** Form an ex out of an expair, using the corresponding semantics.
 714  *  @see expairseq::split_ex_to_pair() */
 715 ex expairseq::recombine_pair_to_ex(const expair &p) const
 716 {
 717         return lst(p.rest,p.coeff);
 718 }
 719
 720 bool expairseq::expair_needs_further_processing(epp it)
 721 {
 722 #if EXPAIRSEQ_USE_HASHTAB
 723         //#  error "FIXME: expair_needs_further_processing not yet implemented for hashtabs, sorry. A.F."
 724 #endif // EXPAIRSEQ_USE_HASHTAB
 725         return false;
 726 }
 727
 728 ex expairseq::default_overall_coeff() const
 729 {
 730         return _ex0;
 731 }
 732
 733 void expairseq::combine_overall_coeff(const ex &c)
 734 {
 735         GINAC_ASSERT(is_exactly_a<numeric>(overall_coeff));
 736         GINAC_ASSERT(is_exactly_a<numeric>(c));
 737         overall_coeff = ex_to<numeric>(overall_coeff).add_dyn(ex_to<numeric>(c));
 738 }
 739
 740 void expairseq::combine_overall_coeff(const ex &c1, const ex &c2)
 741 {
 742         GINAC_ASSERT(is_exactly_a<numeric>(overall_coeff));
 743         GINAC_ASSERT(is_exactly_a<numeric>(c1));
 744         GINAC_ASSERT(is_exactly_a<numeric>(c2));
 745         overall_coeff = ex_to<numeric>(overall_coeff).
 746                         add_dyn(ex_to<numeric>(c1).mul(ex_to<numeric>(c2)));
 747 }
 748
 749 bool expairseq::can_make_flat(const expair &p) const
 750 {
 751         return true;
 752 }
 753
 754
 755 //////////
 756 // non-virtual functions in this class
 757 //////////
 758
 759 void expairseq::construct_from_2_ex_via_exvector(const ex &lh, const ex &rh)
 760 {
 761         exvector v;
 762         v.reserve(2);
 763         v.push_back(lh);
 764         v.push_back(rh);
 765         construct_from_exvector(v);
 766 #if EXPAIRSEQ_USE_HASHTAB
 767         GINAC_ASSERT((hashtabsize==0)||(hashtabsize>=minhashtabsize));
 768         GINAC_ASSERT(hashtabsize==calc_hashtabsize(seq.size()));
 769 #endif // EXPAIRSEQ_USE_HASHTAB
 770 }
 771
 772 void expairseq::construct_from_2_ex(const ex &lh, const ex &rh)
 773 {
 774         if (ex_to<basic>(lh).tinfo()==this->tinfo()) {
 775                 if (ex_to<basic>(rh).tinfo()==this->tinfo()) {
 776 #if EXPAIRSEQ_USE_HASHTAB
 777                         unsigned totalsize = ex_to<expairseq>(lh).seq.size() +
 778                                              ex_to<expairseq>(rh).seq.size();
 779                         if (calc_hashtabsize(totalsize)!=0) {
 780                                 construct_from_2_ex_via_exvector(lh,rh);
 781                         } else {
 782 #endif // EXPAIRSEQ_USE_HASHTAB
 783                                 if(is_a<mul>(lh))
 784                                 {
 785                                         ex newrh=rename_dummy_indices_uniquely(lh, rh);
 786                                         construct_from_2_expairseq(ex_to<expairseq>(lh),
 787                                                                    ex_to<expairseq>(newrh));
 788                                 }
 789                                 else
 790                                         construct_from_2_expairseq(ex_to<expairseq>(lh),
 791                                                                    ex_to<expairseq>(rh));
 792 #if EXPAIRSEQ_USE_HASHTAB
 793                         }
 794 #endif // EXPAIRSEQ_USE_HASHTAB
 795                         return;
 796                 } else {
 797 #if EXPAIRSEQ_USE_HASHTAB
 798                         unsigned totalsize = ex_to<expairseq>(lh).seq.size()+1;
 799                         if (calc_hashtabsize(totalsize)!=0) {
 800                                 construct_from_2_ex_via_exvector(lh, rh);
 801                         } else {
 802 #endif // EXPAIRSEQ_USE_HASHTAB
 803                                 construct_from_expairseq_ex(ex_to<expairseq>(lh), rh);
 804 #if EXPAIRSEQ_USE_HASHTAB
 805                         }
 806 #endif // EXPAIRSEQ_USE_HASHTAB
 807                         return;
 808                 }
 809         } else if (ex_to<basic>(rh).tinfo()==this->tinfo()) {
 810 #if EXPAIRSEQ_USE_HASHTAB
 811                 unsigned totalsize=ex_to<expairseq>(rh).seq.size()+1;
 812                 if (calc_hashtabsize(totalsize)!=0) {
 813                         construct_from_2_ex_via_exvector(lh,rh);
 814                 } else {
 815 #endif // EXPAIRSEQ_USE_HASHTAB
 816                         construct_from_expairseq_ex(ex_to<expairseq>(rh),lh);
 817 #if EXPAIRSEQ_USE_HASHTAB
 818                 }
 819 #endif // EXPAIRSEQ_USE_HASHTAB
 820                 return;
 821         }
 822
 823 #if EXPAIRSEQ_USE_HASHTAB
 824         if (calc_hashtabsize(2)!=0) {
 825                 construct_from_2_ex_via_exvector(lh,rh);
 826                 return;
 827         }
 828         hashtabsize = 0;
 829 #endif // EXPAIRSEQ_USE_HASHTAB
 830
 831         if (is_exactly_a<numeric>(lh)) {
 832                 if (is_exactly_a<numeric>(rh)) {
 833                         combine_overall_coeff(lh);
 834                         combine_overall_coeff(rh);
 835                 } else {
 836                         combine_overall_coeff(lh);
 837                         seq.push_back(split_ex_to_pair(rh));
 838                 }
 839         } else {
 840                 if (is_exactly_a<numeric>(rh)) {
 841                         combine_overall_coeff(rh);
 842                         seq.push_back(split_ex_to_pair(lh));
 843                 } else {
 844                         expair p1 = split_ex_to_pair(lh);
 845                         expair p2 = split_ex_to_pair(rh);
 846
 847                         int cmpval = p1.rest.compare(p2.rest);
 848                         if (cmpval==0) {
 849                                 p1.coeff = ex_to<numeric>(p1.coeff).add_dyn(ex_to<numeric>(p2.coeff));
 850                                 if (!ex_to<numeric>(p1.coeff).is_zero()) {
 851                                         // no further processing is necessary, since this
 852                                         // one element will usually be recombined in eval()
 853                                         seq.push_back(p1);
 854                                 }
 855                         } else {
 856                                 seq.reserve(2);
 857                                 if (cmpval<0) {
 858                                         seq.push_back(p1);
 859                                         seq.push_back(p2);
 860                                 } else {
 861                                         seq.push_back(p2);
 862                                         seq.push_back(p1);
 863                                 }
 864                         }
 865                 }
 866         }
 867 }
 868
 869 void expairseq::construct_from_2_expairseq(const expairseq &s1,
 870                                                                                    const expairseq &s2)
 871 {
 872         combine_overall_coeff(s1.overall_coeff);
 873         combine_overall_coeff(s2.overall_coeff);
 874
 875         epvector::const_iterator first1 = s1.seq.begin();
 876         epvector::const_iterator last1 = s1.seq.end();
 877         epvector::const_iterator first2 = s2.seq.begin();
 878         epvector::const_iterator last2 = s2.seq.end();
 879
 880         seq.reserve(s1.seq.size()+s2.seq.size());
 881
 882         bool needs_further_processing=false;
 883
 884         while (first1!=last1 && first2!=last2) {
 885                 int cmpval = (*first1).rest.compare((*first2).rest);
 886
 887                 if (cmpval==0) {
 888                         // combine terms
 889                         const numeric &newcoeff = ex_to<numeric>(first1->coeff).
 890                                                    add(ex_to<numeric>(first2->coeff));
 891                         if (!newcoeff.is_zero()) {
 892                                 seq.push_back(expair(first1->rest,newcoeff));
 893                                 if (expair_needs_further_processing(seq.end()-1)) {
 894                                         needs_further_processing = true;
 895                                 }
 896                         }
 897                         ++first1;
 898                         ++first2;
 899                 } else if (cmpval<0) {
 900                         seq.push_back(*first1);
 901                         ++first1;
 902                 } else {
 903                         seq.push_back(*first2);
 904                         ++first2;
 905                 }
 906         }
 907
 908         while (first1!=last1) {
 909                 seq.push_back(*first1);
 910                 ++first1;
 911         }
 912         while (first2!=last2) {
 913                 seq.push_back(*first2);
 914                 ++first2;
 915         }
 916
 917         if (needs_further_processing) {
 918                 epvector v = seq;
 919                 seq.clear();
 920                 construct_from_epvector(v);
 921         }
 922 }
 923
 924 void expairseq::construct_from_expairseq_ex(const expairseq &s,
 925                                                                                         const ex &e)
 926 {
 927         combine_overall_coeff(s.overall_coeff);
 928         if (is_exactly_a<numeric>(e)) {
 929                 combine_overall_coeff(e);
 930                 seq = s.seq;
 931                 return;
 932         }
 933
 934         epvector::const_iterator first = s.seq.begin();
 935         epvector::const_iterator last = s.seq.end();
 936         expair p = split_ex_to_pair(e);
 937
 938         seq.reserve(s.seq.size()+1);
 939         bool p_pushed = false;
 940
 941         bool needs_further_processing=false;
 942
 943         // merge p into s.seq
 944         while (first!=last) {
 945                 int cmpval = (*first).rest.compare(p.rest);
 946                 if (cmpval==0) {
 947                         // combine terms
 948                         const numeric &newcoeff = ex_to<numeric>(first->coeff).
 949                                                    add(ex_to<numeric>(p.coeff));
 950                         if (!newcoeff.is_zero()) {
 951                                 seq.push_back(expair(first->rest,newcoeff));
 952                                 if (expair_needs_further_processing(seq.end()-1))
 953                                         needs_further_processing = true;
 954                         }
 955                         ++first;
 956                         p_pushed = true;
 957                         break;
 958                 } else if (cmpval<0) {
 959                         seq.push_back(*first);
 960                         ++first;
 961                 } else {
 962                         seq.push_back(p);
 963                         p_pushed = true;
 964                         break;
 965                 }
 966         }
 967
 968         if (p_pushed) {
 969                 // while loop exited because p was pushed, now push rest of s.seq
 970                 while (first!=last) {
 971                         seq.push_back(*first);
 972                         ++first;
 973                 }
 974         } else {
 975                 // while loop exited because s.seq was pushed, now push p
 976                 seq.push_back(p);
 977         }
 978
 979         if (needs_further_processing) {
 980                 epvector v = seq;
 981                 seq.clear();
 982                 construct_from_epvector(v);
 983         }
 984 }
 985
 986 void expairseq::construct_from_exvector(const exvector &v)
 987 {
 988         // simplifications: +(a,+(b,c),d) -> +(a,b,c,d) (associativity)
 989         //                  +(d,b,c,a) -> +(a,b,c,d) (canonicalization)
 990         //                  +(...,x,*(x,c1),*(x,c2)) -> +(...,*(x,1+c1+c2)) (c1, c2 numeric())
 991         //                  (same for (+,*) -> (*,^)
 992
 993         make_flat(v);
 994 #if EXPAIRSEQ_USE_HASHTAB
 995         combine_same_terms();
 996 #else
 997         canonicalize();
 998         combine_same_terms_sorted_seq();
 999 #endif // EXPAIRSEQ_USE_HASHTAB
1000 }
1001
1002 void expairseq::construct_from_epvector(const epvector &v, bool do_index_renaming)
1003 {
1004         // simplifications: +(a,+(b,c),d) -> +(a,b,c,d) (associativity)
1005         //                  +(d,b,c,a) -> +(a,b,c,d) (canonicalization)
1006         //                  +(...,x,*(x,c1),*(x,c2)) -> +(...,*(x,1+c1+c2)) (c1, c2 numeric())
1007         //                  (same for (+,*) -> (*,^)
1008
1009         make_flat(v, do_index_renaming);
1010 #if EXPAIRSEQ_USE_HASHTAB
1011         combine_same_terms();
1012 #else
1013         canonicalize();
1014         combine_same_terms_sorted_seq();
1015 #endif // EXPAIRSEQ_USE_HASHTAB
1016 }
1017
1018 // Class to handle the renaming of dummy indices. It holds a vector of
1019 // indices that are being used in the expression so-far. If the same
1020 // index occurs again as a dummy index in a factor, it is to be renamed.
1021 // Unless dummy index renaming was swichted of, of course ;-) .
1022 class make_flat_inserter
1023 {
1024         public:
1025                 make_flat_inserter(const epvector &epv, bool b): do_renaming(b)
1026                 {
1027                         if (!do_renaming)
1028                                 return;
1029                         for (epvector::const_iterator i=epv.begin(); i!=epv.end(); ++i)
1030                                 if(are_ex_trivially_equal(i->coeff, _ex1))
1031                                         combine_indices(i->rest.get_free_indices());
1032                 }
1033                 make_flat_inserter(const exvector &v, bool b): do_renaming(b)
1034                 {
1035                         if (!do_renaming)
1036                                 return;
1037                         for (exvector::const_iterator i=v.begin(); i!=v.end(); ++i)
1038                                 combine_indices(i->get_free_indices());
1039                 }
1040                 ex handle_factor(const ex &x, const ex &coeff)
1041                 {
1042                         if (!do_renaming)
1043                                 return x;
1044                         exvector dummies_of_factor;
1045                         if (coeff == _ex1)
1046                                 dummies_of_factor = get_all_dummy_indices_safely(x);
1047                         else if (coeff == _ex2)
1048                                 dummies_of_factor = x.get_free_indices();
1049                         else
1050                                 return x;
1051                         if (dummies_of_factor.size() == 0)
1052                                 return x;
1053                         sort(dummies_of_factor.begin(), dummies_of_factor.end(), ex_is_less());
1054                         ex new_factor = rename_dummy_indices_uniquely(used_indices,
1055                                 dummies_of_factor, x);
1056                         combine_indices(dummies_of_factor);
1057                         return new_factor;
1058                 }
1059         private:
1060                 void combine_indices(const exvector &dummies_of_factor)
1061                 {
1062                         exvector new_dummy_indices;
1063                         set_union(used_indices.begin(), used_indices.end(),
1064                                 dummies_of_factor.begin(), dummies_of_factor.end(),
1065                                 std::back_insert_iterator<exvector>(new_dummy_indices), ex_is_less());
1066                         used_indices.swap(new_dummy_indices);
1067                 }
1068                 bool do_renaming;
1069                 exvector used_indices;
1070 };
1071
1072
1073 /** Combine this expairseq with argument exvector.
1074  *  It cares for associativity as well as for special handling of numerics. */
1075 void expairseq::make_flat(const exvector &v)
1076 {
1077         exvector::const_iterator cit;
1078
1079         // count number of operands which are of same expairseq derived type
1080         // and their cumulative number of operands
1081         int nexpairseqs = 0;
1082         int noperands = 0;
1083
1084         cit = v.begin();
1085         while (cit!=v.end()) {
1086                 if (ex_to<basic>(*cit).tinfo()==this->tinfo()) {
1087                         ++nexpairseqs;
1088                         noperands += ex_to<expairseq>(*cit).seq.size();
1089                 }
1090                 ++cit;
1091         }
1092
1093         // reserve seq and coeffseq which will hold all operands
1094         seq.reserve(v.size()+noperands-nexpairseqs);
1095
1096         // copy elements and split off numerical part
1097         make_flat_inserter mf(v, this->tinfo()==&mul::tinfo_static);
1098         cit = v.begin();
1099         while (cit!=v.end()) {
1100                 if (ex_to<basic>(*cit).tinfo()==this->tinfo()) {
1101                         ex newfactor = mf.handle_factor(*cit, _ex1);
1102                         const expairseq &subseqref = ex_to<expairseq>(newfactor);
1103                         combine_overall_coeff(subseqref.overall_coeff);
1104                         epvector::const_iterator cit_s = subseqref.seq.begin();
1105                         while (cit_s!=subseqref.seq.end()) {
1106                                 seq.push_back(*cit_s);
1107                                 ++cit_s;
1108                         }
1109                 } else {
1110                         if (is_exactly_a<numeric>(*cit))
1111                                 combine_overall_coeff(*cit);
1112                         else {
1113                                 ex newfactor = mf.handle_factor(*cit, _ex1);
1114                                 seq.push_back(split_ex_to_pair(newfactor));
1115                         }
1116                 }
1117                 ++cit;
1118         }
1119 }
1120
1121 /** Combine this expairseq with argument epvector.
1122  *  It cares for associativity as well as for special handling of numerics. */
1123 void expairseq::make_flat(const epvector &v, bool do_index_renaming)
1124 {
1125         epvector::const_iterator cit;
1126
1127         // count number of operands which are of same expairseq derived type
1128         // and their cumulative number of operands
1129         int nexpairseqs = 0;
1130         int noperands = 0;
1131
1132         cit = v.begin();
1133         while (cit!=v.end()) {
1134                 if (ex_to<basic>(cit->rest).tinfo()==this->tinfo()) {
1135                         ++nexpairseqs;
1136                         noperands += ex_to<expairseq>(cit->rest).seq.size();
1137                 }
1138                 ++cit;
1139         }
1140
1141         // reserve seq and coeffseq which will hold all operands
1142         seq.reserve(v.size()+noperands-nexpairseqs);
1143         make_flat_inserter mf(v, do_index_renaming);
1144
1145         // copy elements and split off numerical part
1146         cit = v.begin();
1147         while (cit!=v.end()) {
1148                 if (ex_to<basic>(cit->rest).tinfo()==this->tinfo() &&
1149                     this->can_make_flat(*cit)) {
1150                         ex newrest = mf.handle_factor(cit->rest, cit->coeff);
1151                         const expairseq &subseqref = ex_to<expairseq>(newrest);
1152                         combine_overall_coeff(ex_to<numeric>(subseqref.overall_coeff),
1153                                                             ex_to<numeric>(cit->coeff));
1154                         epvector::const_iterator cit_s = subseqref.seq.begin();
1155                         while (cit_s!=subseqref.seq.end()) {
1156                                 seq.push_back(expair(cit_s->rest,
1157                                                      ex_to<numeric>(cit_s->coeff).mul_dyn(ex_to<numeric>(cit->coeff))));
1158                                 //seq.push_back(combine_pair_with_coeff_to_pair(*cit_s,
1159                                 //                                              (*cit).coeff));
1160                                 ++cit_s;
1161                         }
1162                 } else {
1163                         if (cit->is_canonical_numeric())
1164                                 combine_overall_coeff(mf.handle_factor(cit->rest, _ex1));
1165                         else {
1166                                 ex rest = cit->rest;
1167                                 ex newrest = mf.handle_factor(rest, cit->coeff);
1168                                 if (are_ex_trivially_equal(newrest, rest))
1169                                         seq.push_back(*cit);
1170                                 else
1171                                         seq.push_back(expair(newrest, cit->coeff));
1172                         }
1173                 }
1174                 ++cit;
1175         }
1176 }
1177
1178 /** Brings this expairseq into a sorted (canonical) form. */
1179 void expairseq::canonicalize()
1180 {
1181         std::sort(seq.begin(), seq.end(), expair_rest_is_less());
1182 }
1183
1184
1185 /** Compact a presorted expairseq by combining all matching expairs to one
1186  *  each.  On an add object, this is responsible for 2*x+3*x+y -> 5*x+y, for
1187  *  instance. */
1188 void expairseq::combine_same_terms_sorted_seq()
1189 {
1190         if (seq.size()<2)
1191                 return;
1192
1193         bool needs_further_processing = false;
1194
1195         epvector::iterator itin1 = seq.begin();
1196         epvector::iterator itin2 = itin1+1;
1197         epvector::iterator itout = itin1;
1198         epvector::iterator last = seq.end();
1199         // must_copy will be set to true the first time some combination is
1200         // possible from then on the sequence has changed and must be compacted
1201         bool must_copy = false;
1202         while (itin2!=last) {
1203                 if (itin1->rest.compare(itin2->rest)==0) {
1204                         itin1->coeff = ex_to<numeric>(itin1->coeff).
1205                                        add_dyn(ex_to<numeric>(itin2->coeff));
1206                         if (expair_needs_further_processing(itin1))
1207                                 needs_further_processing = true;
1208                         must_copy = true;
1209                 } else {
1210                         if (!ex_to<numeric>(itin1->coeff).is_zero()) {
1211                                 if (must_copy)
1212                                         *itout = *itin1;
1213                                 ++itout;
1214                         }
1215                         itin1 = itin2;
1216                 }
1217                 ++itin2;
1218         }
1219         if (!ex_to<numeric>(itin1->coeff).is_zero()) {
1220                 if (must_copy)
1221                         *itout = *itin1;
1222                 ++itout;
1223         }
1224         if (itout!=last)
1225                 seq.erase(itout,last);
1226
1227         if (needs_further_processing) {
1228                 epvector v = seq;
1229                 seq.clear();
1230                 construct_from_epvector(v);
1231         }
1232 }
1233
1234 #if EXPAIRSEQ_USE_HASHTAB
1235
1236 unsigned expairseq::calc_hashtabsize(unsigned sz) const
1237 {
1238         unsigned size;
1239         unsigned nearest_power_of_2 = 1 << log2(sz);
1240         // if (nearest_power_of_2 < maxhashtabsize/hashtabfactor) {
1241         //  size = nearest_power_of_2*hashtabfactor;
1242         size = nearest_power_of_2/hashtabfactor;
1243         if (size<minhashtabsize)
1244                 return 0;
1245
1246         // hashtabsize must be a power of 2
1247         GINAC_ASSERT((1U << log2(size))==size);
1248         return size;
1249 }
1250
1251 unsigned expairseq::calc_hashindex(const ex &e) const
1252 {
1253         // calculate hashindex
1254         unsigned hashindex;
1255         if (is_a<numeric>(e)) {
1256                 hashindex = hashmask;
1257         } else {
1258                 hashindex = e.gethash() & hashmask;
1259                 // last hashtab entry is reserved for numerics
1260                 if (hashindex==hashmask) hashindex = 0;
1261         }
1262         GINAC_ASSERT((hashindex<hashtabsize)||(hashtabsize==0));
1263         return hashindex;
1264 }
1265
1266 void expairseq::shrink_hashtab()
1267 {
1268         unsigned new_hashtabsize;
1269         while (hashtabsize!=(new_hashtabsize=calc_hashtabsize(seq.size()))) {
1270                 GINAC_ASSERT(new_hashtabsize<hashtabsize);
1271                 if (new_hashtabsize==0) {
1272                         hashtab.clear();
1273                         hashtabsize = 0;
1274                         canonicalize();
1275                         return;
1276                 }
1277
1278                 // shrink by a factor of 2
1279                 unsigned half_hashtabsize = hashtabsize/2;
1280                 for (unsigned i=0; i<half_hashtabsize-1; ++i)
1281                         hashtab[i].merge(hashtab[i+half_hashtabsize],epp_is_less());
1282                 // special treatment for numeric hashes
1283                 hashtab[0].merge(hashtab[half_hashtabsize-1],epp_is_less());
1284                 hashtab[half_hashtabsize-1] = hashtab[hashtabsize-1];
1285                 hashtab.resize(half_hashtabsize);
1286                 hashtabsize = half_hashtabsize;
1287                 hashmask = hashtabsize-1;
1288         }
1289 }
1290
1291 void expairseq::remove_hashtab_entry(epvector::const_iterator element)
1292 {
1293         if (hashtabsize==0)
1294                 return; // nothing to do
1295
1296         // calculate hashindex of element to be deleted
1297         unsigned hashindex = calc_hashindex((*element).rest);
1298
1299         // find it in hashtab and remove it
1300         epplist &eppl = hashtab[hashindex];
1301         epplist::iterator epplit = eppl.begin();
1302         bool erased = false;
1303         while (epplit!=eppl.end()) {
1304                 if (*epplit == element) {
1305                         eppl.erase(epplit);
1306                         erased = true;
1307                         break;
1308                 }
1309                 ++epplit;
1310         }
1311         if (!erased) {
1312                 std::cout << "tried to erase " << element-seq.begin() << std::endl;
1313                 std::cout << "size " << seq.end()-seq.begin() << std::endl;
1314
1315                 unsigned hashindex = calc_hashindex(element->rest);
1316                 epplist &eppl = hashtab[hashindex];
1317                 epplist::iterator epplit = eppl.begin();
1318                 bool erased = false;
1319                 while (epplit!=eppl.end()) {
1320                         if (*epplit == element) {
1321                                 eppl.erase(epplit);
1322                                 erased = true;
1323                                 break;
1324                         }
1325                         ++epplit;
1326                 }
1327                 GINAC_ASSERT(erased);
1328         }
1329         GINAC_ASSERT(erased);
1330 }
1331
1332 void expairseq::move_hashtab_entry(epvector::const_iterator oldpos,
1333                                    epvector::iterator newpos)
1334 {
1335         GINAC_ASSERT(hashtabsize!=0);
1336
1337         // calculate hashindex of element which was moved
1338         unsigned hashindex=calc_hashindex((*newpos).rest);
1339
1340         // find it in hashtab and modify it
1341         epplist &eppl = hashtab[hashindex];
1342         epplist::iterator epplit = eppl.begin();
1343         while (epplit!=eppl.end()) {
1344                 if (*epplit == oldpos) {
1345                         *epplit = newpos;
1346                         break;
1347                 }
1348                 ++epplit;
1349         }
1350         GINAC_ASSERT(epplit!=eppl.end());
1351 }
1352
1353 void expairseq::sorted_insert(epplist &eppl, epvector::const_iterator elem)
1354 {
1355         epplist::const_iterator current = eppl.begin();
1356         while ((current!=eppl.end()) && ((*current)->is_less(*elem))) {
1357                 ++current;
1358         }
1359         eppl.insert(current,elem);
1360 }
1361
1362 void expairseq::build_hashtab_and_combine(epvector::iterator &first_numeric,
1363                                           epvector::iterator &last_non_zero,
1364                                           std::vector<bool> &touched,
1365                                           unsigned &number_of_zeroes)
1366 {
1367         epp current = seq.begin();
1368
1369         while (current!=first_numeric) {
1370                 if (is_exactly_a<numeric>(current->rest)) {
1371                         --first_numeric;
1372                         iter_swap(current,first_numeric);
1373                 } else {
1374                         // calculate hashindex
1375                         unsigned currenthashindex = calc_hashindex(current->rest);
1376
1377                         // test if there is already a matching expair in the hashtab-list
1378                         epplist &eppl=hashtab[currenthashindex];
1379                         epplist::iterator epplit = eppl.begin();
1380                         while (epplit!=eppl.end()) {
1381                                 if (current->rest.is_equal((*epplit)->rest))
1382                                         break;
1383                                 ++epplit;
1384                         }
1385                         if (epplit==eppl.end()) {
1386                                 // no matching expair found, append this to end of list
1387                                 sorted_insert(eppl,current);
1388                                 ++current;
1389                         } else {
1390                                 // epplit points to a matching expair, combine it with current
1391                                 (*epplit)->coeff = ex_to<numeric>((*epplit)->coeff).
1392                                                    add_dyn(ex_to<numeric>(current->coeff));
1393
1394                                 // move obsolete current expair to end by swapping with last_non_zero element
1395                                 // if this was a numeric, it is swapped with the expair before first_numeric
1396                                 iter_swap(current,last_non_zero);
1397                                 --first_numeric;
1398                                 if (first_numeric!=last_non_zero) iter_swap(first_numeric,current);
1399                                 --last_non_zero;
1400                                 ++number_of_zeroes;
1401                                 // test if combined term has coeff 0 and can be removed is done later
1402                                 touched[(*epplit)-seq.begin()] = true;
1403                         }
1404                 }
1405         }
1406 }
1407
1408 void expairseq::drop_coeff_0_terms(epvector::iterator &first_numeric,
1409                                    epvector::iterator &last_non_zero,
1410                                    std::vector<bool> &touched,
1411                                    unsigned &number_of_zeroes)
1412 {
1413         // move terms with coeff 0 to end and remove them from hashtab
1414         // check only those elements which have been touched
1415         epp current = seq.begin();
1416         size_t i = 0;
1417         while (current!=first_numeric) {
1418                 if (!touched[i]) {
1419                         ++current;
1420                         ++i;
1421                 } else if (!ex_to<numeric>((*current).coeff).is_zero()) {
1422                         ++current;
1423                         ++i;
1424                 } else {
1425                         remove_hashtab_entry(current);
1426
1427                         // move element to the end, unless it is already at the end
1428                         if (current!=last_non_zero) {
1429                                 iter_swap(current,last_non_zero);
1430                                 --first_numeric;
1431                                 bool numeric_swapped = first_numeric!=last_non_zero;
1432                                 if (numeric_swapped)
1433                                         iter_swap(first_numeric,current);
1434                                 epvector::iterator changed_entry;
1435
1436                                 if (numeric_swapped)
1437                                         changed_entry = first_numeric;
1438                                 else
1439                                         changed_entry = last_non_zero;
1440
1441                                 --last_non_zero;
1442                                 ++number_of_zeroes;
1443
1444                                 if (first_numeric!=current) {
1445
1446                                         // change entry in hashtab which referred to first_numeric or last_non_zero to current
1447                                         move_hashtab_entry(changed_entry,current);
1448                                         touched[current-seq.begin()] = touched[changed_entry-seq.begin()];
1449                                 }
1450                         } else {
1451                                 --first_numeric;
1452                                 --last_non_zero;
1453                                 ++number_of_zeroes;
1454                         }
1455                 }
1456         }
1457         GINAC_ASSERT(i==current-seq.begin());
1458 }
1459
1460 /** True if one of the coeffs vanishes, otherwise false.
1461  *  This would be an invariant violation, so this should only be used for
1462  *  debugging purposes. */
1463 bool expairseq::has_coeff_0() const
1464 {
1465         epvector::const_iterator i = seq.begin(), end = seq.end();
1466         while (i != end) {
1467                 if (i->coeff.is_zero())
1468                         return true;
1469                 ++i;
1470         }
1471         return false;
1472 }
1473
1474 void expairseq::add_numerics_to_hashtab(epvector::iterator first_numeric,
1475                                                                                 epvector::const_iterator last_non_zero)
1476 {
1477         if (first_numeric == seq.end()) return; // no numerics
1478
1479         epvector::const_iterator current = first_numeric, last = last_non_zero + 1;
1480         while (current != last) {
1481                 sorted_insert(hashtab[hashmask], current);
1482                 ++current;
1483         }
1484 }
1485
1486 void expairseq::combine_same_terms()
1487 {
1488         // combine same terms, drop term with coeff 0, move numerics to end
1489
1490         // calculate size of hashtab
1491         hashtabsize = calc_hashtabsize(seq.size());
1492
1493         // hashtabsize is a power of 2
1494         hashmask = hashtabsize-1;
1495
1496         // allocate hashtab
1497         hashtab.clear();
1498         hashtab.resize(hashtabsize);
1499
1500         if (hashtabsize==0) {
1501                 canonicalize();
1502                 combine_same_terms_sorted_seq();
1503                 GINAC_ASSERT(!has_coeff_0());
1504                 return;
1505         }
1506
1507         // iterate through seq, move numerics to end,
1508         // fill hashtab and combine same terms
1509         epvector::iterator first_numeric = seq.end();
1510         epvector::iterator last_non_zero = seq.end()-1;
1511
1512         size_t num = seq.size();
1513         std::vector<bool> touched(num);
1514
1515         unsigned number_of_zeroes = 0;
1516
1517         GINAC_ASSERT(!has_coeff_0());
1518         build_hashtab_and_combine(first_numeric,last_non_zero,touched,number_of_zeroes);
1519
1520         // there should not be any terms with coeff 0 from the beginning,
1521         // so it should be safe to skip this step
1522         if (number_of_zeroes!=0) {
1523                 drop_coeff_0_terms(first_numeric,last_non_zero,touched,number_of_zeroes);
1524         }
1525
1526         add_numerics_to_hashtab(first_numeric,last_non_zero);
1527
1528         // pop zero elements
1529         for (unsigned i=0; i<number_of_zeroes; ++i) {
1530                 seq.pop_back();
1531         }
1532
1533         // shrink hashtabsize to calculated value
1534         GINAC_ASSERT(!has_coeff_0());
1535
1536         shrink_hashtab();
1537
1538         GINAC_ASSERT(!has_coeff_0());
1539 }
1540
1541 #endif // EXPAIRSEQ_USE_HASHTAB
1542
1543 /** Check if this expairseq is in sorted (canonical) form.  Useful mainly for
1544  *  debugging or in assertions since being sorted is an invariance. */
1545 bool expairseq::is_canonical() const
1546 {
1547         if (seq.size() <= 1)
1548                 return 1;
1549
1550 #if EXPAIRSEQ_USE_HASHTAB
1551         if (hashtabsize > 0) return 1; // not canoncalized
1552 #endif // EXPAIRSEQ_USE_HASHTAB
1553
1554         epvector::const_iterator it = seq.begin(), itend = seq.end();
1555         epvector::const_iterator it_last = it;
1556         for (++it; it!=itend; it_last=it, ++it) {
1557                 if (!(it_last->is_less(*it) || it_last->is_equal(*it))) {
1558                         if (!is_exactly_a<numeric>(it_last->rest) ||
1559                                 !is_exactly_a<numeric>(it->rest)) {
1560                                 // double test makes it easier to set a breakpoint...
1561                                 if (!is_exactly_a<numeric>(it_last->rest) ||
1562                                         !is_exactly_a<numeric>(it->rest)) {
1563                                         printpair(std::clog, *it_last, 0);
1564                                         std::clog << ">";
1565                                         printpair(std::clog, *it, 0);
1566                                         std::clog << "\n";
1567                                         std::clog << "pair1:" << std::endl;
1568                                         it_last->rest.print(print_tree(std::clog));
1569                                         it_last->coeff.print(print_tree(std::clog));
1570                                         std::clog << "pair2:" << std::endl;
1571                                         it->rest.print(print_tree(std::clog));
1572                                         it->coeff.print(print_tree(std::clog));
1573                                         return 0;
1574                                 }
1575                         }
1576                 }
1577         }
1578         return 1;
1579 }
1580
1581
1582 /** Member-wise expand the expairs in this sequence.
1583  *
1584  *  @see expairseq::expand()
1585  *  @return pointer to epvector containing expanded pairs or zero pointer,
1586  *  if no members were changed. */
1587 std::auto_ptr<epvector> expairseq::expandchildren(unsigned options) const
1588 {
1589         const epvector::const_iterator last = seq.end();
1590         epvector::const_iterator cit = seq.begin();
1591         while (cit!=last) {
1592                 const ex &expanded_ex = cit->rest.expand(options);
1593                 if (!are_ex_trivially_equal(cit->rest,expanded_ex)) {
1594
1595                         // something changed, copy seq, eval and return it
1596                         std::auto_ptr<epvector> s(new epvector);
1597                         s->reserve(seq.size());
1598
1599                         // copy parts of seq which are known not to have changed
1600                         epvector::const_iterator cit2 = seq.begin();
1601                         while (cit2!=cit) {
1602                                 s->push_back(*cit2);
1603                                 ++cit2;
1604                         }
1605
1606                         // copy first changed element
1607                         s->push_back(combine_ex_with_coeff_to_pair(expanded_ex,
1608                                                                    cit2->coeff));
1609                         ++cit2;
1610
1611                         // copy rest
1612                         while (cit2!=last) {
1613                                 s->push_back(combine_ex_with_coeff_to_pair(cit2->rest.expand(options),
1614                                                                            cit2->coeff));
1615                                 ++cit2;
1616                         }
1617                         return s;
1618                 }
1619                 ++cit;
1620         }
1621
1622         return std::auto_ptr<epvector>(0); // signalling nothing has changed
1623 }
1624
1625
1626 /** Member-wise evaluate the expairs in this sequence.
1627  *
1628  *  @see expairseq::eval()
1629  *  @return pointer to epvector containing evaluated pairs or zero pointer,
1630  *  if no members were changed. */
1631 std::auto_ptr<epvector> expairseq::evalchildren(int level) const
1632 {
1633         // returns a NULL pointer if nothing had to be evaluated
1634         // returns a pointer to a newly created epvector otherwise
1635         // (which has to be deleted somewhere else)
1636
1637         if (level==1)
1638                 return std::auto_ptr<epvector>(0);
1639
1640         if (level == -max_recursion_level)
1641                 throw(std::runtime_error("max recursion level reached"));
1642
1643         --level;
1644         epvector::const_iterator last = seq.end();
1645         epvector::const_iterator cit = seq.begin();
1646         while (cit!=last) {
1647                 const ex &evaled_ex = cit->rest.eval(level);
1648                 if (!are_ex_trivially_equal(cit->rest,evaled_ex)) {
1649
1650                         // something changed, copy seq, eval and return it
1651                         std::auto_ptr<epvector> s(new epvector);
1652                         s->reserve(seq.size());
1653
1654                         // copy parts of seq which are known not to have changed
1655                         epvector::const_iterator cit2=seq.begin();
1656                         while (cit2!=cit) {
1657                                 s->push_back(*cit2);
1658                                 ++cit2;
1659                         }
1660
1661                         // copy first changed element
1662                         s->push_back(combine_ex_with_coeff_to_pair(evaled_ex,
1663                                                                    cit2->coeff));
1664                         ++cit2;
1665
1666                         // copy rest
1667                         while (cit2!=last) {
1668                                 s->push_back(combine_ex_with_coeff_to_pair(cit2->rest.eval(level),
1669                                                                            cit2->coeff));
1670                                 ++cit2;
1671                         }
1672                         return s;
1673                 }
1674                 ++cit;
1675         }
1676
1677         return std::auto_ptr<epvector>(0); // signalling nothing has changed
1678 }
1679
1680 /** Member-wise substitute in this sequence.
1681  *
1682  *  @see expairseq::subs()
1683  *  @return pointer to epvector containing pairs after application of subs,
1684  *    or NULL pointer if no members were changed. */
1685 std::auto_ptr<epvector> expairseq::subschildren(const exmap & m, unsigned options) const
1686 {
1687         // When any of the objects to be substituted is a product or power
1688         // we have to recombine the pairs because the numeric coefficients may
1689         // be part of the search pattern.
1690         if (!(options & (subs_options::pattern_is_product | subs_options::pattern_is_not_product))) {
1691
1692                 // Search the list of substitutions and cache our findings
1693                 for (exmap::const_iterator it = m.begin(); it != m.end(); ++it) {
1694                         if (is_exactly_a<mul>(it->first) || is_exactly_a<power>(it->first)) {
1695                                 options |= subs_options::pattern_is_product;
1696                                 break;
1697                         }
1698                 }
1699                 if (!(options & subs_options::pattern_is_product))
1700                         options |= subs_options::pattern_is_not_product;
1701         }
1702
1703         if (options & subs_options::pattern_is_product) {
1704
1705                 // Substitute in the recombined pairs
1706                 epvector::const_iterator cit = seq.begin(), last = seq.end();
1707                 while (cit != last) {
1708
1709                         const ex &orig_ex = recombine_pair_to_ex(*cit);
1710                         const ex &subsed_ex = orig_ex.subs(m, options);
1711                         if (!are_ex_trivially_equal(orig_ex, subsed_ex)) {
1712
1713                                 // Something changed, copy seq, subs and return it
1714                                 std::auto_ptr<epvector> s(new epvector);
1715                                 s->reserve(seq.size());
1716
1717                                 // Copy parts of seq which are known not to have changed
1718                                 s->insert(s->begin(), seq.begin(), cit);
1719
1720                                 // Copy first changed element
1721                                 s->push_back(split_ex_to_pair(subsed_ex));
1722                                 ++cit;
1723
1724                                 // Copy rest
1725                                 while (cit != last) {
1726                                         s->push_back(split_ex_to_pair(recombine_pair_to_ex(*cit).subs(m, options)));
1727                                         ++cit;
1728                                 }
1729                                 return s;
1730                         }
1731
1732                         ++cit;
1733                 }
1734
1735         } else {
1736
1737                 // Substitute only in the "rest" part of the pairs
1738                 epvector::const_iterator cit = seq.begin(), last = seq.end();
1739                 while (cit != last) {
1740
1741                         const ex &subsed_ex = cit->rest.subs(m, options);
1742                         if (!are_ex_trivially_equal(cit->rest, subsed_ex)) {
1743
1744                                 // Something changed, copy seq, subs and return it
1745                                 std::auto_ptr<epvector> s(new epvector);
1746                                 s->reserve(seq.size());
1747
1748                                 // Copy parts of seq which are known not to have changed
1749                                 s->insert(s->begin(), seq.begin(), cit);
1750
1751                                 // Copy first changed element
1752                                 s->push_back(combine_ex_with_coeff_to_pair(subsed_ex, cit->coeff));
1753                                 ++cit;
1754
1755                                 // Copy rest
1756                                 while (cit != last) {
1757                                         s->push_back(combine_ex_with_coeff_to_pair(cit->rest.subs(m, options), cit->coeff));
1758                                         ++cit;
1759                                 }
1760                                 return s;
1761                         }
1762
1763                         ++cit;
1764                 }
1765         }
1766
1767         // Nothing has changed
1768         return std::auto_ptr<epvector>(0);
1769 }
1770
1771 //////////
1772 // static member variables
1773 //////////
1774
1775 #if EXPAIRSEQ_USE_HASHTAB
1776 unsigned expairseq::maxhashtabsize = 0x4000000U;
1777 unsigned expairseq::minhashtabsize = 0x1000U;
1778 unsigned expairseq::hashtabfactor = 1;
1779 #endif // EXPAIRSEQ_USE_HASHTAB
1780
1781 } // namespace GiNaC