ginac/idx.cpp

   1 /** @file idx.cpp
   2  *
   3  *  Implementation of GiNaC's indices. */
   4
   5 /*
   6  *  GiNaC Copyright (C) 1999-2000 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  */
  22
  23 #include <stdexcept>
  24
  25 #include "idx.h"
  26 #include "ex.h"
  27 #include "lst.h"
  28 #include "relational.h"
  29 #include "archive.h"
  30 #include "utils.h"
  31 #include "debugmsg.h"
  32
  33 #ifndef NO_NAMESPACE_GINAC
  34 namespace GiNaC {
  35 #endif // ndef NO_NAMESPACE_GINAC
  36
  37 GINAC_IMPLEMENT_REGISTERED_CLASS(idx, basic)
  38
  39 //////////
  40 // default constructor, destructor, copy constructor assignment operator and helpers
  41 //////////
  42
  43 // public
  44
  45 idx::idx() : inherited(TINFO_idx), symbolic(true), covariant(false)
  46 {
  47         debugmsg("idx default constructor",LOGLEVEL_CONSTRUCT);
  48         serial=next_serial++;
  49         name="index"+ToString(serial);
  50 }
  51
  52 idx::~idx()
  53 {
  54         debugmsg("idx destructor",LOGLEVEL_DESTRUCT);
  55         destroy(false);
  56 }
  57
  58 idx::idx(const idx & other)
  59 {
  60         debugmsg("idx copy constructor",LOGLEVEL_CONSTRUCT);
  61         copy(other);
  62 }
  63
  64 const idx & idx::operator=(const idx & other)
  65 {
  66         debugmsg("idx operator=",LOGLEVEL_ASSIGNMENT);
  67         if (this != &other) {
  68                 destroy(true);
  69                 copy(other);
  70         }
  71         return *this;
  72 }
  73
  74 // protected
  75
  76 void idx::copy(const idx & other)
  77 {
  78         inherited::copy(other);
  79         serial=other.serial;
  80         symbolic=other.symbolic;
  81         name=other.name;
  82         value=other.value;
  83         covariant=other.covariant;
  84 }
  85
  86 void idx::destroy(bool call_parent)
  87 {
  88         if (call_parent) inherited::destroy(call_parent);
  89 }
  90
  91 //////////
  92 // other constructors
  93 //////////
  94
  95 // public
  96
  97 idx::idx(bool cov) : inherited(TINFO_idx), symbolic(true), covariant(cov)
  98 {
  99         debugmsg("idx constructor from bool",LOGLEVEL_CONSTRUCT);
 100         serial = next_serial++;
 101         name = "index"+ToString(serial);
 102 }
 103
 104 idx::idx(const std::string & n, bool cov) : inherited(TINFO_idx),
 105         symbolic(true), name(n), covariant(cov)
 106 {
 107         debugmsg("idx constructor from string,bool",LOGLEVEL_CONSTRUCT);
 108         serial = next_serial++;
 109 }
 110
 111 idx::idx(const char * n, bool cov) : inherited(TINFO_idx), symbolic(true), name(n), covariant(cov)
 112 {
 113         debugmsg("idx constructor from char*,bool",LOGLEVEL_CONSTRUCT);
 114         serial = next_serial++;
 115 }
 116
 117 idx::idx(unsigned v, bool cov) : inherited(TINFO_idx), symbolic(false), value(v), covariant(cov)
 118 {
 119         debugmsg("idx constructor from unsigned,bool",LOGLEVEL_CONSTRUCT);
 120         serial = 0;
 121 }
 122
 123 //////////
 124 // archiving
 125 //////////
 126
 127 /** Construct object from archive_node. */
 128 idx::idx(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst)
 129 {
 130         debugmsg("idx constructor from archive_node", LOGLEVEL_CONSTRUCT);
 131         n.find_bool("symbolic", symbolic);
 132         n.find_bool("covariant", covariant);
 133         if (symbolic) {
 134                 serial = next_serial++;
 135                 if (!(n.find_string("name", name)))
 136                         name = "index" + ToString(serial);
 137         } else {
 138                 serial = 0;
 139                 n.find_unsigned("value", value);
 140         }
 141 }
 142
 143 /** Unarchive the object. */
 144 ex idx::unarchive(const archive_node &n, const lst &sym_lst)
 145 {
 146         ex s = (new idx(n, sym_lst))->setflag(status_flags::dynallocated);
 147
 148         if (ex_to_idx(s).symbolic) {
 149                 // If idx is in sym_lst, return the existing idx
 150                 for (unsigned i=0; i<sym_lst.nops(); i++) {
 151                         if (is_ex_of_type(sym_lst.op(i), idx) && (ex_to_idx(sym_lst.op(i)).name == ex_to_idx(s).name))
 152                                 return sym_lst.op(i);
 153                 }
 154         }
 155         return s;
 156 }
 157
 158 /** Archive the object. */
 159 void idx::archive(archive_node &n) const
 160 {
 161         inherited::archive(n);
 162         n.add_bool("symbolic", symbolic);
 163         n.add_bool("covariant", covariant);
 164         if (symbolic)
 165                 n.add_string("name", name);
 166         else
 167                 n.add_unsigned("value", value);
 168 }
 169
 170 //////////
 171 // functions overriding virtual functions from bases classes
 172 //////////
 173
 174 // public
 175
 176 basic * idx::duplicate() const
 177 {
 178         debugmsg("idx duplicate",LOGLEVEL_DUPLICATE);
 179         return new idx(*this);
 180 }
 181
 182 void idx::printraw(std::ostream & os) const
 183 {
 184         debugmsg("idx printraw",LOGLEVEL_PRINT);
 185
 186         os << "idx(";
 187
 188         if (symbolic) {
 189                 os << "symbolic,name=" << name;
 190         } else {
 191                 os << "non symbolic,value=" << value;
 192         }
 193
 194         if (covariant) {
 195                 os << ",covariant";
 196         } else {
 197                 os << ",contravariant";
 198         }
 199
 200         os << ",serial=" << serial;
 201         os << ",hash=" << hashvalue << ",flags=" << flags;
 202         os << ")";
 203 }
 204
 205 void idx::printtree(std::ostream & os, unsigned indent) const
 206 {
 207         debugmsg("idx printtree",LOGLEVEL_PRINT);
 208
 209         os << std::string(indent,' ') << "idx: ";
 210
 211         if (symbolic) {
 212                 os << "symbolic,name=" << name;
 213         } else {
 214                 os << "non symbolic,value=" << value;
 215         }
 216
 217         if (covariant) {
 218                 os << ",covariant";
 219         } else {
 220                 os << ",contravariant";
 221         }
 222
 223         os << ", serial=" << serial
 224            << ", hash=" << hashvalue
 225            << " (0x" << std::hex << hashvalue << std::dec << ")"
 226            << ", flags=" << flags << std::endl;
 227 }
 228
 229 void idx::print(std::ostream & os, unsigned upper_precedence) const
 230 {
 231         debugmsg("idx print",LOGLEVEL_PRINT);
 232
 233         if (covariant) {
 234                 os << "_";
 235         } else {
 236                 os << "~";
 237         }
 238         if (symbolic) {
 239                 os << name;
 240         } else {
 241                 os << value;
 242         }
 243 }
 244
 245 bool idx::info(unsigned inf) const
 246 {
 247         if (inf==info_flags::idx) return true;
 248         return inherited::info(inf);
 249 }
 250
 251 ex idx::subs(const lst & ls, const lst & lr) const
 252 {
 253         GINAC_ASSERT(ls.nops()==lr.nops());
 254 #ifdef DO_GINAC_ASSERT
 255         for (unsigned i=0; i<ls.nops(); i++) {
 256                 GINAC_ASSERT(is_ex_exactly_of_type(ls.op(i),symbol)||
 257                            is_ex_of_type(ls.op(i),idx));
 258         }
 259 #endif // def DO_GINAC_ASSERT
 260
 261         for (unsigned i=0; i<ls.nops(); i++) {
 262                 if (is_equal(*(ls.op(i)).bp)) {
 263                         return lr.op(i);
 264                 }
 265         }
 266         return *this;
 267 }
 268
 269 // protected
 270
 271 int idx::compare_same_type(const basic & other) const
 272 {
 273         GINAC_ASSERT(is_of_type(other,idx));
 274         const idx & o=static_cast<const idx &>(const_cast<basic &>(other));
 275
 276         if (covariant!=o.covariant) {
 277                 // different co/contravariant
 278                 return covariant ? -1 : 1;
 279         }
 280         if ((!symbolic) && (!o.symbolic)) {
 281                 // non-symbolic, of equal type: compare values
 282                 if (value==o.value) {
 283                         return 0;
 284                 }
 285                 return value<o.value ? -1 : 1;
 286         }
 287         if (symbolic && o.symbolic) {
 288                 // both symbolic: compare serials
 289                 if (serial==o.serial) {
 290                         return 0;
 291                 }
 292                 return serial<o.serial ? -1 : 1;
 293         }
 294         // one symbolic, one value: value is sorted first
 295         return o.symbolic ? -1 : 1;
 296 }
 297
 298 bool idx::is_equal_same_type(const basic & other) const
 299 {
 300         GINAC_ASSERT(is_of_type(other,idx));
 301         const idx & o=static_cast<const idx &>(const_cast<basic &>(other));
 302
 303         if (covariant!=o.covariant) return false;
 304         if (symbolic!=o.symbolic) return false;
 305         if (symbolic && o.symbolic) return serial==o.serial;
 306         return value==o.value;
 307 }
 308
 309 unsigned idx::calchash(void) const
 310 {
 311         hashvalue=golden_ratio_hash(golden_ratio_hash(tinfo_key ^ serial));
 312         setflag(status_flags::hash_calculated);
 313         return hashvalue;
 314 }
 315
 316 //////////
 317 // new virtual functions which can be overridden by derived classes
 318 //////////
 319
 320 // public
 321
 322 bool idx::is_co_contra_pair(const basic & other) const
 323 {
 324         // like is_equal_same_type(), but tests for different covariant status
 325         GINAC_ASSERT(is_of_type(other,idx));
 326         const idx & o=static_cast<const idx &>(const_cast<basic &>(other));
 327
 328         if (covariant==o.covariant) return false;
 329         if (symbolic!=o.symbolic) return false;
 330         if (symbolic && o.symbolic) return serial==o.serial;
 331         return value==o.value;
 332 }
 333
 334 bool idx::is_symbolic(void) const
 335 {
 336         return symbolic;
 337 }
 338
 339 unsigned idx::get_value(void) const
 340 {
 341         return value;
 342 }
 343
 344 bool idx::is_covariant(void) const
 345 {
 346         return covariant;
 347 }
 348
 349 ex idx::toggle_covariant(void) const
 350 {
 351         idx * i_copy=static_cast<idx *>(duplicate());
 352         i_copy->covariant = !i_copy->covariant;
 353         i_copy->clearflag(status_flags::hash_calculated);
 354         return i_copy->setflag(status_flags::dynallocated);
 355 }
 356
 357 //////////
 358 // non-virtual functions in this class
 359 //////////
 360
 361 // none
 362
 363 //////////
 364 // static member variables
 365 //////////
 366
 367 // protected
 368
 369 unsigned idx::next_serial=0;
 370
 371 //////////
 372 // global constants
 373 //////////
 374
 375 const idx some_idx;
 376 const std::type_info & typeid_idx = typeid(some_idx);
 377
 378 //////////
 379 // other functions
 380 //////////
 381
 382 int canonicalize_indices(exvector & iv, bool antisymmetric)
 383 {
 384         if (iv.size()<2) {
 385                 // nothing do to for 0 or 1 indices
 386                 return INT_MAX;
 387         }
 388
 389         bool something_changed=false;
 390         int sig=1;
 391         // simple bubble sort algorithm should be sufficient for the small number of indices needed
 392         exvector::const_iterator last_idx=iv.end();
 393         exvector::const_iterator next_to_last_idx=iv.end()-1;
 394         for (exvector::iterator it1=iv.begin(); it1!=next_to_last_idx; ++it1) {
 395                 for (exvector::iterator it2=it1+1; it2!=last_idx; ++it2) {
 396                         int cmpval=(*it1).compare(*it2);
 397                         if (cmpval==1) {
 398                                 iter_swap(it1,it2);
 399                                 something_changed=true;
 400                                 if (antisymmetric) sig=-sig;
 401                         } else if ((cmpval==0) && antisymmetric) {
 402                                 something_changed=true;
 403                                 sig=0;
 404                         }
 405                 }
 406         }
 407         return something_changed ? sig : INT_MAX;
 408 }
 409
 410 exvector idx_intersect(const exvector & iv1, const exvector & iv2)
 411 {
 412         // build a vector of symbolic indices contained in iv1 and iv2 simultaneously
 413         // assumes (but does not test) that each index occurs at most twice
 414         exvector iv_intersect;
 415         for (exvector::const_iterator cit1=iv1.begin(); cit1!=iv1.end(); ++cit1) {
 416                 GINAC_ASSERT(is_ex_of_type(*cit1,idx));
 417                 if (ex_to_idx(*cit1).is_symbolic()) {
 418                         for (exvector::const_iterator cit2=iv2.begin(); cit2!=iv2.end(); ++cit2) {
 419                                 GINAC_ASSERT(is_ex_of_type(*cit2,idx));
 420                                 if ((*cit1).is_equal(*cit2)) {
 421                                         iv_intersect.push_back(*cit1);
 422                                         break;
 423                                 }
 424                         }
 425                 }
 426         }
 427         return iv_intersect;
 428 }
 429
 430 #define TEST_PERMUTATION(A,B,C,P) \
 431         if ((iv3[B].is_equal(iv2[0]))&&(iv3[C].is_equal(iv2[1]))) { \
 432                 if (antisymmetric) *sig=P; \
 433                 return iv3[A]; \
 434         }
 435
 436 ex permute_free_index_to_front(const exvector & iv3, const exvector & iv2,
 437                                bool antisymmetric, int * sig)
 438 {
 439         // match (return value,iv2) to iv3 by permuting indices
 440         // iv3 is always cyclic
 441
 442         GINAC_ASSERT(iv3.size()==3);
 443         GINAC_ASSERT(iv2.size()==2);
 444
 445         *sig=1;
 446
 447         TEST_PERMUTATION(0,1,2,  1);
 448         TEST_PERMUTATION(0,2,1, -1);
 449         TEST_PERMUTATION(1,0,2, -1);
 450         TEST_PERMUTATION(1,2,0,  1);
 451         TEST_PERMUTATION(2,0,1,  1);
 452         TEST_PERMUTATION(2,1,0, -1);
 453         throw(std::logic_error("permute_free_index_to_front(): no valid permutation found"));
 454 }
 455
 456 unsigned subs_index_in_exvector(exvector & v, const ex & is, const ex & ir)
 457 {
 458         exvector::iterator it;
 459         unsigned replacements=0;
 460         unsigned current_replacements;
 461
 462         GINAC_ASSERT(is_ex_of_type(is,idx));
 463         GINAC_ASSERT(is_ex_of_type(ir,idx));
 464
 465         for (it=v.begin(); it!=v.end(); ++it) {
 466                 current_replacements=count_index(*it,is);
 467                 if (current_replacements>0) {
 468                         (*it)=(*it).subs(is==ir);
 469                 }
 470                 replacements += current_replacements;
 471         }
 472         return replacements;
 473 }
 474
 475 unsigned count_index(const ex & e, const ex & i)
 476 {
 477         exvector idxv=e.get_indices();
 478         unsigned count=0;
 479         for (exvector::const_iterator cit=idxv.begin(); cit!=idxv.end(); ++cit) {
 480                 if ((*cit).is_equal(i)) count++;
 481         }
 482         return count;
 483 }
 484
 485 ex subs_indices(const ex & e, const exvector & idxv_subs,
 486                 const exvector & idxv_repl)
 487 {
 488         GINAC_ASSERT(idxv_subs.size()==idxv_repl.size());
 489         ex res=e;
 490         for (unsigned i=0; i<idxv_subs.size(); ++i) {
 491                 res=res.subs(idxv_subs[i]==idxv_repl[i]);
 492         }
 493         return res;
 494 }
 495
 496 #ifndef NO_NAMESPACE_GINAC
 497 } // namespace GiNaC
 498 #endif // ndef NO_NAMESPACE_GINAC