ginac/ex.cpp

   1 /** @file ex.cpp
   2  *
   3  *  Implementation of GiNaC's light-weight expression handles. */
   4
   5 /*
   6  *  GiNaC Copyright (C) 1999-2001 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 <iostream>
  24 #include <stdexcept>
  25
  26 #include "ex.h"
  27 #include "add.h"
  28 #include "mul.h"
  29 #include "ncmul.h"
  30 #include "numeric.h"
  31 #include "power.h"
  32 #include "relational.h"
  33 #include "indexed.h"
  34 #include "input_lexer.h"
  35 #include "debugmsg.h"
  36 #include "utils.h"
  37
  38 namespace GiNaC {
  39
  40 //////////
  41 // other ctors
  42 //////////
  43
  44 // none (all inlined)
  45
  46 //////////
  47 // functions overriding virtual functions from bases classes
  48 //////////
  49
  50 // none
  51
  52 //////////
  53 // new virtual functions which can be overridden by derived classes
  54 //////////
  55
  56 // none
  57
  58 //////////
  59 // non-virtual functions in this class
  60 //////////
  61
  62 // public
  63
  64 /** Efficiently swap the contents of two expressions. */
  65 void ex::swap(ex & other)
  66 {
  67         debugmsg("ex swap",LOGLEVEL_MEMBER_FUNCTION);
  68
  69         GINAC_ASSERT(bp!=0);
  70         GINAC_ASSERT(bp->flags & status_flags::dynallocated);
  71         GINAC_ASSERT(other.bp!=0);
  72         GINAC_ASSERT(other.bp->flags & status_flags::dynallocated);
  73
  74         basic * tmpbp = bp;
  75         bp = other.bp;
  76         other.bp = tmpbp;
  77 }
  78
  79 /** Print expression to stream. The formatting of the output is determined
  80  *  by the kind of print_context object that is passed. Possible formattings
  81  *  include ginsh-parsable output (the default), tree-like output for
  82  *  debugging, and C++ source.
  83  *  @see print_context */
  84 void ex::print(const print_context & c, unsigned level) const
  85 {
  86         debugmsg("ex print", LOGLEVEL_PRINT);
  87         GINAC_ASSERT(bp!=0);
  88         bp->print(c, level);
  89 }
  90
  91 /** Print expression to stream in a tree-like format suitable for debugging. */
  92 void ex::printtree(std::ostream & os) const
  93 {
  94         debugmsg("ex printtree", LOGLEVEL_PRINT);
  95         GINAC_ASSERT(bp!=0);
  96         bp->print(print_tree(os));
  97 }
  98
  99 /** Little wrapper arount print to be called within a debugger. */
 100 void ex::dbgprint(void) const
 101 {
 102         debugmsg("ex dbgprint", LOGLEVEL_PRINT);
 103         GINAC_ASSERT(bp!=0);
 104         bp->dbgprint();
 105 }
 106
 107 /** Little wrapper arount printtree to be called within a debugger. */
 108 void ex::dbgprinttree(void) const
 109 {
 110         debugmsg("ex dbgprinttree", LOGLEVEL_PRINT);
 111         GINAC_ASSERT(bp!=0);
 112         bp->dbgprinttree();
 113 }
 114
 115 bool ex::info(unsigned inf) const
 116 {
 117         return bp->info(inf);
 118 }
 119
 120 unsigned ex::nops() const
 121 {
 122         GINAC_ASSERT(bp!=0);
 123         return bp->nops();
 124 }
 125
 126 ex ex::expand(unsigned options) const
 127 {
 128         GINAC_ASSERT(bp!=0);
 129         if (bp->flags & status_flags::expanded)
 130                 return *bp;
 131         else
 132                 return bp->expand(options);
 133 }
 134
 135 bool ex::has(const ex & other) const
 136 {
 137         GINAC_ASSERT(bp!=0);
 138         return bp->has(other);
 139 }
 140
 141 int ex::degree(const ex & s) const
 142 {
 143         GINAC_ASSERT(bp!=0);
 144         return bp->degree(s);
 145 }
 146
 147 int ex::ldegree(const ex & s) const
 148 {
 149         GINAC_ASSERT(bp!=0);
 150         return bp->ldegree(s);
 151 }
 152
 153 ex ex::coeff(const ex & s, int n) const
 154 {
 155         GINAC_ASSERT(bp!=0);
 156         return bp->coeff(s,n);
 157 }
 158
 159 ex ex::collect(const ex & s) const
 160 {
 161         GINAC_ASSERT(bp!=0);
 162         return bp->collect(s);
 163 }
 164
 165 ex ex::eval(int level) const
 166 {
 167         GINAC_ASSERT(bp!=0);
 168         return bp->eval(level);
 169 }
 170
 171 ex ex::evalf(int level) const
 172 {
 173         GINAC_ASSERT(bp!=0);
 174         return bp->evalf(level);
 175 }
 176
 177 /** Compute partial derivative of an expression.
 178  *
 179  *  @param s  symbol by which the expression is derived
 180  *  @param nth  order of derivative (default 1)
 181  *  @return partial derivative as a new expression */
 182 ex ex::diff(const symbol & s, unsigned nth) const
 183 {
 184         GINAC_ASSERT(bp!=0);
 185
 186         if (!nth)
 187                 return *this;
 188         else
 189                 return bp->diff(s, nth);
 190 }
 191
 192 ex ex::subs(const lst & ls, const lst & lr) const
 193 {
 194         GINAC_ASSERT(bp!=0);
 195         return bp->subs(ls,lr);
 196 }
 197
 198 ex ex::subs(const ex & e) const
 199 {
 200         GINAC_ASSERT(bp!=0);
 201         return bp->subs(e);
 202 }
 203
 204 /** Return a vector containing the free indices of the object. */
 205 exvector ex::get_free_indices(void) const
 206 {
 207         GINAC_ASSERT(bp!=0);
 208         return bp->get_free_indices();
 209 }
 210
 211 /** Simplify/canonicalize expression containing indexed objects. This
 212  *  performs contraction of dummy indices where possible and checks whether
 213  *  the free indices in sums are consistent.
 214  *
 215  *  @return simplified expression */
 216 ex ex::simplify_indexed(void) const
 217 {
 218         return GiNaC::simplify_indexed(*this);
 219 }
 220
 221 /** Simplify/canonicalize expression containing indexed objects. This
 222  *  performs contraction of dummy indices where possible, checks whether
 223  *  the free indices in sums are consistent, and automatically replaces
 224  *  scalar products by known values if desired.
 225  *
 226  *  @param sp Scalar products to be replaced automatically
 227  *  @return simplified expression */
 228 ex ex::simplify_indexed(const scalar_products & sp) const
 229 {
 230         return GiNaC::simplify_indexed(*this, sp);
 231 }
 232
 233 ex ex::simplify_ncmul(const exvector & v) const
 234 {
 235         GINAC_ASSERT(bp!=0);
 236         return bp->simplify_ncmul(v);
 237 }
 238
 239 ex ex::operator[](const ex & index) const
 240 {
 241         debugmsg("ex operator[ex]",LOGLEVEL_OPERATOR);
 242         GINAC_ASSERT(bp!=0);
 243         return (*bp)[index];
 244 }
 245
 246 ex ex::operator[](int i) const
 247 {
 248         debugmsg("ex operator[int]",LOGLEVEL_OPERATOR);
 249         GINAC_ASSERT(bp!=0);
 250         return (*bp)[i];
 251 }
 252
 253 /** Return operand/member at position i. */
 254 ex ex::op(int i) const
 255 {
 256         debugmsg("ex op()",LOGLEVEL_MEMBER_FUNCTION);
 257         GINAC_ASSERT(bp!=0);
 258         return bp->op(i);
 259 }
 260
 261 /** Return modifyable operand/member at position i. */
 262 ex & ex::let_op(int i)
 263 {
 264         debugmsg("ex let_op()",LOGLEVEL_MEMBER_FUNCTION);
 265         makewriteable();
 266         GINAC_ASSERT(bp!=0);
 267         return bp->let_op(i);
 268 }
 269
 270 /** Left hand side of relational expression. */
 271 ex ex::lhs(void) const
 272 {
 273         debugmsg("ex lhs()",LOGLEVEL_MEMBER_FUNCTION);
 274         GINAC_ASSERT(is_ex_of_type(*this,relational));
 275         return (*static_cast<relational *>(bp)).lhs();
 276 }
 277
 278 /** Right hand side of relational expression. */
 279 ex ex::rhs(void) const
 280 {
 281         debugmsg("ex rhs()",LOGLEVEL_MEMBER_FUNCTION);
 282         GINAC_ASSERT(is_ex_of_type(*this,relational));
 283         return (*static_cast<relational *>(bp)).rhs();
 284 }
 285
 286 unsigned ex::return_type(void) const
 287 {
 288         GINAC_ASSERT(bp!=0);
 289         return bp->return_type();
 290 }
 291
 292 unsigned ex::return_type_tinfo(void) const
 293 {
 294         GINAC_ASSERT(bp!=0);
 295         return bp->return_type_tinfo();
 296 }
 297
 298 unsigned ex::gethash(void) const
 299 {
 300         GINAC_ASSERT(bp!=0);
 301         return bp->gethash();
 302 }
 303
 304 /** Used internally by operator+() to add two ex objects together. */
 305 ex ex::exadd(const ex & rh) const
 306 {
 307         return (new add(*this,rh))->setflag(status_flags::dynallocated);
 308 }
 309
 310 /** Used internally by operator*() to multiply two ex objects together. */
 311 ex ex::exmul(const ex & rh) const
 312 {
 313         // Check if we are constructing a mul object or a ncmul object.  Due to
 314         // ncmul::eval()'s rule to pull out commutative elements we need to check
 315         // only one of the elements.
 316         if (rh.bp->return_type()==return_types::commutative ||
 317             bp->return_type()==return_types::commutative)
 318                 return (new mul(*this,rh))->setflag(status_flags::dynallocated);
 319         else
 320                 return (new ncmul(*this,rh))->setflag(status_flags::dynallocated);
 321 }
 322
 323 // private
 324
 325 /** Make this ex writable (if more than one ex handle the same basic) by
 326  *  unlinking the object and creating an unshared copy of it. */
 327 void ex::makewriteable()
 328 {
 329         debugmsg("ex makewriteable",LOGLEVEL_MEMBER_FUNCTION);
 330         GINAC_ASSERT(bp!=0);
 331         GINAC_ASSERT(bp->flags & status_flags::dynallocated);
 332         if (bp->refcount > 1) {
 333                 basic * bp2 = bp->duplicate();
 334                 ++bp2->refcount;
 335                 bp2->setflag(status_flags::dynallocated);
 336                 --bp->refcount;
 337                 bp = bp2;
 338         }
 339         GINAC_ASSERT(bp->refcount==1);
 340 }
 341
 342 /** Ctor from basic implementation.
 343  *  @see ex::ex(const basic &) */
 344 void ex::construct_from_basic(const basic & other)
 345 {
 346         if ((other.flags & status_flags::evaluated)==0) {
 347                 // cf. copy ctor
 348                 const ex & tmpex = other.eval(1); // evaluate only one (top) level
 349                 bp = tmpex.bp;
 350                 GINAC_ASSERT(bp!=0);
 351                 GINAC_ASSERT(bp->flags & status_flags::dynallocated);
 352                 ++bp->refcount;
 353                 if ((other.flags & status_flags::dynallocated)&&(other.refcount==0))
 354                         delete &const_cast<basic &>(other);
 355         } else {
 356                 if (other.flags & status_flags::dynallocated) {
 357                         // ok, it is already on the heap, so just copy bp:
 358                         bp = &const_cast<basic &>(other);
 359                 } else {
 360                         // create a duplicate on the heap:
 361                         bp = other.duplicate();
 362                         bp->setflag(status_flags::dynallocated);
 363                 }
 364                 GINAC_ASSERT(bp!=0);
 365                 ++bp->refcount;
 366         }
 367         GINAC_ASSERT(bp!=0);
 368         GINAC_ASSERT(bp->flags & status_flags::dynallocated);
 369 }
 370
 371 void ex::construct_from_int(int i)
 372 {
 373         switch (i) {  // some tiny efficiency-hack
 374         case -2:
 375                 bp = _ex_2().bp;
 376                 ++bp->refcount;
 377                 break;
 378         case -1:
 379                 bp = _ex_1().bp;
 380                 ++bp->refcount;
 381                 break;
 382         case 0:
 383                 bp = _ex0().bp;
 384                 ++bp->refcount;
 385                 break;
 386         case 1:
 387                 bp = _ex1().bp;
 388                 ++bp->refcount;
 389                 break;
 390         case 2:
 391                 bp = _ex2().bp;
 392                 ++bp->refcount;
 393                 break;
 394         default:
 395                 bp = new numeric(i);
 396                 bp->setflag(status_flags::dynallocated);
 397                 ++bp->refcount;
 398                 GINAC_ASSERT((bp->flags) & status_flags::dynallocated);
 399                 GINAC_ASSERT(bp->refcount==1);
 400         }
 401 }
 402
 403 void ex::construct_from_uint(unsigned int i)
 404 {
 405         switch (i) {  // some tiny efficiency-hack
 406         case 0:
 407                 bp = _ex0().bp;
 408                 ++bp->refcount;
 409                 break;
 410         case 1:
 411                 bp = _ex1().bp;
 412                 ++bp->refcount;
 413                 break;
 414         case 2:
 415                 bp = _ex2().bp;
 416                 ++bp->refcount;
 417                 break;
 418         default:
 419                 bp = new numeric(i);
 420                 bp->setflag(status_flags::dynallocated);
 421                 ++bp->refcount;
 422                 GINAC_ASSERT((bp->flags) & status_flags::dynallocated);
 423                 GINAC_ASSERT(bp->refcount==1);
 424         }
 425 }
 426
 427 void ex::construct_from_long(long i)
 428 {
 429         switch (i) {  // some tiny efficiency-hack
 430         case -2:
 431                 bp = _ex_2().bp;
 432                 ++bp->refcount;
 433                 break;
 434         case -1:
 435                 bp = _ex_1().bp;
 436                 ++bp->refcount;
 437                 break;
 438         case 0:
 439                 bp = _ex0().bp;
 440                 ++bp->refcount;
 441                 break;
 442         case 1:
 443                 bp = _ex1().bp;
 444                 ++bp->refcount;
 445                 break;
 446         case 2:
 447                 bp = _ex2().bp;
 448                 ++bp->refcount;
 449                 break;
 450         default:
 451                 bp = new numeric(i);
 452                 bp->setflag(status_flags::dynallocated);
 453                 ++bp->refcount;
 454                 GINAC_ASSERT((bp->flags) & status_flags::dynallocated);
 455                 GINAC_ASSERT(bp->refcount==1);
 456         }
 457 }
 458
 459 void ex::construct_from_ulong(unsigned long i)
 460 {
 461         switch (i) {  // some tiny efficiency-hack
 462         case 0:
 463                 bp = _ex0().bp;
 464                 ++bp->refcount;
 465                 break;
 466         case 1:
 467                 bp = _ex1().bp;
 468                 ++bp->refcount;
 469                 break;
 470         case 2:
 471                 bp = _ex2().bp;
 472                 ++bp->refcount;
 473                 break;
 474         default:
 475                 bp = new numeric(i);
 476                 bp->setflag(status_flags::dynallocated);
 477                 ++bp->refcount;
 478                 GINAC_ASSERT((bp->flags) & status_flags::dynallocated);
 479                 GINAC_ASSERT(bp->refcount==1);
 480         }
 481 }
 482
 483 void ex::construct_from_double(double d)
 484 {
 485         bp = new numeric(d);
 486         bp->setflag(status_flags::dynallocated);
 487         ++bp->refcount;
 488         GINAC_ASSERT((bp->flags) & status_flags::dynallocated);
 489         GINAC_ASSERT(bp->refcount==1);
 490 }
 491
 492 void ex::construct_from_string_and_lst(const std::string &s, const ex &l)
 493 {
 494         set_lexer_string(s);
 495         set_lexer_symbols(l);
 496         ginac_yyrestart(NULL);
 497         if (ginac_yyparse())
 498                 throw (std::runtime_error(get_parser_error()));
 499         else {
 500                 bp = parsed_ex.bp;
 501                 GINAC_ASSERT(bp!=0);
 502                 GINAC_ASSERT((bp->flags) & status_flags::dynallocated);
 503                 ++bp->refcount;
 504         }
 505 }
 506
 507 //////////
 508 // static member variables
 509 //////////
 510
 511 // none
 512
 513 //////////
 514 // functions which are not member functions
 515 //////////
 516
 517 // none
 518
 519 //////////
 520 // global functions
 521 //////////
 522
 523 // none
 524
 525
 526 } // namespace GiNaC