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 "lst.h"
  35 #include "input_lexer.h"
  36 #include "debugmsg.h"
  37 #include "utils.h"
  38
  39 namespace GiNaC {
  40
  41 //////////
  42 // other ctors
  43 //////////
  44
  45 // none (all inlined)
  46
  47 //////////
  48 // functions overriding virtual functions from bases classes
  49 //////////
  50
  51 // none
  52
  53 //////////
  54 // new virtual functions which can be overridden by derived classes
  55 //////////
  56
  57 // none
  58
  59 //////////
  60 // non-virtual functions in this class
  61 //////////
  62
  63 // public
  64
  65 /** Efficiently swap the contents of two expressions. */
  66 void ex::swap(ex & other)
  67 {
  68         debugmsg("ex swap",LOGLEVEL_MEMBER_FUNCTION);
  69
  70         GINAC_ASSERT(bp!=0);
  71         GINAC_ASSERT(bp->flags & status_flags::dynallocated);
  72         GINAC_ASSERT(other.bp!=0);
  73         GINAC_ASSERT(other.bp->flags & status_flags::dynallocated);
  74
  75         basic * tmpbp = bp;
  76         bp = other.bp;
  77         other.bp = tmpbp;
  78 }
  79
  80 /** Print expression to stream. The formatting of the output is determined
  81  *  by the kind of print_context object that is passed. Possible formattings
  82  *  include ginsh-parsable output (the default), tree-like output for
  83  *  debugging, and C++ source.
  84  *  @see print_context */
  85 void ex::print(const print_context & c, unsigned level) const
  86 {
  87         debugmsg("ex print", LOGLEVEL_PRINT);
  88         GINAC_ASSERT(bp!=0);
  89         bp->print(c, level);
  90 }
  91
  92 /** Print expression to stream in a tree-like format suitable for debugging. */
  93 void ex::printtree(std::ostream & os) const
  94 {
  95         debugmsg("ex printtree", LOGLEVEL_PRINT);
  96         GINAC_ASSERT(bp!=0);
  97         bp->print(print_tree(os));
  98 }
  99
 100 /** Little wrapper arount print to be called within a debugger. */
 101 void ex::dbgprint(void) const
 102 {
 103         debugmsg("ex dbgprint", LOGLEVEL_PRINT);
 104         GINAC_ASSERT(bp!=0);
 105         bp->dbgprint();
 106 }
 107
 108 /** Little wrapper arount printtree to be called within a debugger. */
 109 void ex::dbgprinttree(void) const
 110 {
 111         debugmsg("ex dbgprinttree", LOGLEVEL_PRINT);
 112         GINAC_ASSERT(bp!=0);
 113         bp->dbgprinttree();
 114 }
 115
 116 ex ex::expand(unsigned options) const
 117 {
 118         GINAC_ASSERT(bp!=0);
 119         if (bp->flags & status_flags::expanded)
 120                 return *bp;
 121         else
 122                 return bp->expand(options);
 123 }
 124
 125 /** Compute partial derivative of an expression.
 126  *
 127  *  @param s  symbol by which the expression is derived
 128  *  @param nth  order of derivative (default 1)
 129  *  @return partial derivative as a new expression */
 130 ex ex::diff(const symbol & s, unsigned nth) const
 131 {
 132         GINAC_ASSERT(bp!=0);
 133
 134         if (!nth)
 135                 return *this;
 136         else
 137                 return bp->diff(s, nth);
 138 }
 139
 140 /** Check whether expression matches a specified pattern. */
 141 bool ex::match(const ex & pattern) const
 142 {
 143         lst repl_lst;
 144         return bp->match(pattern, repl_lst);
 145 }
 146
 147 /** Simplify/canonicalize expression containing indexed objects. This
 148  *  performs contraction of dummy indices where possible and checks whether
 149  *  the free indices in sums are consistent.
 150  *
 151  *  @return simplified expression */
 152 ex ex::simplify_indexed(void) const
 153 {
 154         return GiNaC::simplify_indexed(*this);
 155 }
 156
 157 /** Simplify/canonicalize expression containing indexed objects. This
 158  *  performs contraction of dummy indices where possible, checks whether
 159  *  the free indices in sums are consistent, and automatically replaces
 160  *  scalar products by known values if desired.
 161  *
 162  *  @param sp Scalar products to be replaced automatically
 163  *  @return simplified expression */
 164 ex ex::simplify_indexed(const scalar_products & sp) const
 165 {
 166         return GiNaC::simplify_indexed(*this, sp);
 167 }
 168
 169 ex ex::operator[](const ex & index) const
 170 {
 171         debugmsg("ex operator[ex]",LOGLEVEL_OPERATOR);
 172         GINAC_ASSERT(bp!=0);
 173         return (*bp)[index];
 174 }
 175
 176 ex ex::operator[](int i) const
 177 {
 178         debugmsg("ex operator[int]",LOGLEVEL_OPERATOR);
 179         GINAC_ASSERT(bp!=0);
 180         return (*bp)[i];
 181 }
 182
 183 /** Return modifyable operand/member at position i. */
 184 ex & ex::let_op(int i)
 185 {
 186         debugmsg("ex let_op()",LOGLEVEL_MEMBER_FUNCTION);
 187         makewriteable();
 188         GINAC_ASSERT(bp!=0);
 189         return bp->let_op(i);
 190 }
 191
 192 /** Left hand side of relational expression. */
 193 ex ex::lhs(void) const
 194 {
 195         debugmsg("ex lhs()",LOGLEVEL_MEMBER_FUNCTION);
 196         if (!is_ex_of_type(*this,relational))
 197                 throw std::runtime_error("ex::lhs(): not a relation");
 198         return (*static_cast<relational *>(bp)).lhs();
 199 }
 200
 201 /** Right hand side of relational expression. */
 202 ex ex::rhs(void) const
 203 {
 204         debugmsg("ex rhs()",LOGLEVEL_MEMBER_FUNCTION);
 205         if (!is_ex_of_type(*this,relational))
 206                 throw std::runtime_error("ex::rhs(): not a relation");
 207         return (*static_cast<relational *>(bp)).rhs();
 208 }
 209
 210 // private
 211
 212 /** Make this ex writable (if more than one ex handle the same basic) by
 213  *  unlinking the object and creating an unshared copy of it. */
 214 void ex::makewriteable()
 215 {
 216         debugmsg("ex makewriteable",LOGLEVEL_MEMBER_FUNCTION);
 217         GINAC_ASSERT(bp!=0);
 218         GINAC_ASSERT(bp->flags & status_flags::dynallocated);
 219         if (bp->refcount > 1) {
 220                 basic * bp2 = bp->duplicate();
 221                 ++bp2->refcount;
 222                 bp2->setflag(status_flags::dynallocated);
 223                 --bp->refcount;
 224                 bp = bp2;
 225         }
 226         GINAC_ASSERT(bp->refcount==1);
 227 }
 228
 229 /** Ctor from basic implementation.
 230  *  @see ex::ex(const basic &) */
 231 void ex::construct_from_basic(const basic & other)
 232 {
 233         if ((other.flags & status_flags::evaluated)==0) {
 234                 // cf. copy ctor
 235                 const ex & tmpex = other.eval(1); // evaluate only one (top) level
 236                 bp = tmpex.bp;
 237                 GINAC_ASSERT(bp!=0);
 238                 GINAC_ASSERT(bp->flags & status_flags::dynallocated);
 239                 ++bp->refcount;
 240                 if ((other.flags & status_flags::dynallocated)&&(other.refcount==0))
 241                         delete &const_cast<basic &>(other);
 242         } else {
 243                 if (other.flags & status_flags::dynallocated) {
 244                         // ok, it is already on the heap, so just copy bp:
 245                         bp = &const_cast<basic &>(other);
 246                 } else {
 247                         // create a duplicate on the heap:
 248                         bp = other.duplicate();
 249                         bp->setflag(status_flags::dynallocated);
 250                 }
 251                 GINAC_ASSERT(bp!=0);
 252                 ++bp->refcount;
 253         }
 254         GINAC_ASSERT(bp!=0);
 255         GINAC_ASSERT(bp->flags & status_flags::dynallocated);
 256 }
 257
 258 void ex::construct_from_int(int i)
 259 {
 260         switch (i) {  // some tiny efficiency-hack
 261         case -2:
 262                 bp = _ex_2().bp;
 263                 ++bp->refcount;
 264                 break;
 265         case -1:
 266                 bp = _ex_1().bp;
 267                 ++bp->refcount;
 268                 break;
 269         case 0:
 270                 bp = _ex0().bp;
 271                 ++bp->refcount;
 272                 break;
 273         case 1:
 274                 bp = _ex1().bp;
 275                 ++bp->refcount;
 276                 break;
 277         case 2:
 278                 bp = _ex2().bp;
 279                 ++bp->refcount;
 280                 break;
 281         default:
 282                 bp = new numeric(i);
 283                 bp->setflag(status_flags::dynallocated);
 284                 ++bp->refcount;
 285                 GINAC_ASSERT((bp->flags) & status_flags::dynallocated);
 286                 GINAC_ASSERT(bp->refcount==1);
 287         }
 288 }
 289
 290 void ex::construct_from_uint(unsigned int i)
 291 {
 292         switch (i) {  // some tiny efficiency-hack
 293         case 0:
 294                 bp = _ex0().bp;
 295                 ++bp->refcount;
 296                 break;
 297         case 1:
 298                 bp = _ex1().bp;
 299                 ++bp->refcount;
 300                 break;
 301         case 2:
 302                 bp = _ex2().bp;
 303                 ++bp->refcount;
 304                 break;
 305         default:
 306                 bp = new numeric(i);
 307                 bp->setflag(status_flags::dynallocated);
 308                 ++bp->refcount;
 309                 GINAC_ASSERT((bp->flags) & status_flags::dynallocated);
 310                 GINAC_ASSERT(bp->refcount==1);
 311         }
 312 }
 313
 314 void ex::construct_from_long(long i)
 315 {
 316         switch (i) {  // some tiny efficiency-hack
 317         case -2:
 318                 bp = _ex_2().bp;
 319                 ++bp->refcount;
 320                 break;
 321         case -1:
 322                 bp = _ex_1().bp;
 323                 ++bp->refcount;
 324                 break;
 325         case 0:
 326                 bp = _ex0().bp;
 327                 ++bp->refcount;
 328                 break;
 329         case 1:
 330                 bp = _ex1().bp;
 331                 ++bp->refcount;
 332                 break;
 333         case 2:
 334                 bp = _ex2().bp;
 335                 ++bp->refcount;
 336                 break;
 337         default:
 338                 bp = new numeric(i);
 339                 bp->setflag(status_flags::dynallocated);
 340                 ++bp->refcount;
 341                 GINAC_ASSERT((bp->flags) & status_flags::dynallocated);
 342                 GINAC_ASSERT(bp->refcount==1);
 343         }
 344 }
 345
 346 void ex::construct_from_ulong(unsigned long i)
 347 {
 348         switch (i) {  // some tiny efficiency-hack
 349         case 0:
 350                 bp = _ex0().bp;
 351                 ++bp->refcount;
 352                 break;
 353         case 1:
 354                 bp = _ex1().bp;
 355                 ++bp->refcount;
 356                 break;
 357         case 2:
 358                 bp = _ex2().bp;
 359                 ++bp->refcount;
 360                 break;
 361         default:
 362                 bp = new numeric(i);
 363                 bp->setflag(status_flags::dynallocated);
 364                 ++bp->refcount;
 365                 GINAC_ASSERT((bp->flags) & status_flags::dynallocated);
 366                 GINAC_ASSERT(bp->refcount==1);
 367         }
 368 }
 369
 370 void ex::construct_from_double(double d)
 371 {
 372         bp = new numeric(d);
 373         bp->setflag(status_flags::dynallocated);
 374         ++bp->refcount;
 375         GINAC_ASSERT((bp->flags) & status_flags::dynallocated);
 376         GINAC_ASSERT(bp->refcount==1);
 377 }
 378
 379 void ex::construct_from_string_and_lst(const std::string &s, const ex &l)
 380 {
 381         set_lexer_string(s);
 382         set_lexer_symbols(l);
 383         ginac_yyrestart(NULL);
 384         if (ginac_yyparse())
 385                 throw (std::runtime_error(get_parser_error()));
 386         else {
 387                 bp = parsed_ex.bp;
 388                 GINAC_ASSERT(bp!=0);
 389                 GINAC_ASSERT((bp->flags) & status_flags::dynallocated);
 390                 ++bp->refcount;
 391         }
 392 }
 393
 394 //////////
 395 // static member variables
 396 //////////
 397
 398 // none
 399
 400 //////////
 401 // functions which are not member functions
 402 //////////
 403
 404 // none
 405
 406 //////////
 407 // global functions
 408 //////////
 409
 410 // none
 411
 412
 413 } // namespace GiNaC