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 ex ex::expand(unsigned options) const
 116 {
 117         GINAC_ASSERT(bp!=0);
 118         if (bp->flags & status_flags::expanded)
 119                 return *bp;
 120         else
 121                 return bp->expand(options);
 122 }
 123
 124 /** Compute partial derivative of an expression.
 125  *
 126  *  @param s  symbol by which the expression is derived
 127  *  @param nth  order of derivative (default 1)
 128  *  @return partial derivative as a new expression */
 129 ex ex::diff(const symbol & s, unsigned nth) const
 130 {
 131         GINAC_ASSERT(bp!=0);
 132
 133         if (!nth)
 134                 return *this;
 135         else
 136                 return bp->diff(s, nth);
 137 }
 138
 139 /** Simplify/canonicalize expression containing indexed objects. This
 140  *  performs contraction of dummy indices where possible and checks whether
 141  *  the free indices in sums are consistent.
 142  *
 143  *  @return simplified expression */
 144 ex ex::simplify_indexed(void) const
 145 {
 146         return GiNaC::simplify_indexed(*this);
 147 }
 148
 149 /** Simplify/canonicalize expression containing indexed objects. This
 150  *  performs contraction of dummy indices where possible, checks whether
 151  *  the free indices in sums are consistent, and automatically replaces
 152  *  scalar products by known values if desired.
 153  *
 154  *  @param sp Scalar products to be replaced automatically
 155  *  @return simplified expression */
 156 ex ex::simplify_indexed(const scalar_products & sp) const
 157 {
 158         return GiNaC::simplify_indexed(*this, sp);
 159 }
 160
 161 ex ex::operator[](const ex & index) const
 162 {
 163         debugmsg("ex operator[ex]",LOGLEVEL_OPERATOR);
 164         GINAC_ASSERT(bp!=0);
 165         return (*bp)[index];
 166 }
 167
 168 ex ex::operator[](int i) const
 169 {
 170         debugmsg("ex operator[int]",LOGLEVEL_OPERATOR);
 171         GINAC_ASSERT(bp!=0);
 172         return (*bp)[i];
 173 }
 174
 175 /** Return modifyable operand/member at position i. */
 176 ex & ex::let_op(int i)
 177 {
 178         debugmsg("ex let_op()",LOGLEVEL_MEMBER_FUNCTION);
 179         makewriteable();
 180         GINAC_ASSERT(bp!=0);
 181         return bp->let_op(i);
 182 }
 183
 184 /** Left hand side of relational expression. */
 185 ex ex::lhs(void) const
 186 {
 187         debugmsg("ex lhs()",LOGLEVEL_MEMBER_FUNCTION);
 188         if (!is_ex_of_type(*this,relational))
 189                 throw std::runtime_error("ex::lhs(): not a relation");
 190         return (*static_cast<relational *>(bp)).lhs();
 191 }
 192
 193 /** Right hand side of relational expression. */
 194 ex ex::rhs(void) const
 195 {
 196         debugmsg("ex rhs()",LOGLEVEL_MEMBER_FUNCTION);
 197         if (!is_ex_of_type(*this,relational))
 198                 throw std::runtime_error("ex::rhs(): not a relation");
 199         return (*static_cast<relational *>(bp)).rhs();
 200 }
 201
 202 /** Used internally by operator+() to add two ex objects together. */
 203 ex ex::exadd(const ex & rh) const
 204 {
 205         return (new add(*this,rh))->setflag(status_flags::dynallocated);
 206 }
 207
 208 /** Used internally by operator*() to multiply two ex objects together. */
 209 ex ex::exmul(const ex & rh) const
 210 {
 211         // Check if we are constructing a mul object or a ncmul object.  Due to
 212         // ncmul::eval()'s rule to pull out commutative elements we need to check
 213         // only one of the elements.
 214         if (rh.bp->return_type()==return_types::commutative ||
 215             bp->return_type()==return_types::commutative)
 216                 return (new mul(*this,rh))->setflag(status_flags::dynallocated);
 217         else
 218                 return (new ncmul(*this,rh))->setflag(status_flags::dynallocated);
 219 }
 220
 221 // private
 222
 223 /** Make this ex writable (if more than one ex handle the same basic) by
 224  *  unlinking the object and creating an unshared copy of it. */
 225 void ex::makewriteable()
 226 {
 227         debugmsg("ex makewriteable",LOGLEVEL_MEMBER_FUNCTION);
 228         GINAC_ASSERT(bp!=0);
 229         GINAC_ASSERT(bp->flags & status_flags::dynallocated);
 230         if (bp->refcount > 1) {
 231                 basic * bp2 = bp->duplicate();
 232                 ++bp2->refcount;
 233                 bp2->setflag(status_flags::dynallocated);
 234                 --bp->refcount;
 235                 bp = bp2;
 236         }
 237         GINAC_ASSERT(bp->refcount==1);
 238 }
 239
 240 /** Ctor from basic implementation.
 241  *  @see ex::ex(const basic &) */
 242 void ex::construct_from_basic(const basic & other)
 243 {
 244         if ((other.flags & status_flags::evaluated)==0) {
 245                 // cf. copy ctor
 246                 const ex & tmpex = other.eval(1); // evaluate only one (top) level
 247                 bp = tmpex.bp;
 248                 GINAC_ASSERT(bp!=0);
 249                 GINAC_ASSERT(bp->flags & status_flags::dynallocated);
 250                 ++bp->refcount;
 251                 if ((other.flags & status_flags::dynallocated)&&(other.refcount==0))
 252                         delete &const_cast<basic &>(other);
 253         } else {
 254                 if (other.flags & status_flags::dynallocated) {
 255                         // ok, it is already on the heap, so just copy bp:
 256                         bp = &const_cast<basic &>(other);
 257                 } else {
 258                         // create a duplicate on the heap:
 259                         bp = other.duplicate();
 260                         bp->setflag(status_flags::dynallocated);
 261                 }
 262                 GINAC_ASSERT(bp!=0);
 263                 ++bp->refcount;
 264         }
 265         GINAC_ASSERT(bp!=0);
 266         GINAC_ASSERT(bp->flags & status_flags::dynallocated);
 267 }
 268
 269 void ex::construct_from_int(int i)
 270 {
 271         switch (i) {  // some tiny efficiency-hack
 272         case -2:
 273                 bp = _ex_2().bp;
 274                 ++bp->refcount;
 275                 break;
 276         case -1:
 277                 bp = _ex_1().bp;
 278                 ++bp->refcount;
 279                 break;
 280         case 0:
 281                 bp = _ex0().bp;
 282                 ++bp->refcount;
 283                 break;
 284         case 1:
 285                 bp = _ex1().bp;
 286                 ++bp->refcount;
 287                 break;
 288         case 2:
 289                 bp = _ex2().bp;
 290                 ++bp->refcount;
 291                 break;
 292         default:
 293                 bp = new numeric(i);
 294                 bp->setflag(status_flags::dynallocated);
 295                 ++bp->refcount;
 296                 GINAC_ASSERT((bp->flags) & status_flags::dynallocated);
 297                 GINAC_ASSERT(bp->refcount==1);
 298         }
 299 }
 300
 301 void ex::construct_from_uint(unsigned int i)
 302 {
 303         switch (i) {  // some tiny efficiency-hack
 304         case 0:
 305                 bp = _ex0().bp;
 306                 ++bp->refcount;
 307                 break;
 308         case 1:
 309                 bp = _ex1().bp;
 310                 ++bp->refcount;
 311                 break;
 312         case 2:
 313                 bp = _ex2().bp;
 314                 ++bp->refcount;
 315                 break;
 316         default:
 317                 bp = new numeric(i);
 318                 bp->setflag(status_flags::dynallocated);
 319                 ++bp->refcount;
 320                 GINAC_ASSERT((bp->flags) & status_flags::dynallocated);
 321                 GINAC_ASSERT(bp->refcount==1);
 322         }
 323 }
 324
 325 void ex::construct_from_long(long i)
 326 {
 327         switch (i) {  // some tiny efficiency-hack
 328         case -2:
 329                 bp = _ex_2().bp;
 330                 ++bp->refcount;
 331                 break;
 332         case -1:
 333                 bp = _ex_1().bp;
 334                 ++bp->refcount;
 335                 break;
 336         case 0:
 337                 bp = _ex0().bp;
 338                 ++bp->refcount;
 339                 break;
 340         case 1:
 341                 bp = _ex1().bp;
 342                 ++bp->refcount;
 343                 break;
 344         case 2:
 345                 bp = _ex2().bp;
 346                 ++bp->refcount;
 347                 break;
 348         default:
 349                 bp = new numeric(i);
 350                 bp->setflag(status_flags::dynallocated);
 351                 ++bp->refcount;
 352                 GINAC_ASSERT((bp->flags) & status_flags::dynallocated);
 353                 GINAC_ASSERT(bp->refcount==1);
 354         }
 355 }
 356
 357 void ex::construct_from_ulong(unsigned long i)
 358 {
 359         switch (i) {  // some tiny efficiency-hack
 360         case 0:
 361                 bp = _ex0().bp;
 362                 ++bp->refcount;
 363                 break;
 364         case 1:
 365                 bp = _ex1().bp;
 366                 ++bp->refcount;
 367                 break;
 368         case 2:
 369                 bp = _ex2().bp;
 370                 ++bp->refcount;
 371                 break;
 372         default:
 373                 bp = new numeric(i);
 374                 bp->setflag(status_flags::dynallocated);
 375                 ++bp->refcount;
 376                 GINAC_ASSERT((bp->flags) & status_flags::dynallocated);
 377                 GINAC_ASSERT(bp->refcount==1);
 378         }
 379 }
 380
 381 void ex::construct_from_double(double d)
 382 {
 383         bp = new numeric(d);
 384         bp->setflag(status_flags::dynallocated);
 385         ++bp->refcount;
 386         GINAC_ASSERT((bp->flags) & status_flags::dynallocated);
 387         GINAC_ASSERT(bp->refcount==1);
 388 }
 389
 390 void ex::construct_from_string_and_lst(const std::string &s, const ex &l)
 391 {
 392         set_lexer_string(s);
 393         set_lexer_symbols(l);
 394         ginac_yyrestart(NULL);
 395         if (ginac_yyparse())
 396                 throw (std::runtime_error(get_parser_error()));
 397         else {
 398                 bp = parsed_ex.bp;
 399                 GINAC_ASSERT(bp!=0);
 400                 GINAC_ASSERT((bp->flags) & status_flags::dynallocated);
 401                 ++bp->refcount;
 402         }
 403 }
 404
 405 //////////
 406 // static member variables
 407 //////////
 408
 409 // none
 410
 411 //////////
 412 // functions which are not member functions
 413 //////////
 414
 415 // none
 416
 417 //////////
 418 // global functions
 419 //////////
 420
 421 // none
 422
 423
 424 } // namespace GiNaC