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