ginac/relational.cpp

   1 /** @file relational.cpp
   2  *
   3  *  Implementation of relations between expressions */
   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 "relational.h"
  26 #include "numeric.h"
  27 #include "archive.h"
  28 #include "utils.h"
  29 #include "debugmsg.h"
  30
  31 #ifndef NO_NAMESPACE_GINAC
  32 namespace GiNaC {
  33 #endif // ndef NO_NAMESPACE_GINAC
  34
  35 GINAC_IMPLEMENT_REGISTERED_CLASS(relational, basic)
  36
  37 //////////
  38 // default constructor, destructor, copy constructor assignment operator and helpers
  39 //////////
  40
  41 // public
  42
  43 relational::relational() : basic(TINFO_relational)
  44 {
  45         debugmsg("relational default constructor",LOGLEVEL_CONSTRUCT);
  46 }
  47
  48 relational::~relational()
  49 {
  50         debugmsg("relational destructor",LOGLEVEL_DESTRUCT);
  51         destroy(0);
  52 }
  53
  54 relational::relational(const relational & other)
  55 {
  56         debugmsg("relational copy constructor",LOGLEVEL_CONSTRUCT);
  57         copy(other);
  58 }
  59
  60 const relational & relational::operator=(const relational & other)
  61 {
  62         debugmsg("relational operator=",LOGLEVEL_ASSIGNMENT);
  63         if (this != &other) {
  64                 destroy(1);
  65                 copy(other);
  66         }
  67         return *this;
  68 }
  69
  70 // protected
  71
  72 void relational::copy(const relational & other)
  73 {
  74         basic::copy(other);
  75         lh=other.lh;
  76         rh=other.rh;
  77         o=other.o;
  78 }
  79
  80 void relational::destroy(bool call_parent)
  81 {
  82         if (call_parent) basic::destroy(call_parent);
  83 }
  84
  85 //////////
  86 // other constructors
  87 //////////
  88
  89 // public
  90
  91 relational::relational(const ex & lhs, const ex & rhs, operators oper) : basic(TINFO_relational)
  92 {
  93         debugmsg("relational constructor ex,ex,operator",LOGLEVEL_CONSTRUCT);
  94         lh=lhs;
  95         rh=rhs;
  96         o=oper;
  97 }
  98
  99 //////////
 100 // archiving
 101 //////////
 102
 103 /** Construct object from archive_node. */
 104 relational::relational(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst)
 105 {
 106         debugmsg("relational constructor from archive_node", LOGLEVEL_CONSTRUCT);
 107         unsigned int opi;
 108         if (!(n.find_unsigned("op", opi)))
 109                 throw (std::runtime_error("unknown relational operator in archive"));
 110         o = (operators)opi;
 111         n.find_ex("lh", lh, sym_lst);
 112         n.find_ex("rh", rh, sym_lst);
 113 }
 114
 115 /** Unarchive the object. */
 116 ex relational::unarchive(const archive_node &n, const lst &sym_lst)
 117 {
 118         return (new relational(n, sym_lst))->setflag(status_flags::dynallocated);
 119 }
 120
 121 /** Archive the object. */
 122 void relational::archive(archive_node &n) const
 123 {
 124         inherited::archive(n);
 125         n.add_ex("lh", lh);
 126         n.add_ex("rh", rh);
 127         n.add_unsigned("op", o);
 128 }
 129
 130 //////////
 131 // functions overriding virtual functions from bases classes
 132 //////////
 133
 134 // public
 135
 136 basic * relational::duplicate() const
 137 {
 138         debugmsg("relational duplicate",LOGLEVEL_DUPLICATE);
 139         return new relational(*this);
 140 }
 141
 142 void relational::print(std::ostream & os, unsigned upper_precedence) const
 143 {
 144         debugmsg("relational print",LOGLEVEL_PRINT);
 145         if (precedence<=upper_precedence) os << "(";
 146         lh.print(os,precedence);
 147         switch (o) {
 148         case equal:
 149                 os << "==";
 150                 break;
 151         case not_equal:
 152                 os << "!=";
 153                 break;
 154         case less:
 155                 os << "<";
 156                 break;
 157         case less_or_equal:
 158                 os << "<=";
 159                 break;
 160         case greater:
 161                 os << ">";
 162                 break;
 163         case greater_or_equal:
 164                 os << ">=";
 165                 break;
 166         default:
 167                 os << "(INVALID RELATIONAL OPERATOR)";
 168         }
 169         rh.print(os,precedence);
 170         if (precedence<=upper_precedence) os << ")";
 171 }
 172
 173 void relational::printraw(std::ostream & os) const
 174 {
 175         debugmsg("relational printraw",LOGLEVEL_PRINT);
 176         os << "RELATIONAL(";
 177         lh.printraw(os);
 178         os << ",";
 179         rh.printraw(os);
 180         os << ",";
 181         switch (o) {
 182         case equal:
 183                 os << "==";
 184                 break;
 185         case not_equal:
 186                 os << "!=";
 187                 break;
 188         case less:
 189                 os << "<";
 190                 break;
 191         case less_or_equal:
 192                 os << "<=";
 193                 break;
 194         case greater:
 195                 os << ">";
 196                 break;
 197         case greater_or_equal:
 198                 os << ">=";
 199                 break;
 200         default:
 201                 os << "(INVALID RELATIONAL OPERATOR)";
 202         }
 203         os << ")";
 204 }
 205
 206 void relational::printcsrc(std::ostream & os, unsigned type, unsigned upper_precedence) const
 207 {
 208         debugmsg("relational print csrc", LOGLEVEL_PRINT);
 209         if (precedence<=upper_precedence)
 210                 os << "(";
 211
 212         // Print left-hand expression
 213         lh.bp->printcsrc(os, type, precedence);
 214
 215         // Print relational operator
 216         switch (o) {
 217                 case equal:
 218                         os << "==";
 219                         break;
 220                 case not_equal:
 221                         os << "!=";
 222                         break;
 223                 case less:
 224                         os << "<";
 225                         break;
 226                 case less_or_equal:
 227                         os << "<=";
 228                         break;
 229                 case greater:
 230                         os << ">";
 231                         break;
 232                 case greater_or_equal:
 233                         os << ">=";
 234                         break;
 235                 default:
 236                         os << "(INVALID RELATIONAL OPERATOR)";
 237                         break;
 238         }
 239
 240         // Print right-hand operator
 241         rh.bp->printcsrc(os, type, precedence);
 242
 243         if (precedence <= upper_precedence)
 244                 os << ")";
 245 }
 246
 247 bool relational::info(unsigned inf) const
 248 {
 249         switch (inf) {
 250         case info_flags::relation:
 251                 return 1;
 252         case info_flags::relation_equal:
 253                 return o==equal;
 254         case info_flags::relation_not_equal:
 255                 return o==not_equal;
 256         case info_flags::relation_less:
 257                 return o==less;
 258         case info_flags::relation_less_or_equal:
 259                 return o==less_or_equal;
 260         case info_flags::relation_greater:
 261                 return o==greater;
 262         case info_flags::relation_greater_or_equal:
 263                 return o==greater_or_equal;
 264         }
 265         return 0;
 266 }
 267
 268 unsigned relational::nops() const
 269 {
 270         return 2;
 271 }
 272
 273 ex & relational::let_op(int i)
 274 {
 275         GINAC_ASSERT(i>=0);
 276         GINAC_ASSERT(i<2);
 277
 278         return i==0 ? lh : rh;
 279 }
 280
 281 ex relational::eval(int level) const
 282 {
 283         if (level==1) {
 284                 return this->hold();
 285         }
 286         if (level == -max_recursion_level) {
 287                 throw(std::runtime_error("max recursion level reached"));
 288         }
 289         return (new relational(lh.eval(level-1),rh.eval(level-1),o))->
 290                         setflag(status_flags::dynallocated  |
 291                                         status_flags::evaluated );
 292 }
 293
 294 ex relational::evalf(int level) const
 295 {
 296         if (level==1) {
 297                 return *this;
 298         }
 299         if (level == -max_recursion_level) {
 300                 throw(std::runtime_error("max recursion level reached"));
 301         }
 302         return (new relational(lh.eval(level-1),rh.eval(level-1),o))->
 303                         setflag(status_flags::dynallocated);
 304 }
 305
 306 ex relational::simplify_ncmul(const exvector & v) const
 307 {
 308         return lh.simplify_ncmul(v);
 309 }
 310
 311 // protected
 312
 313 int relational::compare_same_type(const basic & other) const
 314 {
 315         GINAC_ASSERT(is_exactly_of_type(other, relational));
 316         const relational & oth=static_cast<const relational &>(const_cast<basic &>(other));
 317
 318         int cmpval;
 319
 320         if (o == oth.o) {
 321                 cmpval=lh.compare(oth.lh);
 322                 if (cmpval==0) {
 323                         return rh.compare(oth.rh);
 324                 } else {
 325                         return cmpval;
 326                 }
 327         }
 328         if (o<oth.o) {
 329                 return -1;
 330         } else {
 331                 return 1;
 332         }
 333 }
 334
 335 unsigned relational::return_type(void) const
 336 {
 337         GINAC_ASSERT(lh.return_type()==rh.return_type());
 338         return lh.return_type();
 339 }
 340
 341 unsigned relational::return_type_tinfo(void) const
 342 {
 343         GINAC_ASSERT(lh.return_type_tinfo()==rh.return_type_tinfo());
 344         return lh.return_type_tinfo();
 345 }
 346
 347 //////////
 348 // new virtual functions which can be overridden by derived classes
 349 //////////
 350
 351 /** Left hand side of relational. */
 352 ex relational::lhs(void) const
 353 {
 354         return lh;
 355 }
 356
 357 /** Right hand side of relational. */
 358 ex relational::rhs(void) const
 359 {
 360         return rh;
 361 }
 362
 363 //////////
 364 // non-virtual functions in this class
 365 //////////
 366
 367 relational::operator bool() const
 368 {
 369         // please note that (a<b) == false does not imply (a>=b) == true
 370         // a false result means the comparison is either false or undecidable
 371         // (except for !=, where true means unequal or undecidable)
 372         ex df=lh-rh;
 373         if (!is_ex_exactly_of_type(df,numeric)) {
 374                 return o==not_equal ? true : false; // cannot decide on non-numerical results
 375         }
 376         int cmpval=ex_to_numeric(df).compare(_num0());
 377         switch (o) {
 378         case equal:
 379                 return cmpval==0;
 380                 break;
 381         case not_equal:
 382                 return cmpval!=0;
 383                 break;
 384         case less:
 385                 return cmpval<0;
 386                 break;
 387         case less_or_equal:
 388                 return cmpval<=0;
 389                 break;
 390         case greater:
 391                 return cmpval>0;
 392                 break;
 393         case greater_or_equal:
 394                 return cmpval>=0;
 395                 break;
 396         default:
 397                 throw(std::logic_error("invalid relational operator"));
 398         }
 399         return 0;
 400 }
 401
 402 //////////
 403 // static member variables
 404 //////////
 405
 406 // protected
 407
 408 unsigned relational::precedence=20;
 409
 410 //////////
 411 // global constants
 412 //////////
 413
 414 const relational some_relational;
 415 const type_info & typeid_relational=typeid(some_relational);
 416
 417 #ifndef NO_NAMESPACE_GINAC
 418 } // namespace GiNaC
 419 #endif // ndef NO_NAMESPACE_GINAC