ginac/relational.cpp

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