1 /** @file relational.cpp
3 * Implementation of relations between expressions */
6 * GiNaC Copyright (C) 1999-2011 Johannes Gutenberg University Mainz, Germany
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
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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.
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20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 #include "relational.h"
24 #include "operators.h"
28 #include "hash_seed.h"
35 GINAC_IMPLEMENT_REGISTERED_CLASS_OPT(relational, basic,
36 print_func<print_context>(&relational::do_print).
37 print_func<print_tree>(&relational::do_print_tree).
38 print_func<print_python_repr>(&relational::do_print_python_repr))
41 // default constructor
44 relational::relational() { }
52 relational::relational(const ex & lhs, const ex & rhs, operators oper) :
53 lh(lhs), rh(rhs), o(oper) { }
59 void relational::read_archive(const archive_node& n, lst& sym_lst)
61 inherited::read_archive(n, sym_lst);
63 if (!(n.find_unsigned("op", opi)))
64 throw (std::runtime_error("unknown relational operator in archive"));
66 n.find_ex("lh", lh, sym_lst);
67 n.find_ex("rh", rh, sym_lst);
69 GINAC_BIND_UNARCHIVER(relational);
71 void relational::archive(archive_node &n) const
73 inherited::archive(n);
76 n.add_unsigned("op", o);
80 // functions overriding virtual functions from base classes
85 static void print_operator(const print_context & c, relational::operators o)
88 case relational::equal:
91 case relational::not_equal:
94 case relational::less:
97 case relational::less_or_equal:
100 case relational::greater:
103 case relational::greater_or_equal:
107 c.s << "(INVALID RELATIONAL OPERATOR)";
112 void relational::do_print(const print_context & c, unsigned level) const
114 if (precedence() <= level)
116 lh.print(c, precedence());
117 print_operator(c, o);
118 rh.print(c, precedence());
119 if (precedence() <= level)
123 void relational::do_print_python_repr(const print_python_repr & c, unsigned level) const
125 c.s << class_name() << '(';
130 print_operator(c, o);
134 bool relational::info(unsigned inf) const
137 case info_flags::relation:
139 case info_flags::relation_equal:
141 case info_flags::relation_not_equal:
143 case info_flags::relation_less:
145 case info_flags::relation_less_or_equal:
146 return o==less_or_equal;
147 case info_flags::relation_greater:
149 case info_flags::relation_greater_or_equal:
150 return o==greater_or_equal;
155 size_t relational::nops() const
160 ex relational::op(size_t i) const
164 return i==0 ? lh : rh;
167 ex relational::map(map_function & f) const
169 const ex &mapped_lh = f(lh);
170 const ex &mapped_rh = f(rh);
172 if (!are_ex_trivially_equal(lh, mapped_lh)
173 || !are_ex_trivially_equal(rh, mapped_rh))
174 return (new relational(mapped_lh, mapped_rh, o))->setflag(status_flags::dynallocated);
179 ex relational::eval(int level) const
184 if (level == -max_recursion_level)
185 throw(std::runtime_error("max recursion level reached"));
187 return (new relational(lh.eval(level-1),rh.eval(level-1),o))->setflag(status_flags::dynallocated | status_flags::evaluated);
190 ex relational::subs(const exmap & m, unsigned options) const
192 const ex & subsed_lh = lh.subs(m, options);
193 const ex & subsed_rh = rh.subs(m, options);
195 if (!are_ex_trivially_equal(lh, subsed_lh) || !are_ex_trivially_equal(rh, subsed_rh))
196 return relational(subsed_lh, subsed_rh, o).subs_one_level(m, options);
198 return subs_one_level(m, options);
201 ex relational::eval_ncmul(const exvector & v) const
203 return lh.eval_ncmul(v);
208 int relational::compare_same_type(const basic & other) const
210 GINAC_ASSERT(is_exactly_a<relational>(other));
211 const relational &oth = static_cast<const relational &>(other);
212 if (o==oth.o && lh.is_equal(oth.lh) && rh.is_equal(oth.rh))
218 return (o < oth.o) ? -1 : 1;
222 return (o < oth.o) ? -1 : 1;
225 if (oth.o!=greater_or_equal)
226 return (o < oth.o) ? -1 : 1;
230 return (o < oth.o) ? -1 : 1;
232 case greater_or_equal:
233 if (oth.o!=less_or_equal)
234 return (o < oth.o) ? -1 : 1;
237 const int lcmpval = lh.compare(oth.rh);
238 return (lcmpval!=0) ? lcmpval : rh.compare(oth.lh);
241 bool relational::match_same_type(const basic & other) const
243 GINAC_ASSERT(is_exactly_a<relational>(other));
244 const relational &oth = static_cast<const relational &>(other);
249 unsigned relational::return_type() const
251 GINAC_ASSERT(lh.return_type()==rh.return_type());
252 return lh.return_type();
255 return_type_t relational::return_type_tinfo() const
257 GINAC_ASSERT(lh.return_type_tinfo()==rh.return_type_tinfo());
258 return lh.return_type_tinfo();
261 unsigned relational::calchash() const
263 unsigned v = make_hash_seed(typeid(*this));
264 unsigned lhash = lh.gethash();
265 unsigned rhash = rh.gethash();
283 case greater_or_equal:
291 // store calculated hash value only if object is already evaluated
292 if (flags & status_flags::evaluated) {
293 setflag(status_flags::hash_calculated);
301 // new virtual functions which can be overridden by derived classes
304 /** Left hand side of relational. */
305 ex relational::lhs() const
310 /** Right hand side of relational. */
311 ex relational::rhs() const
317 // non-virtual functions in this class
320 relational::safe_bool relational::make_safe_bool(bool cond) const
322 return cond? &safe_bool_helper::nonnull : 0;
325 /** Cast the relational into a boolean, mainly for evaluation within an
326 * if-statement. Note that (a<b) == false does not imply (a>=b) == true in
327 * the general symbolic case. A false result means the comparison is either
328 * false or undecidable (except of course for !=, where true means either
329 * unequal or undecidable). */
330 relational::operator relational::safe_bool() const
333 if (!is_exactly_a<numeric>(df))
334 // cannot decide on non-numerical results
335 return o==not_equal ? make_safe_bool(true) : make_safe_bool(false);
339 return make_safe_bool(ex_to<numeric>(df).is_zero());
341 return make_safe_bool(!ex_to<numeric>(df).is_zero());
343 return make_safe_bool(ex_to<numeric>(df)<(*_num0_p));
345 return make_safe_bool(ex_to<numeric>(df)<=(*_num0_p));
347 return make_safe_bool(ex_to<numeric>(df)>(*_num0_p));
348 case greater_or_equal:
349 return make_safe_bool(ex_to<numeric>(df)>=(*_num0_p));
351 throw(std::logic_error("invalid relational operator"));