G_do_hoelder: fix case with real x values which are not of type cl_R.
[ginac.git] / ginac / relational.cpp
1 /** @file relational.cpp
2  *
3  *  Implementation of relations between expressions */
4
5 /*
6  *  GiNaC Copyright (C) 1999-2018 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
21  */
22
23 #include "relational.h"
24 #include "operators.h"
25 #include "numeric.h"
26 #include "archive.h"
27 #include "utils.h"
28 #include "hash_seed.h"
29
30 #include <iostream>
31 #include <stdexcept>
32
33 namespace GiNaC {
34
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))
39
40 //////////
41 // default constructor
42 //////////
43
44 relational::relational() { }
45
46 //////////
47 // other constructors
48 //////////
49
50 // public
51
52 relational::relational(const ex & lhs, const ex & rhs, operators oper) :
53         lh(lhs), rh(rhs), o(oper) { }
54
55 //////////
56 // archiving
57 //////////
58
59 void relational::read_archive(const archive_node& n, lst& sym_lst)
60 {
61         inherited::read_archive(n, sym_lst);
62         unsigned int opi;
63         if (!(n.find_unsigned("op", opi)))
64                 throw (std::runtime_error("unknown relational operator in archive"));
65         o = (operators)opi;
66         n.find_ex("lh", lh, sym_lst);
67         n.find_ex("rh", rh, sym_lst);
68 }
69 GINAC_BIND_UNARCHIVER(relational);
70
71 void relational::archive(archive_node &n) const
72 {
73         inherited::archive(n);
74         n.add_ex("lh", lh);
75         n.add_ex("rh", rh);
76         n.add_unsigned("op", o);
77 }
78
79 //////////
80 // functions overriding virtual functions from base classes
81 //////////
82
83 // public
84
85 static void print_operator(const print_context & c, relational::operators o)
86 {
87         switch (o) {
88         case relational::equal:
89                 c.s << "==";
90                 break;
91         case relational::not_equal:
92                 c.s << "!=";
93                 break;
94         case relational::less:
95                 c.s << "<";
96                 break;
97         case relational::less_or_equal:
98                 c.s << "<=";
99                 break;
100         case relational::greater:
101                 c.s << ">";
102                 break;
103         case relational::greater_or_equal:
104                 c.s << ">=";
105                 break;
106         default:
107                 c.s << "(INVALID RELATIONAL OPERATOR)";
108                 break;
109         }
110 }
111
112 void relational::do_print(const print_context & c, unsigned level) const
113 {
114         if (precedence() <= level)
115                 c.s << "(";
116         lh.print(c, precedence());
117         print_operator(c, o);
118         rh.print(c, precedence());
119         if (precedence() <= level)
120                 c.s << ")";
121 }
122
123 void relational::do_print_python_repr(const print_python_repr & c, unsigned level) const
124 {
125         c.s << class_name() << '(';
126         lh.print(c);
127         c.s << ',';
128         rh.print(c);
129         c.s << ",'";
130         print_operator(c, o);
131         c.s << "')";
132 }
133
134 bool relational::info(unsigned inf) const
135 {
136         switch (inf) {
137                 case info_flags::relation:
138                         return 1;
139                 case info_flags::relation_equal:
140                         return o==equal;
141                 case info_flags::relation_not_equal:
142                         return o==not_equal;
143                 case info_flags::relation_less:
144                         return o==less;
145                 case info_flags::relation_less_or_equal:
146                         return o==less_or_equal;
147                 case info_flags::relation_greater:
148                         return o==greater;
149                 case info_flags::relation_greater_or_equal:
150                         return o==greater_or_equal;
151         }
152         return 0;
153 }
154
155 size_t relational::nops() const
156 {
157         return 2;
158 }
159
160 ex relational::op(size_t i) const
161 {
162         GINAC_ASSERT(i<2);
163
164         return i==0 ? lh : rh;
165 }
166
167 ex relational::map(map_function & f) const
168 {
169         const ex &mapped_lh = f(lh);
170         const ex &mapped_rh = f(rh);
171
172         if (!are_ex_trivially_equal(lh, mapped_lh)
173          || !are_ex_trivially_equal(rh, mapped_rh))
174                 return dynallocate<relational>(mapped_lh, mapped_rh, o);
175         else
176                 return *this;
177 }
178
179 ex relational::subs(const exmap & m, unsigned options) const
180 {
181         const ex & subsed_lh = lh.subs(m, options);
182         const ex & subsed_rh = rh.subs(m, options);
183
184         if (!are_ex_trivially_equal(lh, subsed_lh) || !are_ex_trivially_equal(rh, subsed_rh))
185                 return relational(subsed_lh, subsed_rh, o).subs_one_level(m, options);
186         else
187                 return subs_one_level(m, options);
188 }
189
190 ex relational::eval_ncmul(const exvector & v) const
191 {
192         return lh.eval_ncmul(v);
193 }
194
195 // protected
196
197 int relational::compare_same_type(const basic & other) const
198 {
199         GINAC_ASSERT(is_exactly_a<relational>(other));
200         const relational &oth = static_cast<const relational &>(other);
201         if (o==oth.o && lh.is_equal(oth.lh) && rh.is_equal(oth.rh))
202                 return 0;
203         switch (o) {
204                 case equal:
205                 case not_equal:
206                         if (oth.o!=o)
207                                 return (o < oth.o) ? -1 : 1;
208                         break;
209                 case less:
210                         if (oth.o!=greater)
211                                 return (o < oth.o) ? -1 : 1;
212                         break;
213                 case less_or_equal:
214                         if (oth.o!=greater_or_equal)
215                                 return (o < oth.o) ? -1 : 1;
216                         break;
217                 case greater:
218                         if (oth.o!=less)
219                                 return (o < oth.o) ? -1 : 1;
220                         break;
221                 case greater_or_equal:
222                         if (oth.o!=less_or_equal)
223                                 return (o < oth.o) ? -1 : 1;
224                         break;
225         }
226         const int lcmpval = lh.compare(oth.rh);
227         return (lcmpval!=0) ? lcmpval : rh.compare(oth.lh);
228 }
229
230 bool relational::match_same_type(const basic & other) const
231 {
232         GINAC_ASSERT(is_exactly_a<relational>(other));
233         const relational &oth = static_cast<const relational &>(other);
234
235         return o == oth.o;
236 }
237
238 unsigned relational::return_type() const
239 {
240         GINAC_ASSERT(lh.return_type()==rh.return_type());
241         return lh.return_type();
242 }
243
244 return_type_t relational::return_type_tinfo() const
245 {
246         GINAC_ASSERT(lh.return_type_tinfo()==rh.return_type_tinfo());
247         return lh.return_type_tinfo();
248 }
249
250 unsigned relational::calchash() const
251 {
252         unsigned v = make_hash_seed(typeid(*this));
253         unsigned lhash = lh.gethash();
254         unsigned rhash = rh.gethash();
255
256         v = rotate_left(v);
257         switch(o) {
258                 case equal:
259                 case not_equal:
260                         if (lhash>rhash) {
261                                 v ^= lhash;
262                                 lhash = rhash;
263                         } else {
264                                 v ^= rhash;
265                         }
266                         break;
267                 case less:
268                 case less_or_equal:
269                         v ^= rhash;
270                         break;
271                 case greater:
272                 case greater_or_equal:
273                         v ^= lhash;
274                         lhash = rhash;
275                         break;
276         }
277         v = rotate_left(v);
278         v ^= lhash;
279
280         // store calculated hash value only if object is already evaluated
281         if (flags & status_flags::evaluated) {
282                 setflag(status_flags::hash_calculated);
283                 hashvalue = v;
284         }
285
286         return v;
287 }
288
289 //////////
290 // new virtual functions which can be overridden by derived classes
291 //////////
292
293 // none
294
295 //////////
296 // non-virtual functions in this class
297 //////////
298
299 relational::safe_bool relational::make_safe_bool(bool cond) const
300 {
301         return cond? &safe_bool_helper::nonnull : nullptr;
302 }
303
304 /** Cast the relational into a Boolean, mainly for evaluation within an
305  *  if-statement.  Note that (a<b) == false does not imply (a>=b) == true in
306  *  the general symbolic case.  A false result means the comparison is either
307  *  false or undecidable (except of course for !=, where true means either
308  *  unequal or undecidable). */
309 relational::operator relational::safe_bool() const
310 {
311         const ex df = lh-rh;
312         if (!is_exactly_a<numeric>(df))
313                 // cannot decide on non-numerical results
314                 return o==not_equal ? make_safe_bool(true) : make_safe_bool(false);
315
316         switch (o) {
317                 case equal:
318                         return make_safe_bool(ex_to<numeric>(df).is_zero());
319                 case not_equal:
320                         return make_safe_bool(!ex_to<numeric>(df).is_zero());
321                 case less:
322                         return make_safe_bool(ex_to<numeric>(df)<(*_num0_p));
323                 case less_or_equal:
324                         return make_safe_bool(ex_to<numeric>(df)<=(*_num0_p));
325                 case greater:
326                         return make_safe_bool(ex_to<numeric>(df)>(*_num0_p));
327                 case greater_or_equal:
328                         return make_safe_bool(ex_to<numeric>(df)>=(*_num0_p));
329                 default:
330                         throw(std::logic_error("invalid relational operator"));
331         }
332 }
333
334 } // namespace GiNaC