1 /*
2 * Copyright 2008-2009 Katholieke Universiteit Leuven
3 *
4 * Use of this software is governed by the MIT license
5 *
6 * Written by Sven Verdoolaege, K.U.Leuven, Departement
7 * Computerwetenschappen, Celestijnenlaan 200A, B-3001 Leuven, Belgium
8 */
9
10 #include <isl_ctx_private.h>
11 #include <isl_map_private.h>
12 #include "isl_basis_reduction.h"
13 #include "isl_scan.h"
14 #include <isl_seq.h>
15 #include "isl_tab.h"
16 #include <isl_val_private.h>
17 #include <isl_vec_private.h>
18
19 struct isl_counter {
20 struct isl_scan_callback callback;
21 isl_int count;
22 isl_int max;
23 };
24
increment_counter(struct isl_scan_callback * cb,__isl_take isl_vec * sample)25 static isl_stat increment_counter(struct isl_scan_callback *cb,
26 __isl_take isl_vec *sample)
27 {
28 struct isl_counter *cnt = (struct isl_counter *)cb;
29
30 isl_int_add_ui(cnt->count, cnt->count, 1);
31
32 isl_vec_free(sample);
33
34 if (isl_int_is_zero(cnt->max) || isl_int_lt(cnt->count, cnt->max))
35 return isl_stat_ok;
36 return isl_stat_error;
37 }
38
increment_range(struct isl_scan_callback * cb,isl_int min,isl_int max)39 static int increment_range(struct isl_scan_callback *cb, isl_int min, isl_int max)
40 {
41 struct isl_counter *cnt = (struct isl_counter *)cb;
42
43 isl_int_add(cnt->count, cnt->count, max);
44 isl_int_sub(cnt->count, cnt->count, min);
45 isl_int_add_ui(cnt->count, cnt->count, 1);
46
47 if (isl_int_is_zero(cnt->max) || isl_int_lt(cnt->count, cnt->max))
48 return 0;
49 isl_int_set(cnt->count, cnt->max);
50 return -1;
51 }
52
53 /* Call callback->add with the current sample value of the tableau "tab".
54 */
add_solution(struct isl_tab * tab,struct isl_scan_callback * callback)55 static int add_solution(struct isl_tab *tab, struct isl_scan_callback *callback)
56 {
57 struct isl_vec *sample;
58
59 if (!tab)
60 return -1;
61 sample = isl_tab_get_sample_value(tab);
62 if (!sample)
63 return -1;
64
65 return callback->add(callback, sample);
66 }
67
scan_0D(__isl_take isl_basic_set * bset,struct isl_scan_callback * callback)68 static isl_stat scan_0D(__isl_take isl_basic_set *bset,
69 struct isl_scan_callback *callback)
70 {
71 struct isl_vec *sample;
72
73 sample = isl_vec_alloc(bset->ctx, 1);
74 isl_basic_set_free(bset);
75
76 if (!sample)
77 return isl_stat_error;
78
79 isl_int_set_si(sample->el[0], 1);
80
81 return callback->add(callback, sample);
82 }
83
84 /* Look for all integer points in "bset", which is assumed to be bounded,
85 * and call callback->add on each of them.
86 *
87 * We first compute a reduced basis for the set and then scan
88 * the set in the directions of this basis.
89 * We basically perform a depth first search, where in each level i
90 * we compute the range in the i-th basis vector direction, given
91 * fixed values in the directions of the previous basis vector.
92 * We then add an equality to the tableau fixing the value in the
93 * direction of the current basis vector to each value in the range
94 * in turn and then continue to the next level.
95 *
96 * The search is implemented iteratively. "level" identifies the current
97 * basis vector. "init" is true if we want the first value at the current
98 * level and false if we want the next value.
99 * Solutions are added in the leaves of the search tree, i.e., after
100 * we have fixed a value in each direction of the basis.
101 */
isl_basic_set_scan(__isl_take isl_basic_set * bset,struct isl_scan_callback * callback)102 isl_stat isl_basic_set_scan(__isl_take isl_basic_set *bset,
103 struct isl_scan_callback *callback)
104 {
105 isl_size dim;
106 struct isl_mat *B = NULL;
107 struct isl_tab *tab = NULL;
108 struct isl_vec *min;
109 struct isl_vec *max;
110 struct isl_tab_undo **snap;
111 int level;
112 int init;
113 enum isl_lp_result res;
114
115 dim = isl_basic_set_dim(bset, isl_dim_all);
116 if (dim < 0) {
117 bset = isl_basic_set_free(bset);
118 return isl_stat_error;
119 }
120
121 if (dim == 0)
122 return scan_0D(bset, callback);
123
124 min = isl_vec_alloc(bset->ctx, dim);
125 max = isl_vec_alloc(bset->ctx, dim);
126 snap = isl_alloc_array(bset->ctx, struct isl_tab_undo *, dim);
127
128 if (!min || !max || !snap)
129 goto error;
130
131 tab = isl_tab_from_basic_set(bset, 0);
132 if (!tab)
133 goto error;
134 if (isl_tab_extend_cons(tab, dim + 1) < 0)
135 goto error;
136
137 tab->basis = isl_mat_identity(bset->ctx, 1 + dim);
138 if (1)
139 tab = isl_tab_compute_reduced_basis(tab);
140 if (!tab)
141 goto error;
142 B = isl_mat_copy(tab->basis);
143 if (!B)
144 goto error;
145
146 level = 0;
147 init = 1;
148
149 while (level >= 0) {
150 int empty = 0;
151 if (init) {
152 res = isl_tab_min(tab, B->row[1 + level],
153 bset->ctx->one, &min->el[level], NULL, 0);
154 if (res == isl_lp_empty)
155 empty = 1;
156 if (res == isl_lp_error || res == isl_lp_unbounded)
157 goto error;
158 isl_seq_neg(B->row[1 + level] + 1,
159 B->row[1 + level] + 1, dim);
160 res = isl_tab_min(tab, B->row[1 + level],
161 bset->ctx->one, &max->el[level], NULL, 0);
162 isl_seq_neg(B->row[1 + level] + 1,
163 B->row[1 + level] + 1, dim);
164 isl_int_neg(max->el[level], max->el[level]);
165 if (res == isl_lp_empty)
166 empty = 1;
167 if (res == isl_lp_error || res == isl_lp_unbounded)
168 goto error;
169 snap[level] = isl_tab_snap(tab);
170 } else
171 isl_int_add_ui(min->el[level], min->el[level], 1);
172
173 if (empty || isl_int_gt(min->el[level], max->el[level])) {
174 level--;
175 init = 0;
176 if (level >= 0)
177 if (isl_tab_rollback(tab, snap[level]) < 0)
178 goto error;
179 continue;
180 }
181 if (level == dim - 1 && callback->add == increment_counter) {
182 if (increment_range(callback,
183 min->el[level], max->el[level]))
184 goto error;
185 level--;
186 init = 0;
187 if (level >= 0)
188 if (isl_tab_rollback(tab, snap[level]) < 0)
189 goto error;
190 continue;
191 }
192 isl_int_neg(B->row[1 + level][0], min->el[level]);
193 if (isl_tab_add_valid_eq(tab, B->row[1 + level]) < 0)
194 goto error;
195 isl_int_set_si(B->row[1 + level][0], 0);
196 if (level < dim - 1) {
197 ++level;
198 init = 1;
199 continue;
200 }
201 if (add_solution(tab, callback) < 0)
202 goto error;
203 init = 0;
204 if (isl_tab_rollback(tab, snap[level]) < 0)
205 goto error;
206 }
207
208 isl_tab_free(tab);
209 free(snap);
210 isl_vec_free(min);
211 isl_vec_free(max);
212 isl_basic_set_free(bset);
213 isl_mat_free(B);
214 return isl_stat_ok;
215 error:
216 isl_tab_free(tab);
217 free(snap);
218 isl_vec_free(min);
219 isl_vec_free(max);
220 isl_basic_set_free(bset);
221 isl_mat_free(B);
222 return isl_stat_error;
223 }
224
isl_set_scan(__isl_take isl_set * set,struct isl_scan_callback * callback)225 isl_stat isl_set_scan(__isl_take isl_set *set,
226 struct isl_scan_callback *callback)
227 {
228 int i;
229
230 if (!set || !callback)
231 goto error;
232
233 set = isl_set_cow(set);
234 set = isl_set_make_disjoint(set);
235 set = isl_set_compute_divs(set);
236 if (!set)
237 goto error;
238
239 for (i = 0; i < set->n; ++i)
240 if (isl_basic_set_scan(isl_basic_set_copy(set->p[i]),
241 callback) < 0)
242 goto error;
243
244 isl_set_free(set);
245 return isl_stat_ok;
246 error:
247 isl_set_free(set);
248 return isl_stat_error;
249 }
250
isl_basic_set_count_upto(__isl_keep isl_basic_set * bset,isl_int max,isl_int * count)251 int isl_basic_set_count_upto(__isl_keep isl_basic_set *bset,
252 isl_int max, isl_int *count)
253 {
254 struct isl_counter cnt = { { &increment_counter } };
255
256 if (!bset)
257 return -1;
258
259 isl_int_init(cnt.count);
260 isl_int_init(cnt.max);
261
262 isl_int_set_si(cnt.count, 0);
263 isl_int_set(cnt.max, max);
264 if (isl_basic_set_scan(isl_basic_set_copy(bset), &cnt.callback) < 0 &&
265 isl_int_lt(cnt.count, cnt.max))
266 goto error;
267
268 isl_int_set(*count, cnt.count);
269 isl_int_clear(cnt.max);
270 isl_int_clear(cnt.count);
271
272 return 0;
273 error:
274 isl_int_clear(cnt.count);
275 return -1;
276 }
277
isl_set_count_upto(__isl_keep isl_set * set,isl_int max,isl_int * count)278 int isl_set_count_upto(__isl_keep isl_set *set, isl_int max, isl_int *count)
279 {
280 struct isl_counter cnt = { { &increment_counter } };
281
282 if (!set)
283 return -1;
284
285 isl_int_init(cnt.count);
286 isl_int_init(cnt.max);
287
288 isl_int_set_si(cnt.count, 0);
289 isl_int_set(cnt.max, max);
290 if (isl_set_scan(isl_set_copy(set), &cnt.callback) < 0 &&
291 isl_int_lt(cnt.count, cnt.max))
292 goto error;
293
294 isl_int_set(*count, cnt.count);
295 isl_int_clear(cnt.max);
296 isl_int_clear(cnt.count);
297
298 return 0;
299 error:
300 isl_int_clear(cnt.count);
301 return -1;
302 }
303
isl_set_count(__isl_keep isl_set * set,isl_int * count)304 int isl_set_count(__isl_keep isl_set *set, isl_int *count)
305 {
306 if (!set)
307 return -1;
308 return isl_set_count_upto(set, set->ctx->zero, count);
309 }
310
311 /* Count the total number of elements in "set" (in an inefficient way) and
312 * return the result.
313 */
isl_set_count_val(__isl_keep isl_set * set)314 __isl_give isl_val *isl_set_count_val(__isl_keep isl_set *set)
315 {
316 isl_val *v;
317
318 if (!set)
319 return NULL;
320 v = isl_val_zero(isl_set_get_ctx(set));
321 v = isl_val_cow(v);
322 if (!v)
323 return NULL;
324 if (isl_set_count(set, &v->n) < 0)
325 v = isl_val_free(v);
326 return v;
327 }
328