1 #include "isl_sample.h"
2 #include "isl_sample_piplib.h"
6 #include "isl_map_private.h"
7 #include "isl_equalities.h"
9 #include "isl_basis_reduction.h"
11 static struct isl_vec
*empty_sample(struct isl_basic_set
*bset
)
15 vec
= isl_vec_alloc(bset
->ctx
, 0);
16 isl_basic_set_free(bset
);
20 /* Construct a zero sample of the same dimension as bset.
21 * As a special case, if bset is zero-dimensional, this
22 * function creates a zero-dimensional sample point.
24 static struct isl_vec
*zero_sample(struct isl_basic_set
*bset
)
27 struct isl_vec
*sample
;
29 dim
= isl_basic_set_total_dim(bset
);
30 sample
= isl_vec_alloc(bset
->ctx
, 1 + dim
);
32 isl_int_set_si(sample
->el
[0], 1);
33 isl_seq_clr(sample
->el
+ 1, dim
);
35 isl_basic_set_free(bset
);
39 static struct isl_vec
*interval_sample(struct isl_basic_set
*bset
)
43 struct isl_vec
*sample
;
45 bset
= isl_basic_set_simplify(bset
);
48 if (isl_basic_set_fast_is_empty(bset
))
49 return empty_sample(bset
);
50 if (bset
->n_eq
== 0 && bset
->n_ineq
== 0)
51 return zero_sample(bset
);
53 sample
= isl_vec_alloc(bset
->ctx
, 2);
54 isl_int_set_si(sample
->block
.data
[0], 1);
57 isl_assert(bset
->ctx
, bset
->n_eq
== 1, goto error
);
58 isl_assert(bset
->ctx
, bset
->n_ineq
== 0, goto error
);
59 if (isl_int_is_one(bset
->eq
[0][1]))
60 isl_int_neg(sample
->el
[1], bset
->eq
[0][0]);
62 isl_assert(bset
->ctx
, isl_int_is_negone(bset
->eq
[0][1]),
64 isl_int_set(sample
->el
[1], bset
->eq
[0][0]);
66 isl_basic_set_free(bset
);
71 if (isl_int_is_one(bset
->ineq
[0][1]))
72 isl_int_neg(sample
->block
.data
[1], bset
->ineq
[0][0]);
74 isl_int_set(sample
->block
.data
[1], bset
->ineq
[0][0]);
75 for (i
= 1; i
< bset
->n_ineq
; ++i
) {
76 isl_seq_inner_product(sample
->block
.data
,
77 bset
->ineq
[i
], 2, &t
);
78 if (isl_int_is_neg(t
))
82 if (i
< bset
->n_ineq
) {
84 return empty_sample(bset
);
87 isl_basic_set_free(bset
);
90 isl_basic_set_free(bset
);
95 static struct isl_mat
*independent_bounds(struct isl_basic_set
*bset
)
98 struct isl_mat
*dirs
= NULL
;
99 struct isl_mat
*bounds
= NULL
;
105 dim
= isl_basic_set_n_dim(bset
);
106 bounds
= isl_mat_alloc(bset
->ctx
, 1+dim
, 1+dim
);
110 isl_int_set_si(bounds
->row
[0][0], 1);
111 isl_seq_clr(bounds
->row
[0]+1, dim
);
114 if (bset
->n_ineq
== 0)
117 dirs
= isl_mat_alloc(bset
->ctx
, dim
, dim
);
119 isl_mat_free(bounds
);
122 isl_seq_cpy(dirs
->row
[0], bset
->ineq
[0]+1, dirs
->n_col
);
123 isl_seq_cpy(bounds
->row
[1], bset
->ineq
[0], bounds
->n_col
);
124 for (j
= 1, n
= 1; n
< dim
&& j
< bset
->n_ineq
; ++j
) {
127 isl_seq_cpy(dirs
->row
[n
], bset
->ineq
[j
]+1, dirs
->n_col
);
129 pos
= isl_seq_first_non_zero(dirs
->row
[n
], dirs
->n_col
);
132 for (i
= 0; i
< n
; ++i
) {
134 pos_i
= isl_seq_first_non_zero(dirs
->row
[i
], dirs
->n_col
);
139 isl_seq_elim(dirs
->row
[n
], dirs
->row
[i
], pos
,
141 pos
= isl_seq_first_non_zero(dirs
->row
[n
], dirs
->n_col
);
149 isl_int
*t
= dirs
->row
[n
];
150 for (k
= n
; k
> i
; --k
)
151 dirs
->row
[k
] = dirs
->row
[k
-1];
155 isl_seq_cpy(bounds
->row
[n
], bset
->ineq
[j
], bounds
->n_col
);
162 static void swap_inequality(struct isl_basic_set
*bset
, int a
, int b
)
164 isl_int
*t
= bset
->ineq
[a
];
165 bset
->ineq
[a
] = bset
->ineq
[b
];
169 /* Skew into positive orthant and project out lineality space.
171 * We perform a unimodular transformation that turns a selected
172 * maximal set of linearly independent bounds into constraints
173 * on the first dimensions that impose that these first dimensions
174 * are non-negative. In particular, the constraint matrix is lower
175 * triangular with positive entries on the diagonal and negative
177 * If "bset" has a lineality space then these constraints (and therefore
178 * all constraints in bset) only involve the first dimensions.
179 * The remaining dimensions then do not appear in any constraints and
180 * we can select any value for them, say zero. We therefore project
181 * out this final dimensions and plug in the value zero later. This
182 * is accomplished by simply dropping the final columns of
183 * the unimodular transformation.
185 static struct isl_basic_set
*isl_basic_set_skew_to_positive_orthant(
186 struct isl_basic_set
*bset
, struct isl_mat
**T
)
188 struct isl_mat
*U
= NULL
;
189 struct isl_mat
*bounds
= NULL
;
191 unsigned old_dim
, new_dim
;
197 isl_assert(bset
->ctx
, isl_basic_set_n_param(bset
) == 0, goto error
);
198 isl_assert(bset
->ctx
, bset
->n_div
== 0, goto error
);
199 isl_assert(bset
->ctx
, bset
->n_eq
== 0, goto error
);
201 old_dim
= isl_basic_set_n_dim(bset
);
202 /* Try to move (multiples of) unit rows up. */
203 for (i
= 0, j
= 0; i
< bset
->n_ineq
; ++i
) {
204 int pos
= isl_seq_first_non_zero(bset
->ineq
[i
]+1, old_dim
);
207 if (isl_seq_first_non_zero(bset
->ineq
[i
]+1+pos
+1,
211 swap_inequality(bset
, i
, j
);
214 bounds
= independent_bounds(bset
);
217 new_dim
= bounds
->n_row
- 1;
218 bounds
= isl_mat_left_hermite(bounds
, 1, &U
, NULL
);
221 U
= isl_mat_drop_cols(U
, 1 + new_dim
, old_dim
- new_dim
);
222 bset
= isl_basic_set_preimage(bset
, isl_mat_copy(U
));
226 isl_mat_free(bounds
);
229 isl_mat_free(bounds
);
231 isl_basic_set_free(bset
);
235 /* Find a sample integer point, if any, in bset, which is known
236 * to have equalities. If bset contains no integer points, then
237 * return a zero-length vector.
238 * We simply remove the known equalities, compute a sample
239 * in the resulting bset, using the specified recurse function,
240 * and then transform the sample back to the original space.
242 static struct isl_vec
*sample_eq(struct isl_basic_set
*bset
,
243 struct isl_vec
*(*recurse
)(struct isl_basic_set
*))
246 struct isl_vec
*sample
;
251 bset
= isl_basic_set_remove_equalities(bset
, &T
, NULL
);
252 sample
= recurse(bset
);
253 if (!sample
|| sample
->size
== 0)
256 sample
= isl_mat_vec_product(T
, sample
);
260 /* Given a basic set that is known to be bounded, find and return
261 * an integer point in the basic set, if there is any.
263 * After handling some trivial cases, we perform a depth first search
264 * for an integer point, by scanning all possible values in the range
265 * attained by a basis vector.
267 * The search is implemented iteratively. "level" identifies the current
268 * basis vector. "init" is true if we want the first value at the current
269 * level and false if we want the next value.
271 * The initial basis is the identity matrix. If the range in some direction
272 * contains more than one integer value, we perform basis reduction based
273 * on the value of ctx->gbr
274 * - ISL_GBR_NEVER: never perform basis reduction
275 * - ISL_GBR_ONCE: only perform basis reduction the first
276 * time such a range is encountered
277 * - ISL_GBR_ALWAYS: always perform basis reduction when
278 * such a range is encountered
280 * When ctx->gbr is set to ISL_GBR_ALWAYS, then we allow the basis
281 * reduction computation to return early. That is, as soon as it
282 * finds a reasonable first direction.
284 static struct isl_vec
*sample_bounded(struct isl_basic_set
*bset
)
289 struct isl_vec
*sample
;
292 enum isl_lp_result res
;
296 struct isl_tab_undo
**snap
;
297 struct isl_tab
*tab
= NULL
;
302 if (isl_basic_set_fast_is_empty(bset
))
303 return empty_sample(bset
);
305 dim
= isl_basic_set_total_dim(bset
);
307 return zero_sample(bset
);
309 return interval_sample(bset
);
311 return sample_eq(bset
, sample_bounded
);
316 min
= isl_vec_alloc(bset
->ctx
, dim
);
317 max
= isl_vec_alloc(bset
->ctx
, dim
);
318 snap
= isl_alloc_array(bset
->ctx
, struct isl_tab_undo
*, dim
);
320 if (!min
|| !max
|| !snap
)
323 tab
= isl_tab_from_basic_set(bset
);
327 tab
->basis
= isl_mat_identity(bset
->ctx
, 1 + dim
);
338 res
= isl_tab_min(tab
, tab
->basis
->row
[1 + level
],
339 bset
->ctx
->one
, &min
->el
[level
], NULL
, 0);
340 if (res
== isl_lp_empty
)
342 if (res
== isl_lp_error
|| res
== isl_lp_unbounded
)
344 if (!empty
&& isl_tab_sample_is_integer(tab
))
346 isl_seq_neg(tab
->basis
->row
[1 + level
] + 1,
347 tab
->basis
->row
[1 + level
] + 1, dim
);
348 res
= isl_tab_min(tab
, tab
->basis
->row
[1 + level
],
349 bset
->ctx
->one
, &max
->el
[level
], NULL
, 0);
350 isl_seq_neg(tab
->basis
->row
[1 + level
] + 1,
351 tab
->basis
->row
[1 + level
] + 1, dim
);
352 isl_int_neg(max
->el
[level
], max
->el
[level
]);
353 if (res
== isl_lp_empty
)
355 if (res
== isl_lp_error
|| res
== isl_lp_unbounded
)
357 if (!empty
&& isl_tab_sample_is_integer(tab
))
359 if (!empty
&& !reduced
&& ctx
->gbr
!= ISL_GBR_NEVER
&&
360 isl_int_lt(min
->el
[level
], max
->el
[level
])) {
361 unsigned gbr_only_first
;
362 if (ctx
->gbr
== ISL_GBR_ONCE
)
363 ctx
->gbr
= ISL_GBR_NEVER
;
365 gbr_only_first
= bset
->ctx
->gbr_only_first
;
366 bset
->ctx
->gbr_only_first
=
367 bset
->ctx
->gbr
== ISL_GBR_ALWAYS
;
368 tab
= isl_tab_compute_reduced_basis(tab
);
369 bset
->ctx
->gbr_only_first
= gbr_only_first
;
370 if (!tab
|| !tab
->basis
)
376 snap
[level
] = isl_tab_snap(tab
);
378 isl_int_add_ui(min
->el
[level
], min
->el
[level
], 1);
380 if (empty
|| isl_int_gt(min
->el
[level
], max
->el
[level
])) {
384 isl_tab_rollback(tab
, snap
[level
]);
387 isl_int_neg(tab
->basis
->row
[1 + level
][0], min
->el
[level
]);
388 tab
= isl_tab_add_valid_eq(tab
, tab
->basis
->row
[1 + level
]);
389 isl_int_set_si(tab
->basis
->row
[1 + level
][0], 0);
390 if (level
< dim
- 1) {
398 sample
= isl_tab_get_sample_value(tab
);
399 isl_vec_free(bset
->sample
);
400 bset
->sample
= isl_vec_copy(sample
);
401 isl_basic_set_free(bset
);
403 sample
= empty_sample(bset
);
413 isl_basic_set_free(bset
);
421 /* Given a basic set "bset" and a value "sample" for the first coordinates
422 * of bset, plug in these values and drop the corresponding coordinates.
424 * We do this by computing the preimage of the transformation
430 * where [1 s] is the sample value and I is the identity matrix of the
431 * appropriate dimension.
433 static struct isl_basic_set
*plug_in(struct isl_basic_set
*bset
,
434 struct isl_vec
*sample
)
440 if (!bset
|| !sample
)
443 total
= isl_basic_set_total_dim(bset
);
444 T
= isl_mat_alloc(bset
->ctx
, 1 + total
, 1 + total
- (sample
->size
- 1));
448 for (i
= 0; i
< sample
->size
; ++i
) {
449 isl_int_set(T
->row
[i
][0], sample
->el
[i
]);
450 isl_seq_clr(T
->row
[i
] + 1, T
->n_col
- 1);
452 for (i
= 0; i
< T
->n_col
- 1; ++i
) {
453 isl_seq_clr(T
->row
[sample
->size
+ i
], T
->n_col
);
454 isl_int_set_si(T
->row
[sample
->size
+ i
][1 + i
], 1);
456 isl_vec_free(sample
);
458 bset
= isl_basic_set_preimage(bset
, T
);
461 isl_basic_set_free(bset
);
462 isl_vec_free(sample
);
466 /* Given a basic set "bset", return any (possibly non-integer) point
469 static struct isl_vec
*rational_sample(struct isl_basic_set
*bset
)
472 struct isl_vec
*sample
;
477 tab
= isl_tab_from_basic_set(bset
);
478 sample
= isl_tab_get_sample_value(tab
);
481 isl_basic_set_free(bset
);
486 /* Given a linear cone "cone" and a rational point "vec",
487 * construct a polyhedron with shifted copies of the constraints in "cone",
488 * i.e., a polyhedron with "cone" as its recession cone, such that each
489 * point x in this polyhedron is such that the unit box positioned at x
490 * lies entirely inside the affine cone 'vec + cone'.
491 * Any rational point in this polyhedron may therefore be rounded up
492 * to yield an integer point that lies inside said affine cone.
494 * Denote the constraints of cone by "<a_i, x> >= 0" and the rational
495 * point "vec" by v/d.
496 * Let b_i = <a_i, v>. Then the affine cone 'vec + cone' is given
497 * by <a_i, x> - b/d >= 0.
498 * The polyhedron <a_i, x> - ceil{b/d} >= 0 is a subset of this affine cone.
499 * We prefer this polyhedron over the actual affine cone because it doesn't
500 * require a scaling of the constraints.
501 * If each of the vertices of the unit cube positioned at x lies inside
502 * this polyhedron, then the whole unit cube at x lies inside the affine cone.
503 * We therefore impose that x' = x + \sum e_i, for any selection of unit
504 * vectors lies inside the polyhedron, i.e.,
506 * <a_i, x'> - ceil{b/d} = <a_i, x> + sum a_i - ceil{b/d} >= 0
508 * The most stringent of these constraints is the one that selects
509 * all negative a_i, so the polyhedron we are looking for has constraints
511 * <a_i, x> + sum_{a_i < 0} a_i - ceil{b/d} >= 0
513 * Note that if cone were known to have only non-negative rays
514 * (which can be accomplished by a unimodular transformation),
515 * then we would only have to check the points x' = x + e_i
516 * and we only have to add the smallest negative a_i (if any)
517 * instead of the sum of all negative a_i.
519 static struct isl_basic_set
*shift_cone(struct isl_basic_set
*cone
,
525 struct isl_basic_set
*shift
= NULL
;
530 isl_assert(cone
->ctx
, cone
->n_eq
== 0, goto error
);
532 total
= isl_basic_set_total_dim(cone
);
534 shift
= isl_basic_set_alloc_dim(isl_basic_set_get_dim(cone
),
537 for (i
= 0; i
< cone
->n_ineq
; ++i
) {
538 k
= isl_basic_set_alloc_inequality(shift
);
541 isl_seq_cpy(shift
->ineq
[k
] + 1, cone
->ineq
[i
] + 1, total
);
542 isl_seq_inner_product(shift
->ineq
[k
] + 1, vec
->el
+ 1, total
,
544 isl_int_cdiv_q(shift
->ineq
[k
][0],
545 shift
->ineq
[k
][0], vec
->el
[0]);
546 isl_int_neg(shift
->ineq
[k
][0], shift
->ineq
[k
][0]);
547 for (j
= 0; j
< total
; ++j
) {
548 if (isl_int_is_nonneg(shift
->ineq
[k
][1 + j
]))
550 isl_int_add(shift
->ineq
[k
][0],
551 shift
->ineq
[k
][0], shift
->ineq
[k
][1 + j
]);
555 isl_basic_set_free(cone
);
558 return isl_basic_set_finalize(shift
);
560 isl_basic_set_free(shift
);
561 isl_basic_set_free(cone
);
566 /* Given a rational point vec in a (transformed) basic set,
567 * such that cone is the recession cone of the original basic set,
568 * "round up" the rational point to an integer point.
570 * We first check if the rational point just happens to be integer.
571 * If not, we transform the cone in the same way as the basic set,
572 * pick a point x in this cone shifted to the rational point such that
573 * the whole unit cube at x is also inside this affine cone.
574 * Then we simply round up the coordinates of x and return the
575 * resulting integer point.
577 static struct isl_vec
*round_up_in_cone(struct isl_vec
*vec
,
578 struct isl_basic_set
*cone
, struct isl_mat
*U
)
582 if (!vec
|| !cone
|| !U
)
585 isl_assert(vec
->ctx
, vec
->size
!= 0, goto error
);
586 if (isl_int_is_one(vec
->el
[0])) {
588 isl_basic_set_free(cone
);
592 total
= isl_basic_set_total_dim(cone
);
593 cone
= isl_basic_set_preimage(cone
, U
);
594 cone
= isl_basic_set_remove_dims(cone
, 0, total
- (vec
->size
- 1));
596 cone
= shift_cone(cone
, vec
);
598 vec
= rational_sample(cone
);
599 vec
= isl_vec_ceil(vec
);
604 isl_basic_set_free(cone
);
608 /* Concatenate two integer vectors, i.e., two vectors with denominator
609 * (stored in element 0) equal to 1.
611 static struct isl_vec
*vec_concat(struct isl_vec
*vec1
, struct isl_vec
*vec2
)
617 isl_assert(vec1
->ctx
, vec1
->size
> 0, goto error
);
618 isl_assert(vec2
->ctx
, vec2
->size
> 0, goto error
);
619 isl_assert(vec1
->ctx
, isl_int_is_one(vec1
->el
[0]), goto error
);
620 isl_assert(vec2
->ctx
, isl_int_is_one(vec2
->el
[0]), goto error
);
622 vec
= isl_vec_alloc(vec1
->ctx
, vec1
->size
+ vec2
->size
- 1);
626 isl_seq_cpy(vec
->el
, vec1
->el
, vec1
->size
);
627 isl_seq_cpy(vec
->el
+ vec1
->size
, vec2
->el
+ 1, vec2
->size
- 1);
639 /* Drop all constraints in bset that involve any of the dimensions
640 * first to first+n-1.
642 static struct isl_basic_set
*drop_constraints_involving
643 (struct isl_basic_set
*bset
, unsigned first
, unsigned n
)
650 bset
= isl_basic_set_cow(bset
);
652 for (i
= bset
->n_ineq
- 1; i
>= 0; --i
) {
653 if (isl_seq_first_non_zero(bset
->ineq
[i
] + 1 + first
, n
) == -1)
655 isl_basic_set_drop_inequality(bset
, i
);
661 /* Give a basic set "bset" with recession cone "cone", compute and
662 * return an integer point in bset, if any.
664 * If the recession cone is full-dimensional, then we know that
665 * bset contains an infinite number of integer points and it is
666 * fairly easy to pick one of them.
667 * If the recession cone is not full-dimensional, then we first
668 * transform bset such that the bounded directions appear as
669 * the first dimensions of the transformed basic set.
670 * We do this by using a unimodular transformation that transforms
671 * the equalities in the recession cone to equalities on the first
674 * The transformed set is then projected onto its bounded dimensions.
675 * Note that to compute this projection, we can simply drop all constraints
676 * involving any of the unbounded dimensions since these constraints
677 * cannot be combined to produce a constraint on the bounded dimensions.
678 * To see this, assume that there is such a combination of constraints
679 * that produces a constraint on the bounded dimensions. This means
680 * that some combination of the unbounded dimensions has both an upper
681 * bound and a lower bound in terms of the bounded dimensions, but then
682 * this combination would be a bounded direction too and would have been
683 * transformed into a bounded dimensions.
685 * We then compute a sample value in the bounded dimensions.
686 * If no such value can be found, then the original set did not contain
687 * any integer points and we are done.
688 * Otherwise, we plug in the value we found in the bounded dimensions,
689 * project out these bounded dimensions and end up with a set with
690 * a full-dimensional recession cone.
691 * A sample point in this set is computed by "rounding up" any
692 * rational point in the set.
694 * The sample points in the bounded and unbounded dimensions are
695 * then combined into a single sample point and transformed back
696 * to the original space.
698 __isl_give isl_vec
*isl_basic_set_sample_with_cone(
699 __isl_take isl_basic_set
*bset
, __isl_take isl_basic_set
*cone
)
703 struct isl_mat
*M
, *U
;
704 struct isl_vec
*sample
;
705 struct isl_vec
*cone_sample
;
707 struct isl_basic_set
*bounded
;
713 total
= isl_basic_set_total_dim(cone
);
714 cone_dim
= total
- cone
->n_eq
;
716 M
= isl_mat_sub_alloc(bset
->ctx
, cone
->eq
, 0, cone
->n_eq
, 1, total
);
717 M
= isl_mat_left_hermite(M
, 0, &U
, NULL
);
722 U
= isl_mat_lin_to_aff(U
);
723 bset
= isl_basic_set_preimage(bset
, isl_mat_copy(U
));
725 bounded
= isl_basic_set_copy(bset
);
726 bounded
= drop_constraints_involving(bounded
, total
- cone_dim
, cone_dim
);
727 bounded
= isl_basic_set_drop_dims(bounded
, total
- cone_dim
, cone_dim
);
728 sample
= sample_bounded(bounded
);
729 if (!sample
|| sample
->size
== 0) {
730 isl_basic_set_free(bset
);
731 isl_basic_set_free(cone
);
735 bset
= plug_in(bset
, isl_vec_copy(sample
));
736 cone_sample
= rational_sample(bset
);
737 cone_sample
= round_up_in_cone(cone_sample
, cone
, isl_mat_copy(U
));
738 sample
= vec_concat(sample
, cone_sample
);
739 sample
= isl_mat_vec_product(U
, sample
);
742 isl_basic_set_free(cone
);
743 isl_basic_set_free(bset
);
747 /* Compute and return a sample point in bset using generalized basis
748 * reduction. We first check if the input set has a non-trivial
749 * recession cone. If so, we perform some extra preprocessing in
750 * sample_with_cone. Otherwise, we directly perform generalized basis
753 static struct isl_vec
*gbr_sample(struct isl_basic_set
*bset
)
756 struct isl_basic_set
*cone
;
758 dim
= isl_basic_set_total_dim(bset
);
760 cone
= isl_basic_set_recession_cone(isl_basic_set_copy(bset
));
762 if (cone
->n_eq
< dim
)
763 return isl_basic_set_sample_with_cone(bset
, cone
);
765 isl_basic_set_free(cone
);
766 return sample_bounded(bset
);
769 static struct isl_vec
*pip_sample(struct isl_basic_set
*bset
)
773 struct isl_vec
*sample
;
775 bset
= isl_basic_set_skew_to_positive_orthant(bset
, &T
);
780 sample
= isl_pip_basic_set_sample(bset
);
782 if (sample
&& sample
->size
!= 0)
783 sample
= isl_mat_vec_product(T
, sample
);
790 static struct isl_vec
*basic_set_sample(struct isl_basic_set
*bset
, int bounded
)
798 if (isl_basic_set_fast_is_empty(bset
))
799 return empty_sample(bset
);
801 dim
= isl_basic_set_n_dim(bset
);
802 isl_assert(ctx
, isl_basic_set_n_param(bset
) == 0, goto error
);
803 isl_assert(ctx
, bset
->n_div
== 0, goto error
);
805 if (bset
->sample
&& bset
->sample
->size
== 1 + dim
) {
806 int contains
= isl_basic_set_contains(bset
, bset
->sample
);
810 struct isl_vec
*sample
= isl_vec_copy(bset
->sample
);
811 isl_basic_set_free(bset
);
815 isl_vec_free(bset
->sample
);
819 return sample_eq(bset
, bounded
? isl_basic_set_sample_bounded
820 : isl_basic_set_sample_vec
);
822 return zero_sample(bset
);
824 return interval_sample(bset
);
826 switch (bset
->ctx
->ilp_solver
) {
828 return pip_sample(bset
);
830 return bounded
? sample_bounded(bset
) : gbr_sample(bset
);
832 isl_assert(bset
->ctx
, 0, );
834 isl_basic_set_free(bset
);
838 __isl_give isl_vec
*isl_basic_set_sample_vec(__isl_take isl_basic_set
*bset
)
840 return basic_set_sample(bset
, 0);
843 /* Compute an integer sample in "bset", where the caller guarantees
844 * that "bset" is bounded.
846 struct isl_vec
*isl_basic_set_sample_bounded(struct isl_basic_set
*bset
)
848 return basic_set_sample(bset
, 1);
851 __isl_give isl_basic_set
*isl_basic_set_from_vec(__isl_take isl_vec
*vec
)
855 struct isl_basic_set
*bset
= NULL
;
862 isl_assert(ctx
, vec
->size
!= 0, goto error
);
864 bset
= isl_basic_set_alloc(ctx
, 0, vec
->size
- 1, 0, vec
->size
- 1, 0);
867 dim
= isl_basic_set_n_dim(bset
);
868 for (i
= dim
- 1; i
>= 0; --i
) {
869 k
= isl_basic_set_alloc_equality(bset
);
872 isl_seq_clr(bset
->eq
[k
], 1 + dim
);
873 isl_int_neg(bset
->eq
[k
][0], vec
->el
[1 + i
]);
874 isl_int_set(bset
->eq
[k
][1 + i
], vec
->el
[0]);
880 isl_basic_set_free(bset
);
885 __isl_give isl_basic_map
*isl_basic_map_sample(__isl_take isl_basic_map
*bmap
)
887 struct isl_basic_set
*bset
;
888 struct isl_vec
*sample_vec
;
890 bset
= isl_basic_map_underlying_set(isl_basic_map_copy(bmap
));
891 sample_vec
= isl_basic_set_sample_vec(bset
);
894 if (sample_vec
->size
== 0) {
895 struct isl_basic_map
*sample
;
896 sample
= isl_basic_map_empty_like(bmap
);
897 isl_vec_free(sample_vec
);
898 isl_basic_map_free(bmap
);
901 bset
= isl_basic_set_from_vec(sample_vec
);
902 return isl_basic_map_overlying_set(bset
, bmap
);
904 isl_basic_map_free(bmap
);
908 __isl_give isl_basic_map
*isl_map_sample(__isl_take isl_map
*map
)
911 isl_basic_map
*sample
= NULL
;
916 for (i
= 0; i
< map
->n
; ++i
) {
917 sample
= isl_basic_map_sample(isl_basic_map_copy(map
->p
[i
]));
920 if (!ISL_F_ISSET(sample
, ISL_BASIC_MAP_EMPTY
))
922 isl_basic_map_free(sample
);
925 sample
= isl_basic_map_empty_like_map(map
);
933 __isl_give isl_basic_set
*isl_set_sample(__isl_take isl_set
*set
)
935 return (isl_basic_set
*) isl_map_sample((isl_map
*)set
);