3 #include "isl_map_private.h"
7 #include "isl_equalities.h"
10 static struct isl_basic_set
*uset_convex_hull_wrap_bounded(struct isl_set
*set
);
12 static void swap_ineq(struct isl_basic_map
*bmap
, unsigned i
, unsigned j
)
18 bmap
->ineq
[i
] = bmap
->ineq
[j
];
23 /* Return 1 if constraint c is redundant with respect to the constraints
24 * in bmap. If c is a lower [upper] bound in some variable and bmap
25 * does not have a lower [upper] bound in that variable, then c cannot
26 * be redundant and we do not need solve any lp.
28 int isl_basic_map_constraint_is_redundant(struct isl_basic_map
**bmap
,
29 isl_int
*c
, isl_int
*opt_n
, isl_int
*opt_d
)
31 enum isl_lp_result res
;
38 total
= isl_basic_map_total_dim(*bmap
);
39 for (i
= 0; i
< total
; ++i
) {
41 if (isl_int_is_zero(c
[1+i
]))
43 sign
= isl_int_sgn(c
[1+i
]);
44 for (j
= 0; j
< (*bmap
)->n_ineq
; ++j
)
45 if (sign
== isl_int_sgn((*bmap
)->ineq
[j
][1+i
]))
47 if (j
== (*bmap
)->n_ineq
)
53 res
= isl_solve_lp(*bmap
, 0, c
, (*bmap
)->ctx
->one
, opt_n
, opt_d
);
54 if (res
== isl_lp_unbounded
)
56 if (res
== isl_lp_error
)
58 if (res
== isl_lp_empty
) {
59 *bmap
= isl_basic_map_set_to_empty(*bmap
);
62 return !isl_int_is_neg(*opt_n
);
65 int isl_basic_set_constraint_is_redundant(struct isl_basic_set
**bset
,
66 isl_int
*c
, isl_int
*opt_n
, isl_int
*opt_d
)
68 return isl_basic_map_constraint_is_redundant(
69 (struct isl_basic_map
**)bset
, c
, opt_n
, opt_d
);
72 /* Compute the convex hull of a basic map, by removing the redundant
73 * constraints. If the minimal value along the normal of a constraint
74 * is the same if the constraint is removed, then the constraint is redundant.
76 * Alternatively, we could have intersected the basic map with the
77 * corresponding equality and the checked if the dimension was that
80 struct isl_basic_map
*isl_basic_map_convex_hull(struct isl_basic_map
*bmap
)
87 bmap
= isl_basic_map_gauss(bmap
, NULL
);
88 if (ISL_F_ISSET(bmap
, ISL_BASIC_MAP_EMPTY
))
90 if (ISL_F_ISSET(bmap
, ISL_BASIC_MAP_NO_REDUNDANT
))
92 if (bmap
->n_ineq
<= 1)
95 tab
= isl_tab_from_basic_map(bmap
);
96 tab
= isl_tab_detect_equalities(bmap
->ctx
, tab
);
97 tab
= isl_tab_detect_redundant(bmap
->ctx
, tab
);
98 bmap
= isl_basic_map_update_from_tab(bmap
, tab
);
99 isl_tab_free(bmap
->ctx
, tab
);
100 ISL_F_SET(bmap
, ISL_BASIC_MAP_NO_IMPLICIT
);
101 ISL_F_SET(bmap
, ISL_BASIC_MAP_NO_REDUNDANT
);
105 struct isl_basic_set
*isl_basic_set_convex_hull(struct isl_basic_set
*bset
)
107 return (struct isl_basic_set
*)
108 isl_basic_map_convex_hull((struct isl_basic_map
*)bset
);
111 /* Check if the set set is bound in the direction of the affine
112 * constraint c and if so, set the constant term such that the
113 * resulting constraint is a bounding constraint for the set.
115 static int uset_is_bound(struct isl_ctx
*ctx
, struct isl_set
*set
,
116 isl_int
*c
, unsigned len
)
124 isl_int_init(opt_denom
);
126 for (j
= 0; j
< set
->n
; ++j
) {
127 enum isl_lp_result res
;
129 if (ISL_F_ISSET(set
->p
[j
], ISL_BASIC_SET_EMPTY
))
132 res
= isl_solve_lp((struct isl_basic_map
*)set
->p
[j
],
133 0, c
, ctx
->one
, &opt
, &opt_denom
);
134 if (res
== isl_lp_unbounded
)
136 if (res
== isl_lp_error
)
138 if (res
== isl_lp_empty
) {
139 set
->p
[j
] = isl_basic_set_set_to_empty(set
->p
[j
]);
144 if (!isl_int_is_one(opt_denom
))
145 isl_seq_scale(c
, c
, opt_denom
, len
);
146 if (first
|| isl_int_is_neg(opt
))
147 isl_int_sub(c
[0], c
[0], opt
);
151 isl_int_clear(opt_denom
);
155 isl_int_clear(opt_denom
);
159 /* Check if "c" is a direction that is independent of the previously found "n"
161 * If so, add it to the list, with the negative of the lower bound
162 * in the constant position, i.e., such that c corresponds to a bounding
163 * hyperplane (but not necessarily a facet).
164 * Assumes set "set" is bounded.
166 static int is_independent_bound(struct isl_ctx
*ctx
,
167 struct isl_set
*set
, isl_int
*c
,
168 struct isl_mat
*dirs
, int n
)
173 isl_seq_cpy(dirs
->row
[n
]+1, c
+1, dirs
->n_col
-1);
175 int pos
= isl_seq_first_non_zero(dirs
->row
[n
]+1, dirs
->n_col
-1);
178 for (i
= 0; i
< n
; ++i
) {
180 pos_i
= isl_seq_first_non_zero(dirs
->row
[i
]+1, dirs
->n_col
-1);
185 isl_seq_elim(dirs
->row
[n
]+1, dirs
->row
[i
]+1, pos
,
186 dirs
->n_col
-1, NULL
);
187 pos
= isl_seq_first_non_zero(dirs
->row
[n
]+1, dirs
->n_col
-1);
193 is_bound
= uset_is_bound(ctx
, set
, dirs
->row
[n
], dirs
->n_col
);
198 isl_int
*t
= dirs
->row
[n
];
199 for (k
= n
; k
> i
; --k
)
200 dirs
->row
[k
] = dirs
->row
[k
-1];
206 /* Compute and return a maximal set of linearly independent bounds
207 * on the set "set", based on the constraints of the basic sets
210 static struct isl_mat
*independent_bounds(struct isl_ctx
*ctx
,
214 struct isl_mat
*dirs
= NULL
;
215 unsigned dim
= isl_set_n_dim(set
);
217 dirs
= isl_mat_alloc(ctx
, dim
, 1+dim
);
222 for (i
= 0; n
< dim
&& i
< set
->n
; ++i
) {
224 struct isl_basic_set
*bset
= set
->p
[i
];
226 for (j
= 0; n
< dim
&& j
< bset
->n_eq
; ++j
) {
227 f
= is_independent_bound(ctx
, set
, bset
->eq
[j
],
234 for (j
= 0; n
< dim
&& j
< bset
->n_ineq
; ++j
) {
235 f
= is_independent_bound(ctx
, set
, bset
->ineq
[j
],
246 isl_mat_free(ctx
, dirs
);
250 static struct isl_basic_set
*isl_basic_set_set_rational(
251 struct isl_basic_set
*bset
)
256 if (ISL_F_ISSET(bset
, ISL_BASIC_MAP_RATIONAL
))
259 bset
= isl_basic_set_cow(bset
);
263 ISL_F_SET(bset
, ISL_BASIC_MAP_RATIONAL
);
265 return isl_basic_set_finalize(bset
);
268 static struct isl_set
*isl_set_set_rational(struct isl_set
*set
)
272 set
= isl_set_cow(set
);
275 for (i
= 0; i
< set
->n
; ++i
) {
276 set
->p
[i
] = isl_basic_set_set_rational(set
->p
[i
]);
286 static struct isl_basic_set
*isl_basic_set_add_equality(struct isl_ctx
*ctx
,
287 struct isl_basic_set
*bset
, isl_int
*c
)
293 if (ISL_F_ISSET(bset
, ISL_BASIC_SET_EMPTY
))
296 isl_assert(ctx
, isl_basic_set_n_param(bset
) == 0, goto error
);
297 isl_assert(ctx
, bset
->n_div
== 0, goto error
);
298 dim
= isl_basic_set_n_dim(bset
);
299 bset
= isl_basic_set_extend(bset
, 0, dim
, 0, 1, 0);
300 i
= isl_basic_set_alloc_equality(bset
);
303 isl_seq_cpy(bset
->eq
[i
], c
, 1 + dim
);
306 isl_basic_set_free(bset
);
310 static struct isl_set
*isl_set_add_equality(struct isl_ctx
*ctx
,
311 struct isl_set
*set
, isl_int
*c
)
315 set
= isl_set_cow(set
);
318 for (i
= 0; i
< set
->n
; ++i
) {
319 set
->p
[i
] = isl_basic_set_add_equality(ctx
, set
->p
[i
], c
);
329 /* Given a union of basic sets, construct the constraints for wrapping
330 * a facet around one of its ridges.
331 * In particular, if each of n the d-dimensional basic sets i in "set"
332 * contains the origin, satisfies the constraints x_1 >= 0 and x_2 >= 0
333 * and is defined by the constraints
337 * then the resulting set is of dimension n*(1+d) and has as contraints
346 static struct isl_basic_set
*wrap_constraints(struct isl_set
*set
)
348 struct isl_basic_set
*lp
;
352 unsigned dim
, lp_dim
;
357 dim
= 1 + isl_set_n_dim(set
);
360 for (i
= 0; i
< set
->n
; ++i
) {
361 n_eq
+= set
->p
[i
]->n_eq
;
362 n_ineq
+= set
->p
[i
]->n_ineq
;
364 lp
= isl_basic_set_alloc(set
->ctx
, 0, dim
* set
->n
, 0, n_eq
, n_ineq
);
367 lp_dim
= isl_basic_set_n_dim(lp
);
368 k
= isl_basic_set_alloc_equality(lp
);
369 isl_int_set_si(lp
->eq
[k
][0], -1);
370 for (i
= 0; i
< set
->n
; ++i
) {
371 isl_int_set_si(lp
->eq
[k
][1+dim
*i
], 0);
372 isl_int_set_si(lp
->eq
[k
][1+dim
*i
+1], 1);
373 isl_seq_clr(lp
->eq
[k
]+1+dim
*i
+2, dim
-2);
375 for (i
= 0; i
< set
->n
; ++i
) {
376 k
= isl_basic_set_alloc_inequality(lp
);
377 isl_seq_clr(lp
->ineq
[k
], 1+lp_dim
);
378 isl_int_set_si(lp
->ineq
[k
][1+dim
*i
], 1);
380 for (j
= 0; j
< set
->p
[i
]->n_eq
; ++j
) {
381 k
= isl_basic_set_alloc_equality(lp
);
382 isl_seq_clr(lp
->eq
[k
], 1+dim
*i
);
383 isl_seq_cpy(lp
->eq
[k
]+1+dim
*i
, set
->p
[i
]->eq
[j
], dim
);
384 isl_seq_clr(lp
->eq
[k
]+1+dim
*(i
+1), dim
*(set
->n
-i
-1));
387 for (j
= 0; j
< set
->p
[i
]->n_ineq
; ++j
) {
388 k
= isl_basic_set_alloc_inequality(lp
);
389 isl_seq_clr(lp
->ineq
[k
], 1+dim
*i
);
390 isl_seq_cpy(lp
->ineq
[k
]+1+dim
*i
, set
->p
[i
]->ineq
[j
], dim
);
391 isl_seq_clr(lp
->ineq
[k
]+1+dim
*(i
+1), dim
*(set
->n
-i
-1));
397 /* Given a facet "facet" of the convex hull of "set" and a facet "ridge"
398 * of that facet, compute the other facet of the convex hull that contains
401 * We first transform the set such that the facet constraint becomes
405 * I.e., the facet lies in
409 * and on that facet, the constraint that defines the ridge is
413 * (This transformation is not strictly needed, all that is needed is
414 * that the ridge contains the origin.)
416 * Since the ridge contains the origin, the cone of the convex hull
417 * will be of the form
422 * with this second constraint defining the new facet.
423 * The constant a is obtained by settting x_1 in the cone of the
424 * convex hull to 1 and minimizing x_2.
425 * Now, each element in the cone of the convex hull is the sum
426 * of elements in the cones of the basic sets.
427 * If a_i is the dilation factor of basic set i, then the problem
428 * we need to solve is
441 * the constraints of each (transformed) basic set.
442 * If a = n/d, then the constraint defining the new facet (in the transformed
445 * -n x_1 + d x_2 >= 0
447 * In the original space, we need to take the same combination of the
448 * corresponding constraints "facet" and "ridge".
450 * If a = -infty = "-1/0", then we just return the original facet constraint.
451 * This means that the facet is unbounded, but has a bounded intersection
452 * with the union of sets.
454 static isl_int
*wrap_facet(struct isl_set
*set
, isl_int
*facet
, isl_int
*ridge
)
457 struct isl_mat
*T
= NULL
;
458 struct isl_basic_set
*lp
= NULL
;
460 enum isl_lp_result res
;
464 set
= isl_set_copy(set
);
466 dim
= 1 + isl_set_n_dim(set
);
467 T
= isl_mat_alloc(set
->ctx
, 3, dim
);
470 isl_int_set_si(T
->row
[0][0], 1);
471 isl_seq_clr(T
->row
[0]+1, dim
- 1);
472 isl_seq_cpy(T
->row
[1], facet
, dim
);
473 isl_seq_cpy(T
->row
[2], ridge
, dim
);
474 T
= isl_mat_right_inverse(set
->ctx
, T
);
475 set
= isl_set_preimage(set
, T
);
479 lp
= wrap_constraints(set
);
480 obj
= isl_vec_alloc(set
->ctx
, 1 + dim
*set
->n
);
483 isl_int_set_si(obj
->block
.data
[0], 0);
484 for (i
= 0; i
< set
->n
; ++i
) {
485 isl_seq_clr(obj
->block
.data
+ 1 + dim
*i
, 2);
486 isl_int_set_si(obj
->block
.data
[1 + dim
*i
+2], 1);
487 isl_seq_clr(obj
->block
.data
+ 1 + dim
*i
+3, dim
-3);
491 res
= isl_solve_lp((struct isl_basic_map
*)lp
, 0,
492 obj
->block
.data
, set
->ctx
->one
, &num
, &den
);
493 if (res
== isl_lp_ok
) {
494 isl_int_neg(num
, num
);
495 isl_seq_combine(facet
, num
, facet
, den
, ridge
, dim
);
499 isl_vec_free(set
->ctx
, obj
);
500 isl_basic_set_free(lp
);
502 isl_assert(set
->ctx
, res
== isl_lp_ok
|| res
== isl_lp_unbounded
,
506 isl_basic_set_free(lp
);
507 isl_mat_free(set
->ctx
, T
);
512 /* Given a set of d linearly independent bounding constraints of the
513 * convex hull of "set", compute the constraint of a facet of "set".
515 * We first compute the intersection with the first bounding hyperplane
516 * and remove the component corresponding to this hyperplane from
517 * other bounds (in homogeneous space).
518 * We then wrap around one of the remaining bounding constraints
519 * and continue the process until all bounding constraints have been
520 * taken into account.
521 * The resulting linear combination of the bounding constraints will
522 * correspond to a facet of the convex hull.
524 static struct isl_mat
*initial_facet_constraint(struct isl_ctx
*ctx
,
525 struct isl_set
*set
, struct isl_mat
*bounds
)
527 struct isl_set
*slice
= NULL
;
528 struct isl_basic_set
*face
= NULL
;
529 struct isl_mat
*m
, *U
, *Q
;
531 unsigned dim
= isl_set_n_dim(set
);
533 isl_assert(ctx
, set
->n
> 0, goto error
);
534 isl_assert(ctx
, bounds
->n_row
== dim
, goto error
);
536 while (bounds
->n_row
> 1) {
537 slice
= isl_set_copy(set
);
538 slice
= isl_set_add_equality(ctx
, slice
, bounds
->row
[0]);
539 face
= isl_set_affine_hull(slice
);
542 if (face
->n_eq
== 1) {
543 isl_basic_set_free(face
);
546 m
= isl_mat_alloc(ctx
, 1 + face
->n_eq
, 1 + dim
);
549 isl_int_set_si(m
->row
[0][0], 1);
550 isl_seq_clr(m
->row
[0]+1, dim
);
551 for (i
= 0; i
< face
->n_eq
; ++i
)
552 isl_seq_cpy(m
->row
[1 + i
], face
->eq
[i
], 1 + dim
);
553 U
= isl_mat_right_inverse(ctx
, m
);
554 Q
= isl_mat_right_inverse(ctx
, isl_mat_copy(ctx
, U
));
555 U
= isl_mat_drop_cols(ctx
, U
, 1 + face
->n_eq
,
557 Q
= isl_mat_drop_rows(ctx
, Q
, 1 + face
->n_eq
,
559 U
= isl_mat_drop_cols(ctx
, U
, 0, 1);
560 Q
= isl_mat_drop_rows(ctx
, Q
, 0, 1);
561 bounds
= isl_mat_product(ctx
, bounds
, U
);
562 bounds
= isl_mat_product(ctx
, bounds
, Q
);
563 while (isl_seq_first_non_zero(bounds
->row
[bounds
->n_row
-1],
564 bounds
->n_col
) == -1) {
566 isl_assert(ctx
, bounds
->n_row
> 1, goto error
);
568 if (!wrap_facet(set
, bounds
->row
[0],
569 bounds
->row
[bounds
->n_row
-1]))
571 isl_basic_set_free(face
);
576 isl_basic_set_free(face
);
577 isl_mat_free(ctx
, bounds
);
581 /* Given the bounding constraint "c" of a facet of the convex hull of "set",
582 * compute a hyperplane description of the facet, i.e., compute the facets
585 * We compute an affine transformation that transforms the constraint
594 * by computing the right inverse U of a matrix that starts with the rows
607 * Since z_1 is zero, we can drop this variable as well as the corresponding
608 * column of U to obtain
616 * with Q' equal to Q, but without the corresponding row.
617 * After computing the facets of the facet in the z' space,
618 * we convert them back to the x space through Q.
620 static struct isl_basic_set
*compute_facet(struct isl_set
*set
, isl_int
*c
)
622 struct isl_mat
*m
, *U
, *Q
;
623 struct isl_basic_set
*facet
= NULL
;
628 set
= isl_set_copy(set
);
629 dim
= isl_set_n_dim(set
);
630 m
= isl_mat_alloc(set
->ctx
, 2, 1 + dim
);
633 isl_int_set_si(m
->row
[0][0], 1);
634 isl_seq_clr(m
->row
[0]+1, dim
);
635 isl_seq_cpy(m
->row
[1], c
, 1+dim
);
636 U
= isl_mat_right_inverse(set
->ctx
, m
);
637 Q
= isl_mat_right_inverse(set
->ctx
, isl_mat_copy(set
->ctx
, U
));
638 U
= isl_mat_drop_cols(set
->ctx
, U
, 1, 1);
639 Q
= isl_mat_drop_rows(set
->ctx
, Q
, 1, 1);
640 set
= isl_set_preimage(set
, U
);
641 facet
= uset_convex_hull_wrap_bounded(set
);
642 facet
= isl_basic_set_preimage(facet
, Q
);
643 isl_assert(ctx
, facet
->n_eq
== 0, goto error
);
646 isl_basic_set_free(facet
);
651 /* Given an initial facet constraint, compute the remaining facets.
652 * We do this by running through all facets found so far and computing
653 * the adjacent facets through wrapping, adding those facets that we
654 * hadn't already found before.
656 * For each facet we have found so far, we first compute its facets
657 * in the resulting convex hull. That is, we compute the ridges
658 * of the resulting convex hull contained in the facet.
659 * We also compute the corresponding facet in the current approximation
660 * of the convex hull. There is no need to wrap around the ridges
661 * in this facet since that would result in a facet that is already
662 * present in the current approximation.
664 * This function can still be significantly optimized by checking which of
665 * the facets of the basic sets are also facets of the convex hull and
666 * using all the facets so far to help in constructing the facets of the
669 * using the technique in section "3.1 Ridge Generation" of
670 * "Extended Convex Hull" by Fukuda et al.
672 static struct isl_basic_set
*extend(struct isl_basic_set
*hull
,
677 struct isl_basic_set
*facet
= NULL
;
678 struct isl_basic_set
*hull_facet
= NULL
;
682 isl_assert(set
->ctx
, set
->n
> 0, goto error
);
684 dim
= isl_set_n_dim(set
);
686 for (i
= 0; i
< hull
->n_ineq
; ++i
) {
687 facet
= compute_facet(set
, hull
->ineq
[i
]);
688 facet
= isl_basic_set_add_equality(facet
->ctx
, facet
, hull
->ineq
[i
]);
689 facet
= isl_basic_set_gauss(facet
, NULL
);
690 facet
= isl_basic_set_normalize_constraints(facet
);
691 hull_facet
= isl_basic_set_copy(hull
);
692 hull_facet
= isl_basic_set_add_equality(hull_facet
->ctx
, hull_facet
, hull
->ineq
[i
]);
693 hull_facet
= isl_basic_set_gauss(hull_facet
, NULL
);
694 hull_facet
= isl_basic_set_normalize_constraints(hull_facet
);
697 if (facet
->n_ineq
+ hull
->n_ineq
> hull
->c_size
)
698 hull
= isl_basic_set_extend_dim(hull
,
699 isl_dim_copy(hull
->dim
), 0, 0, facet
->n_ineq
);
700 for (j
= 0; j
< facet
->n_ineq
; ++j
) {
701 for (f
= 0; f
< hull_facet
->n_ineq
; ++f
)
702 if (isl_seq_eq(facet
->ineq
[j
],
703 hull_facet
->ineq
[f
], 1 + dim
))
705 if (f
< hull_facet
->n_ineq
)
707 k
= isl_basic_set_alloc_inequality(hull
);
710 isl_seq_cpy(hull
->ineq
[k
], hull
->ineq
[i
], 1+dim
);
711 if (!wrap_facet(set
, hull
->ineq
[k
], facet
->ineq
[j
]))
714 isl_basic_set_free(hull_facet
);
715 isl_basic_set_free(facet
);
717 hull
= isl_basic_set_simplify(hull
);
718 hull
= isl_basic_set_finalize(hull
);
721 isl_basic_set_free(hull_facet
);
722 isl_basic_set_free(facet
);
723 isl_basic_set_free(hull
);
727 /* Special case for computing the convex hull of a one dimensional set.
728 * We simply collect the lower and upper bounds of each basic set
729 * and the biggest of those.
731 static struct isl_basic_set
*convex_hull_1d(struct isl_ctx
*ctx
,
734 struct isl_mat
*c
= NULL
;
735 isl_int
*lower
= NULL
;
736 isl_int
*upper
= NULL
;
739 struct isl_basic_set
*hull
;
741 for (i
= 0; i
< set
->n
; ++i
) {
742 set
->p
[i
] = isl_basic_set_simplify(set
->p
[i
]);
746 set
= isl_set_remove_empty_parts(set
);
749 isl_assert(ctx
, set
->n
> 0, goto error
);
750 c
= isl_mat_alloc(ctx
, 2, 2);
754 if (set
->p
[0]->n_eq
> 0) {
755 isl_assert(ctx
, set
->p
[0]->n_eq
== 1, goto error
);
758 if (isl_int_is_pos(set
->p
[0]->eq
[0][1])) {
759 isl_seq_cpy(lower
, set
->p
[0]->eq
[0], 2);
760 isl_seq_neg(upper
, set
->p
[0]->eq
[0], 2);
762 isl_seq_neg(lower
, set
->p
[0]->eq
[0], 2);
763 isl_seq_cpy(upper
, set
->p
[0]->eq
[0], 2);
766 for (j
= 0; j
< set
->p
[0]->n_ineq
; ++j
) {
767 if (isl_int_is_pos(set
->p
[0]->ineq
[j
][1])) {
769 isl_seq_cpy(lower
, set
->p
[0]->ineq
[j
], 2);
772 isl_seq_cpy(upper
, set
->p
[0]->ineq
[j
], 2);
779 for (i
= 0; i
< set
->n
; ++i
) {
780 struct isl_basic_set
*bset
= set
->p
[i
];
784 for (j
= 0; j
< bset
->n_eq
; ++j
) {
788 isl_int_mul(a
, lower
[0], bset
->eq
[j
][1]);
789 isl_int_mul(b
, lower
[1], bset
->eq
[j
][0]);
790 if (isl_int_lt(a
, b
) && isl_int_is_pos(bset
->eq
[j
][1]))
791 isl_seq_cpy(lower
, bset
->eq
[j
], 2);
792 if (isl_int_gt(a
, b
) && isl_int_is_neg(bset
->eq
[j
][1]))
793 isl_seq_neg(lower
, bset
->eq
[j
], 2);
796 isl_int_mul(a
, upper
[0], bset
->eq
[j
][1]);
797 isl_int_mul(b
, upper
[1], bset
->eq
[j
][0]);
798 if (isl_int_lt(a
, b
) && isl_int_is_pos(bset
->eq
[j
][1]))
799 isl_seq_neg(upper
, bset
->eq
[j
], 2);
800 if (isl_int_gt(a
, b
) && isl_int_is_neg(bset
->eq
[j
][1]))
801 isl_seq_cpy(upper
, bset
->eq
[j
], 2);
804 for (j
= 0; j
< bset
->n_ineq
; ++j
) {
805 if (isl_int_is_pos(bset
->ineq
[j
][1]))
807 if (isl_int_is_neg(bset
->ineq
[j
][1]))
809 if (lower
&& isl_int_is_pos(bset
->ineq
[j
][1])) {
810 isl_int_mul(a
, lower
[0], bset
->ineq
[j
][1]);
811 isl_int_mul(b
, lower
[1], bset
->ineq
[j
][0]);
812 if (isl_int_lt(a
, b
))
813 isl_seq_cpy(lower
, bset
->ineq
[j
], 2);
815 if (upper
&& isl_int_is_neg(bset
->ineq
[j
][1])) {
816 isl_int_mul(a
, upper
[0], bset
->ineq
[j
][1]);
817 isl_int_mul(b
, upper
[1], bset
->ineq
[j
][0]);
818 if (isl_int_gt(a
, b
))
819 isl_seq_cpy(upper
, bset
->ineq
[j
], 2);
830 hull
= isl_basic_set_alloc(ctx
, 0, 1, 0, 0, 2);
831 hull
= isl_basic_set_set_rational(hull
);
835 k
= isl_basic_set_alloc_inequality(hull
);
836 isl_seq_cpy(hull
->ineq
[k
], lower
, 2);
839 k
= isl_basic_set_alloc_inequality(hull
);
840 isl_seq_cpy(hull
->ineq
[k
], upper
, 2);
842 hull
= isl_basic_set_finalize(hull
);
844 isl_mat_free(ctx
, c
);
848 isl_mat_free(ctx
, c
);
852 /* Project out final n dimensions using Fourier-Motzkin */
853 static struct isl_set
*set_project_out(struct isl_ctx
*ctx
,
854 struct isl_set
*set
, unsigned n
)
856 return isl_set_remove_dims(set
, isl_set_n_dim(set
) - n
, n
);
859 static struct isl_basic_set
*convex_hull_0d(struct isl_set
*set
)
861 struct isl_basic_set
*convex_hull
;
866 if (isl_set_is_empty(set
))
867 convex_hull
= isl_basic_set_empty(isl_dim_copy(set
->dim
));
869 convex_hull
= isl_basic_set_universe(isl_dim_copy(set
->dim
));
874 /* Compute the convex hull of a pair of basic sets without any parameters or
875 * integer divisions using Fourier-Motzkin elimination.
876 * The convex hull is the set of all points that can be written as
877 * the sum of points from both basic sets (in homogeneous coordinates).
878 * We set up the constraints in a space with dimensions for each of
879 * the three sets and then project out the dimensions corresponding
880 * to the two original basic sets, retaining only those corresponding
881 * to the convex hull.
883 static struct isl_basic_set
*convex_hull_pair(struct isl_basic_set
*bset1
,
884 struct isl_basic_set
*bset2
)
887 struct isl_basic_set
*bset
[2];
888 struct isl_basic_set
*hull
= NULL
;
891 if (!bset1
|| !bset2
)
894 dim
= isl_basic_set_n_dim(bset1
);
895 hull
= isl_basic_set_alloc(bset1
->ctx
, 0, 2 + 3 * dim
, 0,
896 1 + dim
+ bset1
->n_eq
+ bset2
->n_eq
,
897 2 + bset1
->n_ineq
+ bset2
->n_ineq
);
900 for (i
= 0; i
< 2; ++i
) {
901 for (j
= 0; j
< bset
[i
]->n_eq
; ++j
) {
902 k
= isl_basic_set_alloc_equality(hull
);
905 isl_seq_clr(hull
->eq
[k
], (i
+1) * (1+dim
));
906 isl_seq_clr(hull
->eq
[k
]+(i
+2)*(1+dim
), (1-i
)*(1+dim
));
907 isl_seq_cpy(hull
->eq
[k
]+(i
+1)*(1+dim
), bset
[i
]->eq
[j
],
910 for (j
= 0; j
< bset
[i
]->n_ineq
; ++j
) {
911 k
= isl_basic_set_alloc_inequality(hull
);
914 isl_seq_clr(hull
->ineq
[k
], (i
+1) * (1+dim
));
915 isl_seq_clr(hull
->ineq
[k
]+(i
+2)*(1+dim
), (1-i
)*(1+dim
));
916 isl_seq_cpy(hull
->ineq
[k
]+(i
+1)*(1+dim
),
917 bset
[i
]->ineq
[j
], 1+dim
);
919 k
= isl_basic_set_alloc_inequality(hull
);
922 isl_seq_clr(hull
->ineq
[k
], 1+2+3*dim
);
923 isl_int_set_si(hull
->ineq
[k
][(i
+1)*(1+dim
)], 1);
925 for (j
= 0; j
< 1+dim
; ++j
) {
926 k
= isl_basic_set_alloc_equality(hull
);
929 isl_seq_clr(hull
->eq
[k
], 1+2+3*dim
);
930 isl_int_set_si(hull
->eq
[k
][j
], -1);
931 isl_int_set_si(hull
->eq
[k
][1+dim
+j
], 1);
932 isl_int_set_si(hull
->eq
[k
][2*(1+dim
)+j
], 1);
934 hull
= isl_basic_set_set_rational(hull
);
935 hull
= isl_basic_set_remove_dims(hull
, dim
, 2*(1+dim
));
936 hull
= isl_basic_set_convex_hull(hull
);
937 isl_basic_set_free(bset1
);
938 isl_basic_set_free(bset2
);
941 isl_basic_set_free(bset1
);
942 isl_basic_set_free(bset2
);
943 isl_basic_set_free(hull
);
947 /* Compute the convex hull of a set without any parameters or
948 * integer divisions using Fourier-Motzkin elimination.
949 * In each step, we combined two basic sets until only one
952 static struct isl_basic_set
*uset_convex_hull_elim(struct isl_set
*set
)
954 struct isl_basic_set
*convex_hull
= NULL
;
956 convex_hull
= isl_set_copy_basic_set(set
);
957 set
= isl_set_drop_basic_set(set
, convex_hull
);
961 struct isl_basic_set
*t
;
962 t
= isl_set_copy_basic_set(set
);
965 set
= isl_set_drop_basic_set(set
, t
);
968 convex_hull
= convex_hull_pair(convex_hull
, t
);
974 isl_basic_set_free(convex_hull
);
978 /* Compute an initial hull for wrapping containing a single initial
979 * facet by first computing bounds on the set and then using these
980 * bounds to construct an initial facet.
981 * This function is a remnant of an older implementation where the
982 * bounds were also used to check whether the set was bounded.
983 * Since this function will now only be called when we know the
984 * set to be bounded, the initial facet should probably be constructed
985 * by simply using the coordinate directions instead.
987 static struct isl_basic_set
*initial_hull(struct isl_basic_set
*hull
,
990 struct isl_mat
*bounds
= NULL
;
996 bounds
= independent_bounds(set
->ctx
, set
);
999 isl_assert(set
->ctx
, bounds
->n_row
== isl_set_n_dim(set
), goto error
);
1000 bounds
= initial_facet_constraint(set
->ctx
, set
, bounds
);
1003 k
= isl_basic_set_alloc_inequality(hull
);
1006 dim
= isl_set_n_dim(set
);
1007 isl_assert(set
->ctx
, 1 + dim
== bounds
->n_col
, goto error
);
1008 isl_seq_cpy(hull
->ineq
[k
], bounds
->row
[0], bounds
->n_col
);
1009 isl_mat_free(set
->ctx
, bounds
);
1013 isl_basic_set_free(hull
);
1014 isl_mat_free(set
->ctx
, bounds
);
1018 struct max_constraint
{
1024 static int max_constraint_equal(const void *entry
, const void *val
)
1026 struct max_constraint
*a
= (struct max_constraint
*)entry
;
1027 isl_int
*b
= (isl_int
*)val
;
1029 return isl_seq_eq(a
->c
->row
[0] + 1, b
, a
->c
->n_col
- 1);
1032 static void update_constraint(struct isl_ctx
*ctx
, struct isl_hash_table
*table
,
1033 isl_int
*con
, unsigned len
, int n
, int ineq
)
1035 struct isl_hash_table_entry
*entry
;
1036 struct max_constraint
*c
;
1039 c_hash
= isl_seq_hash(con
+ 1, len
, isl_hash_init());
1040 entry
= isl_hash_table_find(ctx
, table
, c_hash
, max_constraint_equal
,
1046 isl_hash_table_remove(ctx
, table
, entry
);
1050 if (isl_int_gt(c
->c
->row
[0][0], con
[0]))
1052 if (isl_int_eq(c
->c
->row
[0][0], con
[0])) {
1057 c
->c
= isl_mat_cow(ctx
, c
->c
);
1058 isl_int_set(c
->c
->row
[0][0], con
[0]);
1062 /* Check whether the constraint hash table "table" constains the constraint
1065 static int has_constraint(struct isl_ctx
*ctx
, struct isl_hash_table
*table
,
1066 isl_int
*con
, unsigned len
, int n
)
1068 struct isl_hash_table_entry
*entry
;
1069 struct max_constraint
*c
;
1072 c_hash
= isl_seq_hash(con
+ 1, len
, isl_hash_init());
1073 entry
= isl_hash_table_find(ctx
, table
, c_hash
, max_constraint_equal
,
1080 return isl_int_eq(c
->c
->row
[0][0], con
[0]);
1083 /* Check for inequality constraints of a basic set without equalities
1084 * such that the same or more stringent copies of the constraint appear
1085 * in all of the basic sets. Such constraints are necessarily facet
1086 * constraints of the convex hull.
1088 * If the resulting basic set is by chance identical to one of
1089 * the basic sets in "set", then we know that this basic set contains
1090 * all other basic sets and is therefore the convex hull of set.
1091 * In this case we set *is_hull to 1.
1093 static struct isl_basic_set
*common_constraints(struct isl_basic_set
*hull
,
1094 struct isl_set
*set
, int *is_hull
)
1097 int min_constraints
;
1099 struct max_constraint
*constraints
= NULL
;
1100 struct isl_hash_table
*table
= NULL
;
1105 for (i
= 0; i
< set
->n
; ++i
)
1106 if (set
->p
[i
]->n_eq
== 0)
1110 min_constraints
= set
->p
[i
]->n_ineq
;
1112 for (i
= best
+ 1; i
< set
->n
; ++i
) {
1113 if (set
->p
[i
]->n_eq
!= 0)
1115 if (set
->p
[i
]->n_ineq
>= min_constraints
)
1117 min_constraints
= set
->p
[i
]->n_ineq
;
1120 constraints
= isl_calloc_array(hull
->ctx
, struct max_constraint
,
1124 table
= isl_alloc_type(hull
->ctx
, struct isl_hash_table
);
1125 if (isl_hash_table_init(hull
->ctx
, table
, min_constraints
))
1128 total
= isl_dim_total(set
->dim
);
1129 for (i
= 0; i
< set
->p
[best
]->n_ineq
; ++i
) {
1130 constraints
[i
].c
= isl_mat_sub_alloc(hull
->ctx
,
1131 set
->p
[best
]->ineq
+ i
, 0, 1, 0, 1 + total
);
1132 if (!constraints
[i
].c
)
1134 constraints
[i
].ineq
= 1;
1136 for (i
= 0; i
< min_constraints
; ++i
) {
1137 struct isl_hash_table_entry
*entry
;
1139 c_hash
= isl_seq_hash(constraints
[i
].c
->row
[0] + 1, total
,
1141 entry
= isl_hash_table_find(hull
->ctx
, table
, c_hash
,
1142 max_constraint_equal
, constraints
[i
].c
->row
[0] + 1, 1);
1145 isl_assert(hull
->ctx
, !entry
->data
, goto error
);
1146 entry
->data
= &constraints
[i
];
1150 for (s
= 0; s
< set
->n
; ++s
) {
1154 for (i
= 0; i
< set
->p
[s
]->n_eq
; ++i
) {
1155 isl_int
*eq
= set
->p
[s
]->eq
[i
];
1156 for (j
= 0; j
< 2; ++j
) {
1157 isl_seq_neg(eq
, eq
, 1 + total
);
1158 update_constraint(hull
->ctx
, table
,
1162 for (i
= 0; i
< set
->p
[s
]->n_ineq
; ++i
) {
1163 isl_int
*ineq
= set
->p
[s
]->ineq
[i
];
1164 update_constraint(hull
->ctx
, table
, ineq
, total
, n
,
1165 set
->p
[s
]->n_eq
== 0);
1170 for (i
= 0; i
< min_constraints
; ++i
) {
1171 if (constraints
[i
].count
< n
)
1173 if (!constraints
[i
].ineq
)
1175 j
= isl_basic_set_alloc_inequality(hull
);
1178 isl_seq_cpy(hull
->ineq
[j
], constraints
[i
].c
->row
[0], 1 + total
);
1181 for (s
= 0; s
< set
->n
; ++s
) {
1182 if (set
->p
[s
]->n_eq
)
1184 if (set
->p
[s
]->n_ineq
!= hull
->n_ineq
)
1186 for (i
= 0; i
< set
->p
[s
]->n_ineq
; ++i
) {
1187 isl_int
*ineq
= set
->p
[s
]->ineq
[i
];
1188 if (!has_constraint(hull
->ctx
, table
, ineq
, total
, n
))
1191 if (i
== set
->p
[s
]->n_ineq
)
1195 isl_hash_table_clear(table
);
1196 for (i
= 0; i
< min_constraints
; ++i
)
1197 isl_mat_free(hull
->ctx
, constraints
[i
].c
);
1202 isl_hash_table_clear(table
);
1205 for (i
= 0; i
< min_constraints
; ++i
)
1206 isl_mat_free(hull
->ctx
, constraints
[i
].c
);
1211 /* Create a template for the convex hull of "set" and fill it up
1212 * obvious facet constraints, if any. If the result happens to
1213 * be the convex hull of "set" then *is_hull is set to 1.
1215 static struct isl_basic_set
*proto_hull(struct isl_set
*set
, int *is_hull
)
1217 struct isl_basic_set
*hull
;
1222 for (i
= 0; i
< set
->n
; ++i
) {
1223 n_ineq
+= set
->p
[i
]->n_eq
;
1224 n_ineq
+= set
->p
[i
]->n_ineq
;
1226 hull
= isl_basic_set_alloc_dim(isl_dim_copy(set
->dim
), 0, 0, n_ineq
);
1227 hull
= isl_basic_set_set_rational(hull
);
1230 return common_constraints(hull
, set
, is_hull
);
1233 static struct isl_basic_set
*uset_convex_hull_wrap(struct isl_set
*set
)
1235 struct isl_basic_set
*hull
;
1238 hull
= proto_hull(set
, &is_hull
);
1239 if (hull
&& !is_hull
) {
1240 if (hull
->n_ineq
== 0)
1241 hull
= initial_hull(hull
, set
);
1242 hull
= extend(hull
, set
);
1249 static int isl_basic_set_is_bounded(struct isl_basic_set
*bset
)
1251 struct isl_tab
*tab
;
1254 tab
= isl_tab_from_recession_cone((struct isl_basic_map
*)bset
);
1255 bounded
= isl_tab_cone_is_bounded(bset
->ctx
, tab
);
1256 isl_tab_free(bset
->ctx
, tab
);
1260 static int isl_set_is_bounded(struct isl_set
*set
)
1264 for (i
= 0; i
< set
->n
; ++i
) {
1265 int bounded
= isl_basic_set_is_bounded(set
->p
[i
]);
1266 if (!bounded
|| bounded
< 0)
1272 /* Compute the convex hull of a set without any parameters or
1273 * integer divisions. Depending on whether the set is bounded,
1274 * we pass control to the wrapping based convex hull or
1275 * the Fourier-Motzkin elimination based convex hull.
1276 * We also handle a few special cases before checking the boundedness.
1278 static struct isl_basic_set
*uset_convex_hull(struct isl_set
*set
)
1281 struct isl_basic_set
*convex_hull
= NULL
;
1283 if (isl_set_n_dim(set
) == 0)
1284 return convex_hull_0d(set
);
1286 set
= isl_set_set_rational(set
);
1290 set
= isl_set_normalize(set
);
1294 convex_hull
= isl_basic_set_copy(set
->p
[0]);
1298 if (isl_set_n_dim(set
) == 1)
1299 return convex_hull_1d(set
->ctx
, set
);
1301 if (!isl_set_is_bounded(set
))
1302 return uset_convex_hull_elim(set
);
1304 return uset_convex_hull_wrap(set
);
1307 isl_basic_set_free(convex_hull
);
1311 /* This is the core procedure, where "set" is a "pure" set, i.e.,
1312 * without parameters or divs and where the convex hull of set is
1313 * known to be full-dimensional.
1315 static struct isl_basic_set
*uset_convex_hull_wrap_bounded(struct isl_set
*set
)
1318 struct isl_basic_set
*convex_hull
= NULL
;
1320 if (isl_set_n_dim(set
) == 0) {
1321 convex_hull
= isl_basic_set_universe(isl_dim_copy(set
->dim
));
1323 convex_hull
= isl_basic_set_set_rational(convex_hull
);
1327 set
= isl_set_set_rational(set
);
1331 set
= isl_set_normalize(set
);
1335 convex_hull
= isl_basic_set_copy(set
->p
[0]);
1339 if (isl_set_n_dim(set
) == 1)
1340 return convex_hull_1d(set
->ctx
, set
);
1342 return uset_convex_hull_wrap(set
);
1348 /* Compute the convex hull of set "set" with affine hull "affine_hull",
1349 * We first remove the equalities (transforming the set), compute the
1350 * convex hull of the transformed set and then add the equalities back
1351 * (after performing the inverse transformation.
1353 static struct isl_basic_set
*modulo_affine_hull(struct isl_ctx
*ctx
,
1354 struct isl_set
*set
, struct isl_basic_set
*affine_hull
)
1358 struct isl_basic_set
*dummy
;
1359 struct isl_basic_set
*convex_hull
;
1361 dummy
= isl_basic_set_remove_equalities(
1362 isl_basic_set_copy(affine_hull
), &T
, &T2
);
1365 isl_basic_set_free(dummy
);
1366 set
= isl_set_preimage(set
, T
);
1367 convex_hull
= uset_convex_hull(set
);
1368 convex_hull
= isl_basic_set_preimage(convex_hull
, T2
);
1369 convex_hull
= isl_basic_set_intersect(convex_hull
, affine_hull
);
1372 isl_basic_set_free(affine_hull
);
1377 /* Compute the convex hull of a map.
1379 * The implementation was inspired by "Extended Convex Hull" by Fukuda et al.,
1380 * specifically, the wrapping of facets to obtain new facets.
1382 struct isl_basic_map
*isl_map_convex_hull(struct isl_map
*map
)
1384 struct isl_basic_set
*bset
;
1385 struct isl_basic_map
*model
= NULL
;
1386 struct isl_basic_set
*affine_hull
= NULL
;
1387 struct isl_basic_map
*convex_hull
= NULL
;
1388 struct isl_set
*set
= NULL
;
1389 struct isl_ctx
*ctx
;
1396 convex_hull
= isl_basic_map_empty_like_map(map
);
1401 map
= isl_map_align_divs(map
);
1402 model
= isl_basic_map_copy(map
->p
[0]);
1403 set
= isl_map_underlying_set(map
);
1407 affine_hull
= isl_set_affine_hull(isl_set_copy(set
));
1410 if (affine_hull
->n_eq
!= 0)
1411 bset
= modulo_affine_hull(ctx
, set
, affine_hull
);
1413 isl_basic_set_free(affine_hull
);
1414 bset
= uset_convex_hull(set
);
1417 convex_hull
= isl_basic_map_overlying_set(bset
, model
);
1419 ISL_F_CLR(convex_hull
, ISL_BASIC_MAP_RATIONAL
);
1423 isl_basic_map_free(model
);
1427 struct isl_basic_set
*isl_set_convex_hull(struct isl_set
*set
)
1429 return (struct isl_basic_set
*)
1430 isl_map_convex_hull((struct isl_map
*)set
);
1433 struct sh_data_entry
{
1434 struct isl_hash_table
*table
;
1435 struct isl_tab
*tab
;
1438 /* Holds the data needed during the simple hull computation.
1440 * n the number of basic sets in the original set
1441 * hull_table a hash table of already computed constraints
1442 * in the simple hull
1443 * p for each basic set,
1444 * table a hash table of the constraints
1445 * tab the tableau corresponding to the basic set
1448 struct isl_ctx
*ctx
;
1450 struct isl_hash_table
*hull_table
;
1451 struct sh_data_entry p
[0];
1454 static void sh_data_free(struct sh_data
*data
)
1460 isl_hash_table_free(data
->ctx
, data
->hull_table
);
1461 for (i
= 0; i
< data
->n
; ++i
) {
1462 isl_hash_table_free(data
->ctx
, data
->p
[i
].table
);
1463 isl_tab_free(data
->ctx
, data
->p
[i
].tab
);
1468 struct ineq_cmp_data
{
1473 static int has_ineq(const void *entry
, const void *val
)
1475 isl_int
*row
= (isl_int
*)entry
;
1476 struct ineq_cmp_data
*v
= (struct ineq_cmp_data
*)val
;
1478 return isl_seq_eq(row
+ 1, v
->p
+ 1, v
->len
) ||
1479 isl_seq_is_neg(row
+ 1, v
->p
+ 1, v
->len
);
1482 static int hash_ineq(struct isl_ctx
*ctx
, struct isl_hash_table
*table
,
1483 isl_int
*ineq
, unsigned len
)
1486 struct ineq_cmp_data v
;
1487 struct isl_hash_table_entry
*entry
;
1491 c_hash
= isl_seq_hash(ineq
+ 1, len
, isl_hash_init());
1492 entry
= isl_hash_table_find(ctx
, table
, c_hash
, has_ineq
, &v
, 1);
1499 /* Fill hash table "table" with the constraints of "bset".
1500 * Equalities are added as two inequalities.
1501 * The value in the hash table is a pointer to the (in)equality of "bset".
1503 static int hash_basic_set(struct isl_hash_table
*table
,
1504 struct isl_basic_set
*bset
)
1507 unsigned dim
= isl_basic_set_total_dim(bset
);
1509 for (i
= 0; i
< bset
->n_eq
; ++i
) {
1510 for (j
= 0; j
< 2; ++j
) {
1511 isl_seq_neg(bset
->eq
[i
], bset
->eq
[i
], 1 + dim
);
1512 if (hash_ineq(bset
->ctx
, table
, bset
->eq
[i
], dim
) < 0)
1516 for (i
= 0; i
< bset
->n_ineq
; ++i
) {
1517 if (hash_ineq(bset
->ctx
, table
, bset
->ineq
[i
], dim
) < 0)
1523 static struct sh_data
*sh_data_alloc(struct isl_set
*set
, unsigned n_ineq
)
1525 struct sh_data
*data
;
1528 data
= isl_calloc(set
->ctx
, struct sh_data
,
1529 sizeof(struct sh_data
) + set
->n
* sizeof(struct sh_data_entry
));
1532 data
->ctx
= set
->ctx
;
1534 data
->hull_table
= isl_hash_table_alloc(set
->ctx
, n_ineq
);
1535 if (!data
->hull_table
)
1537 for (i
= 0; i
< set
->n
; ++i
) {
1538 data
->p
[i
].table
= isl_hash_table_alloc(set
->ctx
,
1539 2 * set
->p
[i
]->n_eq
+ set
->p
[i
]->n_ineq
);
1540 if (!data
->p
[i
].table
)
1542 if (hash_basic_set(data
->p
[i
].table
, set
->p
[i
]) < 0)
1551 /* Check if inequality "ineq" is a bound for basic set "j" or if
1552 * it can be relaxed (by increasing the constant term) to become
1553 * a bound for that basic set. In the latter case, the constant
1555 * Return 1 if "ineq" is a bound
1556 * 0 if "ineq" may attain arbitrarily small values on basic set "j"
1557 * -1 if some error occurred
1559 static int is_bound(struct sh_data
*data
, struct isl_set
*set
, int j
,
1562 enum isl_lp_result res
;
1565 if (!data
->p
[j
].tab
) {
1566 data
->p
[j
].tab
= isl_tab_from_basic_set(set
->p
[j
]);
1567 if (!data
->p
[j
].tab
)
1573 res
= isl_tab_min(data
->ctx
, data
->p
[j
].tab
, ineq
, data
->ctx
->one
,
1575 if (res
== isl_lp_ok
&& isl_int_is_neg(opt
))
1576 isl_int_sub(ineq
[0], ineq
[0], opt
);
1580 return res
== isl_lp_ok
? 1 :
1581 res
== isl_lp_unbounded
? 0 : -1;
1584 /* Check if inequality "ineq" from basic set "i" can be relaxed to
1585 * become a bound on the whole set. If so, add the (relaxed) inequality
1588 * We first check if "hull" already contains a translate of the inequality.
1589 * If so, we are done.
1590 * Then, we check if any of the previous basic sets contains a translate
1591 * of the inequality. If so, then we have already considered this
1592 * inequality and we are done.
1593 * Otherwise, for each basic set other than "i", we check if the inequality
1594 * is a bound on the basic set.
1595 * For previous basic sets, we know that they do not contain a translate
1596 * of the inequality, so we directly call is_bound.
1597 * For following basic sets, we first check if a translate of the
1598 * inequality appears in its description and if so directly update
1599 * the inequality accordingly.
1601 static struct isl_basic_set
*add_bound(struct isl_basic_set
*hull
,
1602 struct sh_data
*data
, struct isl_set
*set
, int i
, isl_int
*ineq
)
1605 struct ineq_cmp_data v
;
1606 struct isl_hash_table_entry
*entry
;
1612 v
.len
= isl_basic_set_total_dim(hull
);
1614 c_hash
= isl_seq_hash(ineq
+ 1, v
.len
, isl_hash_init());
1616 entry
= isl_hash_table_find(hull
->ctx
, data
->hull_table
, c_hash
,
1621 for (j
= 0; j
< i
; ++j
) {
1622 entry
= isl_hash_table_find(hull
->ctx
, data
->p
[j
].table
,
1623 c_hash
, has_ineq
, &v
, 0);
1630 k
= isl_basic_set_alloc_inequality(hull
);
1631 isl_seq_cpy(hull
->ineq
[k
], ineq
, 1 + v
.len
);
1635 for (j
= 0; j
< i
; ++j
) {
1637 bound
= is_bound(data
, set
, j
, hull
->ineq
[k
]);
1644 isl_basic_set_free_inequality(hull
, 1);
1648 for (j
= i
+ 1; j
< set
->n
; ++j
) {
1651 entry
= isl_hash_table_find(hull
->ctx
, data
->p
[j
].table
,
1652 c_hash
, has_ineq
, &v
, 0);
1654 ineq_j
= entry
->data
;
1655 neg
= isl_seq_is_neg(ineq_j
+ 1,
1656 hull
->ineq
[k
] + 1, v
.len
);
1658 isl_int_neg(ineq_j
[0], ineq_j
[0]);
1659 if (isl_int_gt(ineq_j
[0], hull
->ineq
[k
][0]))
1660 isl_int_set(hull
->ineq
[k
][0], ineq_j
[0]);
1662 isl_int_neg(ineq_j
[0], ineq_j
[0]);
1665 bound
= is_bound(data
, set
, j
, hull
->ineq
[k
]);
1672 isl_basic_set_free_inequality(hull
, 1);
1676 entry
= isl_hash_table_find(hull
->ctx
, data
->hull_table
, c_hash
,
1680 entry
->data
= hull
->ineq
[k
];
1684 isl_basic_set_free(hull
);
1688 /* Check if any inequality from basic set "i" can be relaxed to
1689 * become a bound on the whole set. If so, add the (relaxed) inequality
1692 static struct isl_basic_set
*add_bounds(struct isl_basic_set
*bset
,
1693 struct sh_data
*data
, struct isl_set
*set
, int i
)
1696 unsigned dim
= isl_basic_set_total_dim(bset
);
1698 for (j
= 0; j
< set
->p
[i
]->n_eq
; ++j
) {
1699 for (k
= 0; k
< 2; ++k
) {
1700 isl_seq_neg(set
->p
[i
]->eq
[j
], set
->p
[i
]->eq
[j
], 1+dim
);
1701 add_bound(bset
, data
, set
, i
, set
->p
[i
]->eq
[j
]);
1704 for (j
= 0; j
< set
->p
[i
]->n_ineq
; ++j
)
1705 add_bound(bset
, data
, set
, i
, set
->p
[i
]->ineq
[j
]);
1709 /* Compute a superset of the convex hull of set that is described
1710 * by only translates of the constraints in the constituents of set.
1712 static struct isl_basic_set
*uset_simple_hull(struct isl_set
*set
)
1714 struct sh_data
*data
= NULL
;
1715 struct isl_basic_set
*hull
= NULL
;
1723 for (i
= 0; i
< set
->n
; ++i
) {
1726 n_ineq
+= 2 * set
->p
[i
]->n_eq
+ set
->p
[i
]->n_ineq
;
1729 hull
= isl_set_affine_hull(isl_set_copy(set
));
1732 hull
= isl_basic_set_extend_dim(hull
, isl_dim_copy(hull
->dim
),
1737 data
= sh_data_alloc(set
, n_ineq
);
1740 if (hash_basic_set(data
->hull_table
, hull
) < 0)
1743 for (i
= 0; i
< set
->n
; ++i
)
1744 hull
= add_bounds(hull
, data
, set
, i
);
1746 hull
= isl_basic_set_convex_hull(hull
);
1754 isl_basic_set_free(hull
);
1759 /* Compute a superset of the convex hull of map that is described
1760 * by only translates of the constraints in the constituents of map.
1762 struct isl_basic_map
*isl_map_simple_hull(struct isl_map
*map
)
1764 struct isl_set
*set
= NULL
;
1765 struct isl_basic_map
*model
= NULL
;
1766 struct isl_basic_map
*hull
;
1767 struct isl_basic_set
*bset
= NULL
;
1772 hull
= isl_basic_map_empty_like_map(map
);
1777 hull
= isl_basic_map_copy(map
->p
[0]);
1782 map
= isl_map_align_divs(map
);
1783 model
= isl_basic_map_copy(map
->p
[0]);
1785 set
= isl_map_underlying_set(map
);
1787 bset
= uset_simple_hull(set
);
1789 hull
= isl_basic_map_overlying_set(bset
, model
);
1794 struct isl_basic_set
*isl_set_simple_hull(struct isl_set
*set
)
1796 return (struct isl_basic_set
*)
1797 isl_map_simple_hull((struct isl_map
*)set
);