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+1, (*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);
63 isl_int_addmul(*opt_n, *opt_d, c[0]);
65 isl_int_add(*opt_n, *opt_n, c[0]);
66 return !isl_int_is_neg(*opt_n);
69 int isl_basic_set_constraint_is_redundant(struct isl_basic_set **bset,
70 isl_int *c, isl_int *opt_n, isl_int *opt_d)
72 return isl_basic_map_constraint_is_redundant(
73 (struct isl_basic_map **)bset, c, opt_n, opt_d);
76 /* Compute the convex hull of a basic map, by removing the redundant
77 * constraints. If the minimal value along the normal of a constraint
78 * is the same if the constraint is removed, then the constraint is redundant.
80 * Alternatively, we could have intersected the basic map with the
81 * corresponding equality and the checked if the dimension was that
84 struct isl_basic_map *isl_basic_map_convex_hull(struct isl_basic_map *bmap)
91 bmap = isl_basic_map_gauss(bmap, NULL);
92 if (ISL_F_ISSET(bmap, ISL_BASIC_MAP_EMPTY))
94 if (ISL_F_ISSET(bmap, ISL_BASIC_MAP_NO_REDUNDANT))
96 if (bmap->n_ineq <= 1)
99 tab = isl_tab_from_basic_map(bmap);
100 tab = isl_tab_detect_equalities(bmap->ctx, tab);
101 tab = isl_tab_detect_redundant(bmap->ctx, tab);
102 bmap = isl_basic_map_update_from_tab(bmap, tab);
103 isl_tab_free(bmap->ctx, tab);
104 ISL_F_SET(bmap, ISL_BASIC_MAP_NO_IMPLICIT);
105 ISL_F_SET(bmap, ISL_BASIC_MAP_NO_REDUNDANT);
109 struct isl_basic_set *isl_basic_set_convex_hull(struct isl_basic_set *bset)
111 return (struct isl_basic_set *)
112 isl_basic_map_convex_hull((struct isl_basic_map *)bset);
115 /* Check if the set set is bound in the direction of the affine
116 * constraint c and if so, set the constant term such that the
117 * resulting constraint is a bounding constraint for the set.
119 static int uset_is_bound(struct isl_ctx *ctx, struct isl_set *set,
120 isl_int *c, unsigned len)
128 isl_int_init(opt_denom);
130 for (j = 0; j < set->n; ++j) {
131 enum isl_lp_result res;
133 if (ISL_F_ISSET(set->p[j], ISL_BASIC_SET_EMPTY))
136 res = isl_solve_lp((struct isl_basic_map*)set->p[j],
137 0, c+1, ctx->one, &opt, &opt_denom);
138 if (res == isl_lp_unbounded)
140 if (res == isl_lp_error)
142 if (res == isl_lp_empty) {
143 set->p[j] = isl_basic_set_set_to_empty(set->p[j]);
148 if (!isl_int_is_one(opt_denom))
149 isl_seq_scale(c, c, opt_denom, len);
150 if (first || isl_int_lt(opt, c[0]))
151 isl_int_set(c[0], opt);
155 isl_int_clear(opt_denom);
156 isl_int_neg(c[0], c[0]);
160 isl_int_clear(opt_denom);
164 /* Check if "c" is a direction that is independent of the previously found "n"
166 * If so, add it to the list, with the negative of the lower bound
167 * in the constant position, i.e., such that c corresponds to a bounding
168 * hyperplane (but not necessarily a facet).
169 * Assumes set "set" is bounded.
171 static int is_independent_bound(struct isl_ctx *ctx,
172 struct isl_set *set, isl_int *c,
173 struct isl_mat *dirs, int n)
178 isl_seq_cpy(dirs->row[n]+1, c+1, dirs->n_col-1);
180 int pos = isl_seq_first_non_zero(dirs->row[n]+1, dirs->n_col-1);
183 for (i = 0; i < n; ++i) {
185 pos_i = isl_seq_first_non_zero(dirs->row[i]+1, dirs->n_col-1);
190 isl_seq_elim(dirs->row[n]+1, dirs->row[i]+1, pos,
191 dirs->n_col-1, NULL);
192 pos = isl_seq_first_non_zero(dirs->row[n]+1, dirs->n_col-1);
198 is_bound = uset_is_bound(ctx, set, dirs->row[n], dirs->n_col);
203 isl_int *t = dirs->row[n];
204 for (k = n; k > i; --k)
205 dirs->row[k] = dirs->row[k-1];
211 /* Compute and return a maximal set of linearly independent bounds
212 * on the set "set", based on the constraints of the basic sets
215 static struct isl_mat *independent_bounds(struct isl_ctx *ctx,
219 struct isl_mat *dirs = NULL;
220 unsigned dim = isl_set_n_dim(set);
222 dirs = isl_mat_alloc(ctx, dim, 1+dim);
227 for (i = 0; n < dim && i < set->n; ++i) {
229 struct isl_basic_set *bset = set->p[i];
231 for (j = 0; n < dim && j < bset->n_eq; ++j) {
232 f = is_independent_bound(ctx, set, bset->eq[j],
239 for (j = 0; n < dim && j < bset->n_ineq; ++j) {
240 f = is_independent_bound(ctx, set, bset->ineq[j],
251 isl_mat_free(ctx, dirs);
255 static struct isl_basic_set *isl_basic_set_set_rational(
256 struct isl_basic_set *bset)
261 if (ISL_F_ISSET(bset, ISL_BASIC_MAP_RATIONAL))
264 bset = isl_basic_set_cow(bset);
268 ISL_F_SET(bset, ISL_BASIC_MAP_RATIONAL);
270 return isl_basic_set_finalize(bset);
273 static struct isl_set *isl_set_set_rational(struct isl_set *set)
277 set = isl_set_cow(set);
280 for (i = 0; i < set->n; ++i) {
281 set->p[i] = isl_basic_set_set_rational(set->p[i]);
291 static struct isl_basic_set *isl_basic_set_add_equality(struct isl_ctx *ctx,
292 struct isl_basic_set *bset, isl_int *c)
298 if (ISL_F_ISSET(bset, ISL_BASIC_SET_EMPTY))
301 isl_assert(ctx, isl_basic_set_n_param(bset) == 0, goto error);
302 isl_assert(ctx, bset->n_div == 0, goto error);
303 dim = isl_basic_set_n_dim(bset);
304 bset = isl_basic_set_extend(bset, 0, dim, 0, 1, 0);
305 i = isl_basic_set_alloc_equality(bset);
308 isl_seq_cpy(bset->eq[i], c, 1 + dim);
311 isl_basic_set_free(bset);
315 static struct isl_set *isl_set_add_equality(struct isl_ctx *ctx,
316 struct isl_set *set, isl_int *c)
320 set = isl_set_cow(set);
323 for (i = 0; i < set->n; ++i) {
324 set->p[i] = isl_basic_set_add_equality(ctx, set->p[i], c);
334 /* Given a union of basic sets, construct the constraints for wrapping
335 * a facet around one of its ridges.
336 * In particular, if each of n the d-dimensional basic sets i in "set"
337 * contains the origin, satisfies the constraints x_1 >= 0 and x_2 >= 0
338 * and is defined by the constraints
342 * then the resulting set is of dimension n*(1+d) and has as contraints
351 static struct isl_basic_set *wrap_constraints(struct isl_set *set)
353 struct isl_basic_set *lp;
357 unsigned dim, lp_dim;
362 dim = 1 + isl_set_n_dim(set);
365 for (i = 0; i < set->n; ++i) {
366 n_eq += set->p[i]->n_eq;
367 n_ineq += set->p[i]->n_ineq;
369 lp = isl_basic_set_alloc(set->ctx, 0, dim * set->n, 0, n_eq, n_ineq);
372 lp_dim = isl_basic_set_n_dim(lp);
373 k = isl_basic_set_alloc_equality(lp);
374 isl_int_set_si(lp->eq[k][0], -1);
375 for (i = 0; i < set->n; ++i) {
376 isl_int_set_si(lp->eq[k][1+dim*i], 0);
377 isl_int_set_si(lp->eq[k][1+dim*i+1], 1);
378 isl_seq_clr(lp->eq[k]+1+dim*i+2, dim-2);
380 for (i = 0; i < set->n; ++i) {
381 k = isl_basic_set_alloc_inequality(lp);
382 isl_seq_clr(lp->ineq[k], 1+lp_dim);
383 isl_int_set_si(lp->ineq[k][1+dim*i], 1);
385 for (j = 0; j < set->p[i]->n_eq; ++j) {
386 k = isl_basic_set_alloc_equality(lp);
387 isl_seq_clr(lp->eq[k], 1+dim*i);
388 isl_seq_cpy(lp->eq[k]+1+dim*i, set->p[i]->eq[j], dim);
389 isl_seq_clr(lp->eq[k]+1+dim*(i+1), dim*(set->n-i-1));
392 for (j = 0; j < set->p[i]->n_ineq; ++j) {
393 k = isl_basic_set_alloc_inequality(lp);
394 isl_seq_clr(lp->ineq[k], 1+dim*i);
395 isl_seq_cpy(lp->ineq[k]+1+dim*i, set->p[i]->ineq[j], dim);
396 isl_seq_clr(lp->ineq[k]+1+dim*(i+1), dim*(set->n-i-1));
402 /* Given a facet "facet" of the convex hull of "set" and a facet "ridge"
403 * of that facet, compute the other facet of the convex hull that contains
406 * We first transform the set such that the facet constraint becomes
410 * I.e., the facet lies in
414 * and on that facet, the constraint that defines the ridge is
418 * (This transformation is not strictly needed, all that is needed is
419 * that the ridge contains the origin.)
421 * Since the ridge contains the origin, the cone of the convex hull
422 * will be of the form
427 * with this second constraint defining the new facet.
428 * The constant a is obtained by settting x_1 in the cone of the
429 * convex hull to 1 and minimizing x_2.
430 * Now, each element in the cone of the convex hull is the sum
431 * of elements in the cones of the basic sets.
432 * If a_i is the dilation factor of basic set i, then the problem
433 * we need to solve is
446 * the constraints of each (transformed) basic set.
447 * If a = n/d, then the constraint defining the new facet (in the transformed
450 * -n x_1 + d x_2 >= 0
452 * In the original space, we need to take the same combination of the
453 * corresponding constraints "facet" and "ridge".
455 * If a = -infty = "-1/0", then we just return the original facet constraint.
456 * This means that the facet is unbounded, but has a bounded intersection
457 * with the union of sets.
459 static isl_int *wrap_facet(struct isl_set *set, isl_int *facet, isl_int *ridge)
462 struct isl_mat *T = NULL;
463 struct isl_basic_set *lp = NULL;
465 enum isl_lp_result res;
469 set = isl_set_copy(set);
471 dim = 1 + isl_set_n_dim(set);
472 T = isl_mat_alloc(set->ctx, 3, dim);
475 isl_int_set_si(T->row[0][0], 1);
476 isl_seq_clr(T->row[0]+1, dim - 1);
477 isl_seq_cpy(T->row[1], facet, dim);
478 isl_seq_cpy(T->row[2], ridge, dim);
479 T = isl_mat_right_inverse(set->ctx, T);
480 set = isl_set_preimage(set, T);
484 lp = wrap_constraints(set);
485 obj = isl_vec_alloc(set->ctx, dim*set->n);
488 for (i = 0; i < set->n; ++i) {
489 isl_seq_clr(obj->block.data+dim*i, 2);
490 isl_int_set_si(obj->block.data[dim*i+2], 1);
491 isl_seq_clr(obj->block.data+dim*i+3, dim-3);
495 res = isl_solve_lp((struct isl_basic_map *)lp, 0,
496 obj->block.data, set->ctx->one, &num, &den);
497 if (res == isl_lp_ok) {
498 isl_int_neg(num, num);
499 isl_seq_combine(facet, num, facet, den, ridge, dim);
503 isl_vec_free(set->ctx, obj);
504 isl_basic_set_free(lp);
506 isl_assert(set->ctx, res == isl_lp_ok || res == isl_lp_unbounded,
510 isl_basic_set_free(lp);
511 isl_mat_free(set->ctx, T);
516 /* Given a set of d linearly independent bounding constraints of the
517 * convex hull of "set", compute the constraint of a facet of "set".
519 * We first compute the intersection with the first bounding hyperplane
520 * and remove the component corresponding to this hyperplane from
521 * other bounds (in homogeneous space).
522 * We then wrap around one of the remaining bounding constraints
523 * and continue the process until all bounding constraints have been
524 * taken into account.
525 * The resulting linear combination of the bounding constraints will
526 * correspond to a facet of the convex hull.
528 static struct isl_mat *initial_facet_constraint(struct isl_ctx *ctx,
529 struct isl_set *set, struct isl_mat *bounds)
531 struct isl_set *slice = NULL;
532 struct isl_basic_set *face = NULL;
533 struct isl_mat *m, *U, *Q;
535 unsigned dim = isl_set_n_dim(set);
537 isl_assert(ctx, set->n > 0, goto error);
538 isl_assert(ctx, bounds->n_row == dim, goto error);
540 while (bounds->n_row > 1) {
541 slice = isl_set_copy(set);
542 slice = isl_set_add_equality(ctx, slice, bounds->row[0]);
543 face = isl_set_affine_hull(slice);
546 if (face->n_eq == 1) {
547 isl_basic_set_free(face);
550 m = isl_mat_alloc(ctx, 1 + face->n_eq, 1 + dim);
553 isl_int_set_si(m->row[0][0], 1);
554 isl_seq_clr(m->row[0]+1, dim);
555 for (i = 0; i < face->n_eq; ++i)
556 isl_seq_cpy(m->row[1 + i], face->eq[i], 1 + dim);
557 U = isl_mat_right_inverse(ctx, m);
558 Q = isl_mat_right_inverse(ctx, isl_mat_copy(ctx, U));
559 U = isl_mat_drop_cols(ctx, U, 1 + face->n_eq,
561 Q = isl_mat_drop_rows(ctx, Q, 1 + face->n_eq,
563 U = isl_mat_drop_cols(ctx, U, 0, 1);
564 Q = isl_mat_drop_rows(ctx, Q, 0, 1);
565 bounds = isl_mat_product(ctx, bounds, U);
566 bounds = isl_mat_product(ctx, bounds, Q);
567 while (isl_seq_first_non_zero(bounds->row[bounds->n_row-1],
568 bounds->n_col) == -1) {
570 isl_assert(ctx, bounds->n_row > 1, goto error);
572 if (!wrap_facet(set, bounds->row[0],
573 bounds->row[bounds->n_row-1]))
575 isl_basic_set_free(face);
580 isl_basic_set_free(face);
581 isl_mat_free(ctx, bounds);
585 /* Given the bounding constraint "c" of a facet of the convex hull of "set",
586 * compute a hyperplane description of the facet, i.e., compute the facets
589 * We compute an affine transformation that transforms the constraint
598 * by computing the right inverse U of a matrix that starts with the rows
611 * Since z_1 is zero, we can drop this variable as well as the corresponding
612 * column of U to obtain
620 * with Q' equal to Q, but without the corresponding row.
621 * After computing the facets of the facet in the z' space,
622 * we convert them back to the x space through Q.
624 static struct isl_basic_set *compute_facet(struct isl_set *set, isl_int *c)
626 struct isl_mat *m, *U, *Q;
627 struct isl_basic_set *facet = NULL;
632 set = isl_set_copy(set);
633 dim = isl_set_n_dim(set);
634 m = isl_mat_alloc(set->ctx, 2, 1 + dim);
637 isl_int_set_si(m->row[0][0], 1);
638 isl_seq_clr(m->row[0]+1, dim);
639 isl_seq_cpy(m->row[1], c, 1+dim);
640 U = isl_mat_right_inverse(set->ctx, m);
641 Q = isl_mat_right_inverse(set->ctx, isl_mat_copy(set->ctx, U));
642 U = isl_mat_drop_cols(set->ctx, U, 1, 1);
643 Q = isl_mat_drop_rows(set->ctx, Q, 1, 1);
644 set = isl_set_preimage(set, U);
645 facet = uset_convex_hull_wrap_bounded(set);
646 facet = isl_basic_set_preimage(facet, Q);
647 isl_assert(ctx, facet->n_eq == 0, goto error);
650 isl_basic_set_free(facet);
655 /* Given an initial facet constraint, compute the remaining facets.
656 * We do this by running through all facets found so far and computing
657 * the adjacent facets through wrapping, adding those facets that we
658 * hadn't already found before.
660 * For each facet we have found so far, we first compute its facets
661 * in the resulting convex hull. That is, we compute the ridges
662 * of the resulting convex hull contained in the facet.
663 * We also compute the corresponding facet in the current approximation
664 * of the convex hull. There is no need to wrap around the ridges
665 * in this facet since that would result in a facet that is already
666 * present in the current approximation.
668 * This function can still be significantly optimized by checking which of
669 * the facets of the basic sets are also facets of the convex hull and
670 * using all the facets so far to help in constructing the facets of the
673 * using the technique in section "3.1 Ridge Generation" of
674 * "Extended Convex Hull" by Fukuda et al.
676 static struct isl_basic_set *extend(struct isl_basic_set *hull,
681 struct isl_basic_set *facet = NULL;
682 struct isl_basic_set *hull_facet = NULL;
686 isl_assert(set->ctx, set->n > 0, goto error);
688 dim = isl_set_n_dim(set);
690 for (i = 0; i < hull->n_ineq; ++i) {
691 facet = compute_facet(set, hull->ineq[i]);
692 facet = isl_basic_set_add_equality(facet->ctx, facet, hull->ineq[i]);
693 facet = isl_basic_set_gauss(facet, NULL);
694 facet = isl_basic_set_normalize_constraints(facet);
695 hull_facet = isl_basic_set_copy(hull);
696 hull_facet = isl_basic_set_add_equality(hull_facet->ctx, hull_facet, hull->ineq[i]);
697 hull_facet = isl_basic_set_gauss(hull_facet, NULL);
698 hull_facet = isl_basic_set_normalize_constraints(hull_facet);
701 if (facet->n_ineq + hull->n_ineq > hull->c_size)
702 hull = isl_basic_set_extend_dim(hull,
703 isl_dim_copy(hull->dim), 0, 0, facet->n_ineq);
704 for (j = 0; j < facet->n_ineq; ++j) {
705 for (f = 0; f < hull_facet->n_ineq; ++f)
706 if (isl_seq_eq(facet->ineq[j],
707 hull_facet->ineq[f], 1 + dim))
709 if (f < hull_facet->n_ineq)
711 k = isl_basic_set_alloc_inequality(hull);
714 isl_seq_cpy(hull->ineq[k], hull->ineq[i], 1+dim);
715 if (!wrap_facet(set, hull->ineq[k], facet->ineq[j]))
718 isl_basic_set_free(hull_facet);
719 isl_basic_set_free(facet);
721 hull = isl_basic_set_simplify(hull);
722 hull = isl_basic_set_finalize(hull);
725 isl_basic_set_free(hull_facet);
726 isl_basic_set_free(facet);
727 isl_basic_set_free(hull);
731 /* Special case for computing the convex hull of a one dimensional set.
732 * We simply collect the lower and upper bounds of each basic set
733 * and the biggest of those.
735 static struct isl_basic_set *convex_hull_1d(struct isl_ctx *ctx,
738 struct isl_mat *c = NULL;
739 isl_int *lower = NULL;
740 isl_int *upper = NULL;
743 struct isl_basic_set *hull;
745 for (i = 0; i < set->n; ++i) {
746 set->p[i] = isl_basic_set_simplify(set->p[i]);
750 set = isl_set_remove_empty_parts(set);
753 isl_assert(ctx, set->n > 0, goto error);
754 c = isl_mat_alloc(ctx, 2, 2);
758 if (set->p[0]->n_eq > 0) {
759 isl_assert(ctx, set->p[0]->n_eq == 1, goto error);
762 if (isl_int_is_pos(set->p[0]->eq[0][1])) {
763 isl_seq_cpy(lower, set->p[0]->eq[0], 2);
764 isl_seq_neg(upper, set->p[0]->eq[0], 2);
766 isl_seq_neg(lower, set->p[0]->eq[0], 2);
767 isl_seq_cpy(upper, set->p[0]->eq[0], 2);
770 for (j = 0; j < set->p[0]->n_ineq; ++j) {
771 if (isl_int_is_pos(set->p[0]->ineq[j][1])) {
773 isl_seq_cpy(lower, set->p[0]->ineq[j], 2);
776 isl_seq_cpy(upper, set->p[0]->ineq[j], 2);
783 for (i = 0; i < set->n; ++i) {
784 struct isl_basic_set *bset = set->p[i];
788 for (j = 0; j < bset->n_eq; ++j) {
792 isl_int_mul(a, lower[0], bset->eq[j][1]);
793 isl_int_mul(b, lower[1], bset->eq[j][0]);
794 if (isl_int_lt(a, b) && isl_int_is_pos(bset->eq[j][1]))
795 isl_seq_cpy(lower, bset->eq[j], 2);
796 if (isl_int_gt(a, b) && isl_int_is_neg(bset->eq[j][1]))
797 isl_seq_neg(lower, bset->eq[j], 2);
800 isl_int_mul(a, upper[0], bset->eq[j][1]);
801 isl_int_mul(b, upper[1], bset->eq[j][0]);
802 if (isl_int_lt(a, b) && isl_int_is_pos(bset->eq[j][1]))
803 isl_seq_neg(upper, bset->eq[j], 2);
804 if (isl_int_gt(a, b) && isl_int_is_neg(bset->eq[j][1]))
805 isl_seq_cpy(upper, bset->eq[j], 2);
808 for (j = 0; j < bset->n_ineq; ++j) {
809 if (isl_int_is_pos(bset->ineq[j][1]))
811 if (isl_int_is_neg(bset->ineq[j][1]))
813 if (lower && isl_int_is_pos(bset->ineq[j][1])) {
814 isl_int_mul(a, lower[0], bset->ineq[j][1]);
815 isl_int_mul(b, lower[1], bset->ineq[j][0]);
816 if (isl_int_lt(a, b))
817 isl_seq_cpy(lower, bset->ineq[j], 2);
819 if (upper && isl_int_is_neg(bset->ineq[j][1])) {
820 isl_int_mul(a, upper[0], bset->ineq[j][1]);
821 isl_int_mul(b, upper[1], bset->ineq[j][0]);
822 if (isl_int_gt(a, b))
823 isl_seq_cpy(upper, bset->ineq[j], 2);
834 hull = isl_basic_set_alloc(ctx, 0, 1, 0, 0, 2);
835 hull = isl_basic_set_set_rational(hull);
839 k = isl_basic_set_alloc_inequality(hull);
840 isl_seq_cpy(hull->ineq[k], lower, 2);
843 k = isl_basic_set_alloc_inequality(hull);
844 isl_seq_cpy(hull->ineq[k], upper, 2);
846 hull = isl_basic_set_finalize(hull);
848 isl_mat_free(ctx, c);
852 isl_mat_free(ctx, c);
856 /* Project out final n dimensions using Fourier-Motzkin */
857 static struct isl_set *set_project_out(struct isl_ctx *ctx,
858 struct isl_set *set, unsigned n)
860 return isl_set_remove_dims(set, isl_set_n_dim(set) - n, n);
863 static struct isl_basic_set *convex_hull_0d(struct isl_set *set)
865 struct isl_basic_set *convex_hull;
870 if (isl_set_is_empty(set))
871 convex_hull = isl_basic_set_empty(isl_dim_copy(set->dim));
873 convex_hull = isl_basic_set_universe(isl_dim_copy(set->dim));
878 /* Compute the convex hull of a pair of basic sets without any parameters or
879 * integer divisions using Fourier-Motzkin elimination.
880 * The convex hull is the set of all points that can be written as
881 * the sum of points from both basic sets (in homogeneous coordinates).
882 * We set up the constraints in a space with dimensions for each of
883 * the three sets and then project out the dimensions corresponding
884 * to the two original basic sets, retaining only those corresponding
885 * to the convex hull.
887 static struct isl_basic_set *convex_hull_pair(struct isl_basic_set *bset1,
888 struct isl_basic_set *bset2)
891 struct isl_basic_set *bset[2];
892 struct isl_basic_set *hull = NULL;
895 if (!bset1 || !bset2)
898 dim = isl_basic_set_n_dim(bset1);
899 hull = isl_basic_set_alloc(bset1->ctx, 0, 2 + 3 * dim, 0,
900 1 + dim + bset1->n_eq + bset2->n_eq,
901 2 + bset1->n_ineq + bset2->n_ineq);
904 for (i = 0; i < 2; ++i) {
905 for (j = 0; j < bset[i]->n_eq; ++j) {
906 k = isl_basic_set_alloc_equality(hull);
909 isl_seq_clr(hull->eq[k], (i+1) * (1+dim));
910 isl_seq_clr(hull->eq[k]+(i+2)*(1+dim), (1-i)*(1+dim));
911 isl_seq_cpy(hull->eq[k]+(i+1)*(1+dim), bset[i]->eq[j],
914 for (j = 0; j < bset[i]->n_ineq; ++j) {
915 k = isl_basic_set_alloc_inequality(hull);
918 isl_seq_clr(hull->ineq[k], (i+1) * (1+dim));
919 isl_seq_clr(hull->ineq[k]+(i+2)*(1+dim), (1-i)*(1+dim));
920 isl_seq_cpy(hull->ineq[k]+(i+1)*(1+dim),
921 bset[i]->ineq[j], 1+dim);
923 k = isl_basic_set_alloc_inequality(hull);
926 isl_seq_clr(hull->ineq[k], 1+2+3*dim);
927 isl_int_set_si(hull->ineq[k][(i+1)*(1+dim)], 1);
929 for (j = 0; j < 1+dim; ++j) {
930 k = isl_basic_set_alloc_equality(hull);
933 isl_seq_clr(hull->eq[k], 1+2+3*dim);
934 isl_int_set_si(hull->eq[k][j], -1);
935 isl_int_set_si(hull->eq[k][1+dim+j], 1);
936 isl_int_set_si(hull->eq[k][2*(1+dim)+j], 1);
938 hull = isl_basic_set_set_rational(hull);
939 hull = isl_basic_set_remove_dims(hull, dim, 2*(1+dim));
940 hull = isl_basic_set_convex_hull(hull);
941 isl_basic_set_free(bset1);
942 isl_basic_set_free(bset2);
945 isl_basic_set_free(bset1);
946 isl_basic_set_free(bset2);
947 isl_basic_set_free(hull);
951 /* Compute the convex hull of a set without any parameters or
952 * integer divisions using Fourier-Motzkin elimination.
953 * In each step, we combined two basic sets until only one
956 static struct isl_basic_set *uset_convex_hull_elim(struct isl_set *set)
958 struct isl_basic_set *convex_hull = NULL;
960 convex_hull = isl_set_copy_basic_set(set);
961 set = isl_set_drop_basic_set(set, convex_hull);
965 struct isl_basic_set *t;
966 t = isl_set_copy_basic_set(set);
969 set = isl_set_drop_basic_set(set, t);
972 convex_hull = convex_hull_pair(convex_hull, t);
978 isl_basic_set_free(convex_hull);
982 /* Compute an initial hull for wrapping containing a single initial
983 * facet by first computing bounds on the set and then using these
984 * bounds to construct an initial facet.
985 * This function is a remnant of an older implementation where the
986 * bounds were also used to check whether the set was bounded.
987 * Since this function will now only be called when we know the
988 * set to be bounded, the initial facet should probably be constructed
989 * by simply using the coordinate directions instead.
991 static struct isl_basic_set *initial_hull(struct isl_basic_set *hull,
994 struct isl_mat *bounds = NULL;
1000 bounds = independent_bounds(set->ctx, set);
1003 isl_assert(set->ctx, bounds->n_row == isl_set_n_dim(set), goto error);
1004 bounds = initial_facet_constraint(set->ctx, set, bounds);
1007 k = isl_basic_set_alloc_inequality(hull);
1010 dim = isl_set_n_dim(set);
1011 isl_assert(set->ctx, 1 + dim == bounds->n_col, goto error);
1012 isl_seq_cpy(hull->ineq[k], bounds->row[0], bounds->n_col);
1013 isl_mat_free(set->ctx, bounds);
1017 isl_basic_set_free(hull);
1018 isl_mat_free(set->ctx, bounds);
1022 struct max_constraint {
1028 static int max_constraint_equal(const void *entry, const void *val)
1030 struct max_constraint *a = (struct max_constraint *)entry;
1031 isl_int *b = (isl_int *)val;
1033 return isl_seq_eq(a->c->row[0] + 1, b, a->c->n_col - 1);
1036 static void update_constraint(struct isl_ctx *ctx, struct isl_hash_table *table,
1037 isl_int *con, unsigned len, int n, int ineq)
1039 struct isl_hash_table_entry *entry;
1040 struct max_constraint *c;
1043 c_hash = isl_seq_hash(con + 1, len, isl_hash_init());
1044 entry = isl_hash_table_find(ctx, table, c_hash, max_constraint_equal,
1050 isl_hash_table_remove(ctx, table, entry);
1054 if (isl_int_gt(c->c->row[0][0], con[0]))
1056 if (isl_int_eq(c->c->row[0][0], con[0])) {
1061 c->c = isl_mat_cow(ctx, c->c);
1062 isl_int_set(c->c->row[0][0], con[0]);
1066 /* Check whether the constraint hash table "table" constains the constraint
1069 static int has_constraint(struct isl_ctx *ctx, struct isl_hash_table *table,
1070 isl_int *con, unsigned len, int n)
1072 struct isl_hash_table_entry *entry;
1073 struct max_constraint *c;
1076 c_hash = isl_seq_hash(con + 1, len, isl_hash_init());
1077 entry = isl_hash_table_find(ctx, table, c_hash, max_constraint_equal,
1084 return isl_int_eq(c->c->row[0][0], con[0]);
1087 /* Check for inequality constraints of a basic set without equalities
1088 * such that the same or more stringent copies of the constraint appear
1089 * in all of the basic sets. Such constraints are necessarily facet
1090 * constraints of the convex hull.
1092 * If the resulting basic set is by chance identical to one of
1093 * the basic sets in "set", then we know that this basic set contains
1094 * all other basic sets and is therefore the convex hull of set.
1095 * In this case we set *is_hull to 1.
1097 static struct isl_basic_set *common_constraints(struct isl_basic_set *hull,
1098 struct isl_set *set, int *is_hull)
1101 int min_constraints;
1103 struct max_constraint *constraints = NULL;
1104 struct isl_hash_table *table = NULL;
1109 for (i = 0; i < set->n; ++i)
1110 if (set->p[i]->n_eq == 0)
1114 min_constraints = set->p[i]->n_ineq;
1116 for (i = best + 1; i < set->n; ++i) {
1117 if (set->p[i]->n_eq != 0)
1119 if (set->p[i]->n_ineq >= min_constraints)
1121 min_constraints = set->p[i]->n_ineq;
1124 constraints = isl_calloc_array(hull->ctx, struct max_constraint,
1128 table = isl_alloc_type(hull->ctx, struct isl_hash_table);
1129 if (isl_hash_table_init(hull->ctx, table, min_constraints))
1132 total = isl_dim_total(set->dim);
1133 for (i = 0; i < set->p[best]->n_ineq; ++i) {
1134 constraints[i].c = isl_mat_sub_alloc(hull->ctx,
1135 set->p[best]->ineq + i, 0, 1, 0, 1 + total);
1136 if (!constraints[i].c)
1138 constraints[i].ineq = 1;
1140 for (i = 0; i < min_constraints; ++i) {
1141 struct isl_hash_table_entry *entry;
1143 c_hash = isl_seq_hash(constraints[i].c->row[0] + 1, total,
1145 entry = isl_hash_table_find(hull->ctx, table, c_hash,
1146 max_constraint_equal, constraints[i].c->row[0] + 1, 1);
1149 isl_assert(hull->ctx, !entry->data, goto error);
1150 entry->data = &constraints[i];
1154 for (s = 0; s < set->n; ++s) {
1158 for (i = 0; i < set->p[s]->n_eq; ++i) {
1159 isl_int *eq = set->p[s]->eq[i];
1160 for (j = 0; j < 2; ++j) {
1161 isl_seq_neg(eq, eq, 1 + total);
1162 update_constraint(hull->ctx, table,
1166 for (i = 0; i < set->p[s]->n_ineq; ++i) {
1167 isl_int *ineq = set->p[s]->ineq[i];
1168 update_constraint(hull->ctx, table, ineq, total, n,
1169 set->p[s]->n_eq == 0);
1174 for (i = 0; i < min_constraints; ++i) {
1175 if (constraints[i].count < n)
1177 if (!constraints[i].ineq)
1179 j = isl_basic_set_alloc_inequality(hull);
1182 isl_seq_cpy(hull->ineq[j], constraints[i].c->row[0], 1 + total);
1185 for (s = 0; s < set->n; ++s) {
1186 if (set->p[s]->n_eq)
1188 if (set->p[s]->n_ineq != hull->n_ineq)
1190 for (i = 0; i < set->p[s]->n_ineq; ++i) {
1191 isl_int *ineq = set->p[s]->ineq[i];
1192 if (!has_constraint(hull->ctx, table, ineq, total, n))
1195 if (i == set->p[s]->n_ineq)
1199 isl_hash_table_clear(table);
1200 for (i = 0; i < min_constraints; ++i)
1201 isl_mat_free(hull->ctx, constraints[i].c);
1206 isl_hash_table_clear(table);
1209 for (i = 0; i < min_constraints; ++i)
1210 isl_mat_free(hull->ctx, constraints[i].c);
1215 /* Create a template for the convex hull of "set" and fill it up
1216 * obvious facet constraints, if any. If the result happens to
1217 * be the convex hull of "set" then *is_hull is set to 1.
1219 static struct isl_basic_set *proto_hull(struct isl_set *set, int *is_hull)
1221 struct isl_basic_set *hull;
1226 for (i = 0; i < set->n; ++i) {
1227 n_ineq += set->p[i]->n_eq;
1228 n_ineq += set->p[i]->n_ineq;
1230 hull = isl_basic_set_alloc_dim(isl_dim_copy(set->dim), 0, 0, n_ineq);
1231 hull = isl_basic_set_set_rational(hull);
1234 return common_constraints(hull, set, is_hull);
1237 static struct isl_basic_set *uset_convex_hull_wrap(struct isl_set *set)
1239 struct isl_basic_set *hull;
1242 hull = proto_hull(set, &is_hull);
1243 if (hull && !is_hull) {
1244 if (hull->n_ineq == 0)
1245 hull = initial_hull(hull, set);
1246 hull = extend(hull, set);
1253 static int isl_basic_set_is_bounded(struct isl_basic_set *bset)
1255 struct isl_tab *tab;
1258 tab = isl_tab_from_recession_cone((struct isl_basic_map *)bset);
1259 bounded = isl_tab_cone_is_bounded(bset->ctx, tab);
1260 isl_tab_free(bset->ctx, tab);
1264 static int isl_set_is_bounded(struct isl_set *set)
1268 for (i = 0; i < set->n; ++i) {
1269 int bounded = isl_basic_set_is_bounded(set->p[i]);
1270 if (!bounded || bounded < 0)
1276 /* Compute the convex hull of a set without any parameters or
1277 * integer divisions. Depending on whether the set is bounded,
1278 * we pass control to the wrapping based convex hull or
1279 * the Fourier-Motzkin elimination based convex hull.
1280 * We also handle a few special cases before checking the boundedness.
1282 static struct isl_basic_set *uset_convex_hull(struct isl_set *set)
1285 struct isl_basic_set *convex_hull = NULL;
1287 if (isl_set_n_dim(set) == 0)
1288 return convex_hull_0d(set);
1290 set = isl_set_set_rational(set);
1294 set = isl_set_normalize(set);
1298 convex_hull = isl_basic_set_copy(set->p[0]);
1302 if (isl_set_n_dim(set) == 1)
1303 return convex_hull_1d(set->ctx, set);
1305 if (!isl_set_is_bounded(set))
1306 return uset_convex_hull_elim(set);
1308 return uset_convex_hull_wrap(set);
1311 isl_basic_set_free(convex_hull);
1315 /* This is the core procedure, where "set" is a "pure" set, i.e.,
1316 * without parameters or divs and where the convex hull of set is
1317 * known to be full-dimensional.
1319 static struct isl_basic_set *uset_convex_hull_wrap_bounded(struct isl_set *set)
1322 struct isl_basic_set *convex_hull = NULL;
1324 if (isl_set_n_dim(set) == 0) {
1325 convex_hull = isl_basic_set_universe(isl_dim_copy(set->dim));
1327 convex_hull = isl_basic_set_set_rational(convex_hull);
1331 set = isl_set_set_rational(set);
1335 set = isl_set_normalize(set);
1339 convex_hull = isl_basic_set_copy(set->p[0]);
1343 if (isl_set_n_dim(set) == 1)
1344 return convex_hull_1d(set->ctx, set);
1346 return uset_convex_hull_wrap(set);
1352 /* Compute the convex hull of set "set" with affine hull "affine_hull",
1353 * We first remove the equalities (transforming the set), compute the
1354 * convex hull of the transformed set and then add the equalities back
1355 * (after performing the inverse transformation.
1357 static struct isl_basic_set *modulo_affine_hull(struct isl_ctx *ctx,
1358 struct isl_set *set, struct isl_basic_set *affine_hull)
1362 struct isl_basic_set *dummy;
1363 struct isl_basic_set *convex_hull;
1365 dummy = isl_basic_set_remove_equalities(
1366 isl_basic_set_copy(affine_hull), &T, &T2);
1369 isl_basic_set_free(dummy);
1370 set = isl_set_preimage(set, T);
1371 convex_hull = uset_convex_hull(set);
1372 convex_hull = isl_basic_set_preimage(convex_hull, T2);
1373 convex_hull = isl_basic_set_intersect(convex_hull, affine_hull);
1376 isl_basic_set_free(affine_hull);
1381 /* Compute the convex hull of a map.
1383 * The implementation was inspired by "Extended Convex Hull" by Fukuda et al.,
1384 * specifically, the wrapping of facets to obtain new facets.
1386 struct isl_basic_map *isl_map_convex_hull(struct isl_map *map)
1388 struct isl_basic_set *bset;
1389 struct isl_basic_map *model = NULL;
1390 struct isl_basic_set *affine_hull = NULL;
1391 struct isl_basic_map *convex_hull = NULL;
1392 struct isl_set *set = NULL;
1393 struct isl_ctx *ctx;
1400 convex_hull = isl_basic_map_empty_like_map(map);
1405 map = isl_map_align_divs(map);
1406 model = isl_basic_map_copy(map->p[0]);
1407 set = isl_map_underlying_set(map);
1411 affine_hull = isl_set_affine_hull(isl_set_copy(set));
1414 if (affine_hull->n_eq != 0)
1415 bset = modulo_affine_hull(ctx, set, affine_hull);
1417 isl_basic_set_free(affine_hull);
1418 bset = uset_convex_hull(set);
1421 convex_hull = isl_basic_map_overlying_set(bset, model);
1423 ISL_F_CLR(convex_hull, ISL_BASIC_MAP_RATIONAL);
1427 isl_basic_map_free(model);
1431 struct isl_basic_set *isl_set_convex_hull(struct isl_set *set)
1433 return (struct isl_basic_set *)
1434 isl_map_convex_hull((struct isl_map *)set);
1437 struct sh_data_entry {
1438 struct isl_hash_table *table;
1439 struct isl_tab *tab;
1442 /* Holds the data needed during the simple hull computation.
1444 * n the number of basic sets in the original set
1445 * hull_table a hash table of already computed constraints
1446 * in the simple hull
1447 * p for each basic set,
1448 * table a hash table of the constraints
1449 * tab the tableau corresponding to the basic set
1452 struct isl_ctx *ctx;
1454 struct isl_hash_table *hull_table;
1455 struct sh_data_entry p[0];
1458 static void sh_data_free(struct sh_data *data)
1464 isl_hash_table_free(data->ctx, data->hull_table);
1465 for (i = 0; i < data->n; ++i) {
1466 isl_hash_table_free(data->ctx, data->p[i].table);
1467 isl_tab_free(data->ctx, data->p[i].tab);
1472 struct ineq_cmp_data {
1477 static int has_ineq(const void *entry, const void *val)
1479 isl_int *row = (isl_int *)entry;
1480 struct ineq_cmp_data *v = (struct ineq_cmp_data *)val;
1482 return isl_seq_eq(row + 1, v->p + 1, v->len) ||
1483 isl_seq_is_neg(row + 1, v->p + 1, v->len);
1486 static int hash_ineq(struct isl_ctx *ctx, struct isl_hash_table *table,
1487 isl_int *ineq, unsigned len)
1490 struct ineq_cmp_data v;
1491 struct isl_hash_table_entry *entry;
1495 c_hash = isl_seq_hash(ineq + 1, len, isl_hash_init());
1496 entry = isl_hash_table_find(ctx, table, c_hash, has_ineq, &v, 1);
1503 /* Fill hash table "table" with the constraints of "bset".
1504 * Equalities are added as two inequalities.
1505 * The value in the hash table is a pointer to the (in)equality of "bset".
1507 static int hash_basic_set(struct isl_hash_table *table,
1508 struct isl_basic_set *bset)
1511 unsigned dim = isl_basic_set_total_dim(bset);
1513 for (i = 0; i < bset->n_eq; ++i) {
1514 for (j = 0; j < 2; ++j) {
1515 isl_seq_neg(bset->eq[i], bset->eq[i], 1 + dim);
1516 if (hash_ineq(bset->ctx, table, bset->eq[i], dim) < 0)
1520 for (i = 0; i < bset->n_ineq; ++i) {
1521 if (hash_ineq(bset->ctx, table, bset->ineq[i], dim) < 0)
1527 static struct sh_data *sh_data_alloc(struct isl_set *set, unsigned n_ineq)
1529 struct sh_data *data;
1532 data = isl_calloc(set->ctx, struct sh_data,
1533 sizeof(struct sh_data) + set->n * sizeof(struct sh_data_entry));
1536 data->ctx = set->ctx;
1538 data->hull_table = isl_hash_table_alloc(set->ctx, n_ineq);
1539 if (!data->hull_table)
1541 for (i = 0; i < set->n; ++i) {
1542 data->p[i].table = isl_hash_table_alloc(set->ctx,
1543 2 * set->p[i]->n_eq + set->p[i]->n_ineq);
1544 if (!data->p[i].table)
1546 if (hash_basic_set(data->p[i].table, set->p[i]) < 0)
1555 /* Check if inequality "ineq" is a bound for basic set "j" or if
1556 * it can be relaxed (by increasing the constant term) to become
1557 * a bound for that basic set. In the latter case, the constant
1559 * Return 1 if "ineq" is a bound
1560 * 0 if "ineq" may attain arbitrarily small values on basic set "j"
1561 * -1 if some error occurred
1563 static int is_bound(struct sh_data *data, struct isl_set *set, int j,
1566 enum isl_lp_result res;
1569 if (!data->p[j].tab) {
1570 data->p[j].tab = isl_tab_from_basic_set(set->p[j]);
1571 if (!data->p[j].tab)
1577 res = isl_tab_min(data->ctx, data->p[j].tab, ineq, data->ctx->one,
1579 if (res == isl_lp_ok && isl_int_is_neg(opt))
1580 isl_int_sub(ineq[0], ineq[0], opt);
1584 return res == isl_lp_ok ? 1 :
1585 res == isl_lp_unbounded ? 0 : -1;
1588 /* Check if inequality "ineq" from basic set "i" can be relaxed to
1589 * become a bound on the whole set. If so, add the (relaxed) inequality
1592 * We first check if "hull" already contains a translate of the inequality.
1593 * If so, we are done.
1594 * Then, we check if any of the previous basic sets contains a translate
1595 * of the inequality. If so, then we have already considered this
1596 * inequality and we are done.
1597 * Otherwise, for each basic set other than "i", we check if the inequality
1598 * is a bound on the basic set.
1599 * For previous basic sets, we know that they do not contain a translate
1600 * of the inequality, so we directly call is_bound.
1601 * For following basic sets, we first check if a translate of the
1602 * inequality appears in its description and if so directly update
1603 * the inequality accordingly.
1605 static struct isl_basic_set *add_bound(struct isl_basic_set *hull,
1606 struct sh_data *data, struct isl_set *set, int i, isl_int *ineq)
1609 struct ineq_cmp_data v;
1610 struct isl_hash_table_entry *entry;
1616 v.len = isl_basic_set_total_dim(hull);
1618 c_hash = isl_seq_hash(ineq + 1, v.len, isl_hash_init());
1620 entry = isl_hash_table_find(hull->ctx, data->hull_table, c_hash,
1625 for (j = 0; j < i; ++j) {
1626 entry = isl_hash_table_find(hull->ctx, data->p[j].table,
1627 c_hash, has_ineq, &v, 0);
1634 k = isl_basic_set_alloc_inequality(hull);
1635 isl_seq_cpy(hull->ineq[k], ineq, 1 + v.len);
1639 for (j = 0; j < i; ++j) {
1641 bound = is_bound(data, set, j, hull->ineq[k]);
1648 isl_basic_set_free_inequality(hull, 1);
1652 for (j = i + 1; j < set->n; ++j) {
1655 entry = isl_hash_table_find(hull->ctx, data->p[j].table,
1656 c_hash, has_ineq, &v, 0);
1658 ineq_j = entry->data;
1659 neg = isl_seq_is_neg(ineq_j + 1,
1660 hull->ineq[k] + 1, v.len);
1662 isl_int_neg(ineq_j[0], ineq_j[0]);
1663 if (isl_int_gt(ineq_j[0], hull->ineq[k][0]))
1664 isl_int_set(hull->ineq[k][0], ineq_j[0]);
1666 isl_int_neg(ineq_j[0], ineq_j[0]);
1669 bound = is_bound(data, set, j, hull->ineq[k]);
1676 isl_basic_set_free_inequality(hull, 1);
1680 entry = isl_hash_table_find(hull->ctx, data->hull_table, c_hash,
1684 entry->data = hull->ineq[k];
1688 isl_basic_set_free(hull);
1692 /* Check if any inequality from basic set "i" can be relaxed to
1693 * become a bound on the whole set. If so, add the (relaxed) inequality
1696 static struct isl_basic_set *add_bounds(struct isl_basic_set *bset,
1697 struct sh_data *data, struct isl_set *set, int i)
1700 unsigned dim = isl_basic_set_total_dim(bset);
1702 for (j = 0; j < set->p[i]->n_eq; ++j) {
1703 for (k = 0; k < 2; ++k) {
1704 isl_seq_neg(set->p[i]->eq[j], set->p[i]->eq[j], 1+dim);
1705 add_bound(bset, data, set, i, set->p[i]->eq[j]);
1708 for (j = 0; j < set->p[i]->n_ineq; ++j)
1709 add_bound(bset, data, set, i, set->p[i]->ineq[j]);
1713 /* Compute a superset of the convex hull of set that is described
1714 * by only translates of the constraints in the constituents of set.
1716 static struct isl_basic_set *uset_simple_hull(struct isl_set *set)
1718 struct sh_data *data = NULL;
1719 struct isl_basic_set *hull = NULL;
1727 for (i = 0; i < set->n; ++i) {
1730 n_ineq += 2 * set->p[i]->n_eq + set->p[i]->n_ineq;
1733 hull = isl_set_affine_hull(isl_set_copy(set));
1736 hull = isl_basic_set_extend_dim(hull, isl_dim_copy(hull->dim),
1741 data = sh_data_alloc(set, n_ineq);
1744 if (hash_basic_set(data->hull_table, hull) < 0)
1747 for (i = 0; i < set->n; ++i)
1748 hull = add_bounds(hull, data, set, i);
1750 hull = isl_basic_set_convex_hull(hull);
1758 isl_basic_set_free(hull);
1763 /* Compute a superset of the convex hull of map that is described
1764 * by only translates of the constraints in the constituents of map.
1766 struct isl_basic_map *isl_map_simple_hull(struct isl_map *map)
1768 struct isl_set *set = NULL;
1769 struct isl_basic_map *model = NULL;
1770 struct isl_basic_map *hull;
1771 struct isl_basic_set *bset = NULL;
1776 hull = isl_basic_map_empty_like_map(map);
1781 hull = isl_basic_map_copy(map->p[0]);
1786 map = isl_map_align_divs(map);
1787 model = isl_basic_map_copy(map->p[0]);
1789 set = isl_map_underlying_set(map);
1791 bset = uset_simple_hull(set);
1793 hull = isl_basic_map_overlying_set(bset, model);
1798 struct isl_basic_set *isl_set_simple_hull(struct isl_set *set)
1800 return (struct isl_basic_set *)
1801 isl_map_simple_hull((struct isl_map *)set);