2 * Copyright 2010 INRIA Saclay
4 * Use of this software is governed by the GNU LGPLv2.1 license
6 * Written by Sven Verdoolaege, INRIA Saclay - Ile-de-France,
7 * Parc Club Orsay Universite, ZAC des vignes, 4 rue Jacques Monod,
12 #include "isl_map_private.h"
15 /* Given a map that represents a path with the length of the path
16 * encoded as the difference between the last output coordindate
17 * and the last input coordinate, set this length to either
18 * exactly "length" (if "exactly" is set) or at least "length"
19 * (if "exactly" is not set).
21 static __isl_give isl_map *set_path_length(__isl_take isl_map *map,
22 int exactly, int length)
25 struct isl_basic_map *bmap;
34 dim = isl_map_get_dim(map);
35 d = isl_dim_size(dim, isl_dim_in);
36 nparam = isl_dim_size(dim, isl_dim_param);
37 bmap = isl_basic_map_alloc_dim(dim, 0, 1, 1);
39 k = isl_basic_map_alloc_equality(bmap);
42 k = isl_basic_map_alloc_inequality(bmap);
47 isl_seq_clr(c, 1 + isl_basic_map_total_dim(bmap));
48 isl_int_set_si(c[0], -length);
49 isl_int_set_si(c[1 + nparam + d - 1], -1);
50 isl_int_set_si(c[1 + nparam + d + d - 1], 1);
52 bmap = isl_basic_map_finalize(bmap);
53 map = isl_map_intersect(map, isl_map_from_basic_map(bmap));
57 isl_basic_map_free(bmap);
62 /* Check whether the overapproximation of the power of "map" is exactly
63 * the power of "map". Let R be "map" and A_k the overapproximation.
64 * The approximation is exact if
67 * A_k = A_{k-1} \circ R k >= 2
69 * Since A_k is known to be an overapproximation, we only need to check
72 * A_k \subset A_{k-1} \circ R k >= 2
74 * In practice, "app" has an extra input and output coordinate
75 * to encode the length of the path. So, we first need to add
76 * this coordinate to "map" and set the length of the path to
79 static int check_power_exactness(__isl_take isl_map *map,
80 __isl_take isl_map *app)
86 map = isl_map_add(map, isl_dim_in, 1);
87 map = isl_map_add(map, isl_dim_out, 1);
88 map = set_path_length(map, 1, 1);
90 app_1 = set_path_length(isl_map_copy(app), 1, 1);
92 exact = isl_map_is_subset(app_1, map);
95 if (!exact || exact < 0) {
101 app_1 = set_path_length(isl_map_copy(app), 0, 1);
102 app_2 = set_path_length(app, 0, 2);
103 app_1 = isl_map_apply_range(map, app_1);
105 exact = isl_map_is_subset(app_2, app_1);
113 /* Check whether the overapproximation of the power of "map" is exactly
114 * the power of "map", possibly after projecting out the power (if "project"
117 * If "project" is set and if "steps" can only result in acyclic paths,
120 * A = R \cup (A \circ R)
122 * where A is the overapproximation with the power projected out, i.e.,
123 * an overapproximation of the transitive closure.
124 * More specifically, since A is known to be an overapproximation, we check
126 * A \subset R \cup (A \circ R)
128 * Otherwise, we check if the power is exact.
130 * Note that "app" has an extra input and output coordinate to encode
131 * the length of the part. If we are only interested in the transitive
132 * closure, then we can simply project out these coordinates first.
134 static int check_exactness(__isl_take isl_map *map, __isl_take isl_map *app,
142 return check_power_exactness(map, app);
144 d = isl_map_dim(map, isl_dim_in);
145 app = set_path_length(app, 0, 1);
146 app = isl_map_project_out(app, isl_dim_in, d, 1);
147 app = isl_map_project_out(app, isl_dim_out, d, 1);
149 test = isl_map_apply_range(isl_map_copy(map), isl_map_copy(app));
150 test = isl_map_union(test, isl_map_copy(map));
152 exact = isl_map_is_subset(app, test);
167 * The transitive closure implementation is based on the paper
168 * "Computing the Transitive Closure of a Union of Affine Integer
169 * Tuple Relations" by Anna Beletska, Denis Barthou, Wlodzimierz Bielecki and
173 /* Given a set of n offsets v_i (the rows of "steps"), construct a relation
174 * of the given dimension specification (Z^{n+1} -> Z^{n+1})
175 * that maps an element x to any element that can be reached
176 * by taking a non-negative number of steps along any of
177 * the extended offsets v'_i = [v_i 1].
180 * { [x] -> [y] : exists k_i >= 0, y = x + \sum_i k_i v'_i }
182 * For any element in this relation, the number of steps taken
183 * is equal to the difference in the final coordinates.
185 static __isl_give isl_map *path_along_steps(__isl_take isl_dim *dim,
186 __isl_keep isl_mat *steps)
189 struct isl_basic_map *path = NULL;
197 d = isl_dim_size(dim, isl_dim_in);
199 nparam = isl_dim_size(dim, isl_dim_param);
201 path = isl_basic_map_alloc_dim(isl_dim_copy(dim), n, d, n);
203 for (i = 0; i < n; ++i) {
204 k = isl_basic_map_alloc_div(path);
207 isl_assert(steps->ctx, i == k, goto error);
208 isl_int_set_si(path->div[k][0], 0);
211 for (i = 0; i < d; ++i) {
212 k = isl_basic_map_alloc_equality(path);
215 isl_seq_clr(path->eq[k], 1 + isl_basic_map_total_dim(path));
216 isl_int_set_si(path->eq[k][1 + nparam + i], 1);
217 isl_int_set_si(path->eq[k][1 + nparam + d + i], -1);
219 for (j = 0; j < n; ++j)
220 isl_int_set_si(path->eq[k][1 + nparam + 2 * d + j], 1);
222 for (j = 0; j < n; ++j)
223 isl_int_set(path->eq[k][1 + nparam + 2 * d + j],
227 for (i = 0; i < n; ++i) {
228 k = isl_basic_map_alloc_inequality(path);
231 isl_seq_clr(path->ineq[k], 1 + isl_basic_map_total_dim(path));
232 isl_int_set_si(path->ineq[k][1 + nparam + 2 * d + i], 1);
237 path = isl_basic_map_simplify(path);
238 path = isl_basic_map_finalize(path);
239 return isl_map_from_basic_map(path);
242 isl_basic_map_free(path);
250 /* Return PURE_PARAM if only the coefficients of the parameters are non-zero.
251 * Return PURE_VAR if only the coefficients of the set variables are non-zero.
252 * Return IMPURE otherwise.
254 static int purity(__isl_keep isl_basic_set *bset, isl_int *c)
260 n_div = isl_basic_set_dim(bset, isl_dim_div);
261 d = isl_basic_set_dim(bset, isl_dim_set);
262 nparam = isl_basic_set_dim(bset, isl_dim_param);
264 if (isl_seq_first_non_zero(c + 1 + nparam + d, n_div) != -1)
266 if (isl_seq_first_non_zero(c + 1, nparam) == -1)
268 if (isl_seq_first_non_zero(c + 1 + nparam, d) == -1)
273 /* Given a set of offsets "delta", construct a relation of the
274 * given dimension specification (Z^{n+1} -> Z^{n+1}) that
275 * is an overapproximation of the relations that
276 * maps an element x to any element that can be reached
277 * by taking a non-negative number of steps along any of
278 * the elements in "delta".
279 * That is, construct an approximation of
281 * { [x] -> [y] : exists f \in \delta, k \in Z :
282 * y = x + k [f, 1] and k >= 0 }
284 * For any element in this relation, the number of steps taken
285 * is equal to the difference in the final coordinates.
287 * In particular, let delta be defined as
289 * \delta = [p] -> { [x] : A x + a >= and B p + b >= 0 and
290 * C x + C'p + c >= 0 }
292 * then the relation is constructed as
294 * { [x] -> [y] : exists [f, k] \in Z^{n+1} : y = x + f and
295 * A f + k a >= 0 and B p + b >= 0 and k >= 1 }
296 * union { [x] -> [x] }
298 * Existentially quantified variables in \delta are currently ignored.
299 * This is safe, but leads to an additional overapproximation.
301 static __isl_give isl_map *path_along_delta(__isl_take isl_dim *dim,
302 __isl_take isl_basic_set *delta)
304 isl_basic_map *path = NULL;
313 n_div = isl_basic_set_dim(delta, isl_dim_div);
314 d = isl_basic_set_dim(delta, isl_dim_set);
315 nparam = isl_basic_set_dim(delta, isl_dim_param);
316 path = isl_basic_map_alloc_dim(isl_dim_copy(dim), n_div + d + 1,
317 d + 1 + delta->n_eq, delta->n_ineq + 1);
318 off = 1 + nparam + 2 * (d + 1) + n_div;
320 for (i = 0; i < n_div + d + 1; ++i) {
321 k = isl_basic_map_alloc_div(path);
324 isl_int_set_si(path->div[k][0], 0);
327 for (i = 0; i < d + 1; ++i) {
328 k = isl_basic_map_alloc_equality(path);
331 isl_seq_clr(path->eq[k], 1 + isl_basic_map_total_dim(path));
332 isl_int_set_si(path->eq[k][1 + nparam + i], 1);
333 isl_int_set_si(path->eq[k][1 + nparam + d + 1 + i], -1);
334 isl_int_set_si(path->eq[k][off + i], 1);
337 for (i = 0; i < delta->n_eq; ++i) {
338 int p = purity(delta, delta->eq[i]);
341 k = isl_basic_map_alloc_equality(path);
344 isl_seq_clr(path->eq[k], 1 + isl_basic_map_total_dim(path));
346 isl_seq_cpy(path->eq[k] + off,
347 delta->eq[i] + 1 + nparam, d);
348 isl_int_set(path->eq[k][off + d], delta->eq[i][0]);
350 isl_seq_cpy(path->eq[k], delta->eq[i], 1 + nparam);
353 for (i = 0; i < delta->n_ineq; ++i) {
354 int p = purity(delta, delta->ineq[i]);
357 k = isl_basic_map_alloc_inequality(path);
360 isl_seq_clr(path->ineq[k], 1 + isl_basic_map_total_dim(path));
362 isl_seq_cpy(path->ineq[k] + off,
363 delta->ineq[i] + 1 + nparam, d);
364 isl_int_set(path->ineq[k][off + d], delta->ineq[i][0]);
366 isl_seq_cpy(path->ineq[k], delta->ineq[i], 1 + nparam);
369 k = isl_basic_map_alloc_inequality(path);
372 isl_seq_clr(path->ineq[k], 1 + isl_basic_map_total_dim(path));
373 isl_int_set_si(path->ineq[k][0], -1);
374 isl_int_set_si(path->ineq[k][off + d], 1);
376 isl_basic_set_free(delta);
377 path = isl_basic_map_finalize(path);
378 return isl_basic_map_union(path,
379 isl_basic_map_identity(isl_dim_domain(dim)));
382 isl_basic_set_free(delta);
383 isl_basic_map_free(path);
387 /* Given a dimenion specification Z^{n+1} -> Z^{n+1} and a parameter "param",
388 * construct a map that equates the parameter to the difference
389 * in the final coordinates and imposes that this difference is positive.
392 * { [x,x_s] -> [y,y_s] : k = y_s - x_s > 0 }
394 static __isl_give isl_map *equate_parameter_to_length(__isl_take isl_dim *dim,
397 struct isl_basic_map *bmap;
402 d = isl_dim_size(dim, isl_dim_in);
403 nparam = isl_dim_size(dim, isl_dim_param);
404 bmap = isl_basic_map_alloc_dim(dim, 0, 1, 1);
405 k = isl_basic_map_alloc_equality(bmap);
408 isl_seq_clr(bmap->eq[k], 1 + isl_basic_map_total_dim(bmap));
409 isl_int_set_si(bmap->eq[k][1 + param], -1);
410 isl_int_set_si(bmap->eq[k][1 + nparam + d - 1], -1);
411 isl_int_set_si(bmap->eq[k][1 + nparam + d + d - 1], 1);
413 k = isl_basic_map_alloc_inequality(bmap);
416 isl_seq_clr(bmap->ineq[k], 1 + isl_basic_map_total_dim(bmap));
417 isl_int_set_si(bmap->ineq[k][1 + param], 1);
418 isl_int_set_si(bmap->ineq[k][0], -1);
420 bmap = isl_basic_map_finalize(bmap);
421 return isl_map_from_basic_map(bmap);
423 isl_basic_map_free(bmap);
427 /* Check whether "path" is acyclic, where the last coordinates of domain
428 * and range of path encode the number of steps taken.
429 * That is, check whether
431 * { d | d = y - x and (x,y) in path }
433 * does not contain any element with positive last coordinate (positive length)
434 * and zero remaining coordinates (cycle).
436 static int is_acyclic(__isl_take isl_map *path)
441 struct isl_set *delta;
443 delta = isl_map_deltas(path);
444 dim = isl_set_dim(delta, isl_dim_set);
445 for (i = 0; i < dim; ++i) {
447 delta = isl_set_lower_bound_si(delta, isl_dim_set, i, 1);
449 delta = isl_set_fix_si(delta, isl_dim_set, i, 0);
452 acyclic = isl_set_is_empty(delta);
458 /* Given a union of basic maps R = \cup_i R_i \subseteq D \times D
459 * and a dimension specification (Z^{n+1} -> Z^{n+1}),
460 * construct a map that is an overapproximation of the map
461 * that takes an element from the space D \times Z to another
462 * element from the same space, such that the first n coordinates of the
463 * difference between them is a sum of differences between images
464 * and pre-images in one of the R_i and such that the last coordinate
465 * is equal to the number of steps taken.
468 * \Delta_i = { y - x | (x, y) in R_i }
470 * then the constructed map is an overapproximation of
472 * { (x) -> (x + d) | \exists k_i >= 0, \delta_i \in \Delta_i :
473 * d = (\sum_i k_i \delta_i, \sum_i k_i) }
475 * The elements of the singleton \Delta_i's are collected as the
476 * rows of the steps matrix. For all these \Delta_i's together,
477 * a single path is constructed.
478 * For each of the other \Delta_i's, we compute an overapproximation
479 * of the paths along elements of \Delta_i.
480 * Since each of these paths performs an addition, composition is
481 * symmetric and we can simply compose all resulting paths in any order.
483 static __isl_give isl_map *construct_extended_path(__isl_take isl_dim *dim,
484 __isl_keep isl_map *map, int *project)
486 struct isl_mat *steps = NULL;
487 struct isl_map *path = NULL;
491 d = isl_map_dim(map, isl_dim_in);
493 path = isl_map_identity(isl_dim_domain(isl_dim_copy(dim)));
495 steps = isl_mat_alloc(map->ctx, map->n, d);
500 for (i = 0; i < map->n; ++i) {
501 struct isl_basic_set *delta;
503 delta = isl_basic_map_deltas(isl_basic_map_copy(map->p[i]));
505 for (j = 0; j < d; ++j) {
508 fixed = isl_basic_set_fast_dim_is_fixed(delta, j,
511 isl_basic_set_free(delta);
520 path = isl_map_apply_range(path,
521 path_along_delta(isl_dim_copy(dim), delta));
523 isl_basic_set_free(delta);
530 path = isl_map_apply_range(path,
531 path_along_steps(isl_dim_copy(dim), steps));
534 if (project && *project) {
535 *project = is_acyclic(isl_map_copy(path));
550 /* Given a union of basic maps R = \cup_i R_i \subseteq D \times D
551 * and a dimension specification (Z^{n+1} -> Z^{n+1}),
552 * construct a map that is the union of the identity map and
553 * an overapproximation of the map
554 * that takes an element from the dom R \times Z to an
555 * element from ran R \times Z, such that the first n coordinates of the
556 * difference between them is a sum of differences between images
557 * and pre-images in one of the R_i and such that the last coordinate
558 * is equal to the number of steps taken.
561 * \Delta_i = { y - x | (x, y) in R_i }
563 * then the constructed map is an overapproximation of
565 * { (x) -> (x + d) | \exists k_i >= 0, \delta_i \in \Delta_i :
566 * d = (\sum_i k_i \delta_i, \sum_i k_i) and
567 * x in dom R and x + d in ran R } union
570 static __isl_give isl_map *construct_component(__isl_take isl_dim *dim,
571 __isl_keep isl_map *map, int *exact, int project)
573 struct isl_set *domain = NULL;
574 struct isl_set *range = NULL;
575 struct isl_map *app = NULL;
576 struct isl_map *path = NULL;
578 domain = isl_map_domain(isl_map_copy(map));
579 domain = isl_set_coalesce(domain);
580 range = isl_map_range(isl_map_copy(map));
581 range = isl_set_coalesce(range);
582 app = isl_map_from_domain_and_range(domain, range);
583 app = isl_map_add(app, isl_dim_in, 1);
584 app = isl_map_add(app, isl_dim_out, 1);
586 path = construct_extended_path(isl_dim_copy(dim), map,
587 exact && *exact ? &project : NULL);
588 app = isl_map_intersect(app, path);
590 if (exact && *exact &&
591 (*exact = check_exactness(isl_map_copy(map), isl_map_copy(app),
595 return isl_map_union(app, isl_map_identity(isl_dim_domain(dim)));
602 /* Structure for representing the nodes in the graph being traversed
603 * using Tarjan's algorithm.
604 * index represents the order in which nodes are visited.
605 * min_index is the index of the root of a (sub)component.
606 * on_stack indicates whether the node is currently on the stack.
608 struct basic_map_sort_node {
613 /* Structure for representing the graph being traversed
614 * using Tarjan's algorithm.
615 * len is the number of nodes
616 * node is an array of nodes
617 * stack contains the nodes on the path from the root to the current node
618 * sp is the stack pointer
619 * index is the index of the last node visited
620 * order contains the elements of the components separated by -1
621 * op represents the current position in order
623 struct basic_map_sort {
625 struct basic_map_sort_node *node;
633 static void basic_map_sort_free(struct basic_map_sort *s)
643 static struct basic_map_sort *basic_map_sort_alloc(struct isl_ctx *ctx, int len)
645 struct basic_map_sort *s;
648 s = isl_calloc_type(ctx, struct basic_map_sort);
652 s->node = isl_alloc_array(ctx, struct basic_map_sort_node, len);
655 for (i = 0; i < len; ++i)
656 s->node[i].index = -1;
657 s->stack = isl_alloc_array(ctx, int, len);
660 s->order = isl_alloc_array(ctx, int, 2 * len);
670 basic_map_sort_free(s);
674 /* Check whether in the computation of the transitive closure
675 * "bmap1" (R_1) should follow (or be part of the same component as)
678 * That is check whether
682 * is non-empty and that moreover, it is non-empty on the set
683 * of elements that do not get mapped to the same set of elements
684 * by both "R_1 \circ R_2" and "R_2 \circ R_1".
685 * For elements that do get mapped to the same elements by these
686 * two compositions, R_1 and R_2 are commutative, so if these
687 * elements are the only ones for which R_1 \circ R_2 is non-empty,
688 * then you may just as well apply R_1 first.
690 static int basic_map_follows(__isl_keep isl_basic_map *bmap1,
691 __isl_keep isl_basic_map *bmap2)
693 struct isl_map *map12 = NULL;
694 struct isl_map *map21 = NULL;
695 struct isl_map *d = NULL;
696 struct isl_set *dom = NULL;
699 map21 = isl_map_from_basic_map(
700 isl_basic_map_apply_range(
701 isl_basic_map_copy(bmap2),
702 isl_basic_map_copy(bmap1)));
703 empty = isl_map_is_empty(map21);
711 map12 = isl_map_from_basic_map(
712 isl_basic_map_apply_range(
713 isl_basic_map_copy(bmap1),
714 isl_basic_map_copy(bmap2)));
715 d = isl_map_subtract(isl_map_copy(map12), isl_map_copy(map21));
717 isl_map_subtract(isl_map_copy(map21), isl_map_copy(map12)));
718 dom = isl_map_domain(d);
720 map21 = isl_map_intersect_domain(map21, dom);
721 empty = isl_map_is_empty(map21);
726 return empty < 0 ? -1 : !empty;
732 /* Perform Tarjan's algorithm for computing the strongly connected components
733 * in the graph with the disjuncts of "map" as vertices and with an
734 * edge between any pair of disjuncts such that the first has
735 * to be applied after the second.
737 static int power_components_tarjan(struct basic_map_sort *s,
738 __isl_keep isl_map *map, int i)
742 s->node[i].index = s->index;
743 s->node[i].min_index = s->index;
744 s->node[i].on_stack = 1;
746 s->stack[s->sp++] = i;
748 for (j = s->len - 1; j >= 0; --j) {
753 if (s->node[j].index >= 0 &&
754 (!s->node[j].on_stack ||
755 s->node[j].index > s->node[i].min_index))
758 f = basic_map_follows(map->p[i], map->p[j]);
764 if (s->node[j].index < 0) {
765 power_components_tarjan(s, map, j);
766 if (s->node[j].min_index < s->node[i].min_index)
767 s->node[i].min_index = s->node[j].min_index;
768 } else if (s->node[j].index < s->node[i].min_index)
769 s->node[i].min_index = s->node[j].index;
772 if (s->node[i].index != s->node[i].min_index)
776 j = s->stack[--s->sp];
777 s->node[j].on_stack = 0;
778 s->order[s->op++] = j;
780 s->order[s->op++] = -1;
785 /* Given a union of basic maps R = \cup_i R_i \subseteq D \times D
786 * and a dimension specification (Z^{n+1} -> Z^{n+1}),
787 * construct a map that is the union of the identity map and
788 * an overapproximation of the map
789 * that takes an element from the dom R \times Z to an
790 * element from ran R \times Z, such that the first n coordinates of the
791 * difference between them is a sum of differences between images
792 * and pre-images in one of the R_i and such that the last coordinate
793 * is equal to the number of steps taken.
796 * \Delta_i = { y - x | (x, y) in R_i }
798 * then the constructed map is an overapproximation of
800 * { (x) -> (x + d) | \exists k_i >= 0, \delta_i \in \Delta_i :
801 * d = (\sum_i k_i \delta_i, \sum_i k_i) and
802 * x in dom R and x + d in ran R } union
805 * We first split the map into strongly connected components, perform
806 * the above on each component and the join the results in the correct
807 * order. The power of each of the components needs to be extended
808 * with the identity map because a path in the global result need
809 * not go through every component.
810 * The final result will then also contain the identity map, but
811 * this part will be removed when the length of the path is forced
812 * to be strictly positive.
814 static __isl_give isl_map *construct_power_components(__isl_take isl_dim *dim,
815 __isl_keep isl_map *map, int *exact, int project)
818 struct isl_map *path = NULL;
819 struct basic_map_sort *s = NULL;
824 return construct_component(dim, map, exact, project);
826 s = basic_map_sort_alloc(map->ctx, map->n);
829 for (i = map->n - 1; i >= 0; --i) {
830 if (s->node[i].index >= 0)
832 if (power_components_tarjan(s, map, i) < 0)
838 path = isl_map_identity(isl_dim_domain(isl_dim_copy(dim)));
840 struct isl_map *comp;
841 comp = isl_map_alloc_dim(isl_map_get_dim(map), n, 0);
842 while (s->order[i] != -1) {
843 comp = isl_map_add_basic_map(comp,
844 isl_basic_map_copy(map->p[s->order[i]]));
848 path = isl_map_apply_range(path,
849 construct_component(isl_dim_copy(dim), comp,
855 basic_map_sort_free(s);
860 basic_map_sort_free(s);
865 /* Given a union of basic maps R = \cup_i R_i \subseteq D \times D,
866 * construct a map that is an overapproximation of the map
867 * that takes an element from the space D to another
868 * element from the same space, such that the difference between
869 * them is a strictly positive sum of differences between images
870 * and pre-images in one of the R_i.
871 * The number of differences in the sum is equated to parameter "param".
874 * \Delta_i = { y - x | (x, y) in R_i }
876 * then the constructed map is an overapproximation of
878 * { (x) -> (x + d) | \exists k_i >= 0, \delta_i \in \Delta_i :
879 * d = \sum_i k_i \delta_i and k = \sum_i k_i > 0 }
881 * We first construct an extended mapping with an extra coordinate
882 * that indicates the number of steps taken. In particular,
883 * the difference in the last coordinate is equal to the number
884 * of steps taken to move from a domain element to the corresponding
886 * In the final step, this difference is equated to the parameter "param"
887 * and made positive. The extra coordinates are subsequently projected out.
889 static __isl_give isl_map *construct_power(__isl_keep isl_map *map,
890 unsigned param, int *exact, int project)
892 struct isl_map *app = NULL;
893 struct isl_map *diff;
894 struct isl_dim *dim = NULL;
900 dim = isl_map_get_dim(map);
902 d = isl_dim_size(dim, isl_dim_in);
903 dim = isl_dim_add(dim, isl_dim_in, 1);
904 dim = isl_dim_add(dim, isl_dim_out, 1);
906 app = construct_power_components(isl_dim_copy(dim), map,
909 diff = equate_parameter_to_length(dim, param);
910 app = isl_map_intersect(app, diff);
911 app = isl_map_project_out(app, isl_dim_in, d, 1);
912 app = isl_map_project_out(app, isl_dim_out, d, 1);
917 /* Compute the positive powers of "map", or an overapproximation.
918 * The power is given by parameter "param". If the result is exact,
919 * then *exact is set to 1.
920 * If project is set, then we are actually interested in the transitive
921 * closure, so we can use a more relaxed exactness check.
923 static __isl_give isl_map *map_power(__isl_take isl_map *map, unsigned param,
924 int *exact, int project)
926 struct isl_map *app = NULL;
931 map = isl_map_remove_empty_parts(map);
935 if (isl_map_fast_is_empty(map))
938 isl_assert(map->ctx, param < isl_map_dim(map, isl_dim_param), goto error);
940 isl_map_dim(map, isl_dim_in) == isl_map_dim(map, isl_dim_out),
943 app = construct_power(map, param, exact, project);
953 /* Compute the positive powers of "map", or an overapproximation.
954 * The power is given by parameter "param". If the result is exact,
955 * then *exact is set to 1.
957 __isl_give isl_map *isl_map_power(__isl_take isl_map *map, unsigned param,
960 return map_power(map, param, exact, 0);
963 /* Compute the transitive closure of "map", or an overapproximation.
964 * If the result is exact, then *exact is set to 1.
965 * Simply compute the powers of map and then project out the parameter
966 * describing the power.
968 __isl_give isl_map *isl_map_transitive_closure(__isl_take isl_map *map,
976 param = isl_map_dim(map, isl_dim_param);
977 map = isl_map_add(map, isl_dim_param, 1);
978 map = map_power(map, param, exact, 1);
979 map = isl_map_project_out(map, isl_dim_param, param, 1);