/*

 * Copyright 2008-2009 Katholieke Universiteit Leuven

 *

 * Use of this software is governed by the MIT license

 *

 * Written by Sven Verdoolaege, K.U.Leuven, Departement

 * Computerwetenschappen, Celestijnenlaan 200A, B-3001 Leuven, Belgium

 */

#include <isl_map_private.h>

#include <isl_seq.h>

#include <isl/set.h>

#include <isl/map.h>

#include "isl_tab.h"

#include <isl_point_private.h>

#include <isl_vec_private.h>

/* Expand the constraint "c" into "v".  The initial "dim" dimensions

 * are the same, but "v" may have more divs than "c" and the divs of "c"

 * may appear in different positions in "v".

 * The number of divs in "c" is given by "n_div" and the mapping

 * of divs in "c" to divs in "v" is given by "div_map".

 *

 * Although it shouldn't happen in practice, it is theoretically

 * possible that two or more divs in "c" are mapped to the same div in "v".

 * These divs are then necessarily the same, so we simply add their

 * coefficients.

 */

static void expand_constraint(isl_vec *v, unsigned dim,

	isl_int *c, int *div_map, unsigned n_div)

{

	int i;

	isl_seq_cpy(v->el, c, 1 + dim);

	isl_seq_clr(v->el + 1 + dim, v->size - (1 + dim));

	for (i = 0; i < n_div; ++i) {

		int pos = 1 + dim + div_map[i];

		isl_int_add(v->el[pos], v->el[pos], c[1 + dim + i]);

	}

}

/* Add all constraints of bmap to tab.  The equalities of bmap

 * are added as a pair of inequalities.

 */

static int tab_add_constraints(struct isl_tab *tab,

	__isl_keep isl_basic_map *bmap, int *div_map)

{

	int i;

	unsigned dim;

	unsigned tab_total;

	unsigned bmap_total;

	isl_vec *v;

	if (!tab || !bmap)

		return -1;

	tab_total = isl_basic_map_total_dim(tab->bmap);

	bmap_total = isl_basic_map_total_dim(bmap);

	dim = isl_space_dim(tab->bmap->dim, isl_dim_all);

	if (isl_tab_extend_cons(tab, 2 * bmap->n_eq + bmap->n_ineq) < 0)

		return -1;

	v = isl_vec_alloc(bmap->ctx, 1 + tab_total);

	if (!v)

		return -1;

	for (i = 0; i < bmap->n_eq; ++i) {

		expand_constraint(v, dim, bmap->eq[i], div_map, bmap->n_div);

		if (isl_tab_add_ineq(tab, v->el) < 0)

			goto error;

		isl_seq_neg(bmap->eq[i], bmap->eq[i], 1 + bmap_total);

		expand_constraint(v, dim, bmap->eq[i], div_map, bmap->n_div);

		if (isl_tab_add_ineq(tab, v->el) < 0)

			goto error;

		isl_seq_neg(bmap->eq[i], bmap->eq[i], 1 + bmap_total);

		if (tab->empty)

			break;

	}

	for (i = 0; i < bmap->n_ineq; ++i) {

		expand_constraint(v, dim, bmap->ineq[i], div_map, bmap->n_div);

		if (isl_tab_add_ineq(tab, v->el) < 0)

			goto error;

		if (tab->empty)

			break;

	}

	isl_vec_free(v);

	return 0;

error:

	isl_vec_free(v);

	return -1;

}

/* Add a specific constraint of bmap (or its opposite) to tab.

 * The position of the constraint is specified by "c", where

 * the equalities of bmap are counted twice, once for the inequality

 * that is equal to the equality, and once for its negation.

 */

static int tab_add_constraint(struct isl_tab *tab,

	__isl_keep isl_basic_map *bmap, int *div_map, int c, int oppose)

{

	unsigned dim;

	unsigned tab_total;

	unsigned bmap_total;

	isl_vec *v;

	int r;

	if (!tab || !bmap)

		return -1;

	tab_total = isl_basic_map_total_dim(tab->bmap);

	bmap_total = isl_basic_map_total_dim(bmap);

	dim = isl_space_dim(tab->bmap->dim, isl_dim_all);

	v = isl_vec_alloc(bmap->ctx, 1 + tab_total);

	if (!v)

		return -1;

	if (c < 2 * bmap->n_eq) {

		if ((c % 2) != oppose)

			isl_seq_neg(bmap->eq[c/2], bmap->eq[c/2],

					1 + bmap_total);

		if (oppose)

			isl_int_sub_ui(bmap->eq[c/2][0], bmap->eq[c/2][0], 1);

		expand_constraint(v, dim, bmap->eq[c/2], div_map, bmap->n_div);

		r = isl_tab_add_ineq(tab, v->el);

		if (oppose)

			isl_int_add_ui(bmap->eq[c/2][0], bmap->eq[c/2][0], 1);

		if ((c % 2) != oppose)

			isl_seq_neg(bmap->eq[c/2], bmap->eq[c/2],

					1 + bmap_total);

	} else {

		c -= 2 * bmap->n_eq;

		if (oppose) {

			isl_seq_neg(bmap->ineq[c], bmap->ineq[c],

					1 + bmap_total);

			isl_int_sub_ui(bmap->ineq[c][0], bmap->ineq[c][0], 1);

		}

		expand_constraint(v, dim, bmap->ineq[c], div_map, bmap->n_div);

		r = isl_tab_add_ineq(tab, v->el);

		if (oppose) {

			isl_int_add_ui(bmap->ineq[c][0], bmap->ineq[c][0], 1);

			isl_seq_neg(bmap->ineq[c], bmap->ineq[c],

					1 + bmap_total);

		}

	}

	isl_vec_free(v);

	return r;

}

static int tab_add_divs(struct isl_tab *tab, __isl_keep isl_basic_map *bmap,

	int **div_map)

{

	int i, j;

	struct isl_vec *vec;

	unsigned total;

	unsigned dim;

	if (!bmap)

		return -1;

	if (!bmap->n_div)

		return 0;

	if (!*div_map)

		*div_map = isl_alloc_array(bmap->ctx, int, bmap->n_div);

	if (!*div_map)

		return -1;

	total = isl_basic_map_total_dim(tab->bmap);

	dim = total - tab->bmap->n_div;

	vec = isl_vec_alloc(bmap->ctx, 2 + total + bmap->n_div);

	if (!vec)

		return -1;

	for (i = 0; i < bmap->n_div; ++i) {

		isl_seq_cpy(vec->el, bmap->div[i], 2 + dim);

		isl_seq_clr(vec->el + 2 + dim, tab->bmap->n_div);

		for (j = 0; j < i; ++j)

			isl_int_set(vec->el[2 + dim + (*div_map)[j]],

					bmap->div[i][2 + dim + j]);

		for (j = 0; j < tab->bmap->n_div; ++j)

			if (isl_seq_eq(tab->bmap->div[j],

					vec->el, 2 + dim + tab->bmap->n_div))

				break;

		(*div_map)[i] = j;

		if (j == tab->bmap->n_div) {

			vec->size = 2 + dim + tab->bmap->n_div;

			if (isl_tab_add_div(tab, vec, NULL, NULL) < 0)

				goto error;

		}

	}

	isl_vec_free(vec);

	return 0;

error:

	isl_vec_free(vec);

	return -1;

}

/* Freeze all constraints of tableau tab.

 */

static int tab_freeze_constraints(struct isl_tab *tab)

{

	int i;

	for (i = 0; i < tab->n_con; ++i)

		if (isl_tab_freeze_constraint(tab, i) < 0)

			return -1;

	return 0;

}

/* Check for redundant constraints starting at offset.

 * Put the indices of the redundant constraints in index

 * and return the number of redundant constraints.

 */

static int n_non_redundant(isl_ctx *ctx, struct isl_tab *tab,

	int offset, int **index)

{

	int i, n;

	int n_test = tab->n_con - offset;

	if (isl_tab_detect_redundant(tab) < 0)

		return -1;

	if (n_test == 0)

		return 0;

	if (!*index)

		*index = isl_alloc_array(ctx, int, n_test);

	if (!*index)

		return -1;

	for (n = 0, i = 0; i < n_test; ++i) {

		int r;

		r = isl_tab_is_redundant(tab, offset + i);

		if (r < 0)

			return -1;

		if (r)

			continue;

		(*index)[n++] = i;

	}

	return n;

}

/* basic_map_collect_diff calls add on each of the pieces of

 * the set difference between bmap and map until the add method

 * return a negative value.

 */

struct isl_diff_collector {

	int (*add)(struct isl_diff_collector *dc,

		    __isl_take isl_basic_map *bmap);

};

/* Compute the set difference between bmap and map and call

 * dc->add on each of the piece until this function returns

 * a negative value.

 * Return 0 on success and -1 on error.  dc->add returning

 * a negative value is treated as an error, but the calling

 * function can interpret the results based on the state of dc.

 *

 * Assumes that map has known divs.

 *

 * The difference is computed by a backtracking algorithm.

 * Each level corresponds to a basic map in "map".

 * When a node in entered for the first time, we check

 * if the corresonding basic map intersects the current piece

 * of "bmap".  If not, we move to the next level.

 * Otherwise, we split the current piece into as many

 * pieces as there are non-redundant constraints of the current

 * basic map in the intersection.  Each of these pieces is

 * handled by a child of the current node.

 * In particular, if there are n non-redundant constraints,

 * then for each 0 <= i < n, a piece is cut off by adding

 * constraints 0 <= j < i and adding the opposite of constraint i.

 * If there are no non-redundant constraints, meaning that the current

 * piece is a subset of the current basic map, then we simply backtrack.

 *

 * In the leaves, we check if the remaining piece has any integer points

 * and if so, pass it along to dc->add.  As a special case, if nothing

 * has been removed when we end up in a leaf, we simply pass along

 * the original basic map.

 */

static int basic_map_collect_diff(__isl_take isl_basic_map *bmap,

	__isl_take isl_map *map, struct isl_diff_collector *dc)

{

	int i;

	int modified;

	int level;

	int init;

	int empty;

	isl_ctx *ctx;

	struct isl_tab *tab = NULL;

	struct isl_tab_undo **snap = NULL;

	int *k = NULL;

	int *n = NULL;

	int **index = NULL;

	int **div_map = NULL;

	empty = isl_basic_map_is_empty(bmap);

	if (empty) {

		isl_basic_map_free(bmap);

		isl_map_free(map);

		return empty < 0 ? -1 : 0;

	}

	bmap = isl_basic_map_cow(bmap);

	map = isl_map_cow(map);

	if (!bmap || !map)

		goto error;

	ctx = map->ctx;

	snap = isl_alloc_array(map->ctx, struct isl_tab_undo *, map->n);

	k = isl_alloc_array(map->ctx, int, map->n);

	n = isl_alloc_array(map->ctx, int, map->n);

	index = isl_calloc_array(map->ctx, int *, map->n);

	div_map = isl_calloc_array(map->ctx, int *, map->n);

	if (!snap || !k || !n || !index || !div_map)

		goto error;

	bmap = isl_basic_map_order_divs(bmap);

	map = isl_map_order_divs(map);

	tab = isl_tab_from_basic_map(bmap, 1);

	if (!tab)

		goto error;

	modified = 0;

	level = 0;

	init = 1;

	while (level >= 0) {

		if (level >= map->n) {

			int empty;

			struct isl_basic_map *bm;

			if (!modified) {

				if (dc->add(dc, isl_basic_map_copy(bmap)) < 0)

					goto error;

				break;

			}

			bm = isl_basic_map_copy(tab->bmap);

			bm = isl_basic_map_cow(bm);

			bm = isl_basic_map_update_from_tab(bm, tab);

			bm = isl_basic_map_simplify(bm);

			bm = isl_basic_map_finalize(bm);

			empty = isl_basic_map_is_empty(bm);

			if (empty)

				isl_basic_map_free(bm);

			else if (dc->add(dc, bm) < 0)

				goto error;

			if (empty < 0)

				goto error;

			level--;

			init = 0;

			continue;

		}

		if (init) {

			int offset;

			struct isl_tab_undo *snap2;

			snap2 = isl_tab_snap(tab);

			if (tab_add_divs(tab, map->p[level],

					 &div_map[level]) < 0)

				goto error;

			offset = tab->n_con;

			snap[level] = isl_tab_snap(tab);

			if (tab_freeze_constraints(tab) < 0)

				goto error;

			if (tab_add_constraints(tab, map->p[level],

						div_map[level]) < 0)

				goto error;

			k[level] = 0;

			n[level] = 0;

			if (tab->empty) {

				if (isl_tab_rollback(tab, snap2) < 0)

					goto error;

				level++;

				continue;

			}

			modified = 1;

			n[level] = n_non_redundant(ctx, tab, offset,

						    &index[level]);

			if (n[level] < 0)

				goto error;

			if (n[level] == 0) {

				level--;

				init = 0;

				continue;

			}

			if (isl_tab_rollback(tab, snap[level]) < 0)

				goto error;

			if (tab_add_constraint(tab, map->p[level],

					div_map[level], index[level][0], 1) < 0)

				goto error;

			level++;

			continue;

		} else {

			if (k[level] + 1 >= n[level]) {

				level--;

				continue;

			}

			if (isl_tab_rollback(tab, snap[level]) < 0)

				goto error;

			if (tab_add_constraint(tab, map->p[level],

						div_map[level],

						index[level][k[level]], 0) < 0)

				goto error;

			snap[level] = isl_tab_snap(tab);

			k[level]++;

			if (tab_add_constraint(tab, map->p[level],

						div_map[level],

						index[level][k[level]], 1) < 0)

				goto error;

			level++;

			init = 1;

			continue;

		}

	}

	isl_tab_free(tab);

	free(snap);

	free(n);

	free(k);

	for (i = 0; index && i < map->n; ++i)

		free(index[i]);

	free(index);

	for (i = 0; div_map && i < map->n; ++i)

		free(div_map[i]);

	free(div_map);

	isl_basic_map_free(bmap);

	isl_map_free(map);

	return 0;

error:

	isl_tab_free(tab);

	free(snap);

	free(n);

	free(k);

	for (i = 0; index && i < map->n; ++i)

		free(index[i]);

	free(index);

	for (i = 0; div_map && i < map->n; ++i)

		free(div_map[i]);

	free(div_map);

	isl_basic_map_free(bmap);

	isl_map_free(map);

	return -1;

}

/* A diff collector that actually collects all parts of the

 * set difference in the field diff.

 */

struct isl_subtract_diff_collector {

	struct isl_diff_collector dc;

	struct isl_map *diff;

};

/* isl_subtract_diff_collector callback.

 */

static int basic_map_subtract_add(struct isl_diff_collector *dc,

			    __isl_take isl_basic_map *bmap)

{

	struct isl_subtract_diff_collector *sdc;

	sdc = (struct isl_subtract_diff_collector *)dc;

	sdc->diff = isl_map_union_disjoint(sdc->diff,

			isl_map_from_basic_map(bmap));

	return sdc->diff ? 0 : -1;

}

/* Return the set difference between bmap and map.

 */

static __isl_give isl_map *basic_map_subtract(__isl_take isl_basic_map *bmap,

	__isl_take isl_map *map)

{

	struct isl_subtract_diff_collector sdc;

	sdc.dc.add = &basic_map_subtract_add;

	sdc.diff = isl_map_empty_like_basic_map(bmap);

	if (basic_map_collect_diff(bmap, map, &sdc.dc) < 0) {

		isl_map_free(sdc.diff);

		sdc.diff = NULL;

	}

	return sdc.diff;

}

/* Return the set difference between map1 and map2.

 * (U_i A_i) \ (U_j B_j) is computed as U_i (A_i \ (U_j B_j))

 *

 * If "map1" and "map2" are disjoint, then simply return "map1".

 */

static __isl_give isl_map *map_subtract( __isl_take isl_map *map1,

	__isl_take isl_map *map2)

{

	int i;

	int disjoint;

	struct isl_map *diff;

	if (!map1 || !map2)

		goto error;

	isl_assert(map1->ctx, isl_space_is_equal(map1->dim, map2->dim), goto error);

	disjoint = isl_map_is_disjoint(map1, map2);

	if (disjoint < 0)

		goto error;

	if (disjoint) {

		isl_map_free(map2);

		return map1;

	}

	map1 = isl_map_compute_divs(map1);

	map2 = isl_map_compute_divs(map2);

	if (!map1 || !map2)

		goto error;

	map1 = isl_map_remove_empty_parts(map1);

	map2 = isl_map_remove_empty_parts(map2);

	diff = isl_map_empty_like(map1);

	for (i = 0; i < map1->n; ++i) {

		struct isl_map *d;

		d = basic_map_subtract(isl_basic_map_copy(map1->p[i]),

				       isl_map_copy(map2));

		if (ISL_F_ISSET(map1, ISL_MAP_DISJOINT))

			diff = isl_map_union_disjoint(diff, d);

		else

			diff = isl_map_union(diff, d);

	}

	isl_map_free(map1);

	isl_map_free(map2);

	return diff;

error:

	isl_map_free(map1);

	isl_map_free(map2);

	return NULL;

}

__isl_give isl_map *isl_map_subtract( __isl_take isl_map *map1,

	__isl_take isl_map *map2)

{

	return isl_map_align_params_map_map_and(map1, map2, &map_subtract);

}

struct isl_set *isl_set_subtract(struct isl_set *set1, struct isl_set *set2)

{

	return (struct isl_set *)

		isl_map_subtract(

			(struct isl_map *)set1, (struct isl_map *)set2);

}

/* Remove the elements of "dom" from the domain of "map".

 */

static __isl_give isl_map *map_subtract_domain(__isl_take isl_map *map,

	__isl_take isl_set *dom)

{

	isl_map *ext_dom;

	if (!isl_map_compatible_domain(map, dom))

		isl_die(isl_set_get_ctx(dom), isl_error_invalid,

			"incompatible spaces", goto error);

	ext_dom = isl_map_universe(isl_map_get_space(map));

	ext_dom = isl_map_intersect_domain(ext_dom, dom);

	return isl_map_subtract(map, ext_dom);

error:

	isl_map_free(map);

	isl_set_free(dom);

	return NULL;

}

__isl_give isl_map *isl_map_subtract_domain(__isl_take isl_map *map,

	__isl_take isl_set *dom)

{

	return isl_map_align_params_map_map_and(map, dom, &map_subtract_domain);

}

/* Remove the elements of "dom" from the range of "map".

 */

static __isl_give isl_map *map_subtract_range(__isl_take isl_map *map,

	__isl_take isl_set *dom)

{

	isl_map *ext_dom;

	if (!isl_map_compatible_range(map, dom))

		isl_die(isl_set_get_ctx(dom), isl_error_invalid,

			"incompatible spaces", goto error);

	ext_dom = isl_map_universe(isl_map_get_space(map));

	ext_dom = isl_map_intersect_range(ext_dom, dom);

	return isl_map_subtract(map, ext_dom);

error:

	isl_map_free(map);

	isl_set_free(dom);

	return NULL;

}

__isl_give isl_map *isl_map_subtract_range(__isl_take isl_map *map,

	__isl_take isl_set *dom)

{

	return isl_map_align_params_map_map_and(map, dom, &map_subtract_range);

}

/* A diff collector that aborts as soon as its add function is called,

 * setting empty to 0.

 */

struct isl_is_empty_diff_collector {

	struct isl_diff_collector dc;

	int empty;

};

/* isl_is_empty_diff_collector callback.

 */

static int basic_map_is_empty_add(struct isl_diff_collector *dc,

			    __isl_take isl_basic_map *bmap)

{

	struct isl_is_empty_diff_collector *edc;

	edc = (struct isl_is_empty_diff_collector *)dc;

	edc->empty = 0;

	isl_basic_map_free(bmap);

	return -1;

}

/* Check if bmap \ map is empty by computing this set difference

 * and breaking off as soon as the difference is known to be non-empty.

 */

static int basic_map_diff_is_empty(__isl_keep isl_basic_map *bmap,

	__isl_keep isl_map *map)

{

	int r;

	struct isl_is_empty_diff_collector edc;

	r = isl_basic_map_plain_is_empty(bmap);

	if (r)

		return r;

	edc.dc.add = &basic_map_is_empty_add;

	edc.empty = 1;

	r = basic_map_collect_diff(isl_basic_map_copy(bmap),

				   isl_map_copy(map), &edc.dc);

	if (!edc.empty)

		return 0;

	return r < 0 ? -1 : 1;

}

/* Check if map1 \ map2 is empty by checking if the set difference is empty

 * for each of the basic maps in map1.

 */

static int map_diff_is_empty(__isl_keep isl_map *map1, __isl_keep isl_map *map2)

{

	int i;

	int is_empty = 1;

	if (!map1 || !map2)

		return -1;

	for (i = 0; i < map1->n; ++i) {

		is_empty = basic_map_diff_is_empty(map1->p[i], map2);

		if (is_empty < 0 || !is_empty)

			 break;

	}

	return is_empty;

}

/* Return 1 if "bmap" contains a single element.

 */

int isl_basic_map_plain_is_singleton(__isl_keep isl_basic_map *bmap)

{

	if (!bmap)

		return -1;

	if (bmap->n_div)

		return 0;

	if (bmap->n_ineq)

		return 0;

	return bmap->n_eq == isl_basic_map_total_dim(bmap);

}

/* Return 1 if "map" contains a single element.

 */

int isl_map_plain_is_singleton(__isl_keep isl_map *map)

{

	if (!map)

		return -1;

	if (map->n != 1)

		return 0;

	return isl_basic_map_plain_is_singleton(map->p[0]);

}

/* Given a singleton basic map, extract the single element

 * as an isl_point.

 */

static __isl_give isl_point *singleton_extract_point(

	__isl_keep isl_basic_map *bmap)

{

	int j;

	unsigned dim;

	struct isl_vec *point;

	isl_int m;

	if (!bmap)

		return NULL;

	dim = isl_basic_map_total_dim(bmap);

	isl_assert(bmap->ctx, bmap->n_eq == dim, return NULL);

	point = isl_vec_alloc(bmap->ctx, 1 + dim);

	if (!point)

		return NULL;

	isl_int_init(m);

	isl_int_set_si(point->el[0], 1);

	for (j = 0; j < bmap->n_eq; ++j) {

		int i = dim - 1 - j;

		isl_assert(bmap->ctx,

		    isl_seq_first_non_zero(bmap->eq[j] + 1, i) == -1,

		    goto error);

		isl_assert(bmap->ctx,

		    isl_int_is_one(bmap->eq[j][1 + i]) ||

		    isl_int_is_negone(bmap->eq[j][1 + i]),

		    goto error);

		isl_assert(bmap->ctx,

		    isl_seq_first_non_zero(bmap->eq[j]+1+i+1, dim-i-1) == -1,

		    goto error);

		isl_int_gcd(m, point->el[0], bmap->eq[j][1 + i]);

		isl_int_divexact(m, bmap->eq[j][1 + i], m);

		isl_int_abs(m, m);

		isl_seq_scale(point->el, point->el, m, 1 + i);

		isl_int_divexact(m, point->el[0], bmap->eq[j][1 + i]);

		isl_int_neg(m, m);

		isl_int_mul(point->el[1 + i], m, bmap->eq[j][0]);

	}

	isl_int_clear(m);

	return isl_point_alloc(isl_basic_map_get_space(bmap), point);

error:

	isl_int_clear(m);

	isl_vec_free(point);

	return NULL;

}

/* Return 1 is the singleton map "map1" is a subset of "map2",

 * i.e., if the single element of "map1" is also an element of "map2".

 * Assumes "map2" has known divs.

 */

static int map_is_singleton_subset(__isl_keep isl_map *map1,

	__isl_keep isl_map *map2)

{

	int i;

	int is_subset = 0;

	struct isl_point *point;

	if (!map1 || !map2)

		return -1;

	if (map1->n != 1)

		return -1;

	point = singleton_extract_point(map1->p[0]);

	if (!point)

		return -1;

	for (i = 0; i < map2->n; ++i) {

		is_subset = isl_basic_map_contains_point(map2->p[i], point);

		if (is_subset)

			break;

	}

	isl_point_free(point);

	return is_subset;

}

static int map_is_subset(__isl_keep isl_map *map1, __isl_keep isl_map *map2)

{

	int is_subset = 0;

	int empty;

	int rat1, rat2;

	if (!map1 || !map2)

		return -1;

	if (!isl_map_has_equal_space(map1, map2))

		return 0;

	empty = isl_map_is_empty(map1);

	if (empty < 0)

		return -1;

	if (empty)

		return 1;

	empty = isl_map_is_empty(map2);

	if (empty < 0)

		return -1;

	if (empty)

		return 0;

	rat1 = isl_map_has_rational(map1);

	rat2 = isl_map_has_rational(map2);

	if (rat1 < 0 || rat2 < 0)

		return -1;

	if (rat1 && !rat2)

		return 0;

	if (isl_map_plain_is_universe(map2))

		return 1;

	map2 = isl_map_compute_divs(isl_map_copy(map2));

	if (isl_map_plain_is_singleton(map1)) {

		is_subset = map_is_singleton_subset(map1, map2);

		isl_map_free(map2);

		return is_subset;

	}

	is_subset = map_diff_is_empty(map1, map2);

	isl_map_free(map2);

	return is_subset;

}

int isl_map_is_subset(__isl_keep isl_map *map1, __isl_keep isl_map *map2)

{

	return isl_map_align_params_map_map_and_test(map1, map2,

							&map_is_subset);

}

int isl_set_is_subset(struct isl_set *set1, struct isl_set *set2)

{

	return isl_map_is_subset(

			(struct isl_map *)set1, (struct isl_map *)set2);

}

__isl_give isl_map *isl_map_make_disjoint(__isl_take isl_map *map)

{

	int i;

	struct isl_subtract_diff_collector sdc;

	sdc.dc.add = &basic_map_subtract_add;

	if (!map)

		return NULL;

	if (ISL_F_ISSET(map, ISL_MAP_DISJOINT))

		return map;

	if (map->n <= 1)

		return map;

	map = isl_map_compute_divs(map);

	map = isl_map_remove_empty_parts(map);

	if (!map || map->n <= 1)

		return map;

	sdc.diff = isl_map_from_basic_map(isl_basic_map_copy(map->p[0]));

	for (i = 1; i < map->n; ++i) {

		struct isl_basic_map *bmap = isl_basic_map_copy(map->p[i]);

		struct isl_map *copy = isl_map_copy(sdc.diff);

		if (basic_map_collect_diff(bmap, copy, &sdc.dc) < 0) {

			isl_map_free(sdc.diff);

			sdc.diff = NULL;

			break;

		}

	}

	isl_map_free(map);

	return sdc.diff;

}

__isl_give isl_set *isl_set_make_disjoint(__isl_take isl_set *set)