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/*
 * Copyright 2010      INRIA Saclay
 *
 * Use of this software is governed by the GNU LGPLv2.1 license
 *
 * Written by Sven Verdoolaege, INRIA Saclay - Ile-de-France,
 * Parc Club Orsay Universite, ZAC des vignes, 4 rue Jacques Monod,
 * 91893 Orsay, France 
 */

#define ISL_DIM_H
#include <isl_map_private.h>
#include <isl_union_map_private.h>
#include <isl_polynomial_private.h>
#include <isl_point_private.h>
#include <isl_space_private.h>
#include <isl/lp.h>
#include <isl/seq.h>
#include <isl_mat_private.h>
#include <isl_config.h>

enum isl_fold isl_fold_type_negate(enum isl_fold type)
{
        switch (type) {
        case isl_fold_min:
                return isl_fold_max;
        case isl_fold_max:
                return isl_fold_min;
        case isl_fold_list:
                return isl_fold_list;
        }

        isl_die(NULL, isl_error_internal, "unhandled isl_fold type", abort());
}

static __isl_give isl_qpolynomial_fold *qpolynomial_fold_alloc(
        enum isl_fold type, __isl_take isl_space *dim, int n)
{
        isl_qpolynomial_fold *fold;

        if (!dim)
                goto error;

        isl_assert(dim->ctx, n >= 0, goto error);
        fold = isl_calloc(dim->ctx, struct isl_qpolynomial_fold,
                        sizeof(struct isl_qpolynomial_fold) +
                        (n - 1) * sizeof(struct isl_qpolynomial *));
        if (!fold)
                goto error;

        fold->ref = 1;
        fold->size = n;
        fold->n = 0;
        fold->type = type;
        fold->dim = dim;

        return fold;
error:
        isl_space_free(dim);
        return NULL;
}

isl_ctx *isl_qpolynomial_fold_get_ctx(__isl_keep isl_qpolynomial_fold *fold)
{
        return fold ? fold->dim->ctx : NULL;
}

__isl_give isl_space *isl_qpolynomial_fold_get_domain_space(
        __isl_keep isl_qpolynomial_fold *fold)
{
        return fold ? isl_space_copy(fold->dim) : NULL;
}

__isl_give isl_space *isl_qpolynomial_fold_get_space(
        __isl_keep isl_qpolynomial_fold *fold)
{
        isl_space *space;
        if (!fold)
                return NULL;
        space = isl_space_copy(fold->dim);
        space = isl_space_from_domain(space);
        space = isl_space_add_dims(space, isl_dim_out, 1);
        return space;
}

__isl_give isl_qpolynomial_fold *isl_qpolynomial_fold_reset_domain_space(
        __isl_take isl_qpolynomial_fold *fold, __isl_take isl_space *dim)
{
        int i;

        fold = isl_qpolynomial_fold_cow(fold);
        if (!fold || !dim)
                goto error;

        for (i = 0; i < fold->n; ++i) {
                fold->qp[i] = isl_qpolynomial_reset_domain_space(fold->qp[i],
                                                        isl_space_copy(dim));
                if (!fold->qp[i])
                        goto error;
        }

        isl_space_free(fold->dim);
        fold->dim = dim;

        return fold;
error:
        isl_qpolynomial_fold_free(fold);
        isl_space_free(dim);
        return NULL;
}

/* Reset the space of "fold".  This function is called from isl_pw_templ.c
 * and doesn't know if the space of an element object is represented
 * directly or through its domain.  It therefore passes along both.
 */
__isl_give isl_qpolynomial_fold *isl_qpolynomial_fold_reset_space_and_domain(
        __isl_take isl_qpolynomial_fold *fold, __isl_take isl_space *space,
        __isl_take isl_space *domain)
{
        isl_space_free(space);
        return isl_qpolynomial_fold_reset_domain_space(fold, domain);
}

int isl_qpolynomial_fold_involves_dims(__isl_keep isl_qpolynomial_fold *fold,
        enum isl_dim_type type, unsigned first, unsigned n)
{
        int i;

        if (!fold)
                return -1;
        if (fold->n == 0 || n == 0)
                return 0;

        for (i = 0; i < fold->n; ++i) {
                int involves = isl_qpolynomial_involves_dims(fold->qp[i],
                                                            type, first, n);
                if (involves < 0 || involves)
                        return involves;
        }
        return 0;
}

__isl_give isl_qpolynomial_fold *isl_qpolynomial_fold_set_dim_name(
        __isl_take isl_qpolynomial_fold *fold,
        enum isl_dim_type type, unsigned pos, const char *s)
{
        int i;

        fold = isl_qpolynomial_fold_cow(fold);
        if (!fold)
                return NULL;
        fold->dim = isl_space_set_dim_name(fold->dim, type, pos, s);
        if (!fold->dim)
                goto error;

        for (i = 0; i < fold->n; ++i) {
                fold->qp[i] = isl_qpolynomial_set_dim_name(fold->qp[i],
                                                            type, pos, s);
                if (!fold->qp[i])
                        goto error;
        }

        return fold;
error:
        isl_qpolynomial_fold_free(fold);
        return NULL;
}

__isl_give isl_qpolynomial_fold *isl_qpolynomial_fold_drop_dims(
        __isl_take isl_qpolynomial_fold *fold,
        enum isl_dim_type type, unsigned first, unsigned n)
{
        int i;
        enum isl_dim_type set_type;

        if (!fold)
                return NULL;
        if (n == 0)
                return fold;

        set_type = type == isl_dim_in ? isl_dim_set : type;

        fold = isl_qpolynomial_fold_cow(fold);
        if (!fold)
                return NULL;
        fold->dim = isl_space_drop_dims(fold->dim, set_type, first, n);
        if (!fold->dim)
                goto error;

        for (i = 0; i < fold->n; ++i) {
                fold->qp[i] = isl_qpolynomial_drop_dims(fold->qp[i],
                                                            type, first, n);
                if (!fold->qp[i])
                        goto error;
        }

        return fold;
error:
        isl_qpolynomial_fold_free(fold);
        return NULL;
}

__isl_give isl_qpolynomial_fold *isl_qpolynomial_fold_insert_dims(
        __isl_take isl_qpolynomial_fold *fold,
        enum isl_dim_type type, unsigned first, unsigned n)
{
        int i;

        if (!fold)
                return NULL;
        if (n == 0 && !isl_space_is_named_or_nested(fold->dim, type))
                return fold;

        fold = isl_qpolynomial_fold_cow(fold);
        if (!fold)
                return NULL;
        fold->dim = isl_space_insert_dims(fold->dim, type, first, n);
        if (!fold->dim)
                goto error;

        for (i = 0; i < fold->n; ++i) {
                fold->qp[i] = isl_qpolynomial_insert_dims(fold->qp[i],
                                                            type, first, n);
                if (!fold->qp[i])
                        goto error;
        }

        return fold;
error:
        isl_qpolynomial_fold_free(fold);
        return NULL;
}

static int isl_qpolynomial_cst_sign(__isl_keep isl_qpolynomial *qp)
{
        struct isl_upoly_cst *cst;

        cst = isl_upoly_as_cst(qp->upoly);
        if (!cst)
                return 0;

        return isl_int_sgn(cst->n) < 0 ? -1 : 1;
}

static int isl_qpolynomial_aff_sign(__isl_keep isl_set *set,
        __isl_keep isl_qpolynomial *qp)
{
        enum isl_lp_result res;
        isl_vec *aff;
        isl_int opt;
        int sgn = 0;

        aff = isl_qpolynomial_extract_affine(qp);
        if (!aff)
                return 0;

        isl_int_init(opt);

        res = isl_set_solve_lp(set, 0, aff->el + 1, aff->el[0],
                                &opt, NULL, NULL);
        if (res == isl_lp_error)
                goto done;
        if (res == isl_lp_empty ||
            (res == isl_lp_ok && !isl_int_is_neg(opt))) {
                sgn = 1;
                goto done;
        }

        res = isl_set_solve_lp(set, 1, aff->el + 1, aff->el[0],
                                &opt, NULL, NULL);
        if (res == isl_lp_ok && !isl_int_is_pos(opt))
                sgn = -1;

done:
        isl_int_clear(opt);
        isl_vec_free(aff);
        return sgn;
}

/* Determine, if possible, the sign of the quasipolynomial "qp" on
 * the domain "set".
 *
 * If qp is a constant, then the problem is trivial.
 * If qp is linear, then we check if the minimum of the corresponding
 * affine constraint is non-negative or if the maximum is non-positive.
 *
 * Otherwise, we check if the outermost variable "v" has a lower bound "l"
 * in "set".  If so, we write qp(v,v') as
 *
 *      q(v,v') * (v - l) + r(v')
 *
 * if q(v,v') and r(v') have the same known sign, then the original
 * quasipolynomial has the same sign as well.
 *
 * Return
 *      -1 if qp <= 0
 *       1 if qp >= 0
 *       0 if unknown
 */
static int isl_qpolynomial_sign(__isl_keep isl_set *set,
        __isl_keep isl_qpolynomial *qp)
{
        int d;
        int i;
        int is;
        struct isl_upoly_rec *rec;
        isl_vec *v;
        isl_int l;
        enum isl_lp_result res;
        int sgn = 0;

        is = isl_qpolynomial_is_cst(qp, NULL, NULL);
        if (is < 0)
                return 0;
        if (is)
                return isl_qpolynomial_cst_sign(qp);

        is = isl_qpolynomial_is_affine(qp);
        if (is < 0)
                return 0;
        if (is)
                return isl_qpolynomial_aff_sign(set, qp);

        if (qp->div->n_row > 0)
                return 0;

        rec = isl_upoly_as_rec(qp->upoly);
        if (!rec)
                return 0;

        d = isl_space_dim(qp->dim, isl_dim_all);
        v = isl_vec_alloc(set->ctx, 2 + d);
        if (!v)
                return 0;

        isl_seq_clr(v->el + 1, 1 + d);
        isl_int_set_si(v->el[0], 1);
        isl_int_set_si(v->el[2 + qp->upoly->var], 1);

        isl_int_init(l);

        res = isl_set_solve_lp(set, 0, v->el + 1, v->el[0], &l, NULL, NULL);
        if (res == isl_lp_ok) {
                isl_qpolynomial *min;
                isl_qpolynomial *base;
                isl_qpolynomial *r, *q;
                isl_qpolynomial *t;

                min = isl_qpolynomial_cst_on_domain(isl_space_copy(qp->dim), l);
                base = isl_qpolynomial_var_pow_on_domain(isl_space_copy(qp->dim),
                                                qp->upoly->var, 1);

                r = isl_qpolynomial_alloc(isl_space_copy(qp->dim), 0,
                                          isl_upoly_copy(rec->p[rec->n - 1]));
                q = isl_qpolynomial_copy(r);

                for (i = rec->n - 2; i >= 0; --i) {
                        r = isl_qpolynomial_mul(r, isl_qpolynomial_copy(min));
                        t = isl_qpolynomial_alloc(isl_space_copy(qp->dim), 0,
                                                  isl_upoly_copy(rec->p[i]));
                        r = isl_qpolynomial_add(r, t);
                        if (i == 0)
                                break;
                        q = isl_qpolynomial_mul(q, isl_qpolynomial_copy(base));
                        q = isl_qpolynomial_add(q, isl_qpolynomial_copy(r));
                }

                if (isl_qpolynomial_is_zero(q))
                        sgn = isl_qpolynomial_sign(set, r);
                else if (isl_qpolynomial_is_zero(r))
                        sgn = isl_qpolynomial_sign(set, q);
                else {
                        int sgn_q, sgn_r;
                        sgn_r = isl_qpolynomial_sign(set, r);
                        sgn_q = isl_qpolynomial_sign(set, q);
                        if (sgn_r == sgn_q)
                                sgn = sgn_r;
                }

                isl_qpolynomial_free(min);
                isl_qpolynomial_free(base);
                isl_qpolynomial_free(q);
                isl_qpolynomial_free(r);
        }

        isl_int_clear(l);

        isl_vec_free(v);

        return sgn;
}

__isl_give isl_qpolynomial_fold *isl_qpolynomial_fold_fold_on_domain(
        __isl_keep isl_set *set,
        __isl_take isl_qpolynomial_fold *fold1,
        __isl_take isl_qpolynomial_fold *fold2)
{
        int i, j;
        int n1;
        struct isl_qpolynomial_fold *res = NULL;
        int better;

        if (!fold1 || !fold2)
                goto error;

        isl_assert(fold1->dim->ctx, fold1->type == fold2->type, goto error);
        isl_assert(fold1->dim->ctx, isl_space_is_equal(fold1->dim, fold2->dim),
                        goto error);

        better = fold1->type == isl_fold_max ? -1 : 1;

        if (isl_qpolynomial_fold_is_empty(fold1)) {
                isl_qpolynomial_fold_free(fold1);
                return fold2;
        }

        if (isl_qpolynomial_fold_is_empty(fold2)) {
                isl_qpolynomial_fold_free(fold2);
                return fold1;
        }

        res = qpolynomial_fold_alloc(fold1->type, isl_space_copy(fold1->dim),
                                        fold1->n + fold2->n);
        if (!res)
                goto error;

        for (i = 0; i < fold1->n; ++i) {
                res->qp[res->n] = isl_qpolynomial_copy(fold1->qp[i]);
                if (!res->qp[res->n])
                        goto error;
                res->n++;
        }
        n1 = res->n;

        for (i = 0; i < fold2->n; ++i) {
                for (j = n1 - 1; j >= 0; --j) {
                        isl_qpolynomial *d;
                        int sgn;
                        d = isl_qpolynomial_sub(
                                isl_qpolynomial_copy(res->qp[j]),
                                isl_qpolynomial_copy(fold2->qp[i]));
                        sgn = isl_qpolynomial_sign(set, d);
                        isl_qpolynomial_free(d);
                        if (sgn == 0)
                                continue;
                        if (sgn != better)
                                break;
                        isl_qpolynomial_free(res->qp[j]);
                        if (j != n1 - 1)
                                res->qp[j] = res->qp[n1 - 1];
                        n1--;
                        if (n1 != res->n - 1)
                                res->qp[n1] = res->qp[res->n - 1];
                        res->n--;
                }
                if (j >= 0)
                        continue;
                res->qp[res->n] = isl_qpolynomial_copy(fold2->qp[i]);
                if (!res->qp[res->n])
                        goto error;
                res->n++;
        }

        isl_qpolynomial_fold_free(fold1);
        isl_qpolynomial_fold_free(fold2);

        return res;
error:
        isl_qpolynomial_fold_free(res);
        isl_qpolynomial_fold_free(fold1);
        isl_qpolynomial_fold_free(fold2);
        return NULL;
}

__isl_give isl_qpolynomial_fold *isl_qpolynomial_fold_add_qpolynomial(
        __isl_take isl_qpolynomial_fold *fold, __isl_take isl_qpolynomial *qp)
{
        int i;

        if (!fold || !qp)
                goto error;

        if (isl_qpolynomial_is_zero(qp)) {
                isl_qpolynomial_free(qp);
                return fold;
        }

        fold = isl_qpolynomial_fold_cow(fold);
        if (!fold)
                goto error;

        for (i = 0; i < fold->n; ++i) {
                fold->qp[i] = isl_qpolynomial_add(fold->qp[i],
                                                isl_qpolynomial_copy(qp));
                if (!fold->qp[i])
                        goto error;
        }

        isl_qpolynomial_free(qp);
        return fold;
error:
        isl_qpolynomial_fold_free(fold);
        isl_qpolynomial_free(qp);
        return NULL;
}

__isl_give isl_qpolynomial_fold *isl_qpolynomial_fold_add_on_domain(
        __isl_keep isl_set *dom,
        __isl_take isl_qpolynomial_fold *fold1,
        __isl_take isl_qpolynomial_fold *fold2)
{
        int i;
        isl_qpolynomial_fold *res = NULL;

        if (!fold1 || !fold2)
                goto error;

        if (isl_qpolynomial_fold_is_empty(fold1)) {
                isl_qpolynomial_fold_free(fold1);
                return fold2;
        }

        if (isl_qpolynomial_fold_is_empty(fold2)) {
                isl_qpolynomial_fold_free(fold2);
                return fold1;
        }

        if (fold1->n == 1 && fold2->n != 1)
                return isl_qpolynomial_fold_add_on_domain(dom, fold2, fold1);

        if (fold2->n == 1) {
                res = isl_qpolynomial_fold_add_qpolynomial(fold1,
                                        isl_qpolynomial_copy(fold2->qp[0]));
                isl_qpolynomial_fold_free(fold2);
                return res;
        }

        res = isl_qpolynomial_fold_add_qpolynomial(
                                isl_qpolynomial_fold_copy(fold1),
                                isl_qpolynomial_copy(fold2->qp[0]));

        for (i = 1; i < fold2->n; ++i) {
                isl_qpolynomial_fold *res_i;
                res_i = isl_qpolynomial_fold_add_qpolynomial(
                                        isl_qpolynomial_fold_copy(fold1),
                                        isl_qpolynomial_copy(fold2->qp[i]));
                res = isl_qpolynomial_fold_fold_on_domain(dom, res, res_i);
        }

        isl_qpolynomial_fold_free(fold1);
        isl_qpolynomial_fold_free(fold2);
        return res;
error:
        isl_qpolynomial_fold_free(res);
        isl_qpolynomial_fold_free(fold1);
        isl_qpolynomial_fold_free(fold2);
        return NULL;
}

__isl_give isl_qpolynomial_fold *isl_qpolynomial_fold_substitute_equalities(
        __isl_take isl_qpolynomial_fold *fold, __isl_take isl_basic_set *eq)
{
        int i;

        if (!fold || !eq)
                goto error;

        fold = isl_qpolynomial_fold_cow(fold);
        if (!fold)
                return NULL;

        for (i = 0; i < fold->n; ++i) {
                fold->qp[i] = isl_qpolynomial_substitute_equalities(fold->qp[i],
                                                        isl_basic_set_copy(eq));
                if (!fold->qp[i])
                        goto error;
        }

        isl_basic_set_free(eq);
        return fold;
error:
        isl_basic_set_free(eq);
        isl_qpolynomial_fold_free(fold);
        return NULL;
}

__isl_give isl_qpolynomial_fold *isl_qpolynomial_fold_gist(
        __isl_take isl_qpolynomial_fold *fold, __isl_take isl_set *context)
{
        int i;

        if (!fold || !context)
                goto error;

        fold = isl_qpolynomial_fold_cow(fold);
        if (!fold)
                return NULL;

        for (i = 0; i < fold->n; ++i) {
                fold->qp[i] = isl_qpolynomial_gist(fold->qp[i],
                                                        isl_set_copy(context));
                if (!fold->qp[i])
                        goto error;
        }

        isl_set_free(context);
        return fold;
error:
        isl_set_free(context);
        isl_qpolynomial_fold_free(fold);
        return NULL;
}

__isl_give isl_qpolynomial_fold *isl_qpolynomial_fold_gist_params(
        __isl_take isl_qpolynomial_fold *fold, __isl_take isl_set *context)
{
        isl_space *space = isl_qpolynomial_fold_get_domain_space(fold);
        isl_set *dom_context = isl_set_universe(space);
        dom_context = isl_set_intersect_params(dom_context, context);
        return isl_qpolynomial_fold_gist(fold, dom_context);
}

#define HAS_TYPE

#undef PW
#define PW isl_pw_qpolynomial_fold
#undef EL
#define EL isl_qpolynomial_fold
#undef EL_IS_ZERO
#define EL_IS_ZERO is_empty
#undef ZERO
#define ZERO zero
#undef IS_ZERO
#define IS_ZERO is_zero
#undef FIELD
#define FIELD fold
#undef DEFAULT_IS_ZERO
#define DEFAULT_IS_ZERO 1

#define NO_NEG

#include <isl_pw_templ.c>

#undef UNION
#define UNION isl_union_pw_qpolynomial_fold
#undef PART
#define PART isl_pw_qpolynomial_fold
#undef PARTS
#define PARTS pw_qpolynomial_fold
#define ALIGN_DOMAIN

#include <isl_union_templ.c>

__isl_give isl_qpolynomial_fold *isl_qpolynomial_fold_empty(enum isl_fold type,
        __isl_take isl_space *dim)
{
        return qpolynomial_fold_alloc(type, dim, 0);
}

__isl_give isl_qpolynomial_fold *isl_qpolynomial_fold_alloc(
        enum isl_fold type, __isl_take isl_qpolynomial *qp)
{
        isl_qpolynomial_fold *fold;

        if (!qp)
                return NULL;

        fold = qpolynomial_fold_alloc(type, isl_space_copy(qp->dim), 1);
        if (!fold)
                goto error;

        fold->qp[0] = qp;
        fold->n++;

        return fold;
error:
        isl_qpolynomial_fold_free(fold);
        isl_qpolynomial_free(qp);
        return NULL;
}

__isl_give isl_qpolynomial_fold *isl_qpolynomial_fold_copy(
        __isl_keep isl_qpolynomial_fold *fold)
{
        if (!fold)
                return NULL;

        fold->ref++;
        return fold;
}

__isl_give isl_qpolynomial_fold *isl_qpolynomial_fold_dup(
        __isl_keep isl_qpolynomial_fold *fold)
{
        int i;
        isl_qpolynomial_fold *dup;

        if (!fold)
                return NULL;
        dup = qpolynomial_fold_alloc(fold->type,
                                        isl_space_copy(fold->dim), fold->n);
        if (!dup)
                return NULL;
        
        dup->n = fold->n;
        for (i = 0; i < fold->n; ++i) {
                dup->qp[i] = isl_qpolynomial_copy(fold->qp[i]);
                if (!dup->qp[i])
                        goto error;
        }

        return dup;
error:
        isl_qpolynomial_fold_free(dup);
        return NULL;
}

__isl_give isl_qpolynomial_fold *isl_qpolynomial_fold_cow(
        __isl_take isl_qpolynomial_fold *fold)
{
        if (!fold)
                return NULL;

        if (fold->ref == 1)
                return fold;
        fold->ref--;
        return isl_qpolynomial_fold_dup(fold);
}

void isl_qpolynomial_fold_free(__isl_take isl_qpolynomial_fold *fold)
{
        int i;

        if (!fold)
                return;
        if (--fold->ref > 0)
                return;

        for (i = 0; i < fold->n; ++i)
                isl_qpolynomial_free(fold->qp[i]);
        isl_space_free(fold->dim);
        free(fold);
}

int isl_qpolynomial_fold_is_empty(__isl_keep isl_qpolynomial_fold *fold)
{
        if (!fold)
                return -1;

        return fold->n == 0;
}

__isl_give isl_qpolynomial_fold *isl_qpolynomial_fold_fold(
        __isl_take isl_qpolynomial_fold *fold1,
        __isl_take isl_qpolynomial_fold *fold2)
{
        int i;
        struct isl_qpolynomial_fold *res = NULL;

        if (!fold1 || !fold2)
                goto error;

        isl_assert(fold1->dim->ctx, fold1->type == fold2->type, goto error);
        isl_assert(fold1->dim->ctx, isl_space_is_equal(fold1->dim, fold2->dim),
                        goto error);

        if (isl_qpolynomial_fold_is_empty(fold1)) {
                isl_qpolynomial_fold_free(fold1);
                return fold2;
        }

        if (isl_qpolynomial_fold_is_empty(fold2)) {
                isl_qpolynomial_fold_free(fold2);
                return fold1;
        }

        res = qpolynomial_fold_alloc(fold1->type, isl_space_copy(fold1->dim),
                                        fold1->n + fold2->n);
        if (!res)
                goto error;

        for (i = 0; i < fold1->n; ++i) {
                res->qp[res->n] = isl_qpolynomial_copy(fold1->qp[i]);
                if (!res->qp[res->n])
                        goto error;
                res->n++;
        }

        for (i = 0; i < fold2->n; ++i) {
                res->qp[res->n] = isl_qpolynomial_copy(fold2->qp[i]);
                if (!res->qp[res->n])
                        goto error;
                res->n++;
        }

        isl_qpolynomial_fold_free(fold1);
        isl_qpolynomial_fold_free(fold2);

        return res;
error:
        isl_qpolynomial_fold_free(res);
        isl_qpolynomial_fold_free(fold1);
        isl_qpolynomial_fold_free(fold2);
        return NULL;
}

__isl_give isl_pw_qpolynomial_fold *isl_pw_qpolynomial_fold_fold(
        __isl_take isl_pw_qpolynomial_fold *pw1,
        __isl_take isl_pw_qpolynomial_fold *pw2)
{
        int i, j, n;
        struct isl_pw_qpolynomial_fold *res;
        isl_set *set;

        if (!pw1 || !pw2)
                goto error;

        isl_assert(pw1->dim->ctx, isl_space_is_equal(pw1->dim, pw2->dim), goto error);

        if (isl_pw_qpolynomial_fold_is_zero(pw1)) {
                isl_pw_qpolynomial_fold_free(pw1);
                return pw2;
        }

        if (isl_pw_qpolynomial_fold_is_zero(pw2)) {
                isl_pw_qpolynomial_fold_free(pw2);
                return pw1;
        }

        if (pw1->type != pw2->type)
                isl_die(pw1->dim->ctx, isl_error_invalid,
                        "fold types don't match", goto error);

        n = (pw1->n + 1) * (pw2->n + 1);
        res = isl_pw_qpolynomial_fold_alloc_size(isl_space_copy(pw1->dim),
                                                pw1->type, n);

        for (i = 0; i < pw1->n; ++i) {
                set = isl_set_copy(pw1->p[i].set);
                for (j = 0; j < pw2->n; ++j) {
                        struct isl_set *common;
                        isl_qpolynomial_fold *sum;
                        set = isl_set_subtract(set,
                                        isl_set_copy(pw2->p[j].set));
                        common = isl_set_intersect(isl_set_copy(pw1->p[i].set),
                                                isl_set_copy(pw2->p[j].set));
                        if (isl_set_plain_is_empty(common)) {
                                isl_set_free(common);
                                continue;
                        }

                        sum = isl_qpolynomial_fold_fold_on_domain(common,
                               isl_qpolynomial_fold_copy(pw1->p[i].fold),
                               isl_qpolynomial_fold_copy(pw2->p[j].fold));

                        res = isl_pw_qpolynomial_fold_add_piece(res, common, sum);
                }
                res = isl_pw_qpolynomial_fold_add_piece(res, set,
                        isl_qpolynomial_fold_copy(pw1->p[i].fold));
        }

        for (j = 0; j < pw2->n; ++j) {
                set = isl_set_copy(pw2->p[j].set);
                for (i = 0; i < pw1->n; ++i)
                        set = isl_set_subtract(set, isl_set_copy(pw1->p[i].set));
                res = isl_pw_qpolynomial_fold_add_piece(res, set,
                                    isl_qpolynomial_fold_copy(pw2->p[j].fold));
        }

        isl_pw_qpolynomial_fold_free(pw1);
        isl_pw_qpolynomial_fold_free(pw2);

        return res;
error:
        isl_pw_qpolynomial_fold_free(pw1);
        isl_pw_qpolynomial_fold_free(pw2);
        return NULL;
}

__isl_give isl_union_pw_qpolynomial_fold *isl_union_pw_qpolynomial_fold_fold_pw_qpolynomial_fold(
        __isl_take isl_union_pw_qpolynomial_fold *u,
        __isl_take isl_pw_qpolynomial_fold *part)
{
        uint32_t hash;
        struct isl_hash_table_entry *entry;

        u = isl_union_pw_qpolynomial_fold_cow(u);

        if (!part || !u)
                goto error;

        isl_assert(u->dim->ctx, isl_space_match(part->dim, isl_dim_param, u->dim,
                                              isl_dim_param), goto error);

        hash = isl_space_get_hash(part->dim);
        entry = isl_hash_table_find(u->dim->ctx, &u->table, hash,
                                    &has_dim, part->dim, 1);
        if (!entry)
                goto error;

        if (!entry->data)
                entry->data = part;
        else {
                entry->data = isl_pw_qpolynomial_fold_fold(entry->data,
                                            isl_pw_qpolynomial_fold_copy(part));
                if (!entry->data)
                        goto error;
                isl_pw_qpolynomial_fold_free(part);
        }

        return u;
error:
        isl_pw_qpolynomial_fold_free(part);
        isl_union_pw_qpolynomial_fold_free(u);
        return NULL;
}

static int fold_part(__isl_take isl_pw_qpolynomial_fold *part, void *user)
{
        isl_union_pw_qpolynomial_fold **u;
        u = (isl_union_pw_qpolynomial_fold **)user;

        *u = isl_union_pw_qpolynomial_fold_fold_pw_qpolynomial_fold(*u, part);

        return 0;
}

__isl_give isl_union_pw_qpolynomial_fold *isl_union_pw_qpolynomial_fold_fold(
        __isl_take isl_union_pw_qpolynomial_fold *u1,
        __isl_take isl_union_pw_qpolynomial_fold *u2)
{
        u1 = isl_union_pw_qpolynomial_fold_cow(u1);

        if (!u1 || !u2)
                goto error;

        if (isl_union_pw_qpolynomial_fold_foreach_pw_qpolynomial_fold(u2,
                                                        &fold_part, &u1) < 0)
                goto error;

        isl_union_pw_qpolynomial_fold_free(u2);

        return u1;
error:
        isl_union_pw_qpolynomial_fold_free(u1);
        isl_union_pw_qpolynomial_fold_free(u2);
        return NULL;
}

__isl_give isl_pw_qpolynomial_fold *isl_pw_qpolynomial_fold_from_pw_qpolynomial(
        enum isl_fold type, __isl_take isl_pw_qpolynomial *pwqp)
{
        int i;
        isl_pw_qpolynomial_fold *pwf;

        if (!pwqp)
                return NULL;
        
        pwf = isl_pw_qpolynomial_fold_alloc_size(isl_space_copy(pwqp->dim),
                                                type, pwqp->n);

        for (i = 0; i < pwqp->n; ++i)
                pwf = isl_pw_qpolynomial_fold_add_piece(pwf,
                        isl_set_copy(pwqp->p[i].set),
                        isl_qpolynomial_fold_alloc(type,
                                isl_qpolynomial_copy(pwqp->p[i].qp)));

        isl_pw_qpolynomial_free(pwqp);

        return pwf;
}

__isl_give isl_pw_qpolynomial_fold *isl_pw_qpolynomial_fold_add(
        __isl_take isl_pw_qpolynomial_fold *pwf1,
        __isl_take isl_pw_qpolynomial_fold *pwf2)
{
        return isl_pw_qpolynomial_fold_union_add_(pwf1, pwf2);
}

int isl_qpolynomial_fold_plain_is_equal(__isl_keep isl_qpolynomial_fold *fold1,
        __isl_keep isl_qpolynomial_fold *fold2)
{
        int i;

        if (!fold1 || !fold2)
                return -1;

        if (fold1->n != fold2->n)
                return 0;

        /* We probably want to sort the qps first... */
        for (i = 0; i < fold1->n; ++i) {
                int eq = isl_qpolynomial_plain_is_equal(fold1->qp[i], fold2->qp[i]);
                if (eq < 0 || !eq)
                        return eq;
        }

        return 1;
}

__isl_give isl_qpolynomial *isl_qpolynomial_fold_eval(
        __isl_take isl_qpolynomial_fold *fold, __isl_take isl_point *pnt)
{
        isl_qpolynomial *qp;

        if (!fold || !pnt)
                goto error;
        isl_assert(pnt->dim->ctx, isl_space_is_equal(pnt->dim, fold->dim), goto error);
        isl_assert(pnt->dim->ctx,
                fold->type == isl_fold_max || fold->type == isl_fold_min,
                goto error);

        if (fold->n == 0)
                qp = isl_qpolynomial_zero_on_domain(isl_space_copy(fold->dim));
        else {
                int i;
                qp = isl_qpolynomial_eval(isl_qpolynomial_copy(fold->qp[0]),
                                                isl_point_copy(pnt));
                for (i = 1; i < fold->n; ++i) {
                        isl_qpolynomial *qp_i;
                        qp_i = isl_qpolynomial_eval(
                                            isl_qpolynomial_copy(fold->qp[i]),
                                            isl_point_copy(pnt));
                        if (fold->type == isl_fold_max)
                                qp = isl_qpolynomial_max_cst(qp, qp_i);
                        else
                                qp = isl_qpolynomial_min_cst(qp, qp_i);
                }
        }
        isl_qpolynomial_fold_free(fold);
        isl_point_free(pnt);

        return qp;
error:
        isl_qpolynomial_fold_free(fold);
        isl_point_free(pnt);
        return NULL;
}

size_t isl_pw_qpolynomial_fold_size(__isl_keep isl_pw_qpolynomial_fold *pwf)
{
        int i;
        size_t n = 0;

        for (i = 0; i < pwf->n; ++i)
                n += pwf->p[i].fold->n;

        return n;
}

__isl_give isl_qpolynomial *isl_qpolynomial_fold_opt_on_domain(
        __isl_take isl_qpolynomial_fold *fold, __isl_take isl_set *set, int max)
{
        int i;
        isl_qpolynomial *opt;

        if (!set || !fold)
                goto error;

        if (fold->n == 0) {
                isl_space *dim = isl_space_copy(fold->dim);
                isl_set_free(set);
                isl_qpolynomial_fold_free(fold);
                return isl_qpolynomial_zero_on_domain(dim);
        }

        opt = isl_qpolynomial_opt_on_domain(isl_qpolynomial_copy(fold->qp[0]),
                                                isl_set_copy(set), max);
        for (i = 1; i < fold->n; ++i) {
                isl_qpolynomial *opt_i;
                opt_i = isl_qpolynomial_opt_on_domain(
                                isl_qpolynomial_copy(fold->qp[i]),
                                isl_set_copy(set), max);
                if (max)
                        opt = isl_qpolynomial_max_cst(opt, opt_i);
                else
                        opt = isl_qpolynomial_min_cst(opt, opt_i);
        }

        isl_set_free(set);
        isl_qpolynomial_fold_free(fold);

        return opt;
error:
        isl_set_free(set);
        isl_qpolynomial_fold_free(fold);
        return NULL;
}

/* Check whether for each quasi-polynomial in "fold2" there is
 * a quasi-polynomial in "fold1" that dominates it on "set".
 */
static int qpolynomial_fold_covers_on_domain(__isl_keep isl_set *set,
        __isl_keep isl_qpolynomial_fold *fold1,
        __isl_keep isl_qpolynomial_fold *fold2)
{
        int i, j;
        int covers;

        if (!set || !fold1 || !fold2)
                return -1;

        covers = fold1->type == isl_fold_max ? 1 : -1;

        for (i = 0; i < fold2->n; ++i) {
                for (j = 0; j < fold1->n; ++j) {
                        isl_qpolynomial *d;
                        int sgn;

                        d = isl_qpolynomial_sub(
                                isl_qpolynomial_copy(fold1->qp[j]),
                                isl_qpolynomial_copy(fold2->qp[i]));
                        sgn = isl_qpolynomial_sign(set, d);
                        isl_qpolynomial_free(d);
                        if (sgn == covers)
                                break;
                }
                if (j >= fold1->n)
                        return 0;
        }

        return 1;
}

/* Check whether "pwf1" dominated "pwf2", i.e., the domain of "pwf1" contains
 * that of "pwf2" and on each cell, the corresponding fold from pwf1 dominates
 * that of pwf2.
 */
int isl_pw_qpolynomial_fold_covers(__isl_keep isl_pw_qpolynomial_fold *pwf1,
        __isl_keep isl_pw_qpolynomial_fold *pwf2)
{
        int i, j;
        isl_set *dom1, *dom2;
        int is_subset;

        if (!pwf1 || !pwf2)
                return -1;

        if (pwf2->n == 0)
                return 1;
        if (pwf1->n == 0)
                return 0;

        dom1 = isl_pw_qpolynomial_fold_domain(isl_pw_qpolynomial_fold_copy(pwf1));
        dom2 = isl_pw_qpolynomial_fold_domain(isl_pw_qpolynomial_fold_copy(pwf2));
        is_subset = isl_set_is_subset(dom2, dom1);
        isl_set_free(dom1);
        isl_set_free(dom2);

        if (is_subset < 0 || !is_subset)
                return is_subset;

        for (i = 0; i < pwf2->n; ++i) {
                for (j = 0; j < pwf1->n; ++j) {
                        int is_empty;
                        isl_set *common;
                        int covers;

                        common = isl_set_intersect(isl_set_copy(pwf1->p[j].set),
                                                   isl_set_copy(pwf2->p[i].set));
                        is_empty = isl_set_is_empty(common);
                        if (is_empty < 0 || is_empty) {
                                isl_set_free(common);
                                if (is_empty < 0)
                                        return -1;
                                continue;
                        }
                        covers = qpolynomial_fold_covers_on_domain(common,
                                        pwf1->p[j].fold, pwf2->p[i].fold);
                        isl_set_free(common);
                        if (covers < 0 || !covers)
                                return covers;
                }
        }

        return 1;
}

__isl_give isl_qpolynomial_fold *isl_qpolynomial_fold_morph_domain(
        __isl_take isl_qpolynomial_fold *fold, __isl_take isl_morph *morph)
{
        int i;
        isl_ctx *ctx;

        if (!fold || !morph)
                goto error;

        ctx = fold->dim->ctx;
        isl_assert(ctx, isl_space_is_equal(fold->dim, morph->dom->dim), goto error);

        fold = isl_qpolynomial_fold_cow(fold);
        if (!fold)
                goto error;

        isl_space_free(fold->dim);
        fold->dim = isl_space_copy(morph->ran->dim);
        if (!fold->dim)
                goto error;

        for (i = 0; i < fold->n; ++i) {
                fold->qp[i] = isl_qpolynomial_morph_domain(fold->qp[i],
                                                isl_morph_copy(morph));
                if (!fold->qp[i])
                        goto error;
        }

        isl_morph_free(morph);

        return fold;
error:
        isl_qpolynomial_fold_free(fold);
        isl_morph_free(morph);
        return NULL;
}

enum isl_fold isl_qpolynomial_fold_get_type(__isl_keep isl_qpolynomial_fold *fold)
{
        if (!fold)
                return isl_fold_list;
        return fold->type;
}

enum isl_fold isl_union_pw_qpolynomial_fold_get_type(
        __isl_keep isl_union_pw_qpolynomial_fold *upwf)
{
        if (!upwf)
                return isl_fold_list;
        return upwf->type;
}

__isl_give isl_qpolynomial_fold *isl_qpolynomial_fold_lift(
        __isl_take isl_qpolynomial_fold *fold, __isl_take isl_space *dim)
{
        int i;

        if (!fold || !dim)
                goto error;

        if (isl_space_is_equal(fold->dim, dim)) {
                isl_space_free(dim);
                return fold;
        }

        fold = isl_qpolynomial_fold_cow(fold);
        if (!fold)
                goto error;

        isl_space_free(fold->dim);
        fold->dim = isl_space_copy(dim);
        if (!fold->dim)
                goto error;

        for (i = 0; i < fold->n; ++i) {
                fold->qp[i] = isl_qpolynomial_lift(fold->qp[i],
                                                isl_space_copy(dim));
                if (!fold->qp[i])
                        goto error;
        }

        isl_space_free(dim);

        return fold;
error:
        isl_qpolynomial_fold_free(fold);
        isl_space_free(dim);
        return NULL;
}

int isl_qpolynomial_fold_foreach_qpolynomial(
        __isl_keep isl_qpolynomial_fold *fold,
        int (*fn)(__isl_take isl_qpolynomial *qp, void *user), void *user)
{
        int i;

        if (!fold)
                return -1;

        for (i = 0; i < fold->n; ++i)
                if (fn(isl_qpolynomial_copy(fold->qp[i]), user) < 0)
                        return -1;

        return 0;
}

__isl_give isl_qpolynomial_fold *isl_qpolynomial_fold_move_dims(
        __isl_take isl_qpolynomial_fold *fold,
        enum isl_dim_type dst_type, unsigned dst_pos,
        enum isl_dim_type src_type, unsigned src_pos, unsigned n)
{
        int i;

        if (n == 0)
                return fold;

        fold = isl_qpolynomial_fold_cow(fold);
        if (!fold)
                return NULL;

        fold->dim = isl_space_move_dims(fold->dim, dst_type, dst_pos,
                                                src_type, src_pos, n);
        if (!fold->dim)
                goto error;

        for (i = 0; i < fold->n; ++i) {
                fold->qp[i] = isl_qpolynomial_move_dims(fold->qp[i],
                                dst_type, dst_pos, src_type, src_pos, n);
                if (!fold->qp[i])
                        goto error;
        }

        return fold;
error:
        isl_qpolynomial_fold_free(fold);
        return NULL;
}

/* For each 0 <= i < "n", replace variable "first" + i of type "type"
 * in fold->qp[k] by subs[i].
 */
__isl_give isl_qpolynomial_fold *isl_qpolynomial_fold_substitute(
        __isl_take isl_qpolynomial_fold *fold,
        enum isl_dim_type type, unsigned first, unsigned n,
        __isl_keep isl_qpolynomial **subs)
{
        int i;

        if (n == 0)
                return fold;

        fold = isl_qpolynomial_fold_cow(fold);
        if (!fold)
                return NULL;

        for (i = 0; i < fold->n; ++i) {
                fold->qp[i] = isl_qpolynomial_substitute(fold->qp[i],
                                type, first, n, subs);
                if (!fold->qp[i])
                        goto error;
        }

        return fold;
error:
        isl_qpolynomial_fold_free(fold);
        return NULL;
}

static int add_pwqp(__isl_take isl_pw_qpolynomial *pwqp, void *user)
{
        isl_ctx *ctx;
        isl_pw_qpolynomial_fold *pwf;
        isl_union_pw_qpolynomial_fold **upwf;
        uint32_t hash;
        struct isl_hash_table_entry *entry;

        upwf = (isl_union_pw_qpolynomial_fold **)user;

        ctx = pwqp->dim->ctx;
        hash = isl_space_get_hash(pwqp->dim);
        entry = isl_hash_table_find(ctx, &(*upwf)->table,
                                     hash, &has_dim, pwqp->dim, 1);
        if (!entry)
                goto error;

        pwf = isl_pw_qpolynomial_fold_from_pw_qpolynomial((*upwf)->type, pwqp);
        if (!entry->data)
                entry->data = pwf;
        else {
                entry->data = isl_pw_qpolynomial_fold_add(entry->data, pwf);
                if (!entry->data)
                        return -1;
                if (isl_pw_qpolynomial_fold_is_zero(entry->data)) {
                        isl_pw_qpolynomial_fold_free(entry->data);
                        isl_hash_table_remove(ctx, &(*upwf)->table, entry);
                }
        }

        return 0;
error:
        isl_pw_qpolynomial_free(pwqp);
        return -1;
}

__isl_give isl_union_pw_qpolynomial_fold *isl_union_pw_qpolynomial_fold_add_union_pw_qpolynomial(
        __isl_take isl_union_pw_qpolynomial_fold *upwf,
        __isl_take isl_union_pw_qpolynomial *upwqp)
{
        upwf = isl_union_pw_qpolynomial_fold_align_params(upwf,
                                isl_union_pw_qpolynomial_get_space(upwqp));
        upwqp = isl_union_pw_qpolynomial_align_params(upwqp,
                                isl_union_pw_qpolynomial_fold_get_space(upwf));

        upwf = isl_union_pw_qpolynomial_fold_cow(upwf);
        if (!upwf || !upwqp)
                goto error;

        if (isl_union_pw_qpolynomial_foreach_pw_qpolynomial(upwqp, &add_pwqp,
                                                         &upwf) < 0)
                goto error;

        isl_union_pw_qpolynomial_free(upwqp);

        return upwf;
error:
        isl_union_pw_qpolynomial_fold_free(upwf);
        isl_union_pw_qpolynomial_free(upwqp);
        return NULL;
}

static int join_compatible(__isl_keep isl_space *dim1, __isl_keep isl_space *dim2)
{
        int m;
        m = isl_space_match(dim1, isl_dim_param, dim2, isl_dim_param);
        if (m < 0 || !m)
                return m;
        return isl_space_tuple_match(dim1, isl_dim_out, dim2, isl_dim_in);
}

/* Compute the intersection of the range of the map and the domain
 * of the piecewise quasipolynomial reduction and then compute a bound
 * on the associated quasipolynomial reduction over all elements
 * in this intersection.
 *
 * We first introduce some unconstrained dimensions in the
 * piecewise quasipolynomial, intersect the resulting domain
 * with the wrapped map and the compute the sum.
 */
__isl_give isl_pw_qpolynomial_fold *isl_map_apply_pw_qpolynomial_fold(
        __isl_take isl_map *map, __isl_take isl_pw_qpolynomial_fold *pwf,
        int *tight)
{
        isl_ctx *ctx;
        isl_set *dom;
        isl_space *map_dim;
        isl_space *pwf_dim;
        unsigned n_in;
        int ok;

        ctx = isl_map_get_ctx(map);
        if (!ctx)
                goto error;

        map_dim = isl_map_get_space(map);
        pwf_dim = isl_pw_qpolynomial_fold_get_space(pwf);
        ok = join_compatible(map_dim, pwf_dim);
        isl_space_free(map_dim);
        isl_space_free(pwf_dim);
        if (!ok)
                isl_die(ctx, isl_error_invalid, "incompatible dimensions",
                        goto error);

        n_in = isl_map_dim(map, isl_dim_in);
        pwf = isl_pw_qpolynomial_fold_insert_dims(pwf, isl_dim_in, 0, n_in);

        dom = isl_map_wrap(map);
        pwf = isl_pw_qpolynomial_fold_reset_domain_space(pwf,
                                                isl_set_get_space(dom));

        pwf = isl_pw_qpolynomial_fold_intersect_domain(pwf, dom);
        pwf = isl_pw_qpolynomial_fold_bound(pwf, tight);
        
        return pwf;
error:
        isl_map_free(map);
        isl_pw_qpolynomial_fold_free(pwf);
        return NULL;
}

__isl_give isl_pw_qpolynomial_fold *isl_set_apply_pw_qpolynomial_fold(
        __isl_take isl_set *set, __isl_take isl_pw_qpolynomial_fold *pwf,
        int *tight)
{
        return isl_map_apply_pw_qpolynomial_fold(set, pwf, tight);
}

struct isl_apply_fold_data {
        isl_union_pw_qpolynomial_fold *upwf;
        isl_union_pw_qpolynomial_fold *res;
        isl_map *map;
        int tight;
};

static int pw_qpolynomial_fold_apply(__isl_take isl_pw_qpolynomial_fold *pwf,
        void *user)
{
        isl_space *map_dim;
        isl_space *pwf_dim;
        struct isl_apply_fold_data *data = user;
        int ok;

        map_dim = isl_map_get_space(data->map);
        pwf_dim = isl_pw_qpolynomial_fold_get_space(pwf);
        ok = join_compatible(map_dim, pwf_dim);
        isl_space_free(map_dim);
        isl_space_free(pwf_dim);

        if (ok) {
                pwf = isl_map_apply_pw_qpolynomial_fold(isl_map_copy(data->map),
                                    pwf, data->tight ? &data->tight : NULL);
                data->res = isl_union_pw_qpolynomial_fold_fold_pw_qpolynomial_fold(
                                                        data->res, pwf);
        } else
                isl_pw_qpolynomial_fold_free(pwf);

        return 0;
}

static int map_apply(__isl_take isl_map *map, void *user)
{
        struct isl_apply_fold_data *data = user;
        int r;

        data->map = map;
        r = isl_union_pw_qpolynomial_fold_foreach_pw_qpolynomial_fold(
                                data->upwf, &pw_qpolynomial_fold_apply, data);

        isl_map_free(map);
        return r;
}

__isl_give isl_union_pw_qpolynomial_fold *isl_union_map_apply_union_pw_qpolynomial_fold(
        __isl_take isl_union_map *umap,
        __isl_take isl_union_pw_qpolynomial_fold *upwf, int *tight)
{
        isl_space *dim;
        enum isl_fold type;
        struct isl_apply_fold_data data;

        upwf = isl_union_pw_qpolynomial_fold_align_params(upwf,
                                isl_union_map_get_space(umap));
        umap = isl_union_map_align_params(umap,
                                isl_union_pw_qpolynomial_fold_get_space(upwf));

        data.upwf = upwf;
        data.tight = tight ? 1 : 0;
        dim = isl_union_pw_qpolynomial_fold_get_space(upwf);
        type = isl_union_pw_qpolynomial_fold_get_type(upwf);
        data.res = isl_union_pw_qpolynomial_fold_zero(dim, type);
        if (isl_union_map_foreach_map(umap, &map_apply, &data) < 0)
                goto error;

        isl_union_map_free(umap);
        isl_union_pw_qpolynomial_fold_free(upwf);

        if (tight)
                *tight = data.tight;

        return data.res;
error:
        isl_union_map_free(umap);
        isl_union_pw_qpolynomial_fold_free(upwf);
        isl_union_pw_qpolynomial_fold_free(data.res);
        return NULL;
}

__isl_give isl_union_pw_qpolynomial_fold *isl_union_set_apply_union_pw_qpolynomial_fold(
        __isl_take isl_union_set *uset,
        __isl_take isl_union_pw_qpolynomial_fold *upwf, int *tight)
{
        return isl_union_map_apply_union_pw_qpolynomial_fold(uset, upwf, tight);
}

/* Reorder the dimension of "fold" according to the given reordering.
 */
__isl_give isl_qpolynomial_fold *isl_qpolynomial_fold_realign_domain(
        __isl_take isl_qpolynomial_fold *fold, __isl_take isl_reordering *r)
{
        int i;

        fold = isl_qpolynomial_fold_cow(fold);
        if (!fold || !r)
                goto error;

        for (i = 0; i < fold->n; ++i) {
                fold->qp[i] = isl_qpolynomial_realign_domain(fold->qp[i],
                                                    isl_reordering_copy(r));
                if (!fold->qp[i])
                        goto error;
        }

        fold = isl_qpolynomial_fold_reset_domain_space(fold,
                                                    isl_space_copy(r->dim));

        isl_reordering_free(r);

        return fold;
error:
        isl_qpolynomial_fold_free(fold);
        isl_reordering_free(r);
        return NULL;
}

__isl_give isl_qpolynomial_fold *isl_qpolynomial_fold_mul_isl_int(
        __isl_take isl_qpolynomial_fold *fold, isl_int v)
{
        int i;

        if (isl_int_is_one(v))
                return fold;
        if (fold && isl_int_is_zero(v)) {
                isl_qpolynomial_fold *zero;
                isl_space *dim = isl_space_copy(fold->dim);
                zero = isl_qpolynomial_fold_empty(fold->type, dim);
                isl_qpolynomial_fold_free(fold);
                return zero;
        }

        fold = isl_qpolynomial_fold_cow(fold);
        if (!fold)
                return NULL;

        if (isl_int_is_neg(v))
                fold->type = isl_fold_type_negate(fold->type);
        for (i = 0; i < fold->n; ++i) {
                fold->qp[i] = isl_qpolynomial_mul_isl_int(fold->qp[i], v);
                if (!fold->qp[i])
                        goto error;
        }

        return fold;
error:
        isl_qpolynomial_fold_free(fold);
        return NULL;
}

__isl_give isl_qpolynomial_fold *isl_qpolynomial_fold_scale(
        __isl_take isl_qpolynomial_fold *fold, isl_int v)
{
        return isl_qpolynomial_fold_mul_isl_int(fold, v);
}