/// Add an isl constraint to an ScopLib matrix.
///
/// @param user The matrix
/// @param c The constraint
int ScopLib::accessToMatrix_constraint(isl_constraint *c, void *user) {
scoplib_matrix_p m = (scoplib_matrix_p) user;
int nb_params = isl_constraint_dim(c, isl_dim_param);
int nb_in = isl_constraint_dim(c, isl_dim_in);
int nb_div = isl_constraint_dim(c, isl_dim_div);
assert(!nb_div && "Existentially quantified variables not yet supported");
scoplib_vector_p vec =
scoplib_vector_malloc(nb_params + nb_in + 2);
isl_int v;
isl_int_init(v);
// The access dimension has to be one.
isl_constraint_get_coefficient(c, isl_dim_out, 0, &v);
assert((isl_int_is_one(v) || isl_int_is_negone(v))
&& "Access relations not supported in scoplib");
bool inverse = isl_int_is_one(v);
// Assign variables
for (int i = 0; i < nb_in; ++i) {
isl_constraint_get_coefficient(c, isl_dim_in, i, &v);
if (inverse) isl_int_neg(v,v);
isl_int_set(vec->p[i + 1], v);
}
// Assign parameters
for (int i = 0; i < nb_params; ++i) {
isl_constraint_get_coefficient(c, isl_dim_param, i, &v);
if (inverse) isl_int_neg(v,v);
isl_int_set(vec->p[nb_in + i + 1], v);
}
// Assign constant
isl_constraint_get_constant(c, &v);
if (inverse) isl_int_neg(v,v);
isl_int_set(vec->p[nb_in + nb_params + 1], v);
scoplib_matrix_insert_vector(m, vec, m->NbRows);
isl_constraint_free(c);
isl_int_clear(v);
return 0;
}
static struct isl_vec *interval_sample(struct isl_basic_set *bset)
{
int i;
isl_int t;
struct isl_vec *sample;
bset = isl_basic_set_simplify(bset);
if (!bset)
return NULL;
if (isl_basic_set_plain_is_empty(bset))
return empty_sample(bset);
if (bset->n_eq == 0 && bset->n_ineq == 0)
return zero_sample(bset);
sample = isl_vec_alloc(bset->ctx, 2);
if (!sample)
goto error;
if (!bset)
return NULL;
isl_int_set_si(sample->block.data[0], 1);
if (bset->n_eq > 0) {
isl_assert(bset->ctx, bset->n_eq == 1, goto error);
isl_assert(bset->ctx, bset->n_ineq == 0, goto error);
if (isl_int_is_one(bset->eq[0][1]))
isl_int_neg(sample->el[1], bset->eq[0][0]);
else {
isl_assert(bset->ctx, isl_int_is_negone(bset->eq[0][1]),
goto error);
isl_int_set(sample->el[1], bset->eq[0][0]);
}
isl_basic_set_free(bset);
return sample;
}
/* Given a set of modulo constraints
*
* c + A y = 0 mod d
*
* this function computes a particular solution y_0
*
* The input is given as a matrix B = [ c A ] and a vector d.
*
* The output is matrix containing the solution y_0 or
* a zero-column matrix if the constraints admit no integer solution.
*
* The given set of constrains is equivalent to
*
* c + A y = -D x
*
* with D = diag d and x a fresh set of variables.
* Reducing both c and A modulo d does not change the
* value of y in the solution and may lead to smaller coefficients.
* Let M = [ D A ] and [ H 0 ] = M U, the Hermite normal form of M.
* Then
* [ x ]
* M [ y ] = - c
* and so
* [ x ]
* [ H 0 ] U^{-1} [ y ] = - c
* Let
* [ A ] [ x ]
* [ B ] = U^{-1} [ y ]
* then
* H A + 0 B = -c
*
* so B may be chosen arbitrarily, e.g., B = 0, and then
*
* [ x ] = [ -c ]
* U^{-1} [ y ] = [ 0 ]
* or
* [ x ] [ -c ]
* [ y ] = U [ 0 ]
* specifically,
*
* y = U_{2,1} (-c)
*
* If any of the coordinates of this y are non-integer
* then the constraints admit no integer solution and
* a zero-column matrix is returned.
*/
static struct isl_mat *particular_solution(struct isl_mat *B, struct isl_vec *d)
{
int i, j;
struct isl_mat *M = NULL;
struct isl_mat *C = NULL;
struct isl_mat *U = NULL;
struct isl_mat *H = NULL;
struct isl_mat *cst = NULL;
struct isl_mat *T = NULL;
M = isl_mat_alloc(B->ctx, B->n_row, B->n_row + B->n_col - 1);
C = isl_mat_alloc(B->ctx, 1 + B->n_row, 1);
if (!M || !C)
goto error;
isl_int_set_si(C->row[0][0], 1);
for (i = 0; i < B->n_row; ++i) {
isl_seq_clr(M->row[i], B->n_row);
isl_int_set(M->row[i][i], d->block.data[i]);
isl_int_neg(C->row[1 + i][0], B->row[i][0]);
isl_int_fdiv_r(C->row[1+i][0], C->row[1+i][0], M->row[i][i]);
for (j = 0; j < B->n_col - 1; ++j)
isl_int_fdiv_r(M->row[i][B->n_row + j],
B->row[i][1 + j], M->row[i][i]);
}
M = isl_mat_left_hermite(M, 0, &U, NULL);
if (!M || !U)
goto error;
H = isl_mat_sub_alloc(M, 0, B->n_row, 0, B->n_row);
H = isl_mat_lin_to_aff(H);
C = isl_mat_inverse_product(H, C);
if (!C)
goto error;
for (i = 0; i < B->n_row; ++i) {
if (!isl_int_is_divisible_by(C->row[1+i][0], C->row[0][0]))
break;
isl_int_divexact(C->row[1+i][0], C->row[1+i][0], C->row[0][0]);
}
if (i < B->n_row)
cst = isl_mat_alloc(B->ctx, B->n_row, 0);
else
cst = isl_mat_sub_alloc(C, 1, B->n_row, 0, 1);
T = isl_mat_sub_alloc(U, B->n_row, B->n_col - 1, 0, B->n_row);
cst = isl_mat_product(T, cst);
isl_mat_free(M);
isl_mat_free(C);
isl_mat_free(U);
return cst;
error:
isl_mat_free(M);
isl_mat_free(C);
isl_mat_free(U);
return NULL;
}
/* Given an unbounded tableau and an integer point satisfying the tableau,
* construct an initial affine hull containing the recession cone
* shifted to the given point.
*
* The unbounded directions are taken from the last rows of the basis,
* which is assumed to have been initialized appropriately.
*/
static __isl_give isl_basic_set *initial_hull(struct isl_tab *tab,
__isl_take isl_vec *vec)
{
int i;
int k;
struct isl_basic_set *bset = NULL;
struct isl_ctx *ctx;
unsigned dim;
if (!vec || !tab)
return NULL;
ctx = vec->ctx;
isl_assert(ctx, vec->size != 0, goto error);
bset = isl_basic_set_alloc(ctx, 0, vec->size - 1, 0, vec->size - 1, 0);
if (!bset)
goto error;
dim = isl_basic_set_n_dim(bset) - tab->n_unbounded;
for (i = 0; i < dim; ++i) {
k = isl_basic_set_alloc_equality(bset);
if (k < 0)
goto error;
isl_seq_cpy(bset->eq[k] + 1, tab->basis->row[1 + i] + 1,
vec->size - 1);
isl_seq_inner_product(bset->eq[k] + 1, vec->el +1,
vec->size - 1, &bset->eq[k][0]);
isl_int_neg(bset->eq[k][0], bset->eq[k][0]);
}
bset->sample = vec;
bset = isl_basic_set_gauss(bset, NULL);
return bset;
error:
isl_basic_set_free(bset);
isl_vec_free(vec);
return NULL;
}
/* Look for all integer points in "bset", which is assumed to be bounded,
* and call callback->add on each of them.
*
* We first compute a reduced basis for the set and then scan
* the set in the directions of this basis.
* We basically perform a depth first search, where in each level i
* we compute the range in the i-th basis vector direction, given
* fixed values in the directions of the previous basis vector.
* We then add an equality to the tableau fixing the value in the
* direction of the current basis vector to each value in the range
* in turn and then continue to the next level.
*
* The search is implemented iteratively. "level" identifies the current
* basis vector. "init" is true if we want the first value at the current
* level and false if we want the next value.
* Solutions are added in the leaves of the search tree, i.e., after
* we have fixed a value in each direction of the basis.
*/
int isl_basic_set_scan(struct isl_basic_set *bset,
struct isl_scan_callback *callback)
{
unsigned dim;
struct isl_mat *B = NULL;
struct isl_tab *tab = NULL;
struct isl_vec *min;
struct isl_vec *max;
struct isl_tab_undo **snap;
int level;
int init;
enum isl_lp_result res;
if (!bset)
return -1;
dim = isl_basic_set_total_dim(bset);
if (dim == 0)
return scan_0D(bset, callback);
min = isl_vec_alloc(bset->ctx, dim);
max = isl_vec_alloc(bset->ctx, dim);
snap = isl_alloc_array(bset->ctx, struct isl_tab_undo *, dim);
if (!min || !max || !snap)
goto error;
tab = isl_tab_from_basic_set(bset, 0);
if (!tab)
goto error;
if (isl_tab_extend_cons(tab, dim + 1) < 0)
goto error;
tab->basis = isl_mat_identity(bset->ctx, 1 + dim);
if (1)
tab = isl_tab_compute_reduced_basis(tab);
if (!tab)
goto error;
B = isl_mat_copy(tab->basis);
if (!B)
goto error;
level = 0;
init = 1;
while (level >= 0) {
int empty = 0;
if (init) {
res = isl_tab_min(tab, B->row[1 + level],
bset->ctx->one, &min->el[level], NULL, 0);
if (res == isl_lp_empty)
empty = 1;
if (res == isl_lp_error || res == isl_lp_unbounded)
goto error;
isl_seq_neg(B->row[1 + level] + 1,
B->row[1 + level] + 1, dim);
res = isl_tab_min(tab, B->row[1 + level],
bset->ctx->one, &max->el[level], NULL, 0);
isl_seq_neg(B->row[1 + level] + 1,
B->row[1 + level] + 1, dim);
isl_int_neg(max->el[level], max->el[level]);
if (res == isl_lp_empty)
empty = 1;
if (res == isl_lp_error || res == isl_lp_unbounded)
goto error;
snap[level] = isl_tab_snap(tab);
} else
isl_int_add_ui(min->el[level], min->el[level], 1);
if (empty || isl_int_gt(min->el[level], max->el[level])) {
level--;
init = 0;
if (level >= 0)
if (isl_tab_rollback(tab, snap[level]) < 0)
goto error;
continue;
}
if (level == dim - 1 && callback->add == increment_counter) {
if (increment_range(callback,
min->el[level], max->el[level]))
goto error;
level--;
init = 0;
if (level >= 0)
if (isl_tab_rollback(tab, snap[level]) < 0)
goto error;
continue;
}
isl_int_neg(B->row[1 + level][0], min->el[level]);
if (isl_tab_add_valid_eq(tab, B->row[1 + level]) < 0)
goto error;
isl_int_set_si(B->row[1 + level][0], 0);
if (level < dim - 1) {
++level;
init = 1;
continue;
}
if (add_solution(tab, callback) < 0)
goto error;
init = 0;
if (isl_tab_rollback(tab, snap[level]) < 0)
goto error;
}
isl_tab_free(tab);
free(snap);
isl_vec_free(min);
isl_vec_free(max);
isl_basic_set_free(bset);
isl_mat_free(B);
return 0;
error:
isl_tab_free(tab);
free(snap);
isl_vec_free(min);
isl_vec_free(max);
isl_basic_set_free(bset);
isl_mat_free(B);
return -1;
}
__isl_give isl_basic_set *isl_basic_set_box_from_points(
__isl_take isl_point *pnt1, __isl_take isl_point *pnt2)
{
isl_basic_set *bset;
unsigned total;
int i;
int k;
isl_int t;
isl_int_init(t);
if (!pnt1 || !pnt2)
goto error;
isl_assert(pnt1->dim->ctx,
isl_dim_equal(pnt1->dim, pnt2->dim), goto error);
if (isl_point_is_void(pnt1) && isl_point_is_void(pnt2)) {
isl_dim *dim = isl_dim_copy(pnt1->dim);
isl_point_free(pnt1);
isl_point_free(pnt2);
isl_int_clear(t);
return isl_basic_set_empty(dim);
}
if (isl_point_is_void(pnt1)) {
isl_point_free(pnt1);
isl_int_clear(t);
return isl_basic_set_from_point(pnt2);
}
if (isl_point_is_void(pnt2)) {
isl_point_free(pnt2);
isl_int_clear(t);
return isl_basic_set_from_point(pnt1);
}
total = isl_dim_total(pnt1->dim);
bset = isl_basic_set_alloc_dim(isl_dim_copy(pnt1->dim), 0, 0, 2 * total);
for (i = 0; i < total; ++i) {
isl_int_mul(t, pnt1->vec->el[1 + i], pnt2->vec->el[0]);
isl_int_submul(t, pnt2->vec->el[1 + i], pnt1->vec->el[0]);
k = isl_basic_set_alloc_inequality(bset);
if (k < 0)
goto error;
isl_seq_clr(bset->ineq[k] + 1, total);
if (isl_int_is_pos(t)) {
isl_int_set_si(bset->ineq[k][1 + i], -1);
isl_int_set(bset->ineq[k][0], pnt1->vec->el[1 + i]);
} else {
isl_int_set_si(bset->ineq[k][1 + i], 1);
isl_int_neg(bset->ineq[k][0], pnt1->vec->el[1 + i]);
}
isl_int_fdiv_q(bset->ineq[k][0], bset->ineq[k][0], pnt1->vec->el[0]);
k = isl_basic_set_alloc_inequality(bset);
if (k < 0)
goto error;
isl_seq_clr(bset->ineq[k] + 1, total);
if (isl_int_is_pos(t)) {
isl_int_set_si(bset->ineq[k][1 + i], 1);
isl_int_neg(bset->ineq[k][0], pnt2->vec->el[1 + i]);
} else {
isl_int_set_si(bset->ineq[k][1 + i], -1);
isl_int_set(bset->ineq[k][0], pnt2->vec->el[1 + i]);
}
isl_int_fdiv_q(bset->ineq[k][0], bset->ineq[k][0], pnt2->vec->el[0]);
}
bset = isl_basic_set_finalize(bset);
isl_point_free(pnt1);
isl_point_free(pnt2);
isl_int_clear(t);
return bset;
error:
isl_point_free(pnt1);
isl_point_free(pnt2);
isl_int_clear(t);
return NULL;
}
