Viewing file:  isl_range.c (14.77 KB) -rw-r--r--
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#include <isl_ctx_private.h>
#include <isl/val.h>
#include <isl_constraint_private.h>
#include <isl/set.h>
#include <isl_polynomial_private.h>
#include <isl_morph.h>
#include <isl_range.h>
struct range_data {
struct isl_bound *bound;
int *signs;
int sign;
int test_monotonicity;
int monotonicity;
int tight;
isl_qpolynomial *poly;
isl_pw_qpolynomial_fold *pwf;
isl_pw_qpolynomial_fold *pwf_tight;
};
static isl_stat propagate_on_domain(__isl_take isl_basic_set *bset,
__isl_take isl_qpolynomial *poly, struct range_data *data);
/* Check whether the polynomial "poly" has sign "sign" over "bset",
* i.e., if sign == 1, check that the lower bound on the polynomial
* is non-negative and if sign == -1, check that the upper bound on
* the polynomial is non-positive.
*/
static isl_bool has_sign(__isl_keep isl_basic_set *bset,
__isl_keep isl_qpolynomial *poly, int sign, int *signs)
{
struct range_data data_m;
isl_size nparam;
isl_space *space;
isl_val *opt;
isl_bool r;
enum isl_fold type;
nparam = isl_basic_set_dim(bset, isl_dim_param);
if (nparam < 0)
return isl_bool_error;
bset = isl_basic_set_copy(bset);
poly = isl_qpolynomial_copy(poly);
bset = isl_basic_set_move_dims(bset, isl_dim_set, 0,
isl_dim_param, 0, nparam);
poly = isl_qpolynomial_move_dims(poly, isl_dim_in, 0,
isl_dim_param, 0, nparam);
space = isl_qpolynomial_get_space(poly);
space = isl_space_params(space);
space = isl_space_from_domain(space);
space = isl_space_add_dims(space, isl_dim_out, 1);
data_m.test_monotonicity = 0;
data_m.signs = signs;
data_m.sign = -sign;
type = data_m.sign < 0 ? isl_fold_min : isl_fold_max;
data_m.pwf = isl_pw_qpolynomial_fold_zero(space, type);
data_m.tight = 0;
data_m.pwf_tight = NULL;
if (propagate_on_domain(bset, poly, &data_m) < 0)
goto error;
if (sign > 0)
opt = isl_pw_qpolynomial_fold_min(data_m.pwf);
else
opt = isl_pw_qpolynomial_fold_max(data_m.pwf);
if (!opt)
r = isl_bool_error;
else if (isl_val_is_nan(opt) ||
isl_val_is_infty(opt) ||
isl_val_is_neginfty(opt))
r = isl_bool_false;
else
r = isl_bool_ok(sign * isl_val_sgn(opt) >= 0);
isl_val_free(opt);
return r;
error:
isl_pw_qpolynomial_fold_free(data_m.pwf);
return isl_bool_error;
}
/* Return 1 if poly is monotonically increasing in the last set variable,
* -1 if poly is monotonically decreasing in the last set variable,
* 0 if no conclusion,
* -2 on error.
*
* We simply check the sign of p(x+1)-p(x)
*/
static int monotonicity(__isl_keep isl_basic_set *bset,
__isl_keep isl_qpolynomial *poly, struct range_data *data)
{
isl_ctx *ctx;
isl_space *space;
isl_qpolynomial *sub = NULL;
isl_qpolynomial *diff = NULL;
int result = 0;
isl_bool s;
isl_size nvar;
nvar = isl_basic_set_dim(bset, isl_dim_set);
if (nvar < 0)
return -2;
ctx = isl_qpolynomial_get_ctx(poly);
space = isl_qpolynomial_get_domain_space(poly);
sub = isl_qpolynomial_var_on_domain(isl_space_copy(space),
isl_dim_set, nvar - 1);
sub = isl_qpolynomial_add(sub,
isl_qpolynomial_rat_cst_on_domain(space, ctx->one, ctx->one));
diff = isl_qpolynomial_substitute(isl_qpolynomial_copy(poly),
isl_dim_in, nvar - 1, 1, &sub);
diff = isl_qpolynomial_sub(diff, isl_qpolynomial_copy(poly));
s = has_sign(bset, diff, 1, data->signs);
if (s < 0)
goto error;
if (s)
result = 1;
else {
s = has_sign(bset, diff, -1, data->signs);
if (s < 0)
goto error;
if (s)
result = -1;
}
isl_qpolynomial_free(diff);
isl_qpolynomial_free(sub);
return result;
error:
isl_qpolynomial_free(diff);
isl_qpolynomial_free(sub);
return -2;
}
/* Return a positive ("sign" > 0) or negative ("sign" < 0) infinite polynomial
* with domain space "space".
*/
static __isl_give isl_qpolynomial *signed_infty(__isl_take isl_space *space,
int sign)
{
if (sign > 0)
return isl_qpolynomial_infty_on_domain(space);
else
return isl_qpolynomial_neginfty_on_domain(space);
}
static __isl_give isl_qpolynomial *bound2poly(__isl_take isl_constraint *bound,
__isl_take isl_space *space, unsigned pos, int sign)
{
if (!bound)
return signed_infty(space, sign);
isl_space_free(space);
return isl_qpolynomial_from_constraint(bound, isl_dim_set, pos);
}
static int bound_is_integer(__isl_keep isl_constraint *bound, unsigned pos)
{
isl_int c;
int is_int;
if (!bound)
return 1;
isl_int_init(c);
isl_constraint_get_coefficient(bound, isl_dim_set, pos, &c);
is_int = isl_int_is_one(c) || isl_int_is_negone(c);
isl_int_clear(c);
return is_int;
}
struct isl_fixed_sign_data {
int *signs;
int sign;
isl_qpolynomial *poly;
};
/* Add term "term" to data->poly if it has sign data->sign.
* The sign is determined based on the signs of the parameters
* and variables in data->signs. The integer divisions, if
* any, are assumed to be non-negative.
*/
static isl_stat collect_fixed_sign_terms(__isl_take isl_term *term, void *user)
{
struct isl_fixed_sign_data *data = (struct isl_fixed_sign_data *)user;
isl_int n;
int i;
int sign;
isl_size nparam;
isl_size nvar;
isl_size exp;
nparam = isl_term_dim(term, isl_dim_param);
nvar = isl_term_dim(term, isl_dim_set);
if (nparam < 0 || nvar < 0)
return isl_stat_error;
isl_int_init(n);
isl_term_get_num(term, &n);
sign = isl_int_sgn(n);
isl_int_clear(n);
for (i = 0; i < nparam; ++i) {
if (data->signs[i] > 0)
continue;
exp = isl_term_get_exp(term, isl_dim_param, i);
if (exp < 0)
return isl_stat_error;
if (exp % 2)
sign = -sign;
}
for (i = 0; i < nvar; ++i) {
if (data->signs[nparam + i] > 0)
continue;
exp = isl_term_get_exp(term, isl_dim_set, i);
if (exp < 0)
return isl_stat_error;
if (exp % 2)
sign = -sign;
}
if (sign == data->sign) {
isl_qpolynomial *t = isl_qpolynomial_from_term(term);
data->poly = isl_qpolynomial_add(data->poly, t);
} else
isl_term_free(term);
return isl_stat_ok;
}
/* Construct and return a polynomial that consists of the terms
* in "poly" that have sign "sign". The integer divisions, if
* any, are assumed to be non-negative.
*/
__isl_give isl_qpolynomial *isl_qpolynomial_terms_of_sign(
__isl_keep isl_qpolynomial *poly, int *signs, int sign)
{
isl_space *space;
struct isl_fixed_sign_data data = { signs, sign };
space = isl_qpolynomial_get_domain_space(poly);
data.poly = isl_qpolynomial_zero_on_domain(space);
if (isl_qpolynomial_foreach_term(poly, collect_fixed_sign_terms, &data) < 0)
goto error;
return data.poly;
error:
isl_qpolynomial_free(data.poly);
return NULL;
}
/* Helper function to add a guarded polynomial to either pwf_tight or pwf,
* depending on whether the result has been determined to be tight.
*/
static isl_stat add_guarded_poly(__isl_take isl_basic_set *bset,
__isl_take isl_qpolynomial *poly, struct range_data *data)
{
enum isl_fold type = data->sign < 0 ? isl_fold_min : isl_fold_max;
isl_set *set;
isl_qpolynomial_fold *fold;
isl_pw_qpolynomial_fold *pwf;
bset = isl_basic_set_params(bset);
poly = isl_qpolynomial_project_domain_on_params(poly);
fold = isl_qpolynomial_fold_alloc(type, poly);
set = isl_set_from_basic_set(bset);
pwf = isl_pw_qpolynomial_fold_alloc(type, set, fold);
if (data->tight)
data->pwf_tight = isl_pw_qpolynomial_fold_fold(
data->pwf_tight, pwf);
else
data->pwf = isl_pw_qpolynomial_fold_fold(data->pwf, pwf);
return isl_stat_ok;
}
/* Plug in "sub" for the variable at position "pos" in "poly".
*
* If "sub" is an infinite polynomial and if the variable actually
* appears in "poly", then calling isl_qpolynomial_substitute
* to perform the substitution may result in a NaN result.
* In such cases, return positive or negative infinity instead,
* depending on whether an upper bound or a lower bound is being computed,
* and mark the result as not being tight.
*/
static __isl_give isl_qpolynomial *plug_in_at_pos(
__isl_take isl_qpolynomial *poly, int pos,
__isl_take isl_qpolynomial *sub, struct range_data *data)
{
isl_bool involves, infty;
involves = isl_qpolynomial_involves_dims(poly, isl_dim_in, pos, 1);
if (involves < 0)
goto error;
if (!involves) {
isl_qpolynomial_free(sub);
return poly;
}
infty = isl_qpolynomial_is_infty(sub);
if (infty >= 0 && !infty)
infty = isl_qpolynomial_is_neginfty(sub);
if (infty < 0)
goto error;
if (infty) {
isl_space *space = isl_qpolynomial_get_domain_space(poly);
data->tight = 0;
isl_qpolynomial_free(poly);
isl_qpolynomial_free(sub);
return signed_infty(space, data->sign);
}
poly = isl_qpolynomial_substitute(poly, isl_dim_in, pos, 1, &sub);
isl_qpolynomial_free(sub);
return poly;
error:
isl_qpolynomial_free(poly);
isl_qpolynomial_free(sub);
return NULL;
}
/* Given a lower and upper bound on the final variable and constraints
* on the remaining variables where these bounds are active,
* eliminate the variable from data->poly based on these bounds.
* If the polynomial has been determined to be monotonic
* in the variable, then simply plug in the appropriate bound.
* If the current polynomial is tight and if this bound is integer,
* then the result is still tight. In all other cases, the results
* may not be tight.
* Otherwise, plug in the largest bound (in absolute value) in
* the positive terms (if an upper bound is wanted) or the negative terms
* (if a lower bounded is wanted) and the other bound in the other terms.
*
* If all variables have been eliminated, then record the result.
* Ohterwise, recurse on the next variable.
*/
static isl_stat propagate_on_bound_pair(__isl_take isl_constraint *lower,
__isl_take isl_constraint *upper, __isl_take isl_basic_set *bset,
void *user)
{
struct range_data *data = (struct range_data *)user;
int save_tight = data->tight;
isl_qpolynomial *poly;
isl_stat r;
isl_size nvar, nparam;
nvar = isl_basic_set_dim(bset, isl_dim_set);
nparam = isl_basic_set_dim(bset, isl_dim_param);
if (nvar < 0 || nparam < 0)
goto error;
if (data->monotonicity) {
isl_qpolynomial *sub;
isl_space *space = isl_qpolynomial_get_domain_space(data->poly);
if (data->monotonicity * data->sign > 0) {
if (data->tight)
data->tight = bound_is_integer(upper, nvar);
sub = bound2poly(upper, space, nvar, 1);
isl_constraint_free(lower);
} else {
if (data->tight)
data->tight = bound_is_integer(lower, nvar);
sub = bound2poly(lower, space, nvar, -1);
isl_constraint_free(upper);
}
poly = isl_qpolynomial_copy(data->poly);
poly = plug_in_at_pos(poly, nvar, sub, data);
poly = isl_qpolynomial_drop_dims(poly, isl_dim_in, nvar, 1);
} else {
isl_qpolynomial *l, *u;
isl_qpolynomial *pos, *neg;
isl_space *space = isl_qpolynomial_get_domain_space(data->poly);
int sign = data->sign * data->signs[nparam + nvar];
data->tight = 0;
u = bound2poly(upper, isl_space_copy(space), nvar, 1);
l = bound2poly(lower, space, nvar, -1);
pos = isl_qpolynomial_terms_of_sign(data->poly, data->signs, sign);
neg = isl_qpolynomial_terms_of_sign(data->poly, data->signs, -sign);
pos = plug_in_at_pos(pos, nvar, u, data);
neg = plug_in_at_pos(neg, nvar, l, data);
poly = isl_qpolynomial_add(pos, neg);
poly = isl_qpolynomial_drop_dims(poly, isl_dim_in, nvar, 1);
}
if (nvar == 0)
r = add_guarded_poly(bset, poly, data);
else
r = propagate_on_domain(bset, poly, data);
data->tight = save_tight;
return r;
error:
isl_constraint_free(lower);
isl_constraint_free(upper);
isl_basic_set_free(bset);
return isl_stat_error;
}
/* Recursively perform range propagation on the polynomial "poly"
* defined over the basic set "bset" and collect the results in "data".
*/
static isl_stat propagate_on_domain(__isl_take isl_basic_set *bset,
__isl_take isl_qpolynomial *poly, struct range_data *data)
{
isl_bool is_cst;
isl_ctx *ctx;
isl_qpolynomial *save_poly = data->poly;
int save_monotonicity = data->monotonicity;
isl_size d;
d = isl_basic_set_dim(bset, isl_dim_set);
is_cst = isl_qpolynomial_is_cst(poly, NULL, NULL);
if (d < 0 || is_cst < 0)
goto error;
ctx = isl_basic_set_get_ctx(bset);
isl_assert(ctx, d >= 1, goto error);
if (is_cst) {
bset = isl_basic_set_project_out(bset, isl_dim_set, 0, d);
poly = isl_qpolynomial_drop_dims(poly, isl_dim_in, 0, d);
return add_guarded_poly(bset, poly, data);
}
if (data->test_monotonicity)
data->monotonicity = monotonicity(bset, poly, data);
else
data->monotonicity = 0;
if (data->monotonicity < -1)
goto error;
data->poly = poly;
if (isl_basic_set_foreach_bound_pair(bset, isl_dim_set, d - 1,
&propagate_on_bound_pair, data) < 0)
goto error;
isl_basic_set_free(bset);
isl_qpolynomial_free(poly);
data->monotonicity = save_monotonicity;
data->poly = save_poly;
return isl_stat_ok;
error:
isl_basic_set_free(bset);
isl_qpolynomial_free(poly);
data->monotonicity = save_monotonicity;
data->poly = save_poly;
return isl_stat_error;
}
static isl_stat basic_guarded_poly_bound(__isl_take isl_basic_set *bset,
void *user)
{
struct range_data *data = (struct range_data *)user;
isl_ctx *ctx;
isl_size nparam = isl_basic_set_dim(bset, isl_dim_param);
isl_size dim = isl_basic_set_dim(bset, isl_dim_set);
isl_size total = isl_basic_set_dim(bset, isl_dim_all);
isl_stat r;
data->signs = NULL;
if (nparam < 0 || dim < 0 || total < 0)
goto error;
ctx = isl_basic_set_get_ctx(bset);
data->signs = isl_alloc_array(ctx, int, total);
if (isl_basic_set_dims_get_sign(bset, isl_dim_set, 0, dim,
data->signs + nparam) < 0)
goto error;
if (isl_basic_set_dims_get_sign(bset, isl_dim_param, 0, nparam,
data->signs) < 0)
goto error;
r = propagate_on_domain(bset, isl_qpolynomial_copy(data->poly), data);
free(data->signs);
return r;
error:
free(data->signs);
isl_basic_set_free(bset);
return isl_stat_error;
}
static isl_stat qpolynomial_bound_on_domain_range(
__isl_take isl_basic_set *bset, __isl_take isl_qpolynomial *poly,
struct range_data *data)
{
isl_size nparam = isl_basic_set_dim(bset, isl_dim_param);
isl_size nvar = isl_basic_set_dim(bset, isl_dim_set);
isl_set *set = NULL;
if (nparam < 0 || nvar < 0)
goto error;
if (nvar == 0)
return add_guarded_poly(bset, poly, data);
set = isl_set_from_basic_set(bset);
set = isl_set_split_dims(set, isl_dim_param, 0, nparam);
set = isl_set_split_dims(set, isl_dim_set, 0, nvar);
data->poly = poly;
data->test_monotonicity = 1;
if (isl_set_foreach_basic_set(set, &basic_guarded_poly_bound, data) < 0)
goto error;
isl_set_free(set);
isl_qpolynomial_free(poly);
return isl_stat_ok;
error:
isl_set_free(set);
isl_qpolynomial_free(poly);
return isl_stat_error;
}
isl_stat isl_qpolynomial_bound_on_domain_range(__isl_take isl_basic_set *bset,
__isl_take isl_qpolynomial *poly, struct isl_bound *bound)
{
struct range_data data;
isl_stat r;
data.pwf = bound->pwf;
data.pwf_tight = bound->pwf_tight;
data.tight = bound->check_tight;
if (bound->type == isl_fold_min)
data.sign = -1;
else
data.sign = 1;
r = qpolynomial_bound_on_domain_range(bset, poly, &data);
bound->pwf = data.pwf;
bound->pwf_tight = data.pwf_tight;
return r;
}
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