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Finally! RS now refines the calculation when comparing signs.

This commit is contained in:
Luis Peñaranda 2006-10-23 12:52:56 +00:00
parent da7e13c374
commit d3e9b73bf6
2 changed files with 50 additions and 14 deletions
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60
Algebraic_kernel_GBRS/include/CGAL/Gbrs_solve_1.C
View File

@ -29,17 +29,24 @@
CGAL_BEGIN_NAMESPACE
// the default precision of gb/rs
// the default precision of RS to calculate a root (precision is 2^n)
#ifndef CGAL_RS_DEF_PREC
#define CGAL_RS_DEF_PREC 23
#define CGAL_RS_DEF_PREC 15
#endif
// the minimum, used when calculating a sign
#ifndef CGAL_RS_MIN_PREC
#define CGAL_RS_MIN_PREC 5
#endif
// when refining a calculation, increase by this factor
#ifndef CGAL_RS_PREC_FACTOR
#define CGAL_RS_PREC_FACTOR 2
#endif
// after reaching this precision, give up
#ifndef CGAL_RS_MAX_PREC
#define CGAL_RS_MAX_PREC 50
#define CGAL_RS_MAX_PREC 80
#endif
int init_rs () {
@ -73,7 +80,7 @@ int affiche_sols_eqs (mpfi_t *&x) {
return nb_elts;
}
Sign affiche_sols_constr (const Algebraic_1 &a) {
int affiche_sols_constr (const Algebraic_1 &a) {
int ident_sols_eqs,nb_elts,ident_node,ident_vect, nb, ident_elt;
mpfi_t tmp;
mpfi_init(tmp);
@ -92,15 +99,19 @@ Sign affiche_sols_constr (const Algebraic_1 &a) {
}
ident_node = rs_export_list_vect_ibfr_nextnode (ident_node);
}
/*std::cout << "returned value: ";
/*std::cout << "\nreturned value: ";
mpfi_out_str(stdout,10,0,tmp);
std::cout << std::endl;*/
if (mpfi_is_strictly_pos (tmp))
return POSITIVE;
// XXX: mpfi_is_strictly_pos (tmp) doesn't seem to work
if (mpfi_cmp_ui (tmp, 0) > 0)
return 1;
if (mpfi_is_strictly_neg (tmp))
return NEGATIVE;
// TODO: refine the result when needed
return ZERO;
return -1;
if (mpfi_is_zero (tmp))
return 0;
// the interval contains 0 and it isn't a point:
// we have to refine the result
return -2;
}
void create_rs_upoly (mpz_t *poly, const int deg, const int ident_pol) {
@ -143,11 +154,13 @@ inline int solve_1 (mpfi_t *&x, const Rational_polynomial_1 &p1) {
return solve_1 (x, p1, CGAL_RS_DEF_PREC);
}
Sign sign_1 (const Rational_polynomial_1 &p1, const Algebraic_1 &a) {
// TODO: when implemented UNDECIDED as a valid CGAL sign type,
// the return type will change to "Sign"
int sign_1 (const Rational_polynomial_1 &p1, const Algebraic_1 &a,
unsigned int prec) {
mpz_t **constr;
int *degs;
CGAL_assertion_msg (a.is_consistent (),
"this number was not calculated as a root of a polynomial");
// XXX: is this always necessary? can I do it just once?
rs_reset_all ();
// tell RS to find the roots of this polynomial
create_rs_upoly (a.pol().get_coefs (), a.pol().get_degree (),
@ -158,10 +171,29 @@ Sign sign_1 (const Rational_polynomial_1 &p1, const Algebraic_1 &a) {
degs = (int*)malloc(sizeof(int));
*degs = p1.get_degree ();
create_rs_uconstr (constr, degs, rs_get_default_ineqs_u ());
set_rs_precisol (CGAL_RS_MIN_PREC);
set_rs_precisol (prec);
set_rs_verbose (0);
rs_run_algo ("UISOLES");
return affiche_sols_constr (a);
}
Sign sign_1 (const Rational_polynomial_1 &p1, const Algebraic_1 &a) {
CGAL_assertion_msg (a.is_consistent (),
"this number was not calculated as a root of a polynomial");
unsigned int prec = CGAL_RS_MIN_PREC;
while (1)
switch (sign_1 (p1, a, prec)) {
case -1: return NEGATIVE;
break;
case 0: return ZERO;
break;
case 1: return POSITIVE;
break;
default:
if ((prec *= CGAL_RS_PREC_FACTOR) >
CGAL_RS_MAX_PREC)
return ZERO; // TODO: UNDECIDED
}
}
CGAL_END_NAMESPACE

4
Algebraic_kernel_GBRS/test/Gbrs_polynomial/Gbrs_polynomial_1.C
View File

@ -85,6 +85,10 @@ int main () {
print_sign (std::cout, ker.construct_signat_1_object()(q, rootsp[2]));
std::cout << std::endl;
std::cout << "sign of p evaluated at the root 0 of p: ";
print_sign (std::cout, ker.construct_signat_1_object()(p, rootsp[0]));
std::cout << std::endl;
std::cout << "\np(3) = " << p.eval(3) << std::endl;
std::cout << "sign of p evaluated at (coefficient)3: ";
print_sign (std::cout,