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// This tests the rounding mode functions.
#include <CGAL/basic.h>
#include <CGAL/Interval_nt.h>
#include <iostream>
typedef CGAL::Interval_nt_advanced NT_adv;
typedef CGAL::Interval_nt<> NT;
void print_res (bool res)
{ std::cout << (res ? "ok" : "ERROR") << std::endl; }
// The results of 1-epsilon and -1+epsilon are enough
// to detect exactly the current rounding mode.
// 1-MIN_DOUBLE
// +------+-------+
// | 1 | 1-ulp |
// +--------+------+-------+
// -1+MIN_DOUBLE | -1 | near | -inf |
// | -1+ulp | +inf | zero |
// +--------+------+-------+
// I use a global variable here to avoid constant propagation.
double IA_min_double;
CGAL::FPU_CW_t
FPU_empiric_test()
{
IA_min_double = CGAL_IA_STOP_CPROP(CGAL_IA_MIN_DOUBLE);
double y = 1.0, z = -1.0;
double ye, ze;
ye = y - IA_min_double;
ze = z + IA_min_double;
if (y == ye && z == ze) return CGAL_FE_TONEAREST;
if (y == ye) return CGAL_FE_UPWARD;
if (z == ze) return CGAL_FE_DOWNWARD;
return CGAL_FE_TOWARDZERO;
}
void print_rounding_name (CGAL::FPU_CW_t r)
{
switch (r) {
case CGAL_FE_TONEAREST: std::cout << "NEAR\n"; break;
case CGAL_FE_DOWNWARD: std::cout << "DOWN\n"; break;
case CGAL_FE_UPWARD: std::cout << "UP\n"; break;
case CGAL_FE_TOWARDZERO: std::cout << "ZERO\n"; break;
default: std::cout << "unknown !\n";
}
}
int main()
{
bool flag = true;
flag = flag && (FPU_empiric_test() == CGAL_FE_TONEAREST);
std::cout << "default: ";
print_res(flag);
// Should be a no-op.
CGAL::FPU_set_cw(CGAL::FPU_get_cw());
flag = flag && (FPU_empiric_test() == CGAL_FE_TONEAREST);
std::cout << "get/set: ";
print_res(flag);
if (!flag) print_rounding_name(FPU_empiric_test());
// Rounding to zero.
CGAL::FPU_set_cw(CGAL_FE_TOWARDZERO);
flag = flag && (FPU_empiric_test() == CGAL_FE_TOWARDZERO);
std::cout << "zero : ";
print_res(flag);
if (!flag) print_rounding_name(FPU_empiric_test());
// Rounding to infinity.
CGAL::FPU_set_cw(CGAL_FE_UPWARD);
flag = flag && (FPU_empiric_test() == CGAL_FE_UPWARD);
std::cout << "+inf : ";
print_res(flag);
if (!flag) print_rounding_name(FPU_empiric_test());
// Rounding to minus infinity.
CGAL::FPU_set_cw(CGAL_FE_DOWNWARD);
flag = flag && (FPU_empiric_test() == CGAL_FE_DOWNWARD);
std::cout << "-inf : ";
print_res(flag);
if (!flag) print_rounding_name(FPU_empiric_test());
// Rounding to nearest.
CGAL::FPU_set_cw(CGAL_FE_TONEAREST);
flag = flag && (FPU_empiric_test() == CGAL_FE_TONEAREST);
std::cout << "near : ";
print_res(flag);
if (!flag) print_rounding_name(FPU_empiric_test());
return (int) !flag;
}
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