mirror of https://github.com/CGAL/cgal
64 lines
3.0 KiB
C++
64 lines
3.0 KiB
C++
// $URL$
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// $Id$
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#include <CGAL/basic.h>
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#ifdef CGAL_USE_MPFI
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#include <CGAL/Algebraic_kernel_d_1.h>
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#include <CGAL/Gmpz.h>
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#include <vector>
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typedef CGAL::Algebraic_kernel_d_1<CGAL::Gmpz> AK;
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typedef AK::Coefficient Coefficient;
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typedef AK::Polynomial_1 Polynomial_1;
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typedef AK::Algebraic_real_1 Algebraic_real_1;
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typedef AK::Bound Bound;
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typedef std::pair<Bound,Bound> Interval;
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int main(){
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AK ak;
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AK::Construct_algebraic_real_1 construct_algebraic_real_1 = ak.construct_algebraic_real_1_object();
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Polynomial_1 x = CGAL::shift(AK::Polynomial_1(1),1); // the monomial x
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Algebraic_real_1 a = construct_algebraic_real_1(x*x-2,1); // sqrt(2)
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Algebraic_real_1 b = construct_algebraic_real_1(x*x-3,1); // sqrt(3)
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// Algebraic_real_1 is RealEmbeddable (just some functions:)
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std::cout << "sign of a is : " << CGAL::sign(a) << "\n";
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std::cout << "double approximation of a is : " << CGAL::to_double(a) << "\n";
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std::cout << "double approximation of b is : " << CGAL::to_double(b) << "\n";
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std::cout << "double lower bound of a : " << CGAL::to_interval(a).first << "\n";
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std::cout << "double upper bound of a : " << CGAL::to_interval(a).second << "\n";
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std::cout << "LessThanComparable (a<b) : " << (a<b) << "\n\n";
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// use compare_1 with int, Bound, Coefficient, Algebraic_real_1
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AK::Compare_1 compare_1 = ak.compare_1_object();
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std::cout << " compare with an int : " << compare_1(a ,int(2)) << "\n";
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std::cout << " compare with an Coefficient : " << compare_1(a ,Coefficient(2)) << "\n";
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std::cout << " compare with an Bound : " << compare_1(a ,Bound(2)) << "\n";
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std::cout << " compare with another Algebraic_real_1: " << compare_1(a ,b) << "\n\n";
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// get a value between two roots
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AK::Bound_between_1 bound_between_1 = ak.bound_between_1_object();
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std::cout << " value between sqrt(2) and sqrt(3) " << bound_between_1(a,b) << "\n";
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std::cout << " is larger than sqrt(2) " << compare_1(bound_between_1(a,b),a) << "\n";
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std::cout << " is less than sqrt(3) " << compare_1(bound_between_1(a,b),b) << "\n\n";
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// approximate with relative precision
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AK::Approximate_relative_1 approx_r = ak.approximate_relative_1_object();
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std::cout << " lower bound of a with at least 100 bits: "<< approx_r(a,100).first << "\n";
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std::cout << " upper bound of a with at least 100 bits: "<< approx_r(a,100).second << "\n\n";
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// approximate with absolute error
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AK::Approximate_absolute_1 approx_a = ak.approximate_absolute_1_object();
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std::cout << " lower bound of b with error less than 2^-100: "<< approx_a(b,100).first << "\n";
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std::cout << " upper bound of b with error less than 2^-100: "<< approx_a(b,100).second << "\n\n";
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return 0;
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}
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#else
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int main(){
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std::cout << "This example requires CGAL to be configured with library MPFI." << std::endl;
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return 0;
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}
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#endif
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