A simple and generic C++23 polynomial library.
Just include the polyLib.hpp header file in your project:
#include "polyLib.hpp"PolyLib is designed to be as generic as possible. However, your coefficient type must support the following operators:
+*-(including unary-)/==
Additionally, your type must provide two constructors:
A{} // should yield the additive identity (typically 0)
A{1} // should yield the multiplicative identity (typically 1)
poly::poly<double> p(3); // Create a polynomial of degree 3
poly::poly<int> p2({4, 7, 8}); // Represents 4 + 7x + 8x²
poly::poly<int> p3({1, 2}); // Represents 4 + 2x
poly::poly<double> p4({4, 7, 8});
poly::poly<std::complex<double>> p5; // Zero polynomial
// Utils
std::println("{} ", p2); // Will print 4 + 9x + 8x^2
p2 + p3 // 5 + 9x + 8x²
p3 == p3 // true
p2 * p3 // 4 + 15x + 22x^2 + 16x^3
4 * p3 // 16 + 8x
p2 == p4 // false because the types are diffrent!
p2[1] // returns 7
p2[0] // returns 4
p3(1) // evaluates to 6 using Horner's scheme
p4.derivative(); // evaluates to 7 + 16x
// Constructions
std::list<double> l1 = {4, 7, 8};
poly::Poly<double> p5{v1.begin(), v1.end()}; // at least a std::forward_iterator is required
std::vector<double> v1 = {4, 7, 8};
poly::Poly<double> p6{v1}; // copys the vector
poly::Poly<double> p7{std::move(v1)}; // moves the vector
// Interpolation
// There are 2 interpolation Options Newton and Lagrange
poly::Lagrange<double> Lagrange;
poly::Newton<double> Newton; // When using newton you can add points without calculating the new coeffiecnts Matrix. But you cannot delete or modiy any points just add them
Newton.addPoints(2.,4.) // Add a point to the list
Newton.getInterpolationPolynom() // Will return the Polynom
Lagrange.addPoints(2.,4.) // Add a point to the list
Lagrange.getInterpolationPolynom() // Will return the PolynomCheck out the main.cpp file for more examples.
Have fun! 🎉
You can run the Gtests by using this commands in in the PolyLib folder:
mkdir build
cmake -DCMAKE_EXPORT_COMPILE_COMMANDS=ON -S . -B build
cd build && ctest