Justin Marshall
106 lines
3.9 KiB
C++
106 lines
3.9 KiB
C++
#pragma once
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#include "idlib/math/complex.h"
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#include <algorithm>
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#include <cassert>
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#include <cmath>
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#include <new>
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class idPolynomial {
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public:
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int degree;
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int allocated;
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float* coefficient;
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idPolynomial() : degree(-1), allocated(0), coefficient(nullptr) {}
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explicit idPolynomial(const int newDegree) : idPolynomial() { Zero(newDegree); }
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idPolynomial(const idPolynomial& other) : idPolynomial() { *this = other; }
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~idPolynomial() { delete[] coefficient; }
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idPolynomial& operator=(const idPolynomial& other) {
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if (this != &other) {
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Resize(other.degree, false);
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std::copy(other.coefficient, other.coefficient + other.degree + 1,
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coefficient);
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}
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return *this;
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}
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float operator[](const int index) const {
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assert(index >= 0 && index <= degree); return coefficient[index];
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}
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float& operator[](const int index) {
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assert(index >= 0 && index <= degree); return coefficient[index];
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}
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void Zero() { if (coefficient != nullptr) std::fill(coefficient, coefficient + degree + 1, 0.0f); }
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void Zero(const int newDegree) { Resize(newDegree, false); Zero(); }
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int GetDimension() const { return degree + 1; }
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int GetDegree() const { return degree; }
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float GetValue(const float x) const {
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float result = 0.0f;
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for (int index = degree; index >= 0; --index) result = result * x + coefficient[index];
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return result;
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}
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idComplex GetValue(const idComplex& x) const {
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idComplex result(0.0f, 0.0f);
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for (int index = degree; index >= 0; --index)
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result = result * x + coefficient[index];
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return result;
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}
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idPolynomial GetDerivative() const {
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idPolynomial result((std::max)(degree - 1, 0));
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if (degree <= 0) { result[0] = 0.0f; return result; }
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for (int index = 1; index <= degree; ++index)
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result[index - 1] = coefficient[index] * static_cast<float>(index);
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return result;
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}
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idPolynomial GetAntiDerivative() const {
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idPolynomial result(degree + 1);
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result[0] = 0.0f;
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for (int index = 0; index <= degree; ++index)
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result[index + 1] = coefficient[index] / static_cast<float>(index + 1);
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return result;
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}
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bool Compare(const idPolynomial& other) const {
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if (degree != other.degree) return false;
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for (int index = 0; index <= degree; ++index)
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if (coefficient[index] != other.coefficient[index]) return false;
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return true;
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}
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bool Compare(const idPolynomial& other, const float epsilon) const {
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if (degree != other.degree) return false;
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for (int index = 0; index <= degree; ++index)
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if (std::fabs(coefficient[index] - other.coefficient[index]) > epsilon) return false;
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return true;
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}
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bool operator==(const idPolynomial& other) const { return Compare(other); }
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bool operator!=(const idPolynomial& other) const { return !Compare(other); }
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private:
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void Resize(const int newDegree, const bool keep) {
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assert(newDegree >= 0);
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const int required = newDegree + 1;
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if (required > allocated) {
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const int newAllocated = (required + 3) & ~3;
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float* replacement = new float[newAllocated];
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std::fill(replacement, replacement + newAllocated, 0.0f);
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if (keep && coefficient != nullptr) {
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std::copy(coefficient,
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coefficient + (std::min)(degree + 1, required), replacement);
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}
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delete[] coefficient;
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coefficient = replacement;
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allocated = newAllocated;
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} else if (!keep && coefficient != nullptr) {
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std::fill(coefficient, coefficient + allocated, 0.0f);
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}
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degree = newDegree;
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}
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};
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#if defined(_WIN32) && !defined(_WIN64)
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static_assert(sizeof(idPolynomial) == 12, "Recovered idPolynomial ABI changed");
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#endif
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