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// David Eberly, Geometric Tools, Redmond WA 98052
// Copyright (c) 1998-2021
// Distributed under the Boost Software License, Version 1.0.
// https://www.boost.org/LICENSE_1_0.txt
// https://www.geometrictools.com/License/Boost/LICENSE_1_0.txt
// Version: 4.0.2020.01.10
#pragma once
#include <Mathematics/Logger.h>
// Class QFNumber is an implementation for quadratic fields with N >= 1
// square root terms. The theory and details are provided in
// https://www.geometrictools.com/Documentation/QuadraticFields.pdf
// Enable this macro if you want the logging system to trap when arithmetic
// operations are performed on two quadratic elements that do not share the
// same value d
#define GTE_ASSERT_ON_QFNUMBER_MISMATCHED_D
namespace gte
{
// Arithmetic for quadratic fields with N >= 2 square root terms. The
// d-term is rational and the x-coefficients are elements in a quadratic
// field with N-1 >= 1 square root terms.
template <typename T, size_t N>
class QFNumber
{
public:
// The quadratic field numbers is x[0] + x[1] * sqrt(d).
std::array<QFNumber<T, N - 1>, 2> x;
T d;
// Create z = 0 + 0 * sqrt(0), where the 0 coefficients are quadratic
// field elements with N-1 d-terms all set to 0 and x-coefficients all
// set to 0.
QFNumber()
:
d(0)
{
static_assert(N >= 2, "Invalid number of root arguments.");
}
// Create z = 0 + 0 * sqrt(d), where the 0 coefficients are quadratic
// field elements with N-1 d-terms all set to 0 and x-coefficients all
// set to 0.
explicit QFNumber(T const& inD)
:
d(inD)
{
static_assert(N >= 2, "Invalid number of root arguments.");
}
// Create z = x0 + x1 * sqrt(d), where the x-coefficients are
// quadratic field elements with N-1 d-terms.
QFNumber(QFNumber<T, N - 1> const& x0, QFNumber<T, N - 1> const& x1, T const& inD)
:
x{ x0, x1 },
d(inD)
{
static_assert(N >= 2, "Invalid number of root arguments.");
}
// Create z = inX[0] + inX[1] * sqrt(inD), where the x-coefficients are
// quadratic field elements with N-1 d-terms.
QFNumber(std::array<QFNumber<T, N - 1>, 2> const& inX, T const& inD)
:
x(inX),
d(inD)
{
static_assert(N >= 2, "Invalid number of root arguments.");
}
};
// Arithmetic for quadratic fields with 1 square root term.
template <typename T>
class QFNumber<T, 1>
{
public:
// The quadratic field number is x[0] + x[1] * sqrt(d).
std::array<T, 2> x;
T d;
// Create z = 0. You can defer the setting of d until later.
QFNumber()
:
x{ static_cast<T>(0), static_cast<T>(0) },
d(static_cast<T>(0))
{
}
// Create z = 0 + 0 * sqrt(d) = 0.
explicit QFNumber(T const& inD)
:
x{ static_cast<T>(0), static_cast<T>(0) },
d(inD)
{
}
// Create z = x0 + x1 * sqrt(d).
QFNumber(T const& x0, T const& x1, T const& inD)
:
x{ x0, x1 },
d(inD)
{
}
// Create z = inX[0] + inX[1] * sqrt(d).
QFNumber(std::array<T, 2> const& inX, T const& inD)
:
x(inX),
d(inD)
{
}
};
// Unary operations.
template <typename T, size_t N>
QFNumber<T, N> operator+(QFNumber<T, N> const& q)
{
static_assert(N >= 1, "Invalid number of d-terms.");
return q;
}
template <typename T, size_t N>
QFNumber<T, N> operator-(QFNumber<T, N> const& q)
{
static_assert(N >= 1, "Invalid number of d-terms.");
return QFNumber<T, N>(-q.x[0], -q.x[1], q.d);
}
// Arithmetic operations between elements of a quadratic field must occur
// only when the d-values are the same. To trap mismatches, read the
// comments at the beginning of this file.
template <typename T, size_t N>
QFNumber<T, N> operator+(QFNumber<T, N> const& q0, QFNumber<T, N> const& q1)
{
#if defined(GTE_ASSERT_ON_QFNUMBER_MISMATCHED_D)
LogAssert(q0.d == q1.d, "Mismatched d-value.");
#endif
return QFNumber<T, N>(q0.x[0] + q1.x[0], q0.x[1] + q1.x[1], q0.d);
}
template <typename T, size_t N>
QFNumber<T, N> operator+(QFNumber<T, N> const& q, T const& s)
{
return QFNumber<T, N>(q.x[0] + s, q.x[1], q.d);
}
template <typename T, size_t N>
QFNumber<T, N> operator+(T const& s, QFNumber<T, N> const& q)
{
return QFNumber<T, N>(s + q.x[0], q.x[1], q.d);
}
template <typename T, size_t N>
QFNumber<T, N> operator-(QFNumber<T, N> const& q0, QFNumber<T, N> const& q1)
{
#if defined(GTE_ASSERT_ON_QFNUMBER_MISMATCHED_D)
LogAssert(q0.d == q1.d, "Mismatched d-value.");
#endif
return QFNumber<T, N>(q0.x[0] - q1.x[0], q0.x[1] - q1.x[1], q0.d);
}
template <typename T, size_t N>
QFNumber<T, N> operator-(QFNumber<T, N> const& q, T const& s)
{
return QFNumber<T, N>(q.x[0] - s, q.x[1], q.d);
}
template <typename T, size_t N>
QFNumber<T, N> operator-(T const& s, QFNumber<T, N> const& q)
{
return QFNumber<T, N>(s - q.x[0], -q.x[1], q.d);
}
template <typename T, size_t N>
QFNumber<T, N> operator*(QFNumber<T, N> const& q0, QFNumber<T, N> const& q1)
{
#if defined(GTE_ASSERT_ON_QFNUMBER_MISMATCHED_D)
LogAssert(q0.d == q1.d, "Mismatched d-value.");
#endif
return QFNumber<T, N>(
q0.x[0] * q1.x[0] + q0.x[1] * q1.x[1] * q0.d,
q0.x[0] * q1.x[1] + q0.x[1] * q1.x[0],
q0.d);
}
template <typename T, size_t N>
QFNumber<T, N> operator*(QFNumber<T, N> const& q, T const& s)
{
return QFNumber<T, N>(q.x[0] * s, q.x[1] * s, q.d);
}
template <typename T, size_t N>
QFNumber<T, N> operator*(T const& s, QFNumber<T, N> const& q)
{
return QFNumber<T, N>(s * q.x[0], s * q.x[1], q.d);
}
template <typename T, size_t N>
QFNumber<T, N> operator/(QFNumber<T, N> const& q0, QFNumber<T, N> const& q1)
{
#if defined(GTE_ASSERT_ON_QFNUMBER_MISMATCHED_D)
LogAssert(q0.d == q1.d, "Mismatched d-value.");
#endif
auto denom = q1.x[0] * q1.x[0] - q1.x[1] * q1.x[1] * q0.d;
auto numer0 = q0.x[0] * q1.x[0] - q0.x[1] * q1.x[1] * q0.d;
auto numer1 = q0.x[1] * q1.x[0] - q0.x[0] * q1.x[1];
return QFNumber<T, N>(numer0 / denom, numer1 / denom, q0.d);
}
template <typename T, size_t N>
QFNumber<T, N> operator/(QFNumber<T, N> const& q, T const& s)
{
return QFNumber<T, N>(q.x[0] / s, q.x[1] / s, q.d);
}
template <typename T, size_t N>
QFNumber<T, N> operator/(T const& s, QFNumber<T, N> const& q)
{
auto denom = q.x[0] * q.x[0] - q.x[1] * q.x[1] * q.d;
auto x0 = (s * q.x[0]) / denom;
auto x1 = -(s * q.x[1]) / denom;
return QFNumber<T, N>(x0, x1, q.d);
}
// Arithmetic updates between elements of a quadratic field must occur
// only when the d-values are the same. To trap mismatches, read the
// comments at the beginning of this file.
template <typename T, size_t N>
QFNumber<T, N>& operator+=(QFNumber<T, N>& q0, QFNumber<T, N> const& q1)
{
#if defined(GTE_ASSERT_ON_QFNUMBER_MISMATCHED_D)
LogAssert(q0.d == q1.d, "Mismatched d-value.");
#endif
q0.x[0] += q1.x[0];
q0.x[1] += q1.x[1];
return q0;
}
template <typename T, size_t N>
QFNumber<T, N>& operator+=(QFNumber<T, N>& q, T const& s)
{
q.x[0] += s;
return q;
}
template <typename T, size_t N>
QFNumber<T, N>& operator-=(QFNumber<T, N>& q0, QFNumber<T, N> const& q1)
{
#if defined(GTE_ASSERT_ON_QFNUMBER_MISMATCHED_D)
LogAssert(q0.d == q1.d, "Mismatched d-value.");
#endif
q0.x[0] -= q1.x[0];
q0.x[1] -= q1.x[1];
return q0;
}
template <typename T, size_t N>
QFNumber<T, N>& operator-=(QFNumber<T, N>& q, T const& s)
{
q.x[0] -= s;
return q;
}
template <typename T, size_t N>
QFNumber<T, N>& operator*=(QFNumber<T, N>& q0, QFNumber<T, N> const& q1)
{
#if defined(GTE_ASSERT_ON_QFNUMBER_MISMATCHED_D)
LogAssert(q0.d == q1.d, "Mismatched d-value.");
#endif
auto x0 = q0.x[0] * q1.x[0] + q0.x[1] * q1.x[1] * q0.d;
auto x1 = q0.x[0] * q1.x[1] + q0.x[1] * q1.x[0];
q0.x[0] = x0;
q0.x[1] = x1;
return q0;
}
template <typename T, size_t N>
QFNumber<T, N>& operator*=(QFNumber<T, N>& q, T const& s)
{
q.x[0] *= s;
q.x[1] *= s;
return q;
}
template <typename T, size_t N>
QFNumber<T, N>& operator/=(QFNumber<T, N>& q0, QFNumber<T, N> const& q1)
{
#if defined(GTE_ASSERT_ON_QFNUMBER_MISMATCHED_D)
LogAssert(q0.d == q1.d, "Mismatched d-value.");
#endif
auto denom = q1.x[0] * q1.x[0] - q1.x[1] * q1.x[1] * q0.d;
auto numer0 = q0.x[0] * q1.x[0] - q0.x[1] * q1.x[1] * q0.d;
auto numer1 = q0.x[1] * q1.x[0] - q0.x[0] * q1.x[1];
q0.x[0] = numer0 / denom;
q0.x[1] = numer1 / denom;
return q0;
}
template <typename T, size_t N>
QFNumber<T, N>& operator/=(QFNumber<T, N>& q, T const& s)
{
q.x[0] /= s;
q.x[1] /= s;
return q;
}
// Comparisons between numbers of a quadratic field must occur only when
// the d-values are the same. To trap mismatches, read the comments at
// the beginning of this file.
template <typename T, size_t N>
bool operator==(QFNumber<T, N> const& q0, QFNumber<T, N> const& q1)
{
#if defined(GTE_ASSERT_ON_QFNUMBER_MISMATCHED_D)
LogAssert(q0.d == q1.d, "Mismatched d-value.");
#endif
if (q0.d == T(0) || q0.x[1] == q1.x[1])
{
return q0.x[0] == q1.x[0];
}
else if (q0.x[1] > q1.x[1])
{
if (q0.x[0] >= q1.x[0])
{
return false;
}
else // q0.x[0] < q1.x[0]
{
auto diff = q0 - q1;
return diff.x[0] * diff.x[0] == diff.x[1] * diff.x[1] * diff.d;
}
}
else // q0.x[1] < q1.x[1]
{
if (q0.x[0] <= q1.x[0])
{
return false;
}
else // q0.x[0] > q1.x[0]
{
auto diff = q0 - q1;
return diff.x[0] * diff.x[0] == diff.x[1] * diff.x[1] * diff.d;
}
}
}
template <typename T, size_t N>
bool operator!=(QFNumber<T, N> const& q0, QFNumber<T, N> const& q1)
{
return !operator==(q0, q1);
}
template <typename T, size_t N>
bool operator<(QFNumber<T, N> const& q0, QFNumber<T, N> const& q1)
{
#if defined(GTE_ASSERT_ON_QFNUMBER_MISMATCHED_D)
LogAssert(q0.d == q1.d, "Mismatched d-value.");
#endif
if (q0.d == T(0) || q0.x[1] == q1.x[1])
{
return q0.x[0] < q1.x[0];
}
else if (q0.x[1] > q1.x[1])
{
if (q0.x[0] >= q1.x[0])
{
return false;
}
else // q0.x[0] < q1.x[0]
{
auto diff = q0 - q1;
return diff.x[0] * diff.x[0] > diff.x[1] * diff.x[1] * diff.d;
}
}
else // q0.x[1] < q1.x[1]
{
if (q0.x[0] <= q1.x[0])
{
return true;
}
else // q0.x[0] > q1.x[0]
{
auto diff = q0 - q1;
return diff.x[0] * diff.x[0] < diff.x[1] * diff.x[1] * diff.d;
}
}
}
template <typename T, size_t N>
bool operator>(QFNumber<T, N> const& q0, QFNumber<T, N> const& q1)
{
return operator<(q1, q0);
}
template <typename T, size_t N>
bool operator<=(QFNumber<T, N> const& q0, QFNumber<T, N> const& q1)
{
return !operator<(q1, q0);
}
template <typename T, size_t N>
bool operator>=(QFNumber<T, N> const& q0, QFNumber<T, N> const& q1)
{
return !operator<(q0, q1);
}
}