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99 lines
3.7 KiB
C++
99 lines
3.7 KiB
C++
// This file is part of Eigen, a lightweight C++ template library
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// for linear algebra.
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//
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// Copyright (C) 2008 Benoit Jacob <jacob.benoit.1@gmail.com>
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//
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// This Source Code Form is subject to the terms of the Mozilla
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// Public License v. 2.0. If a copy of the MPL was not distributed
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// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
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#ifndef EIGEN_DETERMINANT_H
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#define EIGEN_DETERMINANT_H
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// IWYU pragma: private
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#include "./InternalHeaderCheck.h"
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namespace Eigen {
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namespace internal {
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template <typename Derived>
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EIGEN_DEVICE_FUNC inline const typename Derived::Scalar bruteforce_det3_helper(const MatrixBase<Derived>& matrix, int a,
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int b, int c) {
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return matrix.coeff(0, a) * (matrix.coeff(1, b) * matrix.coeff(2, c) - matrix.coeff(1, c) * matrix.coeff(2, b));
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}
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template <typename Derived, int DeterminantType = Derived::RowsAtCompileTime>
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struct determinant_impl {
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static inline typename traits<Derived>::Scalar run(const Derived& m) {
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if (Derived::ColsAtCompileTime == Dynamic && m.rows() == 0) return typename traits<Derived>::Scalar(1);
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return m.partialPivLu().determinant();
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}
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};
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template <typename Derived>
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struct determinant_impl<Derived, 1> {
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static inline EIGEN_DEVICE_FUNC typename traits<Derived>::Scalar run(const Derived& m) { return m.coeff(0, 0); }
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};
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template <typename Derived>
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struct determinant_impl<Derived, 2> {
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static inline EIGEN_DEVICE_FUNC typename traits<Derived>::Scalar run(const Derived& m) {
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return m.coeff(0, 0) * m.coeff(1, 1) - m.coeff(1, 0) * m.coeff(0, 1);
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}
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};
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template <typename Derived>
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struct determinant_impl<Derived, 3> {
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static inline EIGEN_DEVICE_FUNC typename traits<Derived>::Scalar run(const Derived& m) {
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return bruteforce_det3_helper(m, 0, 1, 2) - bruteforce_det3_helper(m, 1, 0, 2) + bruteforce_det3_helper(m, 2, 0, 1);
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}
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};
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template <typename Derived>
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struct determinant_impl<Derived, 4> {
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typedef typename traits<Derived>::Scalar Scalar;
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static EIGEN_DEVICE_FUNC Scalar run(const Derived& m) {
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Scalar d2_01 = det2(m, 0, 1);
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Scalar d2_02 = det2(m, 0, 2);
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Scalar d2_03 = det2(m, 0, 3);
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Scalar d2_12 = det2(m, 1, 2);
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Scalar d2_13 = det2(m, 1, 3);
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Scalar d2_23 = det2(m, 2, 3);
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Scalar d3_0 = det3(m, 1, d2_23, 2, d2_13, 3, d2_12);
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Scalar d3_1 = det3(m, 0, d2_23, 2, d2_03, 3, d2_02);
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Scalar d3_2 = det3(m, 0, d2_13, 1, d2_03, 3, d2_01);
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Scalar d3_3 = det3(m, 0, d2_12, 1, d2_02, 2, d2_01);
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return internal::pmadd(static_cast<Scalar>(-m(0, 3)), d3_0, static_cast<Scalar>(m(1, 3) * d3_1)) +
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internal::pmadd(static_cast<Scalar>(-m(2, 3)), d3_2, static_cast<Scalar>(m(3, 3) * d3_3));
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}
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protected:
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static EIGEN_DEVICE_FUNC Scalar det2(const Derived& m, Index i0, Index i1) {
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return m(i0, 0) * m(i1, 1) - m(i1, 0) * m(i0, 1);
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}
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static EIGEN_DEVICE_FUNC Scalar det3(const Derived& m, Index i0, const Scalar& d0, Index i1, const Scalar& d1,
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Index i2, const Scalar& d2) {
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return internal::pmadd(m(i0, 2), d0,
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internal::pmadd(static_cast<Scalar>(-m(i1, 2)), d1, static_cast<Scalar>(m(i2, 2) * d2)));
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}
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};
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} // end namespace internal
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/** \lu_module
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*
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* \returns the determinant of this matrix
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*/
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template <typename Derived>
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EIGEN_DEVICE_FUNC inline typename internal::traits<Derived>::Scalar MatrixBase<Derived>::determinant() const {
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eigen_assert(rows() == cols());
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typedef typename internal::nested_eval<Derived, Base::RowsAtCompileTime>::type Nested;
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return internal::determinant_impl<internal::remove_all_t<Nested>>::run(derived());
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}
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} // end namespace Eigen
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#endif // EIGEN_DETERMINANT_H
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