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1 | #ifndef BOOST_QVM_DETAIL_DETERMINANT_IMPL_HPP_INCLUDED |
2 | #define BOOST_QVM_DETAIL_DETERMINANT_IMPL_HPP_INCLUDED | |
92f5a8d4 | 3 | |
1e59de90 | 4 | // Copyright 2008-2022 Emil Dotchevski and Reverge Studios, Inc. |
92f5a8d4 | 5 | |
1e59de90 TL |
6 | // Distributed under the Boost Software License, Version 1.0. (See accompanying |
7 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
92f5a8d4 TL |
8 | |
9 | #include <boost/qvm/inline.hpp> | |
10 | #include <boost/qvm/mat_traits_array.hpp> | |
11 | #include <boost/qvm/static_assert.hpp> | |
12 | ||
1e59de90 TL |
13 | namespace boost { namespace qvm { |
14 | ||
92f5a8d4 | 15 | namespace |
1e59de90 | 16 | qvm_detail |
92f5a8d4 | 17 | { |
1e59de90 TL |
18 | template <int N> |
19 | struct | |
20 | det_size | |
92f5a8d4 | 21 | { |
1e59de90 | 22 | }; |
92f5a8d4 | 23 | |
1e59de90 TL |
24 | template <class M> |
25 | BOOST_QVM_CONSTEXPR BOOST_QVM_INLINE_TRIVIAL | |
26 | typename mat_traits<M>::scalar_type | |
27 | determinant_impl_( M const & a, det_size<2> ) | |
28 | { | |
29 | return | |
30 | mat_traits<M>::template read_element<0,0>(a) * mat_traits<M>::template read_element<1,1>(a) - | |
31 | mat_traits<M>::template read_element<1,0>(a) * mat_traits<M>::template read_element<0,1>(a); | |
32 | } | |
92f5a8d4 | 33 | |
1e59de90 TL |
34 | template <class M,int N> |
35 | BOOST_QVM_CONSTEXPR BOOST_QVM_INLINE_RECURSION | |
36 | typename mat_traits<M>::scalar_type | |
37 | determinant_impl_( M const & a, det_size<N> ) | |
38 | { | |
39 | typedef typename mat_traits<M>::scalar_type T; | |
40 | T m[N-1][N-1]; | |
41 | T det=T(0); | |
42 | for( int j1=0; j1!=N; ++j1 ) | |
43 | { | |
44 | for( int i=1; i!=N; ++i ) | |
92f5a8d4 | 45 | { |
1e59de90 TL |
46 | int j2 = 0; |
47 | for( int j=0; j!=N; ++j ) | |
92f5a8d4 | 48 | { |
1e59de90 TL |
49 | if( j==j1 ) |
50 | continue; | |
51 | m[i-1][j2] = mat_traits<M>::read_element_idx(i,j,a); | |
52 | ++j2; | |
92f5a8d4 | 53 | } |
92f5a8d4 | 54 | } |
1e59de90 TL |
55 | T d=determinant_impl_(m,det_size<N-1>()); |
56 | if( j1&1 ) | |
57 | d=-d; | |
58 | det += mat_traits<M>::read_element_idx(0,j1,a) * d; | |
92f5a8d4 | 59 | } |
1e59de90 TL |
60 | return det; |
61 | } | |
62 | ||
63 | template <class M> | |
64 | BOOST_QVM_CONSTEXPR BOOST_QVM_INLINE_TRIVIAL | |
65 | typename mat_traits<M>::scalar_type | |
66 | determinant_impl( M const & a ) | |
67 | { | |
68 | BOOST_QVM_STATIC_ASSERT(mat_traits<M>::rows==mat_traits<M>::cols); | |
69 | return determinant_impl_(a,det_size<mat_traits<M>::rows>()); | |
92f5a8d4 TL |
70 | } |
71 | } | |
72 | ||
1e59de90 TL |
73 | } } |
74 | ||
92f5a8d4 | 75 | #endif |