61 lines
1.7 KiB
C++
61 lines
1.7 KiB
C++
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#ifndef BOOST_QVM_DETAIL_COFACTOR_IMPL_HPP_INCLUDED
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#define BOOST_QVM_DETAIL_COFACTOR_IMPL_HPP_INCLUDED
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// Copyright 2008-2022 Emil Dotchevski and Reverge Studios, Inc.
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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#include <boost/qvm/detail/determinant_impl.hpp>
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#include <boost/qvm/mat_traits.hpp>
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#include <boost/qvm/static_assert.hpp>
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namespace boost { namespace qvm {
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namespace
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qvm_detail
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{
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template <class A>
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BOOST_QVM_CONSTEXPR BOOST_QVM_INLINE_OPERATIONS
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typename deduce_mat<A>::type
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cofactor_impl( A const & a )
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{
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BOOST_QVM_STATIC_ASSERT(mat_traits<A>::rows==mat_traits<A>::cols);
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int const N=mat_traits<A>::rows;
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typedef typename mat_traits<A>::scalar_type T;
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T c[N-1][N-1];
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typedef typename deduce_mat<A>::type R;
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R b;
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for( int j=0; j!=N; ++j )
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{
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for( int i=0; i!=N; ++i )
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{
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int i1=0;
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for( int ii=0; ii!=N; ++ii )
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{
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if( ii==i )
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continue;
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int j1=0;
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for( int jj=0; jj!=N; ++jj )
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{
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if( jj==j )
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continue;
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c[i1][j1] = mat_traits<A>::read_element_idx(ii,jj,a);
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++j1;
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}
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++i1;
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}
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T det = determinant_impl(c);
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if( (i+j)&1 )
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det=-det;
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write_mat_element_idx(i,j,b,det);
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}
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}
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return b;
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}
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}
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} }
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#endif
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