ecency-mobile/ios/Pods/boost-for-react-native/boost/qvm/detail/determinant_impl.hpp

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//Copyright (c) 2008-2016 Emil Dotchevski and Reverge Studios, Inc.
//Distributed under the Boost Software License, Version 1.0. (See accompanying
//file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
#ifndef UUID_3DCF6B90AE0E11DE9A315BE555D89593
#define UUID_3DCF6B90AE0E11DE9A315BE555D89593
#include <boost/qvm/inline.hpp>
#include <boost/qvm/mat_traits_array.hpp>
#include <boost/qvm/static_assert.hpp>
namespace
boost
{
namespace
qvm
{
namespace
qvm_detail
{
template <int N>
struct
det_size
{
};
template <class M>
BOOST_QVM_INLINE_TRIVIAL
typename mat_traits<M>::scalar_type
determinant_impl_( M const & a, det_size<2> )
{
return
mat_traits<M>::template read_element<0,0>(a) * mat_traits<M>::template read_element<1,1>(a) -
mat_traits<M>::template read_element<1,0>(a) * mat_traits<M>::template read_element<0,1>(a);
}
template <class M,int N>
BOOST_QVM_INLINE_RECURSION
typename mat_traits<M>::scalar_type
determinant_impl_( M const & a, det_size<N> )
{
typedef typename mat_traits<M>::scalar_type T;
T m[N-1][N-1];
T det=T(0);
for( int j1=0; j1!=N; ++j1 )
{
for( int i=1; i!=N; ++i )
{
int j2 = 0;
for( int j=0; j!=N; ++j )
{
if( j==j1 )
continue;
m[i-1][j2] = mat_traits<M>::read_element_idx(i,j,a);
++j2;
}
}
T d=determinant_impl_(m,det_size<N-1>());
if( j1&1 )
d=-d;
det += mat_traits<M>::read_element_idx(0,j1,a) * d;
}
return det;
}
template <class M>
BOOST_QVM_INLINE_TRIVIAL
typename mat_traits<M>::scalar_type
determinant_impl( M const & a )
{
BOOST_QVM_STATIC_ASSERT(mat_traits<M>::rows==mat_traits<M>::cols);
return determinant_impl_(a,det_size<mat_traits<M>::rows>());
}
}
}
}
#endif